JP7807659B2 - Material prediction method - Google Patents
Material prediction methodInfo
- Publication number
- JP7807659B2 JP7807659B2 JP2022111218A JP2022111218A JP7807659B2 JP 7807659 B2 JP7807659 B2 JP 7807659B2 JP 2022111218 A JP2022111218 A JP 2022111218A JP 2022111218 A JP2022111218 A JP 2022111218A JP 7807659 B2 JP7807659 B2 JP 7807659B2
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- coil
- plate
- prediction method
- cumulative
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Investigating And Analyzing Materials By Characteristic Methods (AREA)
- Control Of Metal Rolling (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Description
本発明は、熱間圧延プロセスにおいて製造される鋼板の機械特性を予測する材質予測方法に関する。 The present invention relates to a material quality prediction method for predicting the mechanical properties of steel sheets produced in a hot rolling process.
熱間圧延プロセスにて製造された鋼板は、通常、コイル状に巻き取られた後、冷却される。コイルの冷却過程においては、コイルの外周面、側面及び内周面がコイル内部よりも冷却されやすく、鋼板の長手方向に温度分布が生じる。この鋼板の長手方向の温度分布は、冷却後のコイルの引張強度（ＴＳ）やｒ値、降伏強度（ＹＳ）、一様伸び、破断伸び等の機械特性にバラツキに影響を与える。特に、高強度鋼の鋼板では、巻き取り後も変態が継続するため、コイルの冷却過程で生じる温度分布が材質に与える影響は大きい。機械特性のバラツキは製品としての品質に影響することから、製造した鋼板が全長全幅にわたって所望の機械特性を有するかを予測できることが望まれている。 Steel sheets produced in the hot rolling process are typically cooled after being wound into a coil. During the cooling process, the outer, side, and inner surfaces of the coil cool more easily than the interior of the coil, resulting in a temperature distribution along the steel sheet's length. This temperature distribution along the steel sheet's length affects the variation in mechanical properties of the cooled coil, such as the tensile strength (TS), r-value, yield strength (YS), uniform elongation, and elongation at break. In particular, for high-strength steel sheets, transformation continues even after coiling, so the temperature distribution that occurs during the coil cooling process has a significant impact on the material quality. Because variation in mechanical properties affects the quality of the product, it is desirable to be able to predict whether a manufactured steel sheet will have the desired mechanical properties across its entire length and width.
ここで、温度変化により相変態をする材料の組織を定量的に予測する技術として、例えば特許文献１には、材料に温度変化を与えるための温度条件に基づいて材料の計算対象領域内の複数の計算点の温度を計算し、複数の計算点の温度に基づいて計算対象領域内の核生成回数を計算し、核生成回数に基づいて複数の計算点から析出相の核を生成する析出相生成点を決定し、析出相生成点について析出相の粒成長を計算し、計算された析出相の粒成長に基づいて材料の組織を予測する材料組織予測装置が開示されている。 As a technique for quantitatively predicting the structure of a material that undergoes a phase transformation due to a temperature change, for example, Patent Document 1 discloses a material structure prediction device that calculates the temperatures of multiple calculation points within a calculation region of the material based on temperature conditions for applying a temperature change to the material, calculates the number of nucleation events within the calculation region based on the temperatures of the multiple calculation points, determines precipitate phase generation points that generate nuclei of precipitate phases from the multiple calculation points based on the number of nucleation events, calculates the grain growth of the precipitate phase at the precipitate phase generation points, and predicts the structure of the material based on the calculated grain growth of the precipitate phase.
しかし、上記特許文献１では、金属材サンプルから得られる母相の材料組織に関する情報から、メタラジーに基づき材料の組織を予測する。このため、材料の組織の予測に手間がかかる。 However, in the above-mentioned Patent Document 1, the material structure is predicted based on metallurgy from information on the material structure of the parent phase obtained from a metal material sample. This makes predicting the material structure time-consuming.
そこで、本発明は、上記問題に鑑みてなされたものであり、本発明の目的とするところは、熱間圧延プロセスにおいて製造される鋼板の機械特性を簡便に予測することが可能な、材質予測方法を提供することにある。 The present invention was made in consideration of the above problems, and its object is to provide a material quality prediction method that can easily predict the mechanical properties of steel sheets manufactured in a hot rolling process.
上記課題を解決するために、本発明のある観点によれば、熱間圧延プロセスにおいて製造される高強度鋼の鋼板の機械特性を予測する材質予測方法であって、予め鋼種毎に、複数の鋼板について、コイル巻き取り完了以降の所定の時刻から所定の時間が経過した時刻までの温度取得期間におけるコイルの全長及び全幅にわたる板温度を温度履歴として取得して、製造したコイルの複数の位置において測定した機械特性と、取得した温度履歴から得られる位置での板温度に基づくパラメータとに基づいて、機械特性とパラメータとの相関式を求めておき、圧延対象の鋼板について、温度取得期間におけるコイルの全長及び全幅にわたる板温度を取得して、コイルの任意の位置でのパラメータを算出し、対応する鋼種の相関式から機械特性を求める、材質予測方法が提供される。 In order to solve the above-mentioned problems, one aspect of the present invention provides a material quality prediction method for predicting the mechanical properties of high-strength steel sheets manufactured in a hot rolling process. The method first acquires, for each steel type, the sheet temperatures across the entire length and width of the coil during a temperature acquisition period from a predetermined time after the completion of coil winding until a predetermined time has elapsed, as a temperature history, for multiple steel sheets. A correlation equation between the mechanical properties and parameters is determined based on the mechanical properties measured at multiple positions on the manufactured coil and parameters based on the sheet temperatures at positions obtained from the acquired temperature history. The method then acquires the sheet temperatures across the entire length and width of the coil during the temperature acquisition period for the steel sheet to be rolled, calculates the parameters at any position on the coil, and determines the mechanical properties from the correlation equation for the corresponding steel type.
パラメータは、温度取得期間内の、コイル巻き取り完了から所定の時間が経過した時点での板温度であってもよい。 The parameter may be the plate temperature at a predetermined time after the completion of coil winding during the temperature acquisition period.
また、パラメータは、予め設定された積算開始温度から積算終了温度までの積算期間において、積算開始温度からの板温度の変化量の時間についての積分値である積算温度であってもよい。 The parameter may also be the accumulated temperature, which is the integral of the amount of change in plate temperature from the accumulation start temperature over time during the accumulation period from a preset accumulation start temperature to the accumulation end temperature.
もしくは、パラメータは、予め設定された積算開始温度から積算終了温度までの積算期間において、積算開始温度からの板温度の変化量に累積時間を乗じた積算値である累積積算温度であってもよい。 Alternatively, the parameter may be the cumulative temperature, which is the cumulative value obtained by multiplying the amount of change in plate temperature from the accumulation start temperature by the cumulative time during the accumulation period from a predetermined accumulation start temperature to the accumulation end temperature.
温度履歴は、解析モデルを用いて計算により取得してもよい。 The temperature history may be obtained by calculation using an analytical model.
また、温度履歴は、製造したコイルの温度を実測することにより取得してもよい。 The temperature history may also be obtained by actually measuring the temperature of the manufactured coil.
機械特性は、例えば引張強度であってもよい。 The mechanical property may be, for example, tensile strength.
以上説明したように本発明によれば、熱間圧延プロセスにおいて製造される鋼板の機械特性を簡便に予測することができる。 As described above, the present invention makes it possible to easily predict the mechanical properties of steel sheets produced in a hot rolling process.
以下に添付図面を参照しながら、本発明の好適な実施の形態について詳細に説明する。なお、本明細書及び図面において、実質的に同一の機能構成を有する構成要素については、同一の符号を付することにより重複説明を省略する。 Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Note that in this specification and drawings, components having substantially the same functional configuration will be designated by the same reference numerals, and redundant explanations will be omitted.
［１．設備構成］
まず、図１に基づいて、熱間圧延プロセスの設備構成を説明する。図１は、本実施形態に係る熱間圧延設備１の一例を示す説明図であって、仕上圧延機３０以降の設備を示している。
[1. Equipment configuration]
First, the equipment configuration of a hot rolling process will be described with reference to Fig. 1. Fig. 1 is an explanatory diagram showing an example of a hot rolling equipment 1 according to this embodiment, and shows equipment from a finishing mill 30 onwards.
熱間圧延プロセスでは、熱間圧延設備１により、加熱したスラブを所定の板厚に圧延して、コイル状に巻き取る。加熱炉（図示せず。）にて加熱されたスラブは、粗圧延機（図示せず。）により圧延された後、仕上圧延機３０により所定の板厚にまで圧延される。その後、鋼板は、冷却設備４０を経て、ピンチロール７０によってコイラー８０に誘導され、所定の巻き取り温度でマンドレル８５によりコイル状に巻き取られる。 In the hot rolling process, a heated slab is rolled to a predetermined thickness by hot rolling equipment 1 and wound into a coil. The slab is heated in a heating furnace (not shown), rolled by a roughing mill (not shown), and then rolled to the predetermined thickness by a finishing mill 30. The steel plate then passes through cooling equipment 40 and is guided by pinch rolls 70 to a coiler 80, where it is wound into a coil by a mandrel 85 at the predetermined winding temperature.
熱間圧延プロセスにおける鋼板の全長全幅にわたる温度制御は、予め、所定の材質、例えば引張強度（ＴＳ）やｒ値、降伏強度（ＹＳ）、一様伸び、破断伸び等の機械特性が目標値以内となる巻き取り温度を求めておき、予め求めた巻き取り温度となるように熱間圧延設備１を制御することにより行われる。具体的には、鋼板長手方向（通板方向）の温度は、仕上圧延機３０の入側に設置されたバーヒータ１０による加熱と、仕上圧延機３０とコイラー８０との間に設置された冷却装置４０による冷却とによって制御される。板幅方向の温度は、仕上圧延機３０の入側に設置されたエッジヒータ２０による加熱と、仕上圧延機３０からコイラー８０までの間のランアウトテーブル５０に、冷却装置４０に対応して設置されたエッジマスク５５による冷却調整とにより制御される。 Temperature control over the entire length and width of a steel plate during the hot rolling process is achieved by determining in advance the coiling temperature at which predetermined material properties, such as tensile strength (TS), r-value, yield strength (YS), uniform elongation, and breaking elongation, are within target values, and then controlling the hot rolling equipment 1 to achieve the predetermined coiling temperature. Specifically, the temperature in the longitudinal direction (threading direction) of the steel plate is controlled by heating using a bar heater 10 installed on the entry side of the finishing mill 30 and cooling using a cooling device 40 installed between the finishing mill 30 and the coiler 80. The temperature in the width direction of the plate is controlled by heating using an edge heater 20 installed on the entry side of the finishing mill 30 and cooling adjustment using an edge mask 55 installed on the run-out table 50 between the finishing mill 30 and the coiler 80, corresponding to the cooling device 40.
図１に示す熱間圧延設備１には、仕上圧延機３０の出側に、鋼板の仕上出側温度を測定する仕上出側温度計６１が設置され、冷却装置４０の出側に、コイラー８０による巻き取り前の鋼板の温度を測定する巻取前温度計６３が設置されている。仕上出側温度計６１及び巻取前温度計６３により測定された鋼板の温度に基づき、制御装置（図示せず。）は、鋼板の巻き取り温度が予め求めた巻き取り温度となるように、バーヒータ１０やエッジヒータ２０、冷却装置４０、エッジマスク５５を制御する。 The hot rolling equipment 1 shown in Figure 1 is equipped with a finish exit thermometer 61 at the exit of the finishing rolling mill 30 to measure the finish exit temperature of the steel sheet, and a pre-coiling thermometer 63 at the exit of the cooling device 40 to measure the temperature of the steel sheet before it is coiled by the coiler 80. Based on the temperatures of the steel sheet measured by the finish exit thermometer 61 and the pre-coiling thermometer 63, a control device (not shown) controls the bar heater 10, edge heater 20, cooling device 40, and edge mask 55 so that the coiling temperature of the steel sheet becomes the predetermined coiling temperature.
熱間圧延設備１にて製造されたコイルＣは、コイルヤードに搬送され、保管される。 The coils C produced in the hot rolling equipment 1 are transported to the coil yard and stored.
［２．コイルの機械特性の予測］
熱間圧延プロセスにて製造された鋼板は、コイル状に巻き取られた後、コイルヤードへの搬送中及びコイルヤードにて冷却（空冷）される。鋼板の長手方向における板温度は、巻き取り直後はほぼ均一であるが、冷却時間が長くなるにつれてバラツキが生じる。この鋼板の長手方向の温度分布は、冷却後のコイルの機械特性にバラツキに影響を与える。特に、巻き取り後も変態が継続する高強度鋼の鋼板では、コイルの冷却過程で生じる温度分布が材質に与える影響は大きい。そこで、本願発明者は、コイルの冷却過程における鋼板の温度変化と、冷却後の機械特性との関係を調べるべく、数値解析を実施した。なお、製造されたコイルに求められる機械特性としては引張強度（ＴＳ）やｒ値、降伏強度（ＹＳ）、一様伸び、破断伸び等があるが、以下では、機械特性の一例として引張強度を取り上げ、説明する。
2. Prediction of Coil Mechanical Properties
Steel sheets manufactured through a hot rolling process are coiled and then cooled (air-cooled) during transport to a coil yard and at the coil yard. The temperature of the steel sheet in the longitudinal direction is nearly uniform immediately after coiling, but variations occur as the cooling time increases. This temperature distribution in the longitudinal direction of the steel sheet affects the variations in the mechanical properties of the cooled coil. In particular, for high-strength steel sheets, whose transformation continues even after coiling, the temperature distribution occurring during the coil cooling process has a significant impact on the material properties. Therefore, the inventors of the present application conducted a numerical analysis to investigate the relationship between the temperature change of the steel sheet during the coil cooling process and the mechanical properties after cooling. Note that the mechanical properties required for the manufactured coil include tensile strength (TS), r-value, yield strength (YS), uniform elongation, and elongation at break. Hereinafter, tensile strength will be described as an example of a mechanical property.
数値解析は、図２に示す解析モデルを用いて有限要素解析を実施した。解析モデルとして、１／４周、板幅１／２の軸対称コイルを設定した。コイル仕様は、板幅１０００ｍｍ、板厚２．５ｍｍ、板長１０００ｍとした。外気温度は１５℃とし、熱伝達率については、自然対流２０Ｗ・ｍ－２Ｋ－１、ステファンボルツマン定数σ（＝５．６７×１０－８Ｗ・ｍ－２Ｋ－４）、輻射率０．６とした。なお、板厚は板幅、板長に比べて十分に小さいため、板厚方向の温度分布はないものとみなした。 For the numerical analysis, finite element analysis was performed using the analytical model shown in Figure 2. An axially symmetric coil with a quarter circumference and half plate width was set as the analytical model. The coil specifications were a plate width of 1000 mm, a plate thickness of 2.5 mm, and a plate length of 1000 m. The ambient temperature was set to 15°C, and the heat transfer coefficients were natural convection 20 W·m −2 K −1 , Stefan-Boltzmann constant σ (= 5.67 × 10 −8 W·m −2 K −4 ), and emissivity 0.6. Note that since the plate thickness was sufficiently small compared to the plate width and length, it was assumed that there was no temperature distribution in the plate thickness direction.
かかる数値解析では、図２に示す解析モデルの計算領域Ｓｃの９点（Ｐｅ１～Ｐｅ３、Ｐｑ１～Ｐｑ３、Ｐｃ１～Ｐｃ３）での板温度を計算した。点Ｐｅ１～Ｐｅ３は、コイル側面において、コイル径方向の最外周部、ミドル部、最内周部の位置を示す。点Ｐｑ１～Ｐｑ３は、コイル側面から板幅１／４だけ中央側（クォーター部ともいう。）において、コイル径方向の最外周部、ミドル部、最内周部の位置を示す。点Ｐｃ１～Ｐｃ３は、コイル板幅中央において、コイル径方向の最外周部、ミドル部、最内周部の位置を示す。 In this numerical analysis, the plate temperatures were calculated at nine points (Pe1-Pe3, Pq1-Pq3, Pc1-Pc3) in the calculation domain Sc of the analytical model shown in Figure 2. Points Pe1-Pe3 indicate the positions of the outermost, middle, and innermost parts of the coil radially on the side of the coil. Points Pq1-Pq3 indicate the positions of the outermost, middle, and innermost parts of the coil radially, located 1/4 of the plate width from the side of the coil toward the center (also called the quarter section). Points Pc1-Pc3 indicate the positions of the outermost, middle, and innermost parts of the coil radially, located at the center of the coil plate width.
なお、コイル径方向の最外周部、ミドル部、最内周部は、適宜設定されるが、例えば全長が１０００ｍの鋼板を巻き取ったコイルにおいて、鋼板の先端から５ｍの位置を最内周部、鋼板の先端から５００ｍの位置をミドル部、鋼板の先端から１０００ｍの位置（すなわち尾端の位置）を最外周部としてもよい。 The outermost, middle, and innermost parts of the coil radial direction are set as appropriate. For example, in a coil wound with a steel plate having a total length of 1000 m, the innermost part may be 5 m from the leading edge of the steel plate, the middle part may be 500 m from the leading edge of the steel plate, and the outermost part may be 1000 m from the leading edge of the steel plate (i.e., the tail end).
解析結果を図３に示す。図３では、計算領域Ｓｃの９点のうち、コイル側面、クォーター部、板幅中央それぞれのミドル部（Ｐｅ２、Ｐｑ２、Ｐｃ２）での板温度、コイル側面の最外周部（Ｐｅ１）での板温度、及び、コイル板幅中央の最内周部（Ｐｃ３）での板温度の時間変化（温度履歴）を示している。また、各時間において、計算領域Ｓｃの９点の板温度のうち最大板温度と最小板温度との差をバラツキ（ｍａｘ－ｍｉｎ）として示している。 The analysis results are shown in Figure 3. Figure 3 shows the time change (temperature history) of the strip temperature at nine points in the calculation area Sc: the middle sections (Pe2, Pq2, Pc2) on the coil side, quarter section, and width center of the strip; the strip temperature at the outermost section (Pe1) on the coil side; and the innermost section (Pc3) at the width center of the coil. Also shown at each time point is the difference between the maximum and minimum strip temperatures among the nine strip temperatures at the calculation area Sc, shown as the variation (max-min).
図３より、冷却開始時の板温度はコイルのいずれの位置においてもほぼ同じであるが、外気に触れるコイル側面の最外周部（Ｐｅ１）は急速に温度が低下する。一方で、コイルのミドル部のクォーター部（Ｐｑ２）及び板幅中央（Ｐｃ２）での板温度の低下は緩やかである。板温度のバラツキは、冷却開始から約１００分までは増加し、その後減少する。このように、コイル冷却過程ではコイル位置によって板温度にバラツキが生じていることがわかる。 Figure 3 shows that the strip temperature at the start of cooling is roughly the same at all positions on the coil, but the temperature drops rapidly at the outermost part of the coil side (Pe1) which is exposed to the outside air. On the other hand, the drop in strip temperature is gradual at the quarter part (Pq2) in the middle part of the coil and at the center of the strip width (Pc2). Variation in strip temperature increases for approximately 100 minutes after the start of cooling, then decreases. This shows that variation in strip temperature occurs depending on the position on the coil during the coil cooling process.
次に、コイルの冷却開始から３０分経過後の各コイル位置での板温度と、熱間圧延設備にて実際に製造したこれらのコイルの引張強度（ＴＳ）の測定値との関係を調べた。図４に、各コイル位置でのコイル巻き取り直後から始まるコイル冷却から３０分後の板温度と製造された鋼板の引張強度の測定値とを示す。図４には、コイル板幅中央の径方向位置での比較結果（ａ）、コイルミドル部の板幅方向位置での比較結果（ｂ）、コイル最内周部の板幅方向位置での比較結果（ｃ）、コイル最外周部の板幅方向位置での比較結果（ｄ）を示している。なお、コイルミドル部はコイル全長の半分の位置とした。 Next, we investigated the relationship between the sheet temperature at each coil position 30 minutes after the start of coil cooling and the measured tensile strength (TS) values of these coils actually manufactured in the hot rolling equipment. Figure 4 shows the sheet temperature 30 minutes after coil cooling, which begins immediately after coil winding at each coil position, and the measured tensile strength values of the manufactured steel sheets. Figure 4 also shows the comparison results at the radial position at the center of the coil sheet width (a), the comparison results at the widthwise position of the middle part of the coil (b), the comparison results at the widthwise position of the innermost part of the coil (c), and the comparison results at the widthwise position of the outermost part of the coil (d). The middle part of the coil was defined as halfway along the entire length of the coil.
（ａ）に示すように、コイル板幅中央の径方向位置で板温度を比較すると、ミドル部が最も高く、最外周が最も低い。測定した引張強度も、ミドル部、最内周、最外周に低くなっている。また、（ｂ）～（ｄ）に示すように、板幅方向位置で板温度を比較すると、板幅中央、クォーター部、コイル側面の順に低くなる。測定した引張強度も、板幅中央、クォーター部、コイル側面に低くなっている。図４の各グラフが示す結果に多少のバラツキはあるが、いずれの結果からも板温度が低くなると引張強度（ＴＳ）が高くなることが確認された。 As shown in (a), when comparing strip temperatures at radial positions in the center of the coil strip width, the middle section is highest and the outermost section is lowest. The measured tensile strength also decreases in the middle section, the innermost section, and the outermost section. Furthermore, as shown in (b) to (d), when comparing strip temperatures at positions in the strip width direction, the temperature decreases in the order of the center of the strip width, the quarter section, and the coil side. The measured tensile strength also decreases in the center of the strip width, the quarter section, and the coil side. There is some variation in the results shown in each graph in Figure 4, but all of the results confirm that tensile strength (TS) increases as the strip temperature decreases.
そして、９点のコイル位置における３０分冷却後の板温度と引張強度（ＴＳ）とを整理すると、図５に示すように、一次関数の相関式（ｙ＝－０．６１３７ｘ＋１０４９．７）で表すことができ、自由度決定係数（Ｒ２）が０．９１の相関があることが確認された。これは、コイル冷却過程で生じた板温度分布と最終的な鋼板の引張強度（ＴＳ）とに相関があることを意味する。かかる結果から、本願発明者は、コイル冷却過程における板温度に基づくパラメータと、常温となったコイルの引張強度との関係を相関式として予め求めておけば、圧延対象の鋼板について、所定の熱間圧延条件を設定し、解析モデル用いてコイル冷却過程における板温度を求めることで、上記相関式から製造される鋼板の引張強度を予測できることを想到した。 Then, by organizing the sheet temperature and tensile strength (TS) after 30 minutes of cooling at nine coil positions, it was confirmed that the relationship can be expressed by a linear function correlation equation (y = -0.6137x + 1049.7) as shown in Figure 5, and that there is a correlation with a coefficient of determination ( R2 ) of 0.91. This means that there is a correlation between the sheet temperature distribution generated during the coil cooling process and the final tensile strength (TS) of the steel sheet. From these results, the inventors of the present application conceived that if a correlation equation is previously obtained that expresses the relationship between a parameter based on the sheet temperature during the coil cooling process and the tensile strength of the coil at room temperature, then by setting predetermined hot rolling conditions for the steel sheet to be rolled and determining the sheet temperature during the coil cooling process using an analytical model, it would be possible to predict the tensile strength of the steel sheet to be manufactured from the correlation equation.
ここで、コイル冷却過程における板温度に基づくパラメータとは、コイルの材質に影響するコイル冷却過程での板温度に関する情報をいう。かかるパラメータは、例えば、コイルの冷却開始から所定時間経過後の板温度そのものであってもよく、コイル冷却過程での板温度の変化量の時間についての積分値であってもよい。このようなパラメータを用いれば、コイルの機械特性（例えば引張強度（ＴＳ））との関係を表す適切な相関式を得ることができる。以下、鋼板の引張強度の予測に関し、コイルの板温度に基づくパラメータとして、コイルの板温度を用いる場合（手法Ａ）、コイルの板温度の変化量の時間についての積分値（以下、「積算温度」とも称する。）を用いる場合（手法Ｂ）、及び、コイルの板温度の変化量に累積時間を乗じた積算値（以下、「累積積算温度」とも称する。）を用いる場合（手法Ｃ）について説明する。 Here, the parameter based on the plate temperature during the coil cooling process refers to information related to the plate temperature during the coil cooling process, which affects the material of the coil. This parameter may be, for example, the plate temperature itself after a predetermined time has elapsed since the start of coil cooling, or the integrated value of the change in plate temperature over time during the coil cooling process. Using such parameters, an appropriate correlation equation can be obtained that expresses the relationship with the mechanical properties of the coil (e.g., tensile strength (TS)). Below, we will explain three methods for predicting the tensile strength of steel plates: using the plate temperature of the coil as a parameter based on the plate temperature of the coil (Method A); using the integrated value of the change in plate temperature of the coil over time (hereinafter also referred to as "cumulative temperature") (Method B); and using the integrated value obtained by multiplying the change in plate temperature of the coil by the cumulative time (hereinafter also referred to as "cumulative cumulative temperature") (Method C).
（手法Ａ：コイルの板温度と引張強度との相関式に基づく引張強度の予測）
図５に示したように、コイルの冷却開始から３０分経過後の９点のコイル位置での板温度と鋼板の引張強度（ＴＳ）の測定値との間には、例えば一次関数で表される相関があることがわかる。したがって、コイルの板温度に基づくパラメータとして、コイル巻き取り完了から所定の時間が経過した時点での、コイルの複数位置における板温度を用いて、冷却後に常温となったコイルの機械特性との関係を表すことができる。パラメータとコイルの材質との相関式は、鋼種毎に求める。
(Method A: Prediction of tensile strength based on a correlation equation between coil plate temperature and tensile strength)
As shown in Figure 5, it can be seen that there is a correlation, expressed for example as a linear function, between the measured values of the tensile strength (TS) of the steel sheet and the sheet temperatures at nine coil positions 30 minutes after the start of cooling of the coil. Therefore, the sheet temperatures at multiple positions on the coil at a predetermined time after the completion of coil winding can be used as parameters based on the sheet temperatures of the coil to express the relationship with the mechanical properties of the coil that has reached room temperature after cooling. A correlation equation between the parameters and the coil material is determined for each steel type.
具体的は、まず、相関式を求めるため、１つの鋼種について、コイルの冷却開始時の板温度の異なる複数のコイルの冷却過程の板温度の変化を取得する。板温度は、コンピュータを用いた数値解析により求めてもよく、実測して取得してもよい。例えば、数値解析により求める場合、入力値を鋼板の巻き取り温度として、実機におけるコイルの冷却を模擬した解析を、図２に示した解析モデルを用いた有限要素解析、または、差分法を用いた解析を行う。これにより、コイル巻き取り完了からの冷却完了までの、少なくとも所定の時間が経過するまでの、冷却過程でのコイルの全長及び全幅にわたる板温度の変化（温度履歴）を求めることができる。また、コイルの冷却過程における板温度変化を実測する場合には、例えば熱電対等を用いて鋼板の温度を測定すればよい。 Specifically, to determine the correlation equation, the change in strip temperature during the cooling process of multiple coils for one steel grade, each with different strip temperatures at the start of cooling, is first obtained. The strip temperature can be obtained through numerical analysis using a computer, or through actual measurement. For example, when using numerical analysis, the coiling temperature of the steel strip is used as the input value, and an analysis simulating the cooling of the coil in an actual machine is performed using finite element analysis or a differential analysis using the analytical model shown in Figure 2. This makes it possible to determine the change in strip temperature (temperature history) over the entire length and width of the coil during the cooling process, from the completion of coiling to the completion of cooling, at least until a predetermined time has elapsed. Furthermore, when actually measuring the change in strip temperature during the cooling process of the coil, the temperature of the steel strip can be measured using, for example, a thermocouple or the like.
ここで、温度履歴を取得する温度取得期間は、コイル巻き取り完了以降の所定の時刻から所定の時間が経過した時刻までの所定の時間であって、鋼種に応じて適宜設定される。温度取得期間の長さは、コイルの冷却過程において変態が生じ得る時間に対応しており、通常５～６０分程度、例えば３０分程度に設定される。 The temperature acquisition period for acquiring the temperature history is a predetermined time from a predetermined time after the completion of coil winding until a predetermined time has elapsed, and is set appropriately depending on the steel type. The length of the temperature acquisition period corresponds to the time during which transformation can occur during the coil cooling process, and is typically set to around 5 to 60 minutes, for example around 30 minutes.
また、これらの冷却開始時の板温度の異なる複数のコイルについて、実際に冷却を行い、冷却後に常温となったコイルの引張強度を測定する。引張強度は、コイルの複数の位置で測定される。例えば、図２に示した解析モデルのように、コイルの側面、クォーター部、板幅中央で、最外周部、ミドル部、最内周部それぞれの位置で引張強度を測定すればよい。引張強度の測定位置の数を増やすことで、求める相関式の精度を高めることができる。また、相関式の精度を高めるため、冷却過程における板温度の変化の大きいコイルの最外周部、最内周部の位置での引張強度を求めるとよい。 Additionally, multiple coils with different sheet temperatures at the start of cooling are actually cooled, and the tensile strength of the coils that have returned to room temperature after cooling is measured. Tensile strength is measured at multiple positions on the coil. For example, as in the analytical model shown in Figure 2, tensile strength can be measured at the side, quarter section, and width center of the coil, as well as at the outermost, middle, and innermost sections. Increasing the number of tensile strength measurement positions can improve the accuracy of the correlation equation. Furthermore, to improve the accuracy of the correlation equation, it is advisable to determine the tensile strength at the outermost and innermost sections of the coil, where the sheet temperature changes most during the cooling process.
次いで、数値解析または実測することにより取得されたコイル巻き取り完了から所定の時間が経過した時点でのコイルの板温度と、測定したコイルの引張強度との関係を求める。すなわち、引張強度の測定位置それぞれについて、数値解析または実測することにより取得された冷却開始から所定の時間経過時点での板温度を対応づける。そして、複数位置での板温度と引張強度とに基づき、これらの関係を表す相関式を求める。相関式は、近似式として表され、例えば図５に示したような一次関数であってもよく、二次以上の高次関数、指数関数、対数関数、累乗関数であってもよく、回帰式の形は限定されない。このような近似式を鋼種毎に予め求めておく。 Next, the relationship between the coil plate temperature a predetermined time after completion of coil winding, obtained by numerical analysis or actual measurement, and the measured coil tensile strength is determined. That is, for each tensile strength measurement position, the plate temperature a predetermined time after the start of cooling, obtained by numerical analysis or actual measurement, is associated. Then, based on the plate temperatures and tensile strengths at multiple positions, a correlation equation expressing this relationship is determined. The correlation equation is expressed as an approximation equation and may be, for example, a linear function as shown in Figure 5, or a higher-order function (quadratic or higher), an exponential function, a logarithmic function, or a power function; the form of the regression equation is not limited. Such an approximation equation is determined in advance for each steel type.
圧延対象の鋼板の引張強度を予測する際は、圧延対象の鋼板について、まず、コンピュータを用いた数値解析または実測により、温度取得期間におけるコイルの全長及び全幅にわたる板温度を取得する。板温度の取得は、相関式を求めるために予め実施した数値解析または実測と同様に行えばよい。そして、予め求めた当該鋼種の相関式を用いて、数値解析または実測により得られた、任意の位置における、前記温度取得期間内のコイル巻き取り完了から所定の時間が経過した時点での板温度に対応する引張強度を求める。このように、鋼板の全長及び全幅にわたって板温度を求めれば、コイル全体の各位置における引張強度が求まり、圧延対象の鋼板の引張強度を予測することができる。 When predicting the tensile strength of a steel plate to be rolled, the plate temperature over the entire length and width of the coil during the temperature acquisition period is first obtained using computer-based numerical analysis or actual measurement. The plate temperature can be obtained in the same manner as the numerical analysis or actual measurement previously performed to determine the correlation equation. The correlation equation for the steel type previously determined is then used to determine the tensile strength corresponding to the plate temperature at any position obtained by numerical analysis or actual measurement, at a predetermined time after completion of coil winding within the temperature acquisition period. In this way, by determining the plate temperature over the entire length and width of the steel plate, the tensile strength at each position over the entire coil can be determined, making it possible to predict the tensile strength of the steel plate to be rolled.
（手法Ｂ：コイルの板温度の変化量の積算温度と引張強度との相関式に基づく引張強度の予測）
コイルの板温度に基づくパラメータとして、コイル冷却過程での板温度の変化量の時間についての積分値（積算温度）を用いる場合も、上述の手法Ａと同様に、圧延対象の鋼板の引張強度の予測に用いる相関式を求めればよい。
(Method B: Prediction of tensile strength based on a correlation equation between the cumulative temperature change of the coil plate temperature and the tensile strength)
When the integral value (cumulative temperature) of the amount of change in plate temperature over time during the coil cooling process is used as a parameter based on the plate temperature of the coil, a correlation equation to be used for predicting the tensile strength of the steel plate to be rolled can be obtained, similar to the above-mentioned method A.
具体的は、まず、相関式を求めるため、１つの鋼種について、コイルの冷却開始時の板温度の異なる複数のコイルの冷却過程の板温度の変化（温度履歴）を、コンピュータを用いた数値解析または実測により取得する。また、これらの冷却開始時の板温度の異なる複数のコイルについて、実際に冷却を行い、冷却後に常温となったコイルの引張強度を測定する。これらの処理は、上述の手法Ａと同様に行えばよい。 Specifically, to find the correlation equation, the change in plate temperature (temperature history) during the cooling process for multiple coils of one steel type, each with different plate temperatures at the start of cooling, is obtained through computer-based numerical analysis or actual measurement. These multiple coils with different plate temperatures at the start of cooling are then actually cooled, and the tensile strength of the coils that have returned to room temperature after cooling is measured. These processes can be performed in the same way as in Method A above.
次に、コイルの板温度に基づくパラメータであるコイルの板温度の変化量の時間についての積分値（積算温度）を求める。 Next, calculate the integral (accumulated temperature) of the change in the coil plate temperature over time, which is a parameter based on the coil plate temperature.
まず、積算温度を求めるための積算開始温度Ｔｓｕｍ＿ｓ及び積算終了温度Ｔｓｕｍ＿ｅを一旦設定する。積算開始温度Ｔｓｕｍ＿ｓ及び積算終了温度Ｔｓｕｍ＿ｅは、引張強度の測定位置それぞれにおける温度履歴に対し、共通に用いられる。積算開始温度Ｔｓｕｍ＿ｓ及び積算終了温度Ｔｓｕｍ＿ｅの設定は、積算開始温度Ｔｓｕｍ＿ｓ及び積算終了温度Ｔｓｕｍ＿ｅを任意に設定し、積算開始温度Ｔｓｕｍ＿ｓから積算終了温度Ｔｓｕｍ＿ｅまでの板温度の変化量の時間についての積分値（積算温度）を、引張強度の測定位置それぞれでの温度履歴に対して求める。そして、一旦設定して求めた積算開始温度Ｔｓｕｍ＿ｓ及び積算終了温度Ｔｓｕｍ＿ｅでの複数点の積算温度と引張強度の測定値との自由度決定係数を求め、線形計画法や非線形計画法等の数理最適化手法を用いて自由度決定係数が最も高くなるように積算開始温度Ｔｓｕｍ＿ｓ及び積算終了温度Ｔｓｕｍ＿ｅを変更し、自由度決定係数が最大値となる共通の積算開始温度Ｔｓｕｍ＿ｓ及び積算終了温度Ｔｓｕｍ＿ｅを決定する。 First, the accumulation start temperature Tsum_s and accumulation end temperature Tsum_e are set to calculate the accumulated temperature. The accumulation start temperature Tsum_s and accumulation end temperature Tsum_e are used in common for the temperature history at each tensile strength measurement position. The accumulation start temperature Tsum_s and accumulation end temperature Tsum_e are set arbitrarily, and the integral value (accumulated temperature) of the change in plate temperature over time from the accumulation start temperature Tsum_s to the accumulation end temperature Tsum_e is calculated for the temperature history at each tensile strength measurement position. Then, the coefficient of freedom between the integrated temperatures and the measured tensile strength values at multiple points at the integrated start temperature Tsum_s and integrated end temperature Tsum_e that have been set and calculated is calculated, and a mathematical optimization method such as linear programming or nonlinear programming is used to change the integrated start temperature Tsum_s and integrated end temperature Tsum_e so that the coefficient of freedom is maximized, thereby determining the common integrated start temperature Tsum_s and integrated end temperature Tsum_e at which the coefficient of freedom is maximized.
共通の積算開始温度Ｔｓｕｍ＿ｓ及び積算終了温度Ｔｓｕｍ＿ｅを設定すると、次いで、引張強度の測定位置それぞれでの温度履歴について積算温度を求める。積算温度は、温度履歴が積算開始温度Ｔｓｕｍ＿ｓから積算終了温度Ｔｓｕｍ＿ｅまでの積算期間における、時間ｔにおけるコイルの板温度Ｔ（ｔ）と積算開始温度Ｔｓｕｍ＿ｓとの差ΔＴ（ｔ）（＝Ｔｓｕｍ－ｓ－Ｔ（ｔ））を積算した値である。具体的には下記式（１）で表すことができる。なお、式（１）において、Δｔは板温度の取得時間間隔（板温度取得周期）である。 Once the common accumulation start temperature Tsum_s and accumulation end temperature Tsum_e are set, the accumulated temperature is then calculated for the temperature history at each tensile strength measurement location. The accumulated temperature is the integrated value of the difference ΔT(t) (= Tsum-s-T(t)) between the coil plate temperature T(t) at time t and the accumulation start temperature Tsum_s during the accumulation period from the accumulation start temperature Tsum_s to the accumulation end temperature Tsum_e. Specifically, this can be expressed by the following equation (1). Note that in equation (1), Δt is the time interval between plate temperature acquisition (plate temperature acquisition period).
図６に、コイルの異なる位置において得られた温度履歴Ａ、Ｂ、Ｃを示す。各温度履歴Ａ、Ｂ、Ｃのグラフにおいて横軸は冷却開始（すなわち、コイル巻き取り完了時点）からの時間を示し、縦軸はコイルの板温度を示す。温度履歴Ａが得られたコイルの位置に比べて、温度履歴Ｂが得られたコイルの位置の冷却は緩やかであり、温度履歴Ｃが得られたコイルの位置の冷却は速い。これらの温度履歴Ａ、Ｂ、Ｃに対して共通の積算開始温度Ｔｓｕｍ＿ｓ及び積算終了温度Ｔｓｕｍ＿ｅを設定して算出された、コイルの板温度の変化量ΔＴ（ｔ）の時間についての積分値が、積算温度ＴＴである。温度履歴Ａの積算温度ＴＴに比べて、温度履歴Ｂの積算温度ＴＴは大きく、温度履歴Ｃの積算温度ＴＴは小さくなる。 Figure 6 shows temperature histories A, B, and C obtained at different positions on the coil. In each graph of temperature histories A, B, and C, the horizontal axis represents the time from the start of cooling (i.e., the point at which coil winding is completed), and the vertical axis represents the coil plate temperature. Compared to the coil position where temperature history A was obtained, cooling is slower at the coil position where temperature history B was obtained, and cooling is faster at the coil position where temperature history C was obtained. The integrated value over time of the change in coil plate temperature ΔT(t), calculated by setting a common accumulation start temperature Tsum_s and accumulation end temperature Tsum_e for these temperature histories A, B, and C, is the accumulated temperature TT. Compared to the accumulated temperature TT for temperature history A, the accumulated temperature TT for temperature history B is larger, and the accumulated temperature TT for temperature history C is smaller.
このように引張強度の測定位置それぞれでのコイルの積算温度を算出すると、コイルの積算温度と、測定した鋼板の引張強度との関係を求める。すなわち、引張強度の測定位置それぞれについて、数値解析または実測により得られた温度履歴から算出した積算温度を対応づける。そして、複数位置での積算温度と引張強度とに基づき、これらの関係を表す相関式を求める。相関式は、近似式として表され、例えば図７に示したような一次関数として表すことができる。図７の相関式（ｙ＝－０．００１６ｘ＋８０４．１）には、自由度決定係数（Ｒ２）が０．８８の相関がある。なお、相関式は、二次以上の高次関数、指数関数、対数関数、累乗関数であってもよく、回帰式の形は限定されない。このような近似式を鋼種毎に予め求めておく。 By calculating the cumulative coil temperature at each tensile strength measurement position in this manner, the relationship between the cumulative coil temperature and the measured tensile strength of the steel sheet can be determined. That is, for each tensile strength measurement position, the cumulative temperature calculated from the temperature history obtained by numerical analysis or actual measurement is associated. Then, a correlation equation expressing this relationship is determined based on the cumulative temperature and tensile strength at multiple positions. The correlation equation is expressed as an approximation equation, and can be expressed, for example, as a linear function as shown in FIG. 7. The correlation equation in FIG. 7 (y = -0.0016x + 804.1) has a correlation coefficient of degree of freedom (R 2 ) of 0.88. The correlation equation may be a quadratic or higher order function, an exponential function, a logarithmic function, or a power function, and the form of the regression equation is not limited. Such an approximation equation is determined in advance for each steel type.
圧延対象の鋼板の引張強度を予測する際は、圧延対象の鋼板について、まず、コンピュータを用いた数値解析または実測により、温度取得期間におけるコイルの全長及び全幅にわたる温度履歴を取得する。板温度の取得は、相関式を求めるために予め実施した数値解析または実測と同様に行えばよい。そして、取得された任意の位置における温度履歴から、共通の積算開始温度Ｔｓｕｍ＿ｓ及び積算終了温度Ｔｓｕｍ＿ｅの区間におけるコイルの板温度の変化量ΔＴ（ｔ）の時間についての積分値を積算温度として算出する。その後、予め求めた当該鋼種の相関式を用いて、算出した積算温度に対応する引張強度を求める。このように、鋼板の全長及び全幅にわたって積算温度を求めれば、コイル全体の各位置における引張強度が求まり、圧延対象の鋼板の引張強度を予測することができる。 When predicting the tensile strength of a steel plate to be rolled, the temperature history of the steel plate to be rolled is first obtained over the entire length and width of the coil during the temperature acquisition period using computer-based numerical analysis or actual measurement. The plate temperature can be obtained in the same manner as the numerical analysis or actual measurement previously performed to determine the correlation equation. Then, from the temperature history obtained at any position, the integrated value over time of the change in plate temperature ΔT(t) of the coil in the section between the common accumulation start temperature Tsum_s and accumulation end temperature Tsum_e is calculated as the accumulated temperature. The tensile strength corresponding to the calculated accumulated temperature is then calculated using the previously determined correlation equation for that steel type. In this way, by obtaining the accumulated temperature over the entire length and width of the steel plate, the tensile strength at each position across the entire coil can be determined, making it possible to predict the tensile strength of the steel plate to be rolled.
（手法Ｃ：コイルの板温度の変化量に累積時間を乗じた累積積算温度と引張強度との相関式に基づく引張強度の予測）
手法Ｃは、手法Ｂの変形例であり、コイルの板温度に基づくパラメータとして、コイル冷却過程での板温度の変化量に累積時間を乗じた積算値（累積積算温度）を用いて、圧延対象の鋼板の引張強度を予測する。
(Method C: Prediction of tensile strength based on a correlation equation between the tensile strength and the cumulative temperature obtained by multiplying the change in coil plate temperature by the cumulative time)
Method C is a variation of Method B, in which the tensile strength of the steel plate to be rolled is predicted using an integrated value (accumulated integrated temperature) obtained by multiplying the amount of change in plate temperature during the coil cooling process by the accumulated time as a parameter based on the plate temperature of the coil.
累積積算温度の算出処理では、まず、手法Ｂと同様、温度履歴に対して共通に用いられる積算開始温度Ｔｓｕｍ＿ｓ及び積算終了温度Ｔｓｕｍ＿ｅを設定する。そして、設定した共通の積算開始温度Ｔｓｕｍ＿ｓ及び積算終了温度Ｔｓｕｍ＿ｅに基づき、引張強度の測定位置それぞれでの温度履歴について累積積算温度を求める。累積積算温度は、時間ｔでのコイルの板温度Ｔ（ｔ）と積算開始温度Ｔｓｕｍ＿ｓとの差ΔＴ（ｔ）に、積算開始温度Ｔｓｕｍ＿ｓとなった積算開始時間ｔｓから時間ｔまでの累積時間ｔａ（＝ｔ－ｔｓ）を乗じて、温度履歴が積算開始温度Ｔｓｕｍ＿ｓから積算終了温度Ｔｓｕｍ＿ｅまでの積算期間において積算した値である。具体的には下記式（２）で表すことができる。 In the calculation process of the cumulative integrated temperature, first, as in Method B, an integration start temperature Tsum_s and an integration end temperature Tsum_e that are commonly used for the temperature history are set. Then, based on the set common integration start temperature Tsum_s and integration end temperature Tsum_e, the cumulative integrated temperature is calculated for the temperature history at each tensile strength measurement position. The cumulative integrated temperature is the value obtained by multiplying the difference ΔT(t) between the coil plate temperature T(t) at time t and the integration start temperature Tsum_s by the cumulative time t a (= t - t s ) from the integration start time t s at which the integration start temperature Tsum_s was reached to time t, and integrating it over the integration period from the integration start temperature Tsum_s to the integration end temperature Tsum_e in the temperature history. Specifically, it can be expressed by the following formula (2):
上記式（２）に基づき、引張強度の測定位置それぞれでのコイルの累積積算温度を算出し、コイルの累積積算温度と測定した鋼板の引張強度との関係を求めることで、手法Ｂと同様、圧延対象の鋼鈑の温度履歴を取得すれば、当該鋼板の引張強度を予測することができる。図８に、コイルの累積積算温度と引張強度との関係を示す。手法Ｃで取得する相関式も、近似式として表され、例えば図８に示したような一次関数として表すことができる。図８の相関式（ｙ＝－０．０００００５ｘ＋７８１．９９）には、自由度決定係数（Ｒ２）が０．９５の相関がある。なお、相関式は、二次以上の高次関数、指数関数、対数関数、累乗関数であってもよく、回帰式の形は限定されない。 Based on the above formula (2), the cumulative integrated temperature of the coil at each tensile strength measurement position is calculated, and the relationship between the cumulative integrated temperature of the coil and the measured tensile strength of the steel sheet is determined. Similarly to method B, by obtaining the temperature history of the steel sheet to be rolled, the tensile strength of the steel sheet can be predicted. Figure 8 shows the relationship between the cumulative integrated temperature of the coil and tensile strength. The correlation equation obtained by method C can also be expressed as an approximation equation, for example, as a linear function as shown in Figure 8. The correlation equation in Figure 8 (y = -0.000005x + 781.99) has a correlation coefficient of determination ( R2 ) of 0.95. Note that the correlation equation may be a higher-order function (quadratic or higher), an exponential function, a logarithmic function, or a power function, and the form of the regression equation is not limited.
以上説明したように、コイル冷却過程における板温度に基づくパラメータと引張強度との相関式を予め求めておくことにより、圧延対象の鋼板の引張強度を予測することができる。かかる手法によれば、製造された鋼板の材料組織を解析することなく、簡便に圧延対象の鋼板の引張強度を予測することが可能となる。 As explained above, by determining in advance the correlation equation between the tensile strength and parameters based on the sheet temperature during the coil cooling process, it is possible to predict the tensile strength of the steel sheet to be rolled. This method makes it possible to easily predict the tensile strength of the steel sheet to be rolled without analyzing the material structure of the manufactured steel sheet.
なお、コイルの板温度に基づくパラメータとして、コイルの積算温度または累積積算温度を用いた場合、設定した積算開始温度Ｔｓｕｍ＿ｓ及び積算終了温度Ｔｓｕｍ＿ｅは、コイル冷却時に生じる変態の開始及び終了に対応するものと考えられる。このため、コイルの積算温度または累積積算温度はメタラジーの概念を考慮したパラメータともいえる。一方で、コイルの板温度をパラメータとして用いる場合には、コイルの板温度の積分値（積算温度）をパラメータとして用いる場合よりも簡便に実施でき、計算負荷を軽減することができる。 When the coil's integrated temperature or cumulative integrated temperature is used as a parameter based on the coil's plate temperature, the set integrated start temperature Tsum_s and integrated end temperature Tsum_e are considered to correspond to the start and end of the transformation that occurs when the coil is cooled. For this reason, the coil's integrated temperature or cumulative integrated temperature can also be considered a parameter that takes into account the concept of metallurgy. On the other hand, when the coil's plate temperature is used as a parameter, it is easier to implement than when the integrated value of the coil's plate temperature (integrated temperature) is used as a parameter, and the calculation load can be reduced.
以上、添付図面を参照しながら本発明の好適な実施形態について詳細に説明したが、本発明はかかる例に限定されない。本発明の属する技術の分野における通常の知識を有する者であれば、特許請求の範囲に記載された技術的思想の範疇内において、各種の変更例または修正例に想到し得ることは明らかであり、これらについても、当然に本発明の技術的範囲に属するものと了解される。 The above describes in detail preferred embodiments of the present invention with reference to the accompanying drawings, but the present invention is not limited to such examples. It is clear that a person with ordinary skill in the technical field to which the present invention pertains can conceive of various modifications or alterations within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.
例えば、上記実施形態では、鋼板の温度が仕上圧延機の入側に設置されたバーヒータ及びエッジヒータによる加熱と、仕上圧延機とコイラーとの間のランアウトテーブルに設置された冷却装置及びエッジマスクによる冷却とによって制御される場合を例に説明したが、加熱装置及び冷却装置の設置位置はかかる例に限定されない。 For example, in the above embodiment, an example was described in which the temperature of the steel plate was controlled by heating using a bar heater and edge heater installed on the entry side of the finishing rolling mill, and cooling using a cooling device and edge mask installed on the run-out table between the finishing rolling mill and the coiler, but the installation locations of the heating device and cooling device are not limited to this example.
また、上記実施形態では、機械特性として引張強度を取り上げ説明したが、ｒ値、降伏強度（ＹＳ）、一様伸び、破断伸び等の、他の機械特性についても同様に予測することができる。一例として、図７のように積算温度を横軸、機械特性を縦軸にとり、相関式として一次関数の近似式を求めたとき、相関式の自由度決定係数（Ｒ２）は、ｒ値では０．７０、降伏強度（ＹＳ）では０．９０、一様伸びでは０．９２、破断伸びでは０．８７となった。このように、いずれの機械特性についてもコイルの板温度に基づくパラメータと高い相関があることから、上述した引張強度の予測の場合と同様に、本発明によってこれらの機械特性を予測することが可能である。 Furthermore, while the above embodiment has been described focusing on tensile strength as a mechanical property, other mechanical properties such as r-value, yield strength (YS), uniform elongation, and elongation at break can also be predicted in a similar manner. As an example, as shown in Figure 7, when the horizontal axis represents cumulative temperature and the vertical axis represents mechanical property, and an approximation equation of a linear function is calculated as a correlation equation, the coefficient of determination ( R2 ) of the degree of freedom of the correlation equation is 0.70 for r-value, 0.90 for yield strength (YS), 0.92 for uniform elongation, and 0.87 for elongation at break. As such, since each of the mechanical properties has a high correlation with parameters based on the coil plate temperature, it is possible to predict these mechanical properties using the present invention, just as in the case of predicting tensile strength described above.
なお、以下の構成も本発明の技術的範囲に含まれる。
（１）
熱間圧延プロセスにおいて製造される高強度鋼の鋼板の機械特性を予測する材質予測方法であって、
予め鋼種毎に、複数の鋼板について、
コイル巻き取り完了以降の所定の時刻から所定の時間が経過した時刻までの温度取得期間におけるコイルの全長及び全幅にわたる板温度を温度履歴として取得して、
製造したコイルの複数の位置において測定した機械特性と、取得した前記温度履歴から得られる前記位置での板温度に基づくパラメータとに基づいて、機械特性とパラメータとの相関式を求めておき、
圧延対象の鋼板について、前記温度取得期間におけるコイルの全長及び全幅にわたる板温度を取得して、前記コイルの任意の位置での前記パラメータを算出し、対応する鋼種の前記相関式から機械特性を求める、材質予測方法。
（２）
前記パラメータは、前記温度取得期間内の、コイル巻き取り完了から所定の時間が経過した時点での板温度である、上記（１）に記載の材質予測方法。
（３）
前記パラメータは、予め設定された積算開始温度から積算終了温度までの積算期間において、前記積算開始温度からの板温度の変化量の時間についての積分値である積算温度である、上記（１）に記載の材質予測方法。
（４）
前記パラメータは、予め設定された積算開始温度から積算終了温度までの積算期間において、前記積算開始温度からの板温度の変化量に累積時間を乗じた積算値である累積積算温度である、上記（１）に記載の材質予測方法。
（５）
前記温度履歴は、解析モデルを用いて計算により取得する、上記（１）～（４）のいずれか１項に記載の材質予測方法。
（６）
前記温度履歴は、製造したコイルの温度を実測することにより取得する、上記（１）～（４）のいずれか１項に記載の材質予測方法。
（７）
前記機械特性は、引張強度である、上記（１）～（６）のいずれか１項に記載の材質予測方法。
The following configurations are also included in the technical scope of the present invention.
(1)
A material quality prediction method for predicting mechanical properties of a high-strength steel plate manufactured in a hot rolling process, comprising:
For each steel type, multiple steel plates are
The plate temperatures over the entire length and width of the coil during a temperature acquisition period from a predetermined time after the completion of coil winding until a predetermined time has elapsed are acquired as a temperature history.
A correlation equation between the mechanical properties and the parameters is calculated based on the mechanical properties measured at a plurality of positions of the manufactured coil and the parameters based on the plate temperatures at the positions obtained from the temperature history obtained,
A material quality prediction method comprising: acquiring sheet temperatures over the entire length and width of a coil during the temperature acquisition period for a steel sheet to be rolled; calculating the parameters at any position on the coil; and determining mechanical properties from the correlation equation for the corresponding steel type.
(2)
The material quality prediction method according to (1) above, wherein the parameter is the plate temperature at a point in time when a predetermined time has elapsed since the completion of coil winding within the temperature acquisition period.
(3)
The material quality prediction method according to (1) above, wherein the parameter is an accumulated temperature, which is an integral value of the amount of change in plate temperature from a predetermined accumulation start temperature to an accumulation end temperature over time,
(4)
The material quality prediction method according to (1) above, wherein the parameter is a cumulative integrated temperature, which is an integrated value obtained by multiplying the amount of change in plate temperature from a predetermined integration start temperature to an integration end temperature by an accumulated time, during an integration period from the predetermined integration start temperature to the integration end temperature.
(5)
The material property prediction method according to any one of (1) to (4) above, wherein the temperature history is obtained by calculation using an analytical model.
(6)
The material prediction method according to any one of (1) to (4) above, wherein the temperature history is obtained by actually measuring the temperature of a manufactured coil.
(7)
The material property prediction method according to any one of (1) to (6) above, wherein the mechanical property is tensile strength.
１ 熱間圧延設備
１０ バーヒータ
２０ エッジヒータ
３０ 仕上圧延機
４０ 冷却装置
５０ ランアウトテーブル
６１ 仕上出側温度計
６３ 巻取前温度計
７０ ピンチロール
８０ コイラー
８５ マンドレル
Ｃ コイル
1 Hot rolling equipment 10 Bar heater 20 Edge heater 30 Finishing rolling mill 40 Cooling device 50 Run-out table 61 Finishing exit thermometer 63 Pre-coiling thermometer 70 Pinch roll 80 Coiler 85 Mandrel C Coil
Claims (7)
予め鋼種毎に、複数の鋼板について、
コイル巻き取り完了以降の所定の時刻から所定の時間が経過した時刻までの温度取得期間におけるコイルの全長及び全幅にわたる板温度を温度履歴として取得して、
製造したコイルの複数の位置において測定した機械特性と、取得した前記温度履歴から得られる前記位置での板温度に基づくパラメータとに基づいて、機械特性とパラメータとの相関式を求めておき、
圧延対象の鋼板について、前記温度取得期間におけるコイルの全長及び全幅にわたる板温度を取得して、前記コイルの任意の位置での前記パラメータを算出し、対応する鋼種の前記相関式から機械特性を求める、材質予測方法。 A material quality prediction method for predicting mechanical properties of a high-strength steel plate manufactured in a hot rolling process, comprising:
For each steel type, multiple steel plates are
The plate temperatures over the entire length and width of the coil during a temperature acquisition period from a predetermined time after the completion of coil winding until a predetermined time has elapsed are acquired as a temperature history.
A correlation equation between the mechanical properties and the parameters is calculated based on the mechanical properties measured at a plurality of positions of the manufactured coil and the parameters based on the plate temperatures at the positions obtained from the temperature history obtained,
A material quality prediction method comprising: acquiring sheet temperatures over the entire length and width of a coil during the temperature acquisition period for a steel sheet to be rolled; calculating the parameters at any position on the coil; and determining mechanical properties from the correlation equation for the corresponding steel type.
5. The material property prediction method according to claim 1, wherein the mechanical property is tensile strength.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2022111218A JP7807659B2 (en) | 2022-07-11 | 2022-07-11 | Material prediction method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2022111218A JP7807659B2 (en) | 2022-07-11 | 2022-07-11 | Material prediction method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2024009583A JP2024009583A (en) | 2024-01-23 |
| JP7807659B2 true JP7807659B2 (en) | 2026-01-28 |
Family
ID=89723822
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2022111218A Active JP7807659B2 (en) | 2022-07-11 | 2022-07-11 | Material prediction method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP7807659B2 (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012196692A (en) | 2011-03-22 | 2012-10-18 | Kobe Steel Ltd | Method for cooling control of steel stock and continuous rolling mill |
| JP2015116596A (en) | 2013-12-19 | 2015-06-25 | Ｊｆｅスチール株式会社 | Method for production of hot-rolled steel strip |
| JP2015175004A (en) | 2014-03-13 | 2015-10-05 | Ｊｆｅスチール株式会社 | Manufacturing method of high-strength steel sheet with excellent formability |
| JP2016130334A (en) | 2015-01-13 | 2016-07-21 | Ｊｆｅスチール株式会社 | Hot rolled steel strip, cold rolled steel strip, and production method of hot rolled steel strip |
| JP2018016873A (en) | 2016-07-29 | 2018-02-01 | 株式会社神戸製鋼所 | High strength and high processability cold-rolled steel sheet coil with small variation of strength in coil and manufacturing method thereof |
| JP2020082112A (en) | 2018-11-20 | 2020-06-04 | 東芝三菱電機産業システム株式会社 | Material control support device of metal material |
-
2022
- 2022-07-11 JP JP2022111218A patent/JP7807659B2/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012196692A (en) | 2011-03-22 | 2012-10-18 | Kobe Steel Ltd | Method for cooling control of steel stock and continuous rolling mill |
| JP2015116596A (en) | 2013-12-19 | 2015-06-25 | Ｊｆｅスチール株式会社 | Method for production of hot-rolled steel strip |
| JP2015175004A (en) | 2014-03-13 | 2015-10-05 | Ｊｆｅスチール株式会社 | Manufacturing method of high-strength steel sheet with excellent formability |
| JP2016130334A (en) | 2015-01-13 | 2016-07-21 | Ｊｆｅスチール株式会社 | Hot rolled steel strip, cold rolled steel strip, and production method of hot rolled steel strip |
| JP2018016873A (en) | 2016-07-29 | 2018-02-01 | 株式会社神戸製鋼所 | High strength and high processability cold-rolled steel sheet coil with small variation of strength in coil and manufacturing method thereof |
| JP2020082112A (en) | 2018-11-20 | 2020-06-04 | 東芝三菱電機産業システム株式会社 | Material control support device of metal material |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2024009583A (en) | 2024-01-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5685208B2 (en) | Control device for hot rolling mill for thin plate and control method for hot rolling mill for thin plate | |
| EP1608472B1 (en) | A system for on-line property prediction for hot rolled coil in a hot strip mill | |
| CA2508594C (en) | Method for the process control or process regulation of an installation for the shaping, cooling, and/or heat treatment of metal | |
| US20190201954A1 (en) | Coil width control method and apparatus | |
| KR101516476B1 (en) | Apparatus for calculating set value, method of calculating set value, and program recording medium for calculating set value | |
| JP4402502B2 (en) | Winding temperature controller | |
| JP7807659B2 (en) | Material prediction method | |
| US12140939B2 (en) | Physical model identification system | |
| JP7156318B2 (en) | Rolling mill control method, rolling mill control device, and steel plate manufacturing method | |
| JP2012011448A (en) | Cooling control method of rolled material, and continuous rolling mill to which the cooling control method is applied | |
| JP6295932B2 (en) | Metal strip shape control method and shape control apparatus | |
| JP7230880B2 (en) | Rolling load prediction method, rolling method, method for manufacturing hot-rolled steel sheet, and method for generating rolling load prediction model | |
| JP7294242B2 (en) | Method for predicting surface roughness, method for manufacturing steel strip, and method for generating trained machine learning model | |
| JP7281958B2 (en) | Feature prediction device, manufacturing condition optimization device, control method for feature prediction device, control program | |
| JP7849600B2 (en) | Manufacturing method of hot-rolled steel sheets | |
| US12049677B1 (en) | Cooling a rolled product upstream of a finishing train of a hot rolling mill | |
| JP4696775B2 (en) | Plate width control method and apparatus | |
| JP2021133415A (en) | Model learning method, flying plate thickness changing method, steel plate manufacturing method, model learning device, flying plate thickness changing device and steel plate manufacturing device | |
| JP5381740B2 (en) | Thickness control method of hot rolling mill | |
| JPH01162508A (en) | Cooling control method for steel material | |
| Akela et al. | Optimization of run-out table cooling parameters to control coil collapse in carbon-manganese steels | |
| JP2008161924A (en) | Steel manufacturing method, steel cooling control device, and steel manufacturing device | |
| KR100328929B1 (en) | Apparatus and method for predicting widthwise tensile property during hot rolled strip manufacturing | |
| JP7853566B2 (en) | Prediction device, learning device, prediction program, and learning program | |
| JP7677546B2 (en) | Plate thickness control device for hot rolling mill |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20250317 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20251128 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20251216 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20251229 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 7807659 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |