JPH0715133B2 - Method for manufacturing hot-rolled high-strength steel sheet - Google Patents
Method for manufacturing hot-rolled high-strength steel sheetInfo
- Publication number
- JPH0715133B2 JPH0715133B2 JP63210037A JP21003788A JPH0715133B2 JP H0715133 B2 JPH0715133 B2 JP H0715133B2 JP 63210037 A JP63210037 A JP 63210037A JP 21003788 A JP21003788 A JP 21003788A JP H0715133 B2 JPH0715133 B2 JP H0715133B2
- Authority
- JP
- Japan
- Prior art keywords
- steel
- hot
- strength
- rolling
- tensile strength
- 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.)
- Expired - Lifetime
Links
- 229910000831 Steel Inorganic materials 0.000 title claims description 68
- 239000010959 steel Substances 0.000 title claims description 68
- 238000004519 manufacturing process Methods 0.000 title claims description 17
- 238000000034 method Methods 0.000 title claims description 16
- 239000000463 material Substances 0.000 claims description 34
- 238000005098 hot rolling Methods 0.000 claims description 25
- 238000000926 separation method Methods 0.000 claims description 23
- 238000001816 cooling Methods 0.000 claims description 22
- 229910052748 manganese Inorganic materials 0.000 claims description 14
- 238000005096 rolling process Methods 0.000 claims description 11
- 229910052758 niobium Inorganic materials 0.000 claims description 10
- 238000004804 winding Methods 0.000 claims description 9
- 239000012535 impurity Substances 0.000 claims description 8
- 229910052720 vanadium Inorganic materials 0.000 claims description 7
- 238000010438 heat treatment Methods 0.000 claims description 5
- 229910052742 iron Inorganic materials 0.000 claims description 3
- 238000005728 strengthening Methods 0.000 description 17
- 238000001556 precipitation Methods 0.000 description 16
- 230000000694 effects Effects 0.000 description 8
- 239000000203 mixture Substances 0.000 description 8
- 238000003466 welding Methods 0.000 description 8
- 239000002244 precipitate Substances 0.000 description 5
- 230000009467 reduction Effects 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 241000219307 Atriplex rosea Species 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 239000006104 solid solution Substances 0.000 description 4
- 238000005452 bending Methods 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 238000011835 investigation Methods 0.000 description 3
- 229920006395 saturated elastomer Polymers 0.000 description 3
- 238000005204 segregation Methods 0.000 description 3
- 230000003796 beauty Effects 0.000 description 2
- 230000002950 deficient Effects 0.000 description 2
- 150000004767 nitrides Chemical class 0.000 description 2
- 238000004080 punching Methods 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 230000008023 solidification Effects 0.000 description 2
- 238000009628 steelmaking Methods 0.000 description 2
- 238000009864 tensile test Methods 0.000 description 2
- 210000001015 abdomen Anatomy 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000010953 base metal Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000009661 fatigue test Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 241000894007 species Species 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 150000003568 thioethers Chemical class 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 230000037303 wrinkles Effects 0.000 description 1
Landscapes
- Heat Treatment Of Steel (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は熱間圧延高張力鋼板の製造方法に係り、詳しく
は、主として自動車用ホイールのリム材、ディスク材と
して用いる引張り強度60kgf/mm2以上の熱間圧延高張力
鋼板の製造方法に係る。TECHNICAL FIELD The present invention relates to a method for producing a hot-rolled high-strength steel sheet, and more specifically, to a tensile strength of 60 kgf / mm 2 or more, which is mainly used as a rim material for automobile wheels and a disc material. The present invention relates to a method for manufacturing a hot-rolled high-tensile steel plate.
従来の技術 従来から、熱間圧延高張力鋼板として各種のものがある
が、これらの中で自動車用ホイールに用いられる熱間圧
延高張力鋼板は次の２種類に大別される。その一つは析
出強化を利用したものであり、例えば、特開昭61-17054
1号公報に記載された如く、Ｃ、Si、Mnの基本成分にT
i、Nbを添加する析出強化鋼であって、主としてホイー
ルリム材として用いられるものである。他の一つは、例
えば、特開昭61-79730号公報に記載された如く、Ｃ、S
i、Mnの基本成分で組織強化を計る組織強化鋼であっ
て、主としてホイールディスク材として用いられるもの
である。通常、ホイールリム材に要求される特性として
は、フラッシュバット溶接性／直流バット溶接性と溶接
後の冷間加工性であり、また、ホイールディスク材に要
求される特性としては成形性である。従って、ホイール
リム材に用いられる従来例の析出強化鋼では降伏点が高
く、降伏伸びが大きいため、極く単純な形状を除いては
ホイールディスク用には使用されない。一方、ホイール
ディスクに用いられる従来例の組織強化鋼はフラッシュ
バット溶接性／直流バット溶接後の冷間加工性が悪いた
め、リム用としては45kgf/mm2以下の引張り強度が低い
物を除き、ディスク用のものをリム用として用いられる
ことは無い。従って、引張り強度60kgf/mm2以上のホイ
ール用熱延高張力鋼板はリム用、ディスク用として製造
時から作り分けているのが現状である。2. Description of the Related Art Conventionally, there are various hot-rolled high-tensile steel sheets, and among them, hot-rolled high-tensile steel sheets used for automobile wheels are roughly classified into the following two types. One of them is one utilizing precipitation strengthening. For example, JP-A-61-17054
As described in Japanese Patent Publication No. 1, the basic components of C, Si and Mn have T
It is a precipitation strengthened steel to which i and Nb are added, and is mainly used as a wheel rim material. The other one is, for example, as described in JP-A-61-79730, C, S
It is a structural strengthening steel that measures structural strengthening with the basic components of i and Mn, and is mainly used as a wheel disk material. Generally, the characteristics required for a wheel rim material are flash butt weldability / DC butt weldability and cold workability after welding, and the characteristics required for a wheel disc material are formability. Therefore, the conventional precipitation-strengthened steel used for the wheel rim material has a high yield point and a large yield elongation, and therefore is not used for wheel discs except for extremely simple shapes. On the other hand, the conventional structure strengthened steel used for the wheel disc has poor flash butt weldability / cold workability after DC butt welding, so for rims, except for those with low tensile strength of 45 kgf / mm 2 or less, The one for disc is never used for rim. Therefore, the hot rolled high-tensile steel plate for wheels having a tensile strength of 60 kgf / mm 2 or more is manufactured separately from the time of manufacture for rims and disks.
しかし、これら鋼種に共通した欠点は剪断面、打ち抜き
面に生じるセパレーションであり、これがリムの成形
性、ホイールの耐久強度を劣化させる原因となってい
る。However, the common drawback of these steel types is the separation occurring on the sheared surface and punched surface, which causes deterioration of the formability of the rim and the durability strength of the wheel.
更に自動車用ホイールについて説明する。Further, the automobile wheel will be described.
自動車用ホイールは重要保安部品であり、第一に耐久強
度の高いことを要求されるが、その他に、ファッション
性が重んじられ、形状は複雑であり、目視で判るような
美麗感を損ねるものは極端に嫌われる。特に、上記セパ
レーションはホイールディスクのセンターホールに生じ
て美麗感を損ねる他、飾り窓部に発生して耐久強度を劣
化させる。また、ホイールのリム材、ディスク材に要求
される特性が異なるため、それぞれ別の成分の鋼スラブ
を用いる等の異なる製造条件で製造しており、製造現場
における作業の煩雑化を招くという問題がある。Automobile wheels are important safety parts, and are required to have high durability and strength first, but in addition, fashionability is emphasized, the shape is complicated, and the one that impairs the beauty that can be visually recognized is Extremely disliked. In particular, the above-mentioned separation is generated in the center hole of the wheel disc and impairs the beauty, and also occurs in the decorative window portion to deteriorate the durability strength. In addition, since the properties required for the wheel rim material and the disc material are different, they are manufactured under different manufacturing conditions, such as using steel slabs with different components, which causes a problem that the work at the manufacturing site becomes complicated. is there.
発明が解決しようとする課題 本発明は上記問題の解決を目的とし、具体的には、フラ
ッシュバット溶接性／直流バット溶接性、溶接後の冷感
加工性に優れるとともに、耐セパレーション性に優れ、
つまり、剪断面や、打ち抜き面にセパレーションが生じ
ることがなく、その上、耐久強度が高いという各特性を
全て満足するリム用ならびにディスク用の両用途に使用
できる熱間圧延高張力鋼板の製造方法を提案するもので
ある。The present invention is intended to solve the above problems, specifically, flash butt weldability / DC butt weldability, excellent cold workability after welding, excellent separation resistance,
In other words, a method for producing a hot-rolled high-strength steel sheet that can be used for both rim and disc applications that does not cause separation on the sheared surface or punched surface and that has all the characteristics of high durability strength. Is proposed.
課題を解決するための手段ならびにその作用 すなわち、本発明は下記（１）〜（４）で示される鋼ス
ラブをそれぞれ1200〜1400℃で加熱後730〜880℃で熱間
圧延を終了し、圧延終了後、0.5秒以内に50℃／秒以上
の冷却速度で300〜700℃の温度域まで冷却し巻き取るこ
とを特徴とする。Means for Solving the Problem and Its Action That is, according to the present invention, the steel slabs represented by the following (1) to (4) are heated at 1200 to 1400 ° C., respectively, and then hot rolling is completed at 730 to 880 ° C. After completion, it is characterized in that within 0.5 seconds, it is cooled to a temperature range of 300 to 700 ° C. at a cooling rate of 50 ° C./second or more and wound up.
（１）重量で、C:0.03〜0.10％ならびにMn:0.5％以下と
して低減させて含み、その上で、Si:0.10％以下、P:0.0
3〜0.1％、Al:0.01〜0.1％、Nb:0.03〜0.5％を含有し、
残部はFe及び不可避的不純物からなる鋼スラブ。(1) By weight, the content of C: 0.03 to 0.10% and Mn: 0.5% or less is reduced and included, and Si: 0.10% or less, P: 0.0
3 to 0.1%, Al: 0.01 to 0.1%, Nb: 0.03 to 0.5%,
The balance is a steel slab consisting of Fe and inevitable impurities.
（２）重量で、C:0.03〜0.10％ならびにMn:0.5％以下と
して低減させて含み、その上で、Si:0.10％以下、P:0.0
3〜0.1％、Al:0.01〜0.1％、Nb:0.03〜0.5％を含有し、
更に、Ca:0.0001〜0.001％、REM:0.001〜0.01％の１種
又は２種を含有し、残部はFe及び不可避的不純物からな
る鋼スラブ。(2) By weight, C: 0.03 to 0.10% and Mn: 0.5% or less are included, and Si: 0.10% or less, P: 0.0
3 to 0.1%, Al: 0.01 to 0.1%, Nb: 0.03 to 0.5%,
Further, a steel slab containing Ca: 0.0001 to 0.001%, REM: 0.001 to 0.01%, one or two, and the balance being Fe and inevitable impurities.
（３）重量で、C:0.03〜0.10％ならびにMn:0.5％以下と
して低減させて含み、その上で、Si:0.10％以下、P:0.0
3〜0.1％、Al:0.01〜0.1％、Nb:0.03〜0.5％を含有し、
更に、Ti:0.01〜0.1％、V:0.01〜0.1％の１種又は２種
を含有し、残部はFe及び不可避的不純物からなる鋼スラ
ブ。(3) By weight, C: 0.03 to 0.10% and Mn: 0.5% or less are included, and further, Si: 0.10% or less, P: 0.0
3 to 0.1%, Al: 0.01 to 0.1%, Nb: 0.03 to 0.5%,
Further, a steel slab containing Ti: 0.01 to 0.1%, V: 0.01 to 0.1%, one or two, and the balance being Fe and inevitable impurities.
（４）重量でC:0.03〜0.10％ならびにMn:0.5％以下とし
て含み、その上で、Si:0.10％以下、P:0.03〜0.1％、A
l:0.01〜0.1％、Nb:0.03〜0.5％を含有し、更に、Ti:0.
01〜0.1％、V:0.01〜0.1％の１種又は２種を含有し、更
に加えてCa:0.0001〜0.001％、REM:0.001〜0.01％の１
種又は２種を含み、残部はFe及び不可避的不純物からな
る鋼スラブ。(4) Includes C: 0.03 to 0.10% and Mn: 0.5% or less by weight, and Si: 0.10% or less, P: 0.03 to 0.1%, A
l: 0.01-0.1%, Nb: 0.03-0.5%, and Ti: 0.
01-0.1%, V: 0.01-0.1% of 1 type or 2 types are added, and Ca: 0.0001-0.001%, REM: 0.001-0.01% of 1 type is added.
A steel slab that contains two or more species and the balance Fe and unavoidable impurities.
そこで、これらの手段たる構成ならびにその作用につい
て更に具体的に説明すると、次の通りである。Therefore, the structure and operation of these means will be described more specifically as follows.
本発明者等は自動車用ホイールのリム材及びディスク材
のいずれにも使用可能で、その引張り強度が60kgf/mm2
以上でかつセパレーションのない熱間圧延高張力鋼の製
造について調査、検討を行なった結果、本発明は成立し
たものである。The inventors of the present invention can use both the rim material and the disk material of automobile wheels, and the tensile strength thereof is 60 kgf / mm 2
As a result of investigating and examining the production of the hot-rolled high-strength steel having no separation as described above, the present invention has been established.
本発明の第１の特徴は本発明に用いる鋼スラブでCr量と
ともにMn量が低減させること、なかでも、高張力鋼の必
須成分と云われるMn量を低くおさえることである。この
理由は熱間圧延高張力鋼板を自動車のホイールデスク材
やリム材に適用させるときに、打抜き加工する際に生じ
るセパレーションの原因はMnの偏析帯に生じる層状の第
二相によるということを、本発明者等が知見したところ
に基づくものである。The first feature of the present invention is that the amount of Mn is reduced together with the amount of Cr in the steel slab used in the present invention, and above all, the amount of Mn, which is an essential component of high-strength steel, is kept low. The reason for this is that when applying hot rolled high-strength steel sheets to automobile wheel desk materials and rim materials, the cause of separation that occurs during punching is that the layered second phase that occurs in the segregation zone of Mn causes This is based on the findings of the present inventors.
第２の特徴はMn量の低下による引張り強度（TS）の低下
をＰ添加による固溶強化及びNb添加による析出強化で補
なうようにしたことである。従来、Nbによる析出強化能
はNb量が0.04％以上では飽和すると言われていたが、本
発明者等の調査によれば、熱間圧延条件を上記範囲に保
てば、0.04％を越えるNb量を添加しても強化能は飽和し
ないことを見出したものである。The second feature is that the decrease in tensile strength (TS) due to the decrease in the amount of Mn is compensated by solid solution strengthening by adding P and precipitation strengthening by adding Nb. Conventionally, it has been said that the precipitation strengthening ability by Nb is saturated when the Nb amount is 0.04% or more, but according to the investigation by the present inventors, if the hot rolling condition is kept in the above range, Nb exceeds 0.04%. It was discovered that the strengthening ability is not saturated even if the amount is added.
更に、本発明者等はNbの析出状況を詳細に調査したとこ
ろ以下の結果を得た。すなわち、一般にはNbの析出物は
炭窒化物であると言われているが、NbCとNbNは別個に析
出しており、NbNがNbCの析出に先立って析出している。
このNbNが粗大に析出した場合にはNbCはそれを核として
析出し、強度向上に寄与しなくなる。一方、NbNを微細
に析出させると、NbCも微細に析出する。更に、Ti、Ｖ
の１種又は２種を添加するとNbNの析出が抑止され、微
細なNbCの析出を促進する。これはTi、Ｖを直接的な析
出強化元素として利用するのではなく、間接的にNbCの
析出強化能を向上させるために用いることであり、本発
明の第三の特徴である。Further, the inventors of the present invention conducted a detailed investigation on the Nb precipitation state and obtained the following results. That is, it is generally said that Nb precipitates are carbonitrides, but NbC and NbN are separately precipitated, and NbN is precipitated prior to NbC precipitation.
When this NbN precipitates coarsely, NbC precipitates with it as a nucleus and does not contribute to the strength improvement. On the other hand, when NbN is finely precipitated, NbC is also finely precipitated. Furthermore, Ti, V
Addition of one or two of the above inhibits the precipitation of NbN and promotes the precipitation of fine NbC. This is not the use of Ti and V as direct precipitation strengthening elements but the use of indirectly improving the precipitation strengthening ability of NbC, which is the third feature of the present invention.
また、セパレーションを防止するには、Mn量を低下させ
ればよいことを前述したが、これだけではセパレーショ
ンを無くすことはできない。本発明者等はセパレーショ
ンを生じた試験片を詳細に調査したところ次の結果を得
た。すなわち、セパレート面上にはフィルム状のMnS
が存在する。塊状のMnSは、フィルム状のものとは違
ってセパレーションを起こさない。Mn量を上記の如く
低減しても、セパレーションに関連を持つフィルム状の
MnSの量は減らすことはできても、無くすことはできな
い。しかし、Ca、REMを添加すると、MnSは塊状とな
り、フィルム状のMnSが無くすことができ、耐セパレー
ション性は更に向上する。Further, as described above, in order to prevent the separation, it is necessary to reduce the amount of Mn, but the separation cannot be eliminated by this alone. The present inventors have conducted a detailed investigation on the test piece having separation, and obtained the following results. That is, a film-like MnS film is formed on the separate surface.
Exists. Unlike the film-like one, the block-like MnS does not cause separation. Even if the Mn amount is reduced as described above, a film-like
The amount of MnS can be reduced but not eliminated. However, when Ca and REM are added, MnS becomes a lump and the film-like MnS can be eliminated, and the separation resistance is further improved.
このような知見に基づき、Ca、REM添加によりセパレー
ションを防止したのが第四の特徴である。Based on these findings, the fourth feature is that separation is prevented by adding Ca and REM.
更に加えて、この成分系では、上記の通り、Ｃ量を減ら
しても60kgf/mm2以上の引張り強度を保持できることを
見出したのも大きな特徴であり、これにより、低Ｃ量と
なり、良好な溶接性が実現できる。In addition, it is also a great feature that this component system can maintain the tensile strength of 60 kgf / mm 2 or more even if the C content is reduced as described above, which results in a low C content and good weldability. Can be realized.
以上の通りの特徴にもとずいて、本発明法では、熱間圧
延すべき鋼スラブの組成を調整するが、各成分範囲の限
定理由を示すと、以下の通りである。Based on the characteristics as described above, in the method of the present invention, the composition of the steel slab to be hot-rolled is adjusted, and the reasons for limiting the range of each component are as follows.
C:ホイールリムは短冊状の鋼板の端面を突き合わせて、
溶接してフープ状にしたものを加工して製造される。こ
の場合、母材と溶接部の硬度差が大きいと、溶接部の加
工特性を劣化させ、成形時に割れる現象を生ずる。溶接
部の硬度は材料のＣ量に依存するため、0.10％が溶接後
の加工性を劣化させない上限である。一方、Ｃは鋼板の
強度上昇に有用な元素であり、本発明のようにMnを低減
させた成分系で、TSを60kgf/mm2以上にする場合には0.0
3％以上の添加が必要である。C: The wheel rim is made by abutting the end faces of strip-shaped steel plates,
It is manufactured by welding and forming a hoop. In this case, if the hardness difference between the base material and the welded portion is large, the processing characteristics of the welded portion are deteriorated, and the phenomenon of cracking during forming occurs. Since the hardness of the welded portion depends on the C content of the material, 0.10% is the upper limit that does not deteriorate the workability after welding. On the other hand, C is an element useful for increasing the strength of the steel sheet, and is a component system in which Mn is reduced as in the present invention, and when TS is 60 kgf / mm 2 or more, 0.0
It is necessary to add more than 3%.
Siは固溶強化能の大きな元素であり、熱間圧延高張力鋼
には従来から必要な元素であると云われている。したが
って、本発明法でも、このところを有効に使用する。し
かし、従来例のように0.1％を越えると、赤色スケール
が熱間圧延時に生じるため、0.10％を上限とする。Si is an element having a large solid solution strengthening ability and is said to be an element that has been conventionally required for hot-rolled high-strength steel. Therefore, even in the method of the present invention, this point is effectively used. However, as in the conventional example, if it exceeds 0.1%, a red scale occurs during hot rolling, so 0.10% is made the upper limit.
Mn:Mnは強化能を持ち、このところを有効に利用するた
めに、従来から、熱間圧延高張力鋼には必須成分として
添加されている。Mn: Mn has a strengthening ability, and in order to effectively utilize this, it has been conventionally added as an essential component to hot-rolled high-strength steel.
本発明法でも、このところを有効に利用するため、Mnを
添加する。しかし、Mnはその添加により強化能が高めら
れても、デスク材やリム材の適用には、積極的に添加す
るのは好ましくない。Also in the method of the present invention, Mn is added in order to effectively utilize this point. However, even if Mn enhances the strengthening ability by its addition, it is not preferable to positively add it to a desk material or a rim material.
すなわち、Mnは0.5％を越えると、鋼スラブの連鋳凝固
時に中心部に偏析し、熱間圧延板の板厚中心部に層状の
第二相を形成する。つまり、上記のようにMnがフィルム
状になって第二相が形成され、これに起因して上記の通
り、突抜き時にセパレーションが起こる。That is, when Mn exceeds 0.5%, segregation occurs in the central portion of the steel slab during continuous casting and solidification, and a layered second phase is formed in the central portion of the thickness of the hot-rolled sheet. That is, as described above, Mn becomes a film and a second phase is formed. Due to this, separation occurs at the time of punching as described above.
そこで、この層状組織を形成しない範囲として、Mnは0.
5％以下とする。Therefore, as a range in which this layered structure is not formed, Mn is 0.
5% or less.
P:Siのように赤色スケールを生じることなく、また、Mn
のように層状の第二相を形成することもない。このた
め、本発明法では耐セパレーションの上からMnを低減さ
せることにともなってＰを比較的多く添加し、固溶強化
能を有効に利用する。しかし、0.1％を越えると粒界偏
析による脆化が生じるため、0.1％を上限とする。ま
た、0.03％未満では強度に対する寄与が少なくなるので
0.03％を下限とする。Without producing a red scale like P: Si,
It does not form a layered second phase as in the above. For this reason, in the method of the present invention, a relatively large amount of P is added together with the reduction of Mn from the standpoint of separation resistance, and the solid solution strengthening ability is effectively utilized. However, if it exceeds 0.1%, embrittlement due to grain boundary segregation occurs, so 0.1% is made the upper limit. Also, if it is less than 0.03%, the contribution to the strength decreases, so
The lower limit is 0.03%.
Al:製鋼工程での脱酸に必要な最少量0.01％を下限と
し、脱酸効果が飽和する0.1％を上限とする。Al: The minimum amount required for deoxidation in the steelmaking process is 0.01% as the lower limit, and 0.1% at which the deoxidizing effect is saturated is the upper limit.
Nb:本発明法では、上記の通り、Mnの低減にともなって
重要な添加元素である。すなわち、Nbの析出強化、細粒
化機構により、Mn低減による強度低下を補うとともに高
い疲労強度を付与する成分であるが、0.03％未満では強
化に対する寄与は小さくなるため、0.03％を下限とす
る。0.5％を越えるNbの添加は伸びフランジ性を劣化さ
せるため、上限は0.5％とする。Nb: In the method of the present invention, as described above, it is an important additional element along with the reduction of Mn. That is, the precipitation strengthening of Nb, by a grain refining mechanism, is a component that supplements the strength reduction due to Mn reduction and imparts high fatigue strength, but if it is less than 0.03%, the contribution to strengthening becomes small, so 0.03% is the lower limit. . Addition of Nb in excess of 0.5% deteriorates stretch flangeability, so the upper limit is made 0.5%.
Ti:上記の通り、Tiは、Nbの析出に先んじて窒化物とし
て析出し、固溶Ｎをトラップすることにより、粗大なNb
Nの析出を防ぐ。この効果を有効に生かすためには0.01
％以上の添加が必要である。しかし、過度に添加する
と、粗大な窒化物となるため、0.1％を上限とする。Ti: As described above, Ti precipitates as a nitride prior to the precipitation of Nb and traps solid solution N to form coarse Nb.
Prevents N precipitation. 0.01 to effectively utilize this effect
% Or more must be added. However, if added excessively, it will become a coarse nitride, so 0.1% is made the upper limit.
V:Tiと同様な効果があり、同じ理由により0.01％を下限
とし、0.1％を上限とする。本発明ではこれに加えて、C
a、REMの１種又は２種を添加できる。その成分範囲限定
理由は次の通りである。It has the same effect as V: Ti. For the same reason, 0.01% is the lower limit and 0.1% is the upper limit. In the present invention, in addition to this, C
One or two of a and REM can be added. The reason for limiting the component range is as follows.
Ca:フィルム状のMnSの析出を抑止するには、0.0001％以
上の添加が必要となるのでこれを下限とし、粗大な硫化
物を生じて成形性を劣化させる0.001％を上限とする。In order to suppress precipitation of Ca: film-like MnS, 0.0001% or more must be added, so this is the lower limit, and the upper limit is 0.001%, which causes coarse sulfides to deteriorate the formability.
REM:REMについてもCaと同様な効果があり、同じ理由に
より、0.001％を下限とし、製鋼工程上の制約から0.01
％を上限とする。REM: REM has the same effect as Ca. For the same reason, the lower limit is 0.001%, and 0.01% due to restrictions in the steelmaking process.
% Is the upper limit.
また、ＳはMnと結合してMnSを生成し加工性を劣化させ
るので、可及的に少ないことが望ましく、例えば0.005
％以下が好ましい。Further, since S combines with Mn to form MnS and deteriorates workability, it is desirable that S is as small as possible, for example, 0.005
% Or less is preferable.
上記のような組成を前提して、加熱、熱間圧延及び冷却
等の各条件について説明すると、次の通りである。Each condition of heating, hot rolling, cooling, etc. will be described below on the premise of the above composition.
スラブ熱温度：スラブ凝固時に生じる粗大なNb炭化物を
溶解させるために1200〜1400℃とする。Slab heat temperature: Set to 1200 to 1400 ° C to dissolve coarse Nb carbide generated during slab solidification.
熱間圧延終了温度:Mn量低下に伴う強度低下を析出強化
で補う他に、結晶粒微細化強化を併用すれば、強度は向
上する。このためにはAr3直上で圧延を施すのが効果的
であるため、熱間圧延終了温度は750℃を下限とし、実
用上、微細効果を保てる880℃を上限とする。End temperature of hot rolling: Strength is improved by using precipitation strengthening in addition to compensating for strength reduction due to decrease in Mn amount, and grain refinement strengthening. For this purpose, it is effective to carry out rolling just above Ar 3 , so the hot rolling end temperature is set to 750 ° C as the lower limit, and 880 ° C for practically maintaining the fine effect as the upper limit.
熱延終了後の保持時間：熱延終了後は直ちに冷却を開始
した方が結晶粒微細化の効果は大であるが、熱間圧延ミ
ルの構造上空冷時間が生じる。強度を低下させないため
の最長空冷時間は0.5秒であるので、保持時間は0.5秒以
内とする。Holding time after completion of hot rolling: It is more effective to start cooling immediately after completion of hot rolling, but the effect of grain refinement is greater, but air cooling time occurs due to the structure of the hot rolling mill. The maximum air-cooling time is 0.5 seconds to prevent the strength from decreasing, so the holding time should be within 0.5 seconds.
冷却速度：冷却速度が遅い場合にはα変態後、α粒が成
長し、粗大化し、微細化効果による強度向上が望めない
ため、50℃／秒以上とする。また、冷却速度は速い方が
良く特に上限は設けないが通常の熱延ミル能力の上限は
200℃／秒程度である。Cooling rate: If the cooling rate is slow, α grains grow and become coarse after α transformation, and it is not possible to expect strength improvement due to the effect of refining, so it is set to 50 ° C./sec or more. In addition, the faster the cooling rate is, the better the upper limit is not set.
It is about 200 ° C / sec.
巻き取り温度：巻き取り温度は高い方が巻き取り後のNb
Cの析出が起こりやすいため望ましいが、高すぎると粗
大な析出物となり、強度向上に寄与しないため、700℃
を上限とする。一方、巻き取り温度が低いと、鋼板の形
状不良が生じやすくなるため、300℃を下限とする。Winding temperature: Higher winding temperature is Nb after winding
Precipitation of C tends to occur, which is desirable, but if it is too high, it will become a coarse precipitate and will not contribute to strength improvement.
Is the upper limit. On the other hand, if the winding temperature is low, the steel sheet is likely to have a defective shape, so the lower limit is 300 ° C.
以上説明したように、Ｃ、Si、Mn、Ｐ、Al、Nb等の各元
素成分を特定量含有した組成の鋼を特定の条件下加熱、
熱間圧延及び冷却等の処理をすると、自動車ホイールの
リム材、ディスク材等に好適に用いることができるTSが
60kgf/mm2以上でセパレーション等がない優れた熱間圧
延高張力鋼を容易に製造することができる。As described above, steel having a composition containing a specific amount of each elemental component such as C, Si, Mn, P, Al, and Nb is heated under specific conditions,
When hot rolling and cooling are performed, TS that can be suitably used for rim materials of automobile wheels, disk materials, etc.
It is possible to easily produce an excellent hot-rolled high-strength steel having a separation of 60 kgf / mm 2 or more and no separation or the like.
なお、明細書記載の％はいずれも重量％を示す。In addition,% in the description means% by weight.
実施例 第１表に示す成分の鋼スラブを用いて第２表の条件で熱
間圧延を行なった。その結果、得られた機械特性を第３
表及び第１図及び第２図に示す。Example Using the steel slabs having the components shown in Table 1, hot rolling was performed under the conditions shown in Table 2. As a result, the obtained mechanical properties are
The results are shown in the table and FIGS. 1 and 2.
第１図から最終圧延温度が730〜880℃の範囲でTSが60kg
f/mm2以上になることが判る。第２図は冷却開始までの
保持時間が0.5秒以内のときにTS＞60kgf/mm2となること
を示している。 From Fig. 1, TS is 60kg in the final rolling temperature range of 730-880 ℃.
It can be seen that f / mm 2 or more. Figure 2 shows that TS> 60kgf / mm 2 when the holding time before the start of cooling is within 0.5 seconds.
次に、Ti、Ｖを添加した第４表に示す成分の鋼を第５表
に示す条件で熱間圧延を行なった。その結果を第６表及
び第３図、第４図、第５図、第６図及び第７図に示す。Next, steels having the components shown in Table 4 to which Ti and V were added were hot-rolled under the conditions shown in Table 5. The results are shown in Table 6, FIG. 3, FIG. 4, FIG. 5, FIG. 6, and FIG.
第３図からスラブ加熱温度が1200℃以上で、引張り強度
（TS）60kgf/mm2以上の特性が得られることが判る。第
４図は熱延終了温度が730〜880℃の範囲で引張り強度60
kgf/mm2以上になることを示すものである。また、第５
図は熱間圧延終了後の保持時間が0.5秒以内の時に引張
り強度が60kgf/mm2以上となることを示している。第６
図は冷却速度が50℃／秒以上の時に引張り強度が60kgf/
mm2以上になることを示すものである。第７図は巻き取
り温度が700℃以下の範囲でTS＞60kgf/mm2となる事を示
しているが、200℃になると熱間圧延後の板の形状が不
良で実生産に適さないことを示している。従って、巻き
取り温度の範囲は300〜700℃とする。第６表に示した2
B、2C、2D、2F、2G、2H、2L、2M、2P、2R、2Sの記号の
試料は本発明法適用例であり、これらはいずれも引張り
強度60kgf/mm2以上となっている。これに対して、2A、2
E、2I、2J、2K、2O、2Tの記号の試料は本発明法非適用
例であり、いずれも強度不足である。試料2Qは強度レベ
ルは60kgf/mm2以上であるが、上述のように形状不良の
ため、本発明範囲としない。 It can be seen from Fig. 3 that tensile strength (TS) of 60 kgf / mm 2 or more can be obtained when the slab heating temperature is 1200 ° C or more. Fig. 4 shows the tensile strength of 60 when the hot rolling finish temperature is in the range of 730-880 ℃.
It indicates that the weight will be kgf / mm 2 or more. Also, the fifth
The figure shows that the tensile strength exceeds 60 kgf / mm 2 when the holding time after hot rolling is within 0.5 seconds. Sixth
The figure shows that the tensile strength is 60kgf / when the cooling rate is 50 ℃ / sec or more.
This indicates that the size becomes mm 2 or more. Figure 7 shows that TS> 60kgf / mm 2 when the coiling temperature is below 700 ℃, but at 200 ℃, the shape of the plate after hot rolling is bad and it is not suitable for actual production. Is shown. Therefore, the winding temperature range is 300 to 700 ° C. 2 shown in Table 6
The samples with the symbols B, 2C, 2D, 2F, 2G, 2H, 2L, 2M, 2P, 2R and 2S are application examples of the method of the present invention, and all have tensile strengths of 60 kgf / mm 2 or more. In contrast, 2A, 2
The samples with symbols E, 2I, 2J, 2K, 2O, and 2T are examples to which the method of the present invention is not applied, and all have insufficient strength. Although the strength level of Sample 2Q is 60 kgf / mm 2 or more, it is not within the scope of the present invention because of the defective shape as described above.
化学成分を変化させた鋼種での機械特性を調べるため
に、第７表に示す成分の鋼スラブを第８表に示す熱間圧
延条件で圧延し、板厚3.2mmの熱間圧延鋼板とした。こ
れらの鋼板の性状、機械特性及びホイール疲労強度を下
記に示す方法によって測定し、その結果を第９表に示し
た。製造時のコイル形状（耳伸び、腹伸び、しわなど）
及び赤色スケールは目視で判定した。また、層状第二相
は圧延方向に沿った断面組織を顕微鏡で調べ、中心部の
層状第二相の程度を判定した。引張り強度は鋼板の圧延
方向に沿った引張り試験片により、引張り強度（TS）を
調べた。また、サイドベンド伸びは板面内曲げ試験機を
用い、鋼板の圧延方向と直角方向に切り出した試片を用
いて測定し、その結果を母材のサイドベンド伸び（％）
とした。また、通常のフラッシュバット溶接を行なった
試験片の溶接部のサイドベンド試験も行ない、溶接後の
サイドベンド伸びの変化を調べ、その結果を溶接部のサ
イドベンド伸び（％）とした。セパレーションは引張り
試験後の破断面を観察して、セパレーションの程度を調
べた。また、ホイール疲労強度は製造した鋼板を用い
て、ホイールを試作し、ホイールの耐久強度を調べた。In order to investigate the mechanical properties of steels with different chemical compositions, steel slabs with the ingredients shown in Table 7 were rolled under the hot rolling conditions shown in Table 8 to obtain hot rolled steel sheets with a thickness of 3.2 mm. . The properties, mechanical properties and wheel fatigue strength of these steel sheets were measured by the methods described below, and the results are shown in Table 9. Coil shape during manufacturing (ear extension, belly extension, wrinkles, etc.)
The red scale was visually evaluated. Further, the layered second phase was examined with a microscope for a cross-sectional structure along the rolling direction, and the degree of the layered second phase in the central portion was determined. As for the tensile strength, the tensile strength (TS) was examined by a tensile test piece along the rolling direction of the steel sheet. In addition, the side bend elongation was measured using a plate bending tester and a test piece cut out in a direction perpendicular to the rolling direction of the steel sheet, and the result was measured as the side bend elongation (%) of the base metal.
And In addition, a side bend test of the weld portion of a test piece subjected to normal flash butt welding was also performed, and the change in side bend elongation after welding was examined, and the result was taken as the side bend elongation (%) of the weld portion. As for the separation, the degree of separation was examined by observing the fracture surface after the tensile test. For the wheel fatigue strength, a wheel was prototyped using the manufactured steel sheet, and the durability strength of the wheel was examined.
なお、ホイールの疲労試験には２種類の方法が使用され
ているので、両方の試験方法によってホイール疲労強度
を測定した。一方はタイヤを装着して回転するドラムに
押しつけ、クラックが発生してエア漏れを生じるまでの
回転数を耐久強度とする方法であり、ここでは1000kgf
の荷重で試験を行なった。他方はホイールを固定して回
転曲げモーメントを負荷し、クラック発生までの回転数
を耐久強度とする方法であり、ここでは、150kgf・ｍの
回転曲げモーメントを負荷した。Since two types of methods are used for the wheel fatigue test, the wheel fatigue strength was measured by both test methods. One is a method in which the tires are mounted and pressed against a rotating drum, and the number of rotations until cracks occur and air leakage occurs is the durable strength.
The test was performed under the load of. The other is a method in which the wheel is fixed and a rotational bending moment is applied, and the number of revolutions until the crack is generated is the durability strength. Here, a rotational bending moment of 150 kgf · m is applied.
第９表中に＊を付した記号の素材は本発明の成分範囲ま
たは製造条件からはずれるために所要の特性が得られな
いものである。鋼１はＣ量が低いため、引張り強度が60
kgf/mm2以下である。鋼４はMn量が高すぎ、サイドベン
ド伸び不良である。鋼７はＣ量が高すぎるため、溶接部
のサイドベンド伸びが低い。鋼８はSi量が高く、赤色ス
ケールが発生する。鋼９はMn量が高いため、中心部の層
状第二相が顕著であり、このためサイドベンド伸びが低
い。鋼12はＰ量が低いため、引張り強度が60kgf/mm2に
達しない。鋼16はＰ量が高いため、溶接部のサイドベン
ド伸びが低い。素材記号の鋼５−１、５−４、５−６、
５−８、５−９、5-12は成分は鋼と同じであり、本発明
の範囲内であるが、熱間圧延条件が範囲外であるため、
引張り強度が60kgf/mm2以下（５−１、６、８、９）、
または溶接部のサイドベンド伸びが低い（５−４）、あ
るいはコイル形状が悪い（5-12）など、諸特性の劣化が
見られる。鋼19はNb量が低いことにより、引張り強度が
60kgf/mm2に達していない。鋼22はNb量が高いことによ
り溶接部サイドベンド伸びが低い。鋼26はTi量が高いた
め、また、鋼29はＶ量が高いため、それぞれサイドベン
ド伸びが悪い。サイドベンド伸びの悪い鋼はホイールの
耐久強度が低い。また、TS不足もホイール耐久強度劣化
を招く。 The materials marked with * in Table 9 are out of the composition range or manufacturing conditions of the present invention, so that the required properties cannot be obtained. Steel 1 has a low C content, so the tensile strength is 60.
It is less than kgf / mm 2 . Steel 4 has an excessively high Mn content and has poor side bend elongation. Steel 7 has a too high C content, and thus has a low side bend elongation in the welded portion. Steel 8 has a high Si content and a red scale occurs. Since Steel 9 has a high Mn content, the layered second phase in the central portion is remarkable, and therefore the side bend elongation is low. Steel 12 has a low P content, so the tensile strength does not reach 60 kgf / mm 2 . Steel 16 has a high P content, so the side bend elongation of the weld is low. Material symbol steel 5-1, 5-4, 5-6,
5-8, 5-9, and 5-12 have the same composition as steel and are within the scope of the present invention, but the hot rolling conditions are out of the range.
Tensile strength of 60 kgf / mm 2 or less (5-1, 6, 8, 9),
In addition, deterioration of various characteristics is observed, such as low side bend elongation (5-4) of the welded portion or poor coil shape (5-12). Steel 19 has a low tensile strength due to its low Nb content.
It has not reached 60kgf / mm 2 . Steel 22 has a low weld side bend elongation due to the high Nb content. Steel 26 has a high Ti content, and Steel 29 has a high V content, so the side bend elongation is poor. Steel with poor sidebend elongation has low wheel durability. Insufficient TS also causes deterioration of wheel durability.
以上説明した以外の鋼はすべて本発明の製造法に適合す
るものであり、良好な特性が得られている。All of the steels other than those described above are suitable for the manufacturing method of the present invention, and have excellent properties.
〈発明の効果〉 以上詳しく説明したように、本発明法は、Ｃ、MnにSiを
添加した鋼スラブ組成において、C:0.03〜0.10％ならび
にMn:0.5％以下として低減する一方、P:0.03〜0.1％な
らびにNb:0.03〜0.5％を基本成分として添加して、鋼ス
ラブの組成を調整し、この調整された鋼スラブを1200〜
1400℃で加熱後、730〜880℃の熱間圧延、圧延後0.5秒
以内の300〜700℃の温度域までの冷却、巻き取りを行な
うものである。<Effects of the Invention> As described in detail above, according to the method of the present invention, in the steel slab composition in which Si is added to C and Mn, C: 0.03 to 0.10% and Mn: 0.5% or less while reducing P: 0.03. ~ 0.1% and Nb: 0.03-0.5% are added as basic components to adjust the composition of the steel slab.
After heating at 1400 ℃, hot rolling at 730 ~ 880 ℃, cooling to a temperature range of 300 ~ 700 ℃ within 0.5 seconds after rolling, and winding.
従って、本発明方法により得られる鋼板は、基本成分の
Ｃ、Mn、とくに、Mnが大巾に低減されているのにも拘ら
ず、引張り強度60kgf/mm2以上を示し、その上で、フラ
ッシュバット溶接性／直流バット溶接性、溶接後の冷間
加工性に優れる。とくに、リム材やディスク材として必
要な耐セパレーション性に優れ、これに加えて、耐久強
度が高いという各特性を全て満足する。自動車用ホイー
ルのリム材、ディスク材の両用に使用することができ、
従来法のようにリム用材、ディスク用材として別々に製
造する必要がない。Therefore, the steel sheet obtained by the method of the present invention shows a tensile strength of 60 kgf / mm 2 or more, even though the basic components C and Mn, especially Mn, are greatly reduced, and flash Excellent in butt weldability / DC butt weldability and cold workability after welding. In particular, it has excellent separation resistance required as a rim material and a disk material, and in addition to this, it satisfies all the characteristics of high durability strength. It can be used as both rim material for automobile wheels and disk material,
Unlike the conventional method, it is not necessary to separately manufacture a rim material and a disk material.
第１図及び第２図は本発明に係る実施例に用いた一例の
鋼スラブの最終圧延温度と引張り強度（TS）との関係を
示すグラフ及び熱間圧延後冷却開始までの保持時間と引
張り強度（TS）との関係を示すグラフ、第３図、第４
図、第５図、第６図及び第７図はそれぞれ他の実施例に
用いた一例の鋼スラブのスラブ加熱温度と引張り強度と
の関係を示すグラフ、熱間圧延終了温度と引張り強度と
の関係を示すグラフ、熱間圧延後冷却開始までの保持時
間と引張り強度との関係を示すグラフ、熱間圧延後の冷
却速度と引張り強度との関係を示すグラフ及び巻き取り
温度と引張り温度との関係を示すグラフである。FIG. 1 and FIG. 2 are graphs showing the relationship between the final rolling temperature and the tensile strength (TS) of the steel slab of one example used in the examples according to the present invention, and the holding time and the pulling after the hot rolling until the start of cooling. Graph showing the relationship with strength (TS), Fig. 3, Fig. 4
FIG. 5, FIG. 6, FIG. 6 and FIG. 7 are graphs showing the relationship between the slab heating temperature and the tensile strength of the steel slab of one example used in other examples, respectively, the hot rolling end temperature and the tensile strength. Graph showing the relationship, a graph showing the relationship between the holding time and the tensile strength after cooling after hot rolling, a graph showing the relationship between the cooling rate and the tensile strength after hot rolling and the winding temperature and the tensile temperature It is a graph which shows a relationship.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭54−57420（ＪＰ，Ａ) 特開 昭61−79730（ＪＰ，Ａ) ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-54-57420 (JP, A) JP-A-61-79730 (JP, A)
Claims (4)
以下として低減させて含み、その上で、Si:0.10％以
下、P:0.03〜0.1％、Al:0.01〜0.1％、Nb:0.03〜0.5％
を含んで、残部はFe及び不可避的不純物からなる鋼スラ
ブを、1200〜1400℃で加熱後、730〜880℃で熱間圧延を
終了し、圧延終了後、0.5秒以内に50℃／秒以上の冷却
速度で300〜700℃の温度域まで冷却し、その後、巻き取
ることを特徴とする引張り強度60kgf/mm2以上を有し耐
セパレーション性に優れる自動車ホイールディスク材並
びにリム材用熱間圧延高張力鋼板の製造方法。1. By weight, C: 0.03 to 0.10% and Mn: 0.5%
Included after being reduced as below, and Si: 0.10% or less, P: 0.03-0.1%, Al: 0.01-0.1%, Nb: 0.03-0.5%
Including, the balance is steel slab consisting of Fe and unavoidable impurities, after heating at 1200 ~ 1400 ℃, finish the hot rolling at 730 ~ 880 ℃, after the completion of rolling, 50 ℃ / sec or more within 0.5 seconds Hot rolling for automobile wheel disc materials and rim materials with a tensile strength of 60 kgf / mm 2 or more and excellent separation resistance, characterized by cooling to a temperature range of 300 to 700 ° C at a cooling rate of Method for manufacturing high-strength steel sheet.
以下として低減させて含み、その上で、Si:0.10％以
下、P:0.03〜0.1％、Al:0.01〜0.1％。、Nb:0.03〜0.5
％を含有し、更に、Ca:0.0001〜0.001％、REM:0.001〜
0.01％の１種又は２種を含有し、残部はFe及び不可避的
不純物からなる鋼スラブを1200〜1400℃で加熱後730〜8
80℃で熱間圧延を終了し、圧延終了後、0.5秒以内に50
℃／秒以上の冷却速度で300〜700℃の温度域まで冷却
し、その後、巻き取ることを特徴とする引張り強度60kg
f/mm2以上を有し耐セパレーション性に優れる自動車ホ
イールディスク材並びにリム材用熱間圧延高張力鋼板の
製造方法。2. By weight, C: 0.03 to 0.10% and Mn: 0.5%
It is reduced and included as below, and Si: 0.10% or less, P: 0.03 to 0.1%, Al: 0.01 to 0.1%. , Nb: 0.03-0.5
%, Further, Ca: 0.0001 to 0.001%, REM: 0.001 to
Steel slab containing 0.01% of 1 or 2 and balance of Fe and unavoidable impurities is heated at 1200-1400 ℃ 730-8
Finish hot rolling at 80 ℃, and within 50 seconds after rolling, 50
Tensile strength of 60kg, characterized by cooling to a temperature range of 300-700 ℃ at a cooling rate of ℃ / sec or more, and then winding.
A method for producing an automobile wheel disk material having f / mm 2 or more and excellent separation resistance and a hot-rolled high-strength steel sheet for rim materials.
以下として低減させて含み、その上で、Si:0.10％以
下、P:0.03〜0.1％、Al:0.01〜0.1％、Nb:0.03〜0.5％
を含有し、更に、Ti:0.01〜0.1％、V:0.01〜0.1％の１
種又は２種を含有し、残部はFe及び不可避的不純物から
なる鋼スラブを1200〜1400℃で加熱後730〜880℃で熱間
圧延を終了し、圧延終了後、0.5秒以内に50℃／秒以上
の冷却速度で300〜700℃の温度域まで冷却し、その後、
巻き取ることを特徴とする引張り強度60kgf/mm2以上を
有し耐セパレーション性に優れる自動車ホイールディス
ク材並びにリム材用熱間圧延高張力鋼板の製造方法。3. C: 0.03 to 0.10% and Mn: 0.5% by weight
Included after being reduced as below, and Si: 0.10% or less, P: 0.03-0.1%, Al: 0.01-0.1%, Nb: 0.03-0.5%
In addition, Ti: 0.01-0.1%, V: 0.01-0.1% 1
Steel slabs containing two or more species, the balance being Fe and unavoidable impurities, are heated at 1200-1400 ° C, then hot-rolled at 730-880 ° C, and 50 ° C / 0.5 ° C within 0.5 seconds after rolling. Cool to a temperature range of 300 to 700 ° C at a cooling rate of more than a second, then
A method for producing an automobile wheel disk material having a tensile strength of 60 kgf / mm 2 or more and excellent in separation resistance and a hot-rolled high-strength steel sheet for rim materials, which is characterized by being wound up.
以下として低減させて含み、その上で、Si:0.10％以
下、P:0.03〜0.1％、Al:0.01〜0.1％、Nb:0.03〜0.5％
を含有し、更に、Ti:0.01〜0.1％、V:0.01〜0.1％の１
種又は２種を含有し、更に加えてCa:0.0001〜0.001％、
REM:0.001〜0.01％の１種又は２種を含み、残部はFe及
び不可避的不純物からなる鋼スラブを1200〜1400℃で加
熱後730〜880℃で熱間圧延を終了し、圧延終了後、0.5
秒以内に50℃／秒以上の冷却速度で300〜700℃の温度域
まで冷却し、その後、巻き取ることを特徴とする引張り
強度60kgf/mm2以上を有し耐セパレーション性に優れる
自動車ホイールディスク材並びにリム材用熱間圧延高張
力鋼板の製造方法。4. By weight, C: 0.03 to 0.10% and Mn: 0.5%
Included after being reduced as below, and Si: 0.10% or less, P: 0.03-0.1%, Al: 0.01-0.1%, Nb: 0.03-0.5%
In addition, Ti: 0.01-0.1%, V: 0.01-0.1% 1
Containing two or more species, and in addition Ca: 0.0001 to 0.001%,
REM: 0.001 to 0.01% of 1 type or 2 types, the balance is a steel slab consisting of Fe and unavoidable impurities, heated at 1200 to 1400 ° C, finished hot rolling at 730 to 880 ° C, and finished rolling. 0.5
An automobile wheel disk with a tensile strength of 60 kgf / mm 2 or more and excellent separation resistance, which is characterized by cooling to a temperature range of 300 to 700 ° C. within a second at a cooling rate of 50 ° C./second or more and then winding. For manufacturing hot-rolled high-strength steel sheets for steel and rim materials.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63210037A JPH0715133B2 (en) | 1988-06-30 | 1988-08-24 | Method for manufacturing hot-rolled high-strength steel sheet |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16339688 | 1988-06-30 | ||
| JP63-163396 | 1988-06-30 | ||
| JP63210037A JPH0715133B2 (en) | 1988-06-30 | 1988-08-24 | Method for manufacturing hot-rolled high-strength steel sheet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0277520A JPH0277520A (en) | 1990-03-16 |
| JPH0715133B2 true JPH0715133B2 (en) | 1995-02-22 |
Family
ID=26488845
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63210037A Expired - Lifetime JPH0715133B2 (en) | 1988-06-30 | 1988-08-24 | Method for manufacturing hot-rolled high-strength steel sheet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0715133B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20150112511A (en) * | 2014-03-28 | 2015-10-07 | 현대제철 주식회사 | Hot-rolled steel sheet and method of manufacturing the same |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112442638A (en) * | 2019-08-27 | 2021-03-05 | 宝山钢铁股份有限公司 | Hot-rolled wheel steel with tensile strength of 500MPa or more and manufacturing method thereof |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5929647B2 (en) * | 1977-10-17 | 1984-07-21 | 川崎製鉄株式会社 | Method for manufacturing non-tempered high tensile strength hot rolled steel sheet with excellent workability |
| JPS6179730A (en) * | 1984-09-28 | 1986-04-23 | Kawasaki Steel Corp | Manufacture of high-tension hot-rolled steel sheet having composite structure |
-
1988
- 1988-08-24 JP JP63210037A patent/JPH0715133B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20150112511A (en) * | 2014-03-28 | 2015-10-07 | 현대제철 주식회사 | Hot-rolled steel sheet and method of manufacturing the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0277520A (en) | 1990-03-16 |
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