JPH0699754B2 - Heat treatment method for metal tubes - Google Patents
Heat treatment method for metal tubesInfo
- Publication number
- JPH0699754B2 JPH0699754B2 JP59150758A JP15075884A JPH0699754B2 JP H0699754 B2 JPH0699754 B2 JP H0699754B2 JP 59150758 A JP59150758 A JP 59150758A JP 15075884 A JP15075884 A JP 15075884A JP H0699754 B2 JPH0699754 B2 JP H0699754B2
- Authority
- JP
- Japan
- Prior art keywords
- safe end
- nozzle
- coolant
- temperature
- nucleate boiling
- 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
- 238000010438 heat treatment Methods 0.000 title claims description 32
- 239000002184 metal Substances 0.000 title claims description 15
- 238000000034 method Methods 0.000 title claims description 10
- 239000002826 coolant Substances 0.000 claims description 47
- 238000009835 boiling Methods 0.000 claims description 30
- 230000035882 stress Effects 0.000 claims description 19
- 230000008646 thermal stress Effects 0.000 claims description 17
- 238000001816 cooling Methods 0.000 claims description 12
- 230000008859 change Effects 0.000 claims description 10
- 230000007797 corrosion Effects 0.000 description 10
- 238000005260 corrosion Methods 0.000 description 10
- 230000009471 action Effects 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 238000005336 cracking Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000012530 fluid Substances 0.000 description 3
- 229910000963 austenitic stainless steel Inorganic materials 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 230000000717 retained effect Effects 0.000 description 2
- 230000032258 transport Effects 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Landscapes
- Heat Treatment Of Articles (AREA)
Description
【発明の詳細な説明】 「産業上の利用分野」 本発明は金属管の熱処理方法に係わり、特に、腐食性流
体を輸送する金属管に用いて好適な熱処理方法に関する
ものである。TECHNICAL FIELD The present invention relates to a heat treatment method for metal pipes, and more particularly to a heat treatment method suitable for use in metal pipes that transport corrosive fluids.
「従来の技術」 一般に、鉄鋼材料においては、引っ張り応力と腐食因子
とが共存する場合、腐食疲労あるいは応力腐食割れが急
速に進行することが知られている。"Prior Art" It is generally known that in steel materials, when a tensile stress and a corrosion factor coexist, corrosion fatigue or stress corrosion cracking rapidly progresses.
従って、腐食性流体を輸送する管に残留引っ張り応力が
存在すると、前述した腐食因子と残留引っ張り応力との
共存状態が形成されて、管の腐食疲労や応力腐食割れの
原因となる。Therefore, if residual tensile stress is present in the pipe that transports the corrosive fluid, a coexistence state of the above-mentioned corrosion factor and residual tensile stress is formed, which causes corrosion fatigue and stress corrosion cracking of the pipe.
そこで従来では、例えば金属管の内面に腐食因子が接続
させられる場合、金属管の内部に冷却材を挿通させなが
ら金属管を誘導加熱して金属管の内外面間に降伏点以上
の熱応力が生じる温度差を与えて、金属管の内面に残留
圧縮応力を発生させる熱処理方法が考えられている。Therefore, in the related art, for example, when a corrosion factor is connected to the inner surface of the metal pipe, the metal pipe is induction-heated while the coolant is inserted into the metal pipe to cause thermal stress at a yield point or higher between the inner and outer surfaces of the metal pipe. A heat treatment method has been considered in which a residual compressive stress is generated on the inner surface of the metal tube by giving a generated temperature difference.
「発明が解決しようとする問題点」 本発明は、前述した従来の技術における次のような問題
点を解決せんとするものである。"Problems to be Solved by the Invention" The present invention is intended to solve the following problems in the above-described conventional techniques.
すなわち、前述した従来の方法は、直管等の単純な形状
の金属管への適用が可能であるが、二重管のような冷却
材を流動状態に維持することのできない形状の金属管へ
の適用が困難である。また、冷却材の強制対流による冷
却作用によってのみ、管の熱処理面の冷却を行なうもの
であるから、前述した温度差を得るまでに時間を要し、
また、前記内面温度が変動しやすく温度差を一定値に制
御することが難しいといった問題点である。That is, the above-mentioned conventional method can be applied to a metal pipe having a simple shape such as a straight pipe, but to a metal pipe having a shape such as a double pipe that cannot maintain the coolant in a fluid state. Is difficult to apply. Further, since the heat treatment surface of the pipe is cooled only by the cooling action of the convection of the coolant, it takes time to obtain the above-mentioned temperature difference,
Further, there is a problem that the inner surface temperature is likely to change and it is difficult to control the temperature difference to a constant value.
「問題点を解決するための手段」 本発明は前述した従来の問題点を有効に解決する金属管
の熱処理方法を提供する。"Means for Solving Problems" The present invention provides a heat treatment method for a metal tube which effectively solves the above-mentioned conventional problems.
原子炉圧力容器に対して水平に配され、サーマルスリー
ブとノズル及びセーフエンドとが二重管構造をなしてい
るとともに、これらの間に非流動状態の冷却材が介在し
ている場合のノズル及びセーフエンドの内面を熱処理す
る方法として、ノズル及びセーフエンドの加熱によりこ
れらの内面の冷却材をその圧力と飽和温度とに基づき核
沸騰させ、核沸騰時に生じた蒸気のノズルの基部方向へ
の移動により冷却材を核沸騰部分に流入させるととも
に、核沸騰状態を保持してノズル及びセーフエンドの内
面の温度変化を少なくしながらノズル及びセーフエンド
の内外面に降伏点以上の熱応力を生じさせる温度差を与
えた後、ノズル及びセーフエンドの加熱を中断して冷却
することにより、ノズル及びセーフエンドの熱処理面に
残留圧縮応力を生じさせる技術を採用する。It is arranged horizontally with respect to the reactor pressure vessel, the thermal sleeve, the nozzle and the safe end form a double pipe structure, and the nozzle and the nozzle when the non-flowing coolant is interposed between them. As a method of heat-treating the inner surface of the safe end, by heating the nozzle and the safe end, the coolant on these inner surfaces is nucleated to boil based on its pressure and saturation temperature, and the steam generated during nucleate boiling moves toward the base of the nozzle. The temperature at which the coolant is allowed to flow into the nucleate boiling part by maintaining the nucleate boiling state to reduce the temperature change of the inner surface of the nozzle and the safe end while causing the thermal stress above the yield point on the inner and outer surfaces of the nozzle and the safe end. After making the difference, the heating of the nozzle and safe end is interrupted and cooled to generate residual compressive stress on the heat treated surface of the nozzle and safe end. To adopt the technology to.
「作用」 二重管構造をなしているサーマルスリーブとノズル及び
セーフエンドとの間に介在している冷却材は、非流動状
態となるが、ノズル及びセーフエンドの温度を高めて、
冷却材を核沸騰状態に導くとともに、核沸騰状態の保持
を行なうと、ノズル及びセーフエンドの内面の温度は、
核沸騰領域での熱流束の変化が大きいこと、つまり、高
い熱伝導性が得られることに基づいて温度変化が例えば
約７℃〜約20℃の範囲に抑制されて、温度変化が少なく
なる。"Action" The coolant interposed between the thermal sleeve and the nozzle and the safe end, which has a double pipe structure, is in a non-flowing state, but the temperature of the nozzle and the safe end is increased,
When the nucleate boiling state of the coolant is maintained and the nucleate boiling state is maintained, the temperature of the inner surface of the nozzle and safe end is
Due to the large change in the heat flux in the nucleate boiling region, that is, the high thermal conductivity being obtained, the temperature change is suppressed within a range of, for example, about 7 ° C. to about 20 ° C., and the temperature change is reduced.
核沸騰により生じた蒸気は、ノズルの基部方向への移動
により解放されるため、代りに冷却材が核沸騰部分に流
入する入れ替えがなされる。The steam generated by the nucleate boiling is released by the movement of the nozzle toward the base portion, so that the coolant is replaced by the coolant flowing into the nucleate boiling portion.
核沸騰温度を基準として、ノズル及びセーフエンドの内
外面に降伏点以上の熱応力を生じさせる温度差を与える
と、加熱部分の冷却後に、ノズル及びセーフエンドの熱
処理面に、圧縮方向の残留応力が付与されることにな
る。If a temperature difference that causes a thermal stress above the yield point is generated on the inner and outer surfaces of the nozzle and safe end based on the nucleate boiling temperature, residual stress in the compression direction will be applied to the heat treated surfaces of the nozzle and safe end after cooling the heated part. Will be given.
「実施例」 以下、本発明の好適な一実施例について、第１図〜第４
図に基づき説明する。[Example] Hereinafter, a preferred example of the present invention will be described with reference to Figs.
A description will be given based on the figure.
本実施例は、第１図に示すように、原子炉圧力容器１に
設けられ、サーマルスリーブ２が内部に溶接されたノズ
ル３およびセーフエンド４へ本発明を適用したもので、
前記セーフエンド４の内面にすなわちサーマルスリーブ
２と対向する面に残留圧縮応力を生じさせるようにした
ものである。In this embodiment, as shown in FIG. 1, the present invention is applied to a nozzle 3 and a safe end 4 which are provided in a reactor pressure vessel 1 and have a thermal sleeve 2 welded therein.
A residual compressive stress is generated on the inner surface of the safe end 4, that is, on the surface facing the thermal sleeve 2.
その詳細について説明すれば、前記ノズル３およびセー
フエンド４の外周に誘導加熱コイル等の加熱手段５を配
設するとともに、セーフエンド４の内部に、該セーフエ
ンド４とサーマルスリーブ２との間の間隙を含めて水等
の冷却材Ｗを充満させておく。Explaining in detail, a heating means 5 such as an induction heating coil is arranged on the outer periphery of the nozzle 3 and the safe end 4, and the space between the safe end 4 and the thermal sleeve 2 is provided inside the safe end 4. The coolant W such as water is filled up including the gap.
これより、前記加熱手段５を駆動して前記セーフエンド
４を変態温度以下まで加熱して、少なくともセーフエン
ド４と接触する冷却材Ｗを核沸騰させ、セーフエンド４
の内面との熱交換を行なわせる。なお、核沸騰により生
じた蒸気は膨張を伴うことになるが、第１図に示すサー
マルスリーブ２とノズル３の基部との間が、原子炉圧力
容器１の内部において解放状態となるために、蒸気が内
方（第１図にあって右方）に送り出されるとともに、代
りに冷却材が、核沸騰部分に下方または周方向から流入
して、両者の入れ替えがなされる。As a result, the heating means 5 is driven to heat the safe end 4 to a temperature not higher than the transformation temperature, and at least the coolant W that comes into contact with the safe end 4 is nucleate-boiled.
Heat exchange with the inner surface of the. Although the steam generated by the nucleate boiling is accompanied by expansion, the space between the thermal sleeve 2 and the base of the nozzle 3 shown in FIG. 1 is released inside the reactor pressure vessel 1, The steam is sent inward (to the right in FIG. 1) and, instead, the coolant flows into the nucleate boiling portion from below or in the circumferential direction, and the two are exchanged.
この核沸騰は、冷却材Ｗが水であるとき、前記セーフエ
ンド４の内面温度をTwとし、また、少なくとも該セーフ
エンド４の内面と接触する部分の冷却材Ｗの飽和温度を
Tsとすると、第２図に示すように、一般に、Tw−Tsが約
７℃〜約20℃の範囲Ａにおいて発生する。This nucleate boiling is such that, when the coolant W is water, the inner surface temperature of the safe end 4 is Tw, and at least the saturation temperature of the coolant W in contact with the inner surface of the safe end 4 is set to Tw.
Assuming Ts, as shown in FIG. 2, Tw-Ts generally occurs in the range A of about 7 ° C. to about 20 ° C.
そしてこの核沸騰が発生すると、前記セーフエンド４の
内面から冷却材Ｗへ伝達される熱量が急激に増加し、セ
ーフエンド４の内面が急激に冷却される。When this nucleate boiling occurs, the amount of heat transferred from the inner surface of the safe end 4 to the coolant W sharply increases, and the inner surface of the safe end 4 is rapidly cooled.
このような加熱および冷却作用によって、セーフエンド
４の内面側の温度上昇速度を冷却材Ｗの核沸騰により急
激に抑制しかつ外面側の温度上昇速度を維持して大きな
温度上昇速度差を生じさせ、この大きな温度上昇速度差
により、セーフエンド４の内外面間に温度差を生じさせ
るとともに、前述した加熱、冷却操作を所定時間継続し
て、前記温度差を第３図に示すように徐々に大きくし、
セーフエンド４の内外面間に所望の温度差ΔT1を生じさ
せる。With such heating and cooling action, the temperature increase rate on the inner surface side of the safe end 4 is rapidly suppressed by nucleate boiling of the coolant W, and the temperature increase rate on the outer surface side is maintained to cause a large temperature increase rate difference. This large temperature rise rate difference causes a temperature difference between the inner and outer surfaces of the safe end 4, and the heating and cooling operations described above are continued for a predetermined period of time to gradually increase the temperature difference as shown in FIG. Make it bigger,
A desired temperature difference ΔT 1 is generated between the inner and outer surfaces of the safe end 4.
該所望の温度差ΔT1は、セーフエンド４の両面間に相異
なる方向の降伏点以上の熱応力を生じさせるのに必要な
温度差であって、セーフエンド４の内外面間に生じる熱
応力と両面間に与えられる温度差ΔＴ（T0−Tw）との関
係を示す次の近似式によって導かれる。The desired temperature difference ΔT 1 is a temperature difference required to generate a thermal stress equal to or higher than the yield point in different directions between both surfaces of the safe end 4, and the thermal stress generated between the inner and outer surfaces of the safe end 4. And the temperature difference ΔT (T 0 −Tw) given between the two surfaces are derived by the following approximate expression.
ΔＴ＝±２（１−ν）σ/Eα ・・・・（１） 但し、 ΔT;セーフエンド内外面間の温度差 σ；セーフエンドの軸方向および周方向に生じる熱応力 E;ヤング係数 α；線膨張係数 ν；ポアソン比 なお、前記（１）式中負は圧縮熱応力、正は引っ張り熱
応力をそれぞれ示し、本実施例では、セーフエンド４の
内面側が引っ張り熱応力で外面側が圧縮熱応力である。ΔT = ± 2 (1-ν) σ / Eα (1) where ΔT: temperature difference between the inner and outer surfaces of the safe end σ; thermal stress generated in the axial and circumferential directions of the safe end E; Young's coefficient α Linear expansion coefficient ν; Poisson's ratio Note that in the above formula (1), negative indicates compressive thermal stress and positive indicates tensile thermal stress. In this embodiment, the inner surface of the safe end 4 is tensile thermal stress and the outer surface is compressive thermal stress. It is stress.
ここで、原子力プラント、特に原子炉圧力容器のセーフ
エンド４にあっては、主にオーステナイト系ステンレス
鋼が用いられているから、該オーステナイト系ステンレ
ス鋼の降伏点σ１＝20kg/mm2（降伏点は温度によって変
化するために、平均値を採用する）と、ヤング係数Ｅ＝
1.9×104kg/mm2と、ν＝0.3〜0.5とを前記（１）式に代
入すると、降伏点σ１以上の熱応力を生じさせるのに必
要な温度差ΔT1は約200℃以上であることが導かれる。Here, since the austenitic stainless steel is mainly used in the nuclear power plant, especially in the safe end 4 of the reactor pressure vessel, the yield point σ 1 = 20 kg / mm 2 (yield of the austenitic stainless steel is used. Since the points change with temperature, the average value is adopted) and Young's modulus E =
Substituting 1.9 × 10 4 kg / mm 2 and ν = 0.3 to 0.5 into the equation (1), the temperature difference ΔT 1 required to generate the thermal stress at the yield point σ 1 or more is about 200 ° C. or more. Is led to.
そして、前記セーフエンド４内を２〜2.5気圧としてセ
ーフエンド４内に冷却材Ｗ（水）を充満させた状態と
し、入熱量を200kwとしてセーフエンド４の加熱および
冷却を行なうと、加熱を開始してから約１分30秒後にお
いて前記セーフエンド４の内面温度が140℃となり、２
〜2.5気圧における冷却材Ｗの飽和温度Tsが約120℃であ
ることから、これらの温度差が前述した範囲Ａ内の約20
℃となって冷却材Ｗが核沸騰させられて、該セーフエン
ド４内面の温度が140℃に維持される。一方、前述した
加熱を継続すると、外面温度は継続して上昇させられ加
熱開始約５分後において378℃となされる。この結果、
前記セーフエンド４の内外面間に238℃の温度差を生じ
させ、これによって、第４図に曲線Ｂで示すような熱応
力＋σ２、−σ３を生じさせることができる。Then, the safe end 4 is heated to 2 to 2.5 atmospheres to fill the safe end 4 with the coolant W (water), and when the safe end 4 is heated and cooled with the heat input amount of 200 kw, heating is started. After about 1 minute and 30 seconds, the inner surface temperature of the safe end 4 becomes 140 ° C and 2
Since the saturation temperature Ts of the coolant W at about 2.5 atm is about 120 ° C., the temperature difference between them is about 20 within the range A described above.
C., the coolant W is nucleated and the temperature of the inner surface of the safe end 4 is maintained at 140.degree. On the other hand, if the above-mentioned heating is continued, the outer surface temperature is continuously raised and reaches 378 ° C. about 5 minutes after the start of heating. As a result,
A temperature difference of 238 [deg.] C. is generated between the inner and outer surfaces of the safe end 4, whereby the thermal stress + [sigma] 2 ,-[sigma] 3 as shown by the curve B in FIG. 4 can be generated.
このようにして、セーフエンド４の内外面間に温度差Δ
T1を与えたのちに、加熱を停止してセーフエンド４を常
温まで冷却する。この加熱を停止する時期は、前述した
温度差ΔT1を与えた直後に行なうことが効率的である。
その理由は、セーフエンド４に降伏点σ１以上の熱応力
を生じさせる温度差が得られれば十分であること、ま
た、セーフエンド４の内面温度Twと前述した飽和温度Ts
との差が前記範囲Ａを越えてしまうと、冷却材Ｗが核沸
騰から膜沸騰へ移行して第２図に示すように伝熱性が低
下してしまうこと等である。In this way, the temperature difference Δ between the inner and outer surfaces of the safe end 4 is
After giving T 1 , the heating is stopped and the safe end 4 is cooled to room temperature. It is efficient to stop the heating immediately after the temperature difference ΔT 1 is applied.
The reason is that it is sufficient to obtain a temperature difference that causes a thermal stress at the yield end σ 1 or more in the safe end 4, and the inner surface temperature Tw of the safe end 4 and the saturation temperature Ts described above.
If the difference exceeds the above range A, the coolant W shifts from nucleate boiling to film boiling, and the heat transfer property decreases as shown in FIG.
そして、セーフエンド４を常温まで冷却すると、温度の
低い内面側がまず冷却収縮させられたのちに、それに続
いて外面側が冷却収縮させられることによって内面側が
圧縮される。Then, when the safe end 4 is cooled to room temperature, the inner surface side having a low temperature is first shrunk by cooling, and then the outer surface side is subsequently shrunk by cooling, so that the inner surface side is compressed.
これによって第４図に曲線Ｃで示すように、内面側に残
留圧縮応力σ４（約25kg/mm2）を生じさせ、また、外面
側に残留引っ張り応力σ５（約18kg/mm2）を生じさせる
ことができる。Thus, as shown by curve C in FIG. 4, cause residual compressive stress sigma 4 (about 25 kg / mm 2) on the inner surface side and tensile stress remains in the outer surface side sigma 5 (about 18 kg / mm 2) Can be generated.
したがって、冷却材Ｗが滞留している場合でもセーフエ
ンド４の内面に残留圧縮応力を生じさせて、セーフエン
ド４の腐食疲労や腐食割れを有効に防止することができ
る。かつ、セーフエンド４内面の温度を冷却材Ｗの核沸
騰によりその飽和温度と所定の温度差に維持して、セー
フエンド４の内外面間の温度差を容易に制御することが
できる。Therefore, even if the coolant W is retained, residual compressive stress is generated on the inner surface of the safe end 4, and corrosion fatigue and corrosion cracking of the safe end 4 can be effectively prevented. Moreover, the temperature of the inner surface of the safe end 4 can be maintained at a predetermined temperature difference from its saturation temperature by the nucleate boiling of the coolant W, and the temperature difference between the inner and outer surfaces of the safe end 4 can be easily controlled.
一方、前記実施例においては、冷却材Ｗを滞留させた状
態で熱処理を行なった例について示したが、これに代え
て、冷却材Ｗを強制的に流動させながら熱処理を実施す
ることもでき、その一例について詳述すれば次のとおり
である。On the other hand, in the above-mentioned embodiment, the example in which the heat treatment is performed in the state where the coolant W is retained is shown, but instead of this, the heat treatment can be performed while the coolant W is forced to flow, An example thereof is described in detail below.
まず、前述した実施例と同様にセーフエンド４を加熱
し、セーフエンド４内に冷却材Ｗを強制的に流し込んで
該冷却材Ｗを核沸騰させるとともに前記加熱を停止する
ことにより、セーフエンド４の内面を急速に冷却して該
セーフエンド４の内外面間に、前記温度差ΔT1を与え
る。First, the safe end 4 is heated in the same manner as in the above-described embodiment, the coolant W is forcibly poured into the safe end 4 to nucleate the coolant W, and the heating is stopped. The inner surface of the safe end 4 is rapidly cooled to provide the temperature difference ΔT 1 between the inner and outer surfaces of the safe end 4.
次いで加熱を停止してセーフエンド４を常温まで冷却す
ると、前記実施例と同様にセーフエンド４の内面側に残
留圧縮応力を生じさせることができる。Next, when the heating is stopped and the safe end 4 is cooled to room temperature, residual compressive stress can be generated on the inner surface side of the safe end 4 as in the above embodiment.
ちなみに、セーフエンド４の加熱温度を約300℃とし、
流し込む冷却材Ｗの温度を40℃前後とし、かつ、その流
速を8m/secとして処理を行なうと、加熱停止後にセーフ
エンド４の外面側の温度が第５図中に曲線Ｄで示すよう
な変化をし、また、内面側の温度が同図中に曲線Ｅで示
すような変化をする。そして、冷却開始後（加熱停止
後）約0.6〜0,7秒後に、冷却材Ｗの核沸騰および強制対
流による冷却作用により、セーフエンド４内面の急激な
冷却がなされて、該セーフエンド４内面の温度が冷却材
Ｗの飽和温度近傍の120℃まで冷却され、続いて冷却材
Ｗの強制対流による冷却作用が継続されて、冷却開始後
約４秒で約202℃の温度差をセーフエンド４の内外面間
に与えることができる。この温度差は、セーフエンド４
へ前述した降伏点σ１以上の熱応力を生じさせるのに十
分な温度差である。この第５図の例において、冷却開始
直後にセーフエンド４の内面温度Twと冷却材Ｗの飽和温
度Tsとの温度差が膜沸騰を生じさせる温度差の270℃〜2
80℃となるが、冷却材Ｗの強制対流によって蒸気膜の生
成を不安定にして、核沸騰と同様な状態となす。By the way, the heating temperature of the safe end 4 is about 300 ℃,
When the temperature of the poured coolant W is set to around 40 ° C. and the flow rate is set to 8 m / sec, the temperature on the outer surface side of the safe end 4 changes after the heating is stopped as shown by a curve D in FIG. In addition, the temperature on the inner surface side changes as shown by the curve E in the figure. Then, about 0.6 to 0.7 seconds after the start of cooling (after the heating is stopped), the inner surface of the safe end 4 is rapidly cooled by the cooling action of the coolant W by nucleate boiling and forced convection, and the inner surface of the safe end 4 is cooled. Is cooled to 120 ° C, which is close to the saturation temperature of the coolant W, and then the cooling action by forced convection of the coolant W is continued. Can be given between the inner and outer surfaces of the. This temperature difference is safe end 4
The temperature difference is sufficient to cause the thermal stress above the yield point σ 1 described above. In the example of FIG. 5, the temperature difference between the inner surface temperature Tw of the safe end 4 and the saturation temperature Ts of the coolant W immediately after the start of cooling is 270 ° C. to 2 ° C. which is a temperature difference that causes film boiling.
Although the temperature is 80 ° C., forced convection of the coolant W destabilizes the formation of the vapor film, resulting in a state similar to nucleate boiling.
このような方法によれば、前述した実施例の核沸騰によ
る冷却作用に、冷却材Ｗの強制対流による熱伝達作用を
加え、内面側における熱交換効率を高めて、前述した温
度差を早期に発生させることができる。According to such a method, in addition to the cooling action by the nucleate boiling in the above-described embodiment, the heat transfer action by the forced convection of the coolant W is added to increase the heat exchange efficiency on the inner surface side, and the above-mentioned temperature difference is promptly obtained. Can be generated.
なお、前記実施例において、本発明をサーマルスリーブ
２を備えたセーフエンド４へ適用した例について説明し
たが、これに限定されるものではなく、通常の配管等へ
の適用も可能である。また、外面側に腐食因子が存在す
る場合には、加熱装置４や冷却材Ｗの配置関係を前述し
た位置と逆にすることにより、前記外面側へ容易に残留
圧縮応力を与えることができる。さらに、原子力プラン
トに用いられている管以外の管へ適用できることはもち
ろんである。In addition, although the example which applied this invention to the safe end 4 provided with the thermal sleeve 2 was demonstrated in the said Example, it is not limited to this, It is applicable also to normal piping etc. Further, when a corrosion factor exists on the outer surface side, the residual compressive stress can be easily applied to the outer surface side by reversing the positional relationship of the heating device 4 and the coolant W to the positions described above. Furthermore, it is needless to say that it can be applied to tubes other than those used in nuclear power plants.
「発明の効果」 以上説明したように、本発明に係わる金属管の熱処理方
法によれば、以下の効果を奏する。"Effects of the Invention" As described above, the heat treatment method for a metal tube according to the present invention has the following effects.
ノズル及びセーフエンドの内面の冷却材をその圧力と
飽和温度とに基づき核沸騰させ、核沸騰状態を保持して
ノズル及びセーフエンドの内面の温度変化を少なくしな
がら、ノズル及びセーフエンドの内外面に降伏点以上の
熱応力を生じさせる温度差を与えるものであるから、核
沸騰領域における熱流束の変化の割りに温度変化が少な
くなる現象を利用して、核沸騰温度を基準として加熱状
態の金属管の他の部分との間に発生させる温度差を正確
に設定して、熱処理面に、残留圧縮応力を確実にかつ高
い精度で付与することができる。The coolant on the inner surfaces of the nozzle and safe end is nucleated to boil based on its pressure and saturation temperature, and while maintaining the nucleate boiling state, the temperature changes on the inner surfaces of the nozzle and safe end are reduced, while the inner and outer surfaces of the nozzle and safe end are reduced. Since it gives a temperature difference that causes a thermal stress above the yield point, the phenomenon that the temperature change is small for the change in the heat flux in the nucleate boiling region is used to It is possible to accurately set the temperature difference generated between the metal tube and the other part of the metal tube and to reliably and highly accurately apply the residual compressive stress to the heat-treated surface.
冷却材が核沸騰時に蒸気化して膨張することに基づい
て、蒸気が圧力上昇により解放部分に逃げる現象と、冷
却材との密度差により上昇流となる現象とを利用し、蒸
気が核沸騰領域から流出して代りに冷却材が下方等から
流入する流れを生じさせ、サーマルスリーブとノズル及
びセーフエンドとが二重管構造をなして、流動状態とな
っていない部分にあっても、ノズル及びセーフエンドの
内面に残留圧縮応力を容易に付与することができる。Based on the fact that the coolant vaporizes and expands during nucleate boiling, the phenomenon that the vapor escapes to the open part due to the pressure increase and the phenomenon that the vapor becomes an upward flow due to the difference in density with the coolant are used. Flowing out of the coolant instead, and causing a flow of the coolant flowing in from below, etc., and the thermal sleeve and the nozzle and the safe end form a double pipe structure, and even if there is a portion that is not in a fluidized state, The residual compressive stress can be easily applied to the inner surface of the safe end.
冷却材が水である場合に、多量の蒸気が発生している
ことを知る等によって、核沸騰状態であるか否かの確認
が容易であり、核沸騰領域における広い範囲の供給熱量
とあいまって、熱処理時の作業性を向上させることがで
きる。When the coolant is water, it is easy to confirm whether it is in the nucleate boiling state by knowing that a large amount of steam is generated. The workability during heat treatment can be improved.
第１図〜第４図は本発明の一実施例を示すもので、第１
図は一実施例が適用された原子炉圧力容器のノズルを示
す縦断面図、第２図は冷却材の核沸騰を説明するための
温度と伝熱量との関係を示す図、第３図はノズル内外面
間の温度分布を示す図、第４図はノズル内外面間の熱応
力および残留応力の分布を示す図、第５図は本発明の他
の実施例を説明するためのノズル内外面の温度変化曲線
図である。 １……原子炉圧力容器、２……サーマルスリーブ、３…
…ノズル、４……セーフエンド、５……加熱装置、Ｗ…
…冷却材。1 to 4 show an embodiment of the present invention.
1 is a longitudinal sectional view showing a nozzle of a reactor pressure vessel to which an embodiment is applied, FIG. 2 is a view showing a relationship between temperature and heat transfer amount for explaining nucleate boiling of a coolant, and FIG. 3 is FIG. 4 is a diagram showing the temperature distribution between the inner and outer surfaces of the nozzle, FIG. 4 is a diagram showing the distribution of thermal stress and residual stress between the inner and outer surfaces of the nozzle, and FIG. 5 is an inner and outer surface of the nozzle for explaining another embodiment of the present invention. 3 is a temperature change curve diagram of FIG. 1 ... Reactor pressure vessel, 2 ... Thermal sleeve, 3 ...
… Nozzle, 4… Safe end, 5… Heating device, W…
… Coolant.
Claims (1)
れ、サーマルスリーブ（２）とノズル（３）及びセーフ
エンド（４）とが二重管構造をなしているとともに、こ
れらの間に非流動状態の冷却材が介在している場合のノ
ズル及びセーフエンドの内面を熱処理する方法であっ
て、ノズル及びセーフエンドの加熱によりこれらの内面
の冷却材をその圧力と飽和温度とに基づき核沸騰させ、
核沸騰時に生じた蒸気のノズルの基部方向への移動によ
り冷却材を核沸騰部分に流入させるとともに、核沸騰状
態を保持してノズル及びセーフエンドの内面の温度変化
を少なくしながらノズル及びセーフエンドの内外面に降
伏点以上の熱応力を生じさせる温度差を与えた後、ノズ
ル及びセーフエンドの加熱を中断して冷却することによ
り、ノズル及びセーフエンドの熱処理面に残留圧縮応力
を生じさせることを特徴とする金属管の熱処理方法。1. A thermal sleeve (2), a nozzle (3) and a safe end (4) which are arranged horizontally with respect to a reactor pressure vessel (1) form a double pipe structure, and these A method of heat-treating the inner surfaces of the nozzle and the safe end when a non-flowing coolant is interposed between the nozzle and the safe end.The heating of the nozzle and the safe end brings the inner surface of the coolant to its pressure and saturation temperature. Nucleate boiling based on
The coolant generated in the nucleate boiling moves toward the base of the nozzle to allow the coolant to flow into the nucleate boiling portion, while maintaining the nucleate boiling state to reduce the temperature change on the inner surface of the nozzle and the safe end, and the nozzle and the safe end. A residual compressive stress is generated on the heat treated surface of the nozzle and safe end by interrupting the heating of the nozzle and safe end after cooling by giving a temperature difference that causes a thermal stress above the yield point to the inner and outer surfaces of A heat treatment method for a metal tube, characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59150758A JPH0699754B2 (en) | 1984-07-20 | 1984-07-20 | Heat treatment method for metal tubes |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59150758A JPH0699754B2 (en) | 1984-07-20 | 1984-07-20 | Heat treatment method for metal tubes |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6130626A JPS6130626A (en) | 1986-02-12 |
| JPH0699754B2 true JPH0699754B2 (en) | 1994-12-07 |
Family
ID=15503768
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59150758A Expired - Lifetime JPH0699754B2 (en) | 1984-07-20 | 1984-07-20 | Heat treatment method for metal tubes |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0699754B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6223934A (en) * | 1985-07-24 | 1987-01-31 | Hitachi Ltd | Heat treatment of welded structure |
| JP2624649B2 (en) * | 1986-05-30 | 1997-06-25 | 株式会社東芝 | Method for improving residual stress in double metal tubes, etc. |
| JPS63171828A (en) * | 1987-01-12 | 1988-07-15 | Ishikawajima Harima Heavy Ind Co Ltd | How to improve residual stress in double metal pipes, etc. |
| JPH03219023A (en) * | 1990-01-24 | 1991-09-26 | Hitachi Ltd | Method and apparatus for strengthening pressure proof of metal-made hollow structure, and pressure proof hollow structure made with this method and method for using the same under pressure proof condition |
| US8514998B2 (en) | 2005-01-31 | 2013-08-20 | Hitachi-Ge Nuclear Energy, Ltd. | Induction heating stress improvement |
| JP4847885B2 (en) * | 2007-02-02 | 2011-12-28 | 日立Ｇｅニュークリア・エナジー株式会社 | Method for reducing residual stress in piping |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5338246A (en) * | 1976-09-21 | 1978-04-08 | Toshiba Corp | Amplifier circuit |
-
1984
- 1984-07-20 JP JP59150758A patent/JPH0699754B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6130626A (en) | 1986-02-12 |
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