JPH0360888B2 - - Google Patents
Info
- Publication number
- JPH0360888B2 JPH0360888B2 JP2779583A JP2779583A JPH0360888B2 JP H0360888 B2 JPH0360888 B2 JP H0360888B2 JP 2779583 A JP2779583 A JP 2779583A JP 2779583 A JP2779583 A JP 2779583A JP H0360888 B2 JPH0360888 B2 JP H0360888B2
- Authority
- JP
- Japan
- Prior art keywords
- sec
- heating
- temperature
- electric resistance
- cooling
- 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
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- 238000001816 cooling Methods 0.000 claims description 31
- 238000003466 welding Methods 0.000 claims description 19
- 238000010438 heat treatment Methods 0.000 claims description 16
- 238000011282 treatment Methods 0.000 claims description 12
- 229910000859 α-Fe Inorganic materials 0.000 claims description 11
- 229910000831 Steel Inorganic materials 0.000 claims description 7
- 239000010959 steel Substances 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 238000000034 method Methods 0.000 claims description 3
- 239000012535 impurity Substances 0.000 claims description 2
- 230000007704 transition Effects 0.000 description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 230000000694 effects Effects 0.000 description 5
- 239000010953 base metal Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000008236 heating water Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 229910011208 Ti—N Inorganic materials 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000005469 granulation Methods 0.000 description 1
- 230000003179 granulation Effects 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000001000 micrograph Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000000879 optical micrograph Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/50—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for welded joints
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
Description
本発明は電縫溶接部が母材部と同程度に低温靭
性のすぐれた高張力電縫鋼管の製造方法に関する
ものである。
従来の製造方法では母材部はコントロールドロ
ーリング、制御冷却により微細なフエライトがで
き、低温靭性のすぐれたものが得られるが、電縫
溶接部は圧延組織が消失し、粗大な鋳造組織が形
成され、また溶接から急冷されることによりクリ
ーンフエライトが出来ないため低温靭性が悪くな
るという欠点を有していた。
本発明は上記の欠点を有利に解消するものであ
り、その要旨とするところはＣ：0.01〜0.08％、
Mn1.5％、Si0.5％、Ｐ0.03％、Ｓ0.008
％、Ti0.04％、Nb：0.001〜0.050％、Ｖ：
0.001〜0.050％、Ｎ0.010％、脱酸度を調整する
ことにより残存するsolAl、残部Fe及び不可避的
不純物よりなる素材鋼板を用い電縫溶接し、その
後電縫溶接部を790℃〜1050℃で５秒以上加熱し、
750℃〜950℃の温度から30℃／sec〜150℃／sec
で急冷し、電縫溶接部を微細アシキユラーフエラ
イト組織にしたのち、電縫溶接部を400℃〜700℃
で１分以内加熱してストレスリリーフ処理を行う
ことを特徴とする低温靭性のすぐれた高張力電縫
鋼管の製造方法である。
即ち本発明は素材の成分、電縫溶接した後の電
縫溶接部の加熱条件とその後の冷却条件を制限
し、更にストレスリリーフ処理を行うことにより
電縫溶接部が母材部と同程度に低温靭性のすぐれ
た電縫鋼管を製造することを可能としたもので極
めて有利なものである。
次に本発明について詳細に説明する。
先ず素材の成分について述べるとＣについては
結晶粒微細化による靭性向上のため、0.01〜0.08
％とし、強度の点については他の元素にて補な
う。
Mnは1.5％より多量の場合、溶接性の点から悪
影響を及びすため1.5％以下が望ましくなる。
Siは強度を保たせる上で必要であるが0.5％よ
り多量の場合、電縫溶接部でのペネトレーターの
発生が容易となるため、0.5％以下とする。
Ｐは偏析により悪影響を及ぼすのでＰは0.03％
以下とする。
ＳについてもMnSの長く伸ばされた介在物に
より靭性劣化するため低い方が望ましく0.008％
以下とする。
TiとＮは微細なTi−Ｎとして析出し、この微
細なTi−Ｎが溶接部の組織を微細化させ、靭性
を向上させる点からTiは0.04％以下、Ｎは0.010
％以下含有する。
Nb，Ｖにおいては強度確保上必要でNbは
0.001〜0.050％の範囲とし、Ｖは0.001〜0.050％
の範囲とする。
なお素材はAlで脱酸し、その際残存する通常
の量のAlを含有する。
Ｂについては必須元素ではないが、0.0002〜
0.0025％の範囲で添加するとより靭性が向上し好
ましいものである。
次に電縫溶接後の加熱、冷却条件について述べ
る。本発明は電縫溶接部のみを電縫溶接後790℃
〜1050℃の範囲で５秒以上加熱するものであり、
これにより電縫溶接において生成された鋳造組織
を破壊する。加熱温度が790℃未満では完全に鋳
造組織を破壊するまでには至らず、1050℃超では
結晶粒の粗大化が起こり好ましくない。
又加熱時間が５秒未満では溶接部の鋳造組織を
完全に破壊することができず好ましくない。
冷却条件についても冷却開始温度を750℃〜950
℃とするもので、その冷却速度も30℃／sec〜150
℃／secとするものである。その限定理由はAr3
変態点を通過する際の速度が30℃／sec以上でな
いと、整粒均一化が行われず、その上限も150
℃／secが好ましい。又、温度についてもAr3変
態点近傍の750℃未満になると結晶粒の整粒均一
化が行われない。逆に、950℃超から水冷を開始
すると低温で開始するのと同様に組織の改善効果
が認められない。
このような加熱、冷却条件について、本発明者
等は種々の実験を行つた。第１図は電縫溶接後、
700℃〜1100℃の範囲において、５秒以上加熱し
た後、冷却速度を５℃／secと50℃／secと変えて
低温靭性について調べた結果を示している。
その結果によれば冷却速度が50℃／secのもの
は５℃／secに比べ遷移温度（vTrS）は低くなり
低温靭性は向上することが明らかとなつた。
第２図は冷却開始温度750℃〜950℃の範囲にお
いて冷却速度の変化による遷移温度（vTrS）の
値をＣの含有量を変えて示したもので、Ｃ：0.08
％の含有量においては30℃／sec〜150℃／secの
範囲において、低温靭性が良くなつており、Ｃ：
0.15％の含有量においてはあまり良好な結果は得
られない。
第３図はＣ：0.08％の成分系における電縫溶接
後の光学顕微鏡写真（400倍）であり、電縫溶接
後、970℃で５秒加熱後、５℃／sec空冷した時の
ａ溶接部、ｂ母材部と50℃／sec水冷した時のｃ
溶接部の組織を示す。
なおａはvTrS＝−20℃、フエライト粒度No.＝
10.9、ｂはvTrS＝−80℃、フエライト粒度No.＝
12.8、ｃはvTrS＝−40℃、フエライト粒度No.＝
12.6である。
即ち第３図から明らかなように電縫溶接後の加
熱、冷却条件を制御する本発明によればポストノ
ルマ（５℃／sec空冷）の粗大なフエライト粒に
比べ超微細なフエライト組織になり、母材部並の
フエライト粒度となり、低温靭性が良好となる。
第４図は本発明の実施による溶接部の硬度と遷
移温度の変化の状態を示している。領域Ａは本発
明の加熱−水冷およびストレスリリーフ処理を全
く行つていない場合を示している。領域Ｂは加熱
−水冷処理を行つた場合を示しており、溶接部の
硬度は上昇するがフエライトの細粒化により、遷
移温度は低下する。矢印ａは加熱−水冷処理の効
果を示している。なお、領域Ｂに移る領域Ａの範
囲は遷移温度が−20℃で溶接部硬度Hv（500ｇ）
が180〜210の範囲である。また、領域Ｃは領域Ｂ
のものにストレスリリーフ処理を行つた場合であ
り、矢印ｂはストレスリリーフ処理の効果を示し
ている。ストレスリリーフ処理により溶接部は硬
度および遷移温度が共に低下する。
以上のように本発明は電縫溶接後の加熱冷却条
件を790℃〜1050℃で５秒以上加熱し、冷却開始
温度を750℃〜950℃から30℃／sec〜150℃／sec
の冷却速度で水冷を行ない、そののちストレスリ
リーフを行うことにより溶接部でも低温靭性の良
性な電縫鋼管が得られるものでその効果は極めて
大である。
400〜700℃で１分以内加熱してストレスリリー
フ処理を行う理由は400℃未満はストレスリリー
フ効果がないので、400℃以上必要であり、700℃
超であると粒が粗大化するため、特にAc3点を越
えると粗大化が急速に進行するため、Ac3点以下
でストレスリリーフを行なう必要がある。
また時間はストレスリリーフが行なわれるでき
るだけ短かい時間がよく、１分以内が望ましい。
１分超になると粗大化しはじめ、低温靭性に望ま
しくない。
次に本発明を実施する設備の概略を第５図に示
す。図中符号１は電縫溶接部、２は溶接ロール、
３はNo.１ポストノルマライザー、４はNo.２ポスト
ノルマライザー、５はNo.３ポストノルマライザー
で、その後６の水冷ゾーンを設置し、任意に冷却
開始温度、水冷冷却速度を設定するものである。
また、符号７はストレスリリーフ処理の加熱炉で
ある。図中矢印で示す進行方向に管Ｐは送られ、
順次加熱、冷却される。
次に本発明の実施例を表１に示す。
The present invention relates to a method for producing a high-strength electric resistance welded steel pipe in which the electric resistance welded portion has excellent low-temperature toughness comparable to that of the base metal portion. In conventional manufacturing methods, fine ferrite is formed in the base metal through controlled drawing and controlled cooling, resulting in a product with excellent low-temperature toughness, but in the electric resistance welded part, the rolled structure disappears and a coarse cast structure is formed. Moreover, since clean ferrite cannot be formed due to rapid cooling after welding, low-temperature toughness deteriorates. The present invention advantageously solves the above-mentioned drawbacks, and its gist is that C: 0.01-0.08%;
Mn1.5%, Si0.5%, P0.03%, S0.008
%, Ti0.04%, Nb: 0.001-0.050%, V:
0.001~0.050%, N0.010%, remaining solAl by adjusting the degree of deoxidation, residual Fe, and unavoidable impurities are used for electric resistance welding, and then the electric resistance welded part is heated to 790℃~1050℃. Heat for more than 5 seconds,
30℃/sec to 150℃/sec from a temperature of 750℃ to 950℃
After cooling the ERW welded part to a fine axial ferrite structure, heat the ERW welded part to 400℃~700℃.
This is a method for manufacturing high-strength electric resistance welded steel pipes with excellent low-temperature toughness, which is characterized by performing stress relief treatment by heating within 1 minute. In other words, the present invention limits the composition of the material, the heating conditions for the ERW welded part after ERW welding, and the subsequent cooling conditions, and further performs stress relief treatment to make the ERW welded part as similar to the base material. This is extremely advantageous because it makes it possible to manufacture electrical resistance welded steel pipes with excellent low-temperature toughness. Next, the present invention will be explained in detail. First, regarding the ingredients of the material, C is 0.01 to 0.08 to improve toughness through grain refinement.
%, and the strength is supplemented with other elements. If the amount of Mn is more than 1.5%, it will have an adverse effect on weldability, so it is preferable that the amount is 1.5% or less. Si is necessary to maintain strength, but if the amount is more than 0.5%, penetrators will easily occur in the electric resistance welding area, so it should be kept at 0.5% or less. P has a negative effect due to segregation, so P is 0.03%.
The following shall apply. As for S, the longer MnS inclusions cause toughness deterioration, so a lower value is preferable, 0.008%.
The following shall apply. Ti and N precipitate as fine Ti-N, and this fine Ti-N refines the structure of the weld and improves toughness, so Ti is less than 0.04% and N is 0.010%.
Contains less than %. Nb and V are necessary to ensure strength, and Nb is
The range is 0.001 to 0.050%, and V is 0.001 to 0.050%.
The range shall be . The material is deoxidized with Al and contains the usual amount of Al that remains. B is not an essential element, but 0.0002~
It is preferable to add it in a range of 0.0025% because it further improves toughness. Next, the heating and cooling conditions after electric resistance welding will be described. In this invention, only the ERW welding part is heated to 790℃ after ERW welding.
It is heated in the range of ~1050℃ for 5 seconds or more,
This destroys the cast structure generated during electric resistance welding. If the heating temperature is less than 790°C, the cast structure will not be completely destroyed, and if it exceeds 1050°C, the crystal grains will become coarse, which is undesirable. Moreover, if the heating time is less than 5 seconds, the cast structure of the welded part cannot be completely destroyed, which is not preferable. Regarding cooling conditions, the cooling start temperature is 750℃~950℃.
℃, and the cooling rate is 30℃/sec to 150℃.
℃/sec. The reason for this limitation is Ar 3
If the speed of passing through the transformation point is not 30°C/sec or higher, granulation will not be uniform, and the upper limit is 150°C/sec or higher.
C/sec is preferred. Furthermore, when the temperature is lower than 750° C. near the Ar 3 transformation point, the crystal grains are not uniformly sized. On the other hand, if water cooling is started at a temperature higher than 950°C, no improvement in the structure will be observed, as is the case if water cooling is started at a lower temperature. The present inventors conducted various experiments regarding such heating and cooling conditions. Figure 1 shows after electric resistance welding.
The results show the results of investigating low-temperature toughness by heating in the range of 700°C to 1100°C for 5 seconds or more and then changing the cooling rate to 5°C/sec and 50°C/sec. The results revealed that a cooling rate of 50°C/sec lowers the transition temperature (vTrS) and improves low-temperature toughness compared to 5°C/sec. Figure 2 shows the transition temperature (vTrS) due to changes in cooling rate in the cooling start temperature range of 750°C to 950°C, with the C content changed; C: 0.08
% content, the low-temperature toughness is improved in the range of 30°C/sec to 150°C/sec, and C:
Not very good results are obtained at a content of 0.15%. Figure 3 is an optical micrograph (400x) after electric resistance welding in a component system with C: 0.08%. Part, b When cooled with water at 50°C/sec with base metal part c
The structure of the weld is shown. Note that a is vTrS = -20℃, ferrite particle size No. =
10.9, b is vTrS = -80℃, ferrite particle size No. =
12.8, c is vTrS = -40℃, ferrite particle size No. =
It is 12.6. That is, as is clear from FIG. 3, according to the present invention, which controls the heating and cooling conditions after electric resistance welding, the ferrite structure becomes ultra-fine compared to the coarse ferrite grains of post-normal (5°C/sec air cooling). It has a ferrite grain size comparable to that of the base metal, and has good low-temperature toughness. FIG. 4 shows the changes in hardness and transition temperature of the weld according to the practice of the present invention. Region A shows the case where the heating-water cooling and stress relief treatments of the present invention were not performed at all. Region B shows the case where the heating-water cooling treatment is performed, and although the hardness of the weld increases, the transition temperature decreases due to the refinement of the ferrite grains. Arrow a indicates the effect of heating-water cooling treatment. In addition, in the range of region A that moves to region B, the transition temperature is -20℃ and the weld hardness Hv (500g)
ranges from 180 to 210. Also, area C is area B
This is a case where stress relief treatment was applied to the object, and arrow b indicates the effect of stress relief treatment. The stress relief treatment reduces both the hardness and transition temperature of the weld. As described above, the present invention has heating and cooling conditions after electric resistance welding: heating at 790°C to 1050°C for 5 seconds or more, and adjusting the cooling start temperature from 750°C to 950°C to 30°C/sec to 150°C/sec.
By performing water cooling at a cooling rate of , followed by stress relief, it is possible to obtain a benign ERW steel pipe with low-temperature toughness even at the welded part, which is extremely effective. The reason why stress relief treatment is performed by heating at 400 to 700℃ for less than 1 minute is because there is no stress relief effect below 400℃, so 400℃ or higher is required, and 700℃
If it is too high, the grains will become coarse, and especially if the Ac value exceeds 3 points, the coarsening will proceed rapidly, so it is necessary to carry out stress relief at an Ac value of 3 points or less. Moreover, the time is preferably as short as possible for stress relief to be performed, preferably within 1 minute.
If it exceeds 1 minute, it will begin to coarsen, which is not desirable for low temperature toughness. Next, FIG. 5 shows an outline of the equipment for carrying out the present invention. In the figure, code 1 is an electric resistance welding part, 2 is a welding roll,
3 is the No. 1 post normalizer, 4 is the No. 2 post normalizer, 5 is the No. 3 post normalizer, and then the water cooling zone 6 is installed, and the cooling start temperature and water cooling cooling rate can be set arbitrarily. It is.
Further, reference numeral 7 is a heating furnace for stress relief treatment. The pipe P is sent in the direction of movement shown by the arrow in the figure,
It is heated and cooled sequentially. Next, Table 1 shows examples of the present invention.
【表】【table】
【表】
第１表から明らかなように本発明によれば電縫
鋼管の遷移温度を従来のものに比べて20℃以上低
下させることができ、低温靭性は著しく向上す
る。[Table] As is clear from Table 1, according to the present invention, the transition temperature of the electric resistance welded steel pipe can be lowered by 20°C or more compared to the conventional pipe, and the low-temperature toughness is significantly improved.
第１図は電縫溶接後の加熱温度と遷移温度との
関係を示す図、第２図は冷却速度と遷移温度との
関係を示す図、第３図ａ，ｂ，ｃはＣ：0.08％の
成分系における電縫溶接後の顕微鏡写真（400
倍）、第４図は本発明の方法により溶接部の硬度
と遷移温度が変化する状態を示す図、および第５
図は本発明を実施する設備の概略図である。
１…電縫溶接部、２…溶接ロール、３…No.１ポ
ストノルマライザー、４…No.２ポストノルマライ
ザー、５…No.３ポストノルマライザー、６…水冷
ゾーン、７…ストレスリリーフ処理用加熱炉。
Figure 1 is a diagram showing the relationship between heating temperature and transition temperature after electric resistance welding, Figure 2 is a diagram showing the relationship between cooling rate and transition temperature, Figure 3 a, b, and c are C: 0.08% Micrograph after electric resistance welding in the component system (400
Figure 4 is a diagram showing how the hardness and transition temperature of the weld zone change according to the method of the present invention;
The figure is a schematic diagram of the equipment implementing the invention. 1...Erw welding part, 2...Welding roll, 3...No.1 post normalizer, 4...No.2 post normalizer, 5...No.3 post normalizer, 6...water cooling zone, 7...for stress relief treatment heating furnace.
Claims (1)
Ｐ0.03％、Ｓ0.008％、Ti0.04％、Nb：
0.001〜0.050％、Ｖ：0.001〜0.050％、Ｎ0.010
％、脱酸度を調整することにより残存するsolAl、
残部Fe及び不可避的不純物よりなる素材鋼板を
用い電縫溶接し、その後電縫溶接部を790℃〜
1050℃で５秒以上加熱し、750℃〜950℃の温度か
ら30℃／sec〜150℃／secで急冷し、電縫溶接部
を微細アシキユラーフエライト組織にしたのち、
400℃〜700℃で１分以内加熱してストレスリリー
フ処理を行うことを特徴とする低温靭性のすぐれ
た高張力電縫鋼管の製造方法。1 C: 0.01-0.08%, Mn1.5%, Si0.5%,
P0.03%, S0.008%, Ti0.04%, Nb:
0.001-0.050%, V: 0.001-0.050%, N0.010
%, remaining solAl by adjusting the degree of deacidification,
ERW welding is performed using a steel plate with the remainder Fe and unavoidable impurities, and then the ERW welded part is heated to 790℃~
After heating at 1050℃ for 5 seconds or more and rapidly cooling from a temperature of 750℃ to 950℃ at a rate of 30℃/sec to 150℃/sec to create a fine axial ferrite structure in the electric resistance weld,
A method for manufacturing a high-tensile resistance welded steel pipe with excellent low-temperature toughness, characterized by performing stress relief treatment by heating at 400°C to 700°C for less than 1 minute.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2779583A JPS59153839A (en) | 1983-02-23 | 1983-02-23 | Production of high tension electric welded steel pipe having excellent low temperature toughness |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2779583A JPS59153839A (en) | 1983-02-23 | 1983-02-23 | Production of high tension electric welded steel pipe having excellent low temperature toughness |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59153839A JPS59153839A (en) | 1984-09-01 |
| JPH0360888B2 true JPH0360888B2 (en) | 1991-09-18 |
Family
ID=12230905
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2779583A Granted JPS59153839A (en) | 1983-02-23 | 1983-02-23 | Production of high tension electric welded steel pipe having excellent low temperature toughness |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59153839A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013153819A1 (en) | 2012-04-13 | 2013-10-17 | Ｊｆｅスチール株式会社 | High-strength thick-walled electric-resistance-welded steel pipe having excellent low-temperature toughness, and method for manufacturing same |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61238940A (en) * | 1985-04-12 | 1986-10-24 | Nippon Steel Corp | Low-temperature tough hardening steel excelling in toughness in weld zone |
| JPS61270338A (en) * | 1985-05-24 | 1986-11-29 | Nippon Steel Corp | Production of seam welded steel pipe having excellent stress corrosion cracking resistance in seam welded part |
| JPH0610309B2 (en) * | 1985-06-07 | 1994-02-09 | 日新製鋼株式会社 | Post-heat treatment method for welding heat affected zone of ERW steel pipe |
| JPS621842A (en) * | 1985-06-26 | 1987-01-07 | Nippon Steel Corp | Tough, high tension steel having superior toughness in weld zone |
| JPS62180034A (en) * | 1986-02-04 | 1987-08-07 | Kawasaki Steel Corp | Ti-type uoe steel tube excellent in heat treatment characteristics in weld zone |
| JPS62202049A (en) * | 1986-02-28 | 1987-09-05 | Nippon Steel Corp | Electric welded tube having high resistance to selective corrosion in electric weld zone and its production |
| JPS62274049A (en) * | 1986-05-22 | 1987-11-28 | Nippon Steel Corp | Continuously-cast steel for resistance welded tube excellent in sour resistance and toughness at low temperature |
-
1983
- 1983-02-23 JP JP2779583A patent/JPS59153839A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013153819A1 (en) | 2012-04-13 | 2013-10-17 | Ｊｆｅスチール株式会社 | High-strength thick-walled electric-resistance-welded steel pipe having excellent low-temperature toughness, and method for manufacturing same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59153839A (en) | 1984-09-01 |
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