JPS6147884B2 - - Google Patents
Info
- Publication number
- JPS6147884B2 JPS6147884B2 JP12199883A JP12199883A JPS6147884B2 JP S6147884 B2 JPS6147884 B2 JP S6147884B2 JP 12199883 A JP12199883 A JP 12199883A JP 12199883 A JP12199883 A JP 12199883A JP S6147884 B2 JPS6147884 B2 JP S6147884B2
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- welded
- hot
- steel
- electric resistance
- 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
Links
- 229910000831 Steel Inorganic materials 0.000 claims description 40
- 239000010959 steel Substances 0.000 claims description 40
- 239000011572 manganese Substances 0.000 claims description 13
- 238000004519 manufacturing process Methods 0.000 claims description 12
- 229910052799 carbon Inorganic materials 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 claims description 6
- 238000005098 hot rolling Methods 0.000 claims description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 5
- 229910052748 manganese Inorganic materials 0.000 claims description 5
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 2
- 239000012535 impurity Substances 0.000 claims 1
- 238000005096 rolling process Methods 0.000 claims 1
- 238000003466 welding Methods 0.000 description 8
- 239000008186 active pharmaceutical agent Substances 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 238000005336 cracking Methods 0.000 description 6
- 238000010606 normalization Methods 0.000 description 5
- 238000001816 cooling Methods 0.000 description 4
- 238000005520 cutting process Methods 0.000 description 4
- 238000002844 melting Methods 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- 238000004804 winding Methods 0.000 description 4
- 238000009749 continuous casting Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000010953 base metal Substances 0.000 description 2
- 239000000498 cooling water Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000009864 tensile test Methods 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- 229910000677 High-carbon steel Inorganic materials 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000003749 cleanliness Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000003129 oil well Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 102200003959 rs11556986 Human genes 0.000 description 1
- 102220005308 rs33960931 Human genes 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 229910000859 α-Fe Inorganic materials 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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
-
- 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
- C21D9/08—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes
Description
（産業上の利用分野）
本発明は高炭素、高Mn電縫鋼管の製造方法に
関する。
（従来技術）
高炭素鋼電縫鋼管として、従来からJIS S40C
〜S50Cの電縫鋼管が商品化されているが、高炭
素、高Mn（特にMn1％以上）の電縫鋼管は極め
て少なく、シームレスミルからの供給が大半を占
めていた。
この理由として、C0.40〜0.50％、Mn1.3〜1.6
％の高炭素、高Mn鋼では、特に熱延コイルの強
度が高いため成形が困難で、ミルパワーの増大を
伴い、また、これら焼入性の高い成分は、特に電
縫ミルで急熱急冷を受けた溶接部の硬度が著しく
高くなるための溶接部に割れが発生したり、定尺
切断用のカツトオフの刃の損傷が激しく、刃の寿
命が短いため、時々ミルを停止したりするため造
管歩留が著しく低下する等により品質上、コスト
上問題があり、電縫ミルでは工業的に生産できな
かつた。この対策として、特に中径電縫ミルでは
造管後、溶接部のみをポストアニーラー又はシー
ムアニーラーと呼ばれる局部加熱用の設備で焼鈍
又は焼準して製造していた。しかし、ポストアニ
ーラーを持たない電縫ミルでは製造困難であつ
た。
一方品質面においては電縫ミルで溶接部のみを
ポストアニーラーで焼鈍した鋼管は、円周方向の
部位（位置）によつて機械的性質が異なり、また
鋼管の長手方向の機械的性質も不均一なため、例
えば圧潰特性、耐食性等の品質面で問題があつ
た。
（発明の目的）
以上の問題点を種々検討研究した結果、本発明
は成分系、熱延コイルの強度、造管方法、
鋼管全体の焼準、等の検討によつてポストアニー
ラー設備をもたない電縫ミルでも工業的生産が可
能な高炭素、高Mn電縫鋼管の製造方法を提供す
ることを目的とする。
（発明の構成・作用）
本発明の要旨とするところは、C0.38〜0.42
％、Si0.20〜0.30％、Mn1.35〜1.65％、P0.025％
以下、S0.010％以下、T.Al 0.010〜0.035％、
Ti0.010〜0.030％、N0.0060％以下で残部の大部
分がFeで、不可避的不純物からなるスラブを仕
上温度850〜920℃、捲取温度700〜800℃の熱延条
件で熱延鋼板としたのち、該熱延鋼板を管状体に
成形し、該管状体のエツジ部を加熱して溶接し、
鋼管としたのち750〜950℃の温度に５〜10分加熱
して、焼準することを特徴とする高炭素、高マン
ガン電縫鋼管の製造方法である。
以下、本発明について、API、Ｋ−55油井用電
縫鋼管の例をもつて詳細説明する。
まず、鋼管の成分であるが、Ｃは0.38％未満で
は、CrとはＢを含有し、焼入性の高めない限
り、API、Ｋ−55の引張強度66.8Kg/mm2以上の規
格を満足しない。Ｃは多量に添加すると引張強度
向上に効果的であるが、Ｃが0.42％を超えると上
述した如く、造管後溶接部割れが発生するため好
ましくない。
Siは脱酸剤及び強度向上元素として0.20％以上
必要であり、強度面から含有量は多いほど好まし
いが、0.30％を超えると熱延工程で鋼板表面に、
しま状スケールが発生するため、0.20〜0.30％に
規定した。
MnはCeq（Ｃ＋1/5Mn）が0.63以上ないと、焼
準後の機械的性質、特に引張強度が、66.8Kg/mm2
以上を満足しない。従つて、Ｃ量の下限である
0.38％のとき、Mnの最低量は1.35％となる。Mn
はその量が多いほど、機械的性質が向上するが、
1.65％を超えと、偏析しやすい元素のため肉厚
中央部に巨大な偏析帯が現われること、連続鋳
造でスラブ割れが発生しやすいこと、合金鋼成
分扱いとなり、輸出時関税率が高くなる等溶製
上、コスト上好ましくない。
Ｐは粒界に偏析しやすく、扁平値を低下せしめ
ること、又連続鋳造で製造する場合、溶製温度を
高くなるため復リンが起るため、上限のみを
0.025％に規定した。Ｐは低いほどよいが、Ｐを
0.010％以下にする場合は、例えば2slag−L.F.
（レードルフアネス）等の特別な工程を要する。
Ｓは靭性、扁平値の低下等弊害元素の一つであ
るが、0.010％以下ではその影響は小さいことと
工業的に製造可能であることからその上限のみを
規定した。
T.Alは焼準後のフエライト結晶粒度を細粒に
すること及び脱酸剤として必要であるが、細粒に
必要なsol.Alとして最低0.006％以上必要であ
り、このときT.AlのうちAl含有量が0.010〜0.015
％のときsol.AlとInsol.Alの分配（比率）は６：
４であるため、下限のT.Alを0.010％とした。T.
Alは0.035％を超えるとアルミナ介在物が多く
なること、細粒効果が飽和すること、コスト
が高くなる等により上限を0.035％迄とした。
本発明の鋼管素材（スラブ）を連続鋳造で製造
する場合、スラブ割れ防止のため、Tiを使用す
る。スラブ割れは、Ｃ、Mn量とも関連するが、
主としてＮに起因するとされ、ＮをTiで固定す
ることによりスラブ割れを防止する。この場合、
熱延前のスラブ加熱および鋼管焼準によつて生成
するsol.Al、即ちAlNを考慮すると鋼中ＮはAlと
Tiの化合物となる。従つてAlと結合するＮは
0.0031％（sol.Al 0.006×Ｎ／Ａｌ→（0.006×１４／
２７）→
0.0031％）であり、残りのＮがTiと結合するた
め、これに必要なTiは0.010となる。
（0.006−0.0031）×Ｔｉ／Ｎ
→（0.0029×４８／１４）→0.010）
又、Ti単独でＮ全部を固定する場合、Tiは
0.021％（0.006・Ｔｉ／Ｎ→0.006×４８／１４→0.021
）必要と
なる。溶製時においては、AlをTiより先に投入
するため、Ti単独で固定することはない。従つ
てTiの下限は0.010％でよい。一方、Tiは0.030％
を超えると、TiN、TiC、TiS、TiCN等を形成す
るため介在物が多くなり、鋼の清浄度を悪くする
ため好ましくない。
Ｎはスラブ割れ防止のため少量ほど好ましい
が、溶製上経済性を考慮すると0.0060％以下が好
ましい。
次に本発明成分の素材（スラグ）を熱延でコイ
ルに圧延する場合、仕上温度850〜920℃、捲取温
度700〜800℃の熱延条件で熱延コイルを製造す
る。
仕上温度850℃未満、捲取温度700℃未満ではコ
イルの強度（引張強さ）が60Kg/mm2より大巾に高
くなるため、電縫ミルで成形時に大パワーを要
し、又、スプリングバツクによる溶接部割れが発
生しやすいため好ましくない。
一方、仕上温度920℃および捲取温度800℃を超
える条件では、コイルの強度は著しく低下する
が、コイル表面のスケール疵、冷却水量を押える
ためロール寿命を低下する等から好ましくない。
本発明の成分鋼を本発明の熱延条件で熱間圧延
として、熱延鋼板としたのち、該熱延鋼板を管状
体に成形し、該管状体のエツジ部を加熱して溶接
し、鋼管としたのち、次いで連続して内、外面の
溶接ビードを切削したのち、鋼管全体を室温程度
まで冷却し、定形ロール群で所定の寸法精度に仕
上げた後、切断装置（カツトオフともいう）で切
断し、スキツドに移送する。
この製造ラインにおいて、鋼管を冷却するた
め、溶接部は急冷を受けて非溶接部に比較し、著
しく硬くなる。
次に熱処理方法について説明する。
通常、特にＣ、Mnが多く含有されると溶接部
は硬くなり、定形ロールで鋼管の外径および真円
度を向上させるとき、適当な外径リダクシヨンを
与えるため、溶接部から割れが発生し、切断工程
でカツトオフの刃の寿命が低下する。
この対策として、本発明者らは、特公昭55−
8565号公報記載の発明思想を応用してこの問題を
解決した。
即ち電縫溶接鋼管の冷却方法において、溶接点
後方で鋼管溶接部の外表面をMs点直上近傍の温
度まで冷却し、鋼管溶接部の温度がMs点より高
い範囲内で溶接部肉厚方向にほぼ均一になつたの
ち、直ちに鋼管全体を室温まで冷却する方法であ
る。
具体的には、溶接部外表面の冷却水量及び冷却
時間を変えて溶接部の硬さをHv650からHv450へ
と低下させることにより、溶接部割れの防止、カ
ツトオフの刃寿命を通常成分である0.30〜0.35％
Ｃ含有の電縫管をカツトオフする場合の刃の寿命
とほぼ同じ程度まで向上させた。
このようにして製造された電縫鋼管を次に鋼管
全体を750〜950℃の温度で焼準処理する。
（実施例）
第１図は第１表に示すNo.1の鋼成分で鋼管サ
イズ外径114.3φ、肉厚6.35mmのAPI、Ｋ−55相当
の電縫鋼管溶接ままのものを各温度で10分保持し
たのち空冷する熱処理（焼準）を行ない、溶接部
及び母材部からAPI弧状引張試験片を加工して引
張試験した結果を示すものである。
(Industrial Application Field) The present invention relates to a method for manufacturing high carbon, high Mn electric resistance welded steel pipes. (Conventional technology) JIS S40C has traditionally been used as high carbon steel ERW steel pipe.
~ S50C ERW steel pipes have been commercialized, but high carbon, high Mn (especially Mn 1% or more) ERW steel pipes are extremely rare, and most of them are supplied from seamless mills. The reason for this is C0.40~0.50%, Mn1.3~1.6
% high carbon and high Mn steel, it is difficult to form the hot-rolled coil due to its high strength, which requires an increase in mill power. The hardness of the welded part becomes extremely high, causing cracks in the welded part, and the cut-off blade for cutting to length is severely damaged, and the life of the blade is short, so the mill has to be stopped from time to time. There were problems in terms of quality and cost due to a significant decrease in tube yield, etc., and it could not be industrially produced using an electric resistance welding mill. As a countermeasure against this problem, particularly in medium-diameter electric resistance welding mills, after pipe production, only the welded part is annealed or normalized using local heating equipment called a post annealer or seam annealer. However, it was difficult to manufacture using an electric resistance welding mill without a post annealer. On the other hand, in terms of quality, steel pipes annealed only at the welded part using a post annealer in an electric resistance welding mill have different mechanical properties depending on the circumferential region (position), and the mechanical properties in the longitudinal direction of the steel pipe also vary. Because of the uniformity, there were problems in terms of quality, such as crushing properties and corrosion resistance. (Purpose of the Invention) As a result of various studies and studies on the above-mentioned problems, the present invention has disclosed the composition system, the strength of hot-rolled coils, the pipe manufacturing method,
The purpose of this study is to provide a method for producing high-carbon, high-Mn electric resistance welded steel pipes that can be industrially produced even in electric resistance welding mills without post-annealer equipment by examining the normalization of the entire steel pipe. (Structure and operation of the invention) The gist of the present invention is that C0.38 to 0.42
%, Si0.20~0.30%, Mn1.35~1.65%, P0.025%
Below, S0.010% or less, T.Al 0.010~0.035%,
A hot-rolled steel plate is produced by hot rolling conditions such as a finishing temperature of 850-920℃ and a winding temperature of 700-800℃. After that, the hot-rolled steel sheet is formed into a tubular body, the edge portion of the tubular body is heated and welded,
This is a method for producing a high carbon, high manganese electric resistance welded steel pipe, which is characterized in that the steel pipe is made into a steel pipe and then heated to a temperature of 750 to 950°C for 5 to 10 minutes to normalize it. Hereinafter, the present invention will be explained in detail using an example of API, K-55 electric resistance welded steel pipe for oil wells. First, regarding the components of steel pipes, if C is less than 0.38%, Cr contains B, and as long as hardenability is not increased, it satisfies the API, K-55 tensile strength standard of 66.8 Kg/mm 2 or more. do not. Adding a large amount of C is effective in improving tensile strength, but if C exceeds 0.42%, as mentioned above, cracks will occur in the weld after pipe making, which is not preferable. Si is required to be at least 0.20% as a deoxidizing agent and strength-improving element, and from the viewpoint of strength, a higher content is preferable, but if it exceeds 0.30%, it will form on the surface of the steel sheet during the hot rolling process.
Since striped scale occurs, it is specified at 0.20 to 0.30%. If Mn Ceq (C + 1/5Mn) is not 0.63 or more, the mechanical properties after normalization, especially the tensile strength, will be 66.8Kg/mm 2
Not satisfied with the above. Therefore, the lower limit of the amount of C is
At 0.38%, the minimum amount of Mn is 1.35%. Mn
The larger the amount, the better the mechanical properties,
If it exceeds 1.65%, a huge segregation band will appear in the center of the wall thickness due to elements that are easy to segregate, slab cracking will easily occur during continuous casting, and it will be treated as an alloy steel component, resulting in higher customs duties when exporting. It is unfavorable in terms of melting and cost. P tends to segregate at grain boundaries, lowering the flatness value, and when manufacturing by continuous casting, the melting temperature increases, causing rephosphorus, so only the upper limit is set.
It was set at 0.025%. The lower P is, the better;
If you want to set it to 0.010% or less, for example, 2slag−LF
Requires a special process such as (redel fanes). S is one of the harmful elements such as a decrease in toughness and flatness value, but only the upper limit was specified because the effect is small at 0.010% or less and it can be manufactured industrially. T.Al is necessary to make the ferrite crystal grain size fine after normalization and as a deoxidizer, but at least 0.006% or more is required as sol.Al necessary for fine graining. Of which, Al content is 0.010~0.015
%, the distribution (ratio) of sol.Al and Insol.Al is 6:
4, the lower limit T.Al was set to 0.010%. T.
If Al exceeds 0.035%, alumina inclusions will increase, the fine grain effect will be saturated, and the cost will increase, so the upper limit was set to 0.035%. When manufacturing the steel pipe material (slab) of the present invention by continuous casting, Ti is used to prevent slab cracking. Slab cracking is also related to C and Mn content,
This is mainly caused by N, and by fixing N with Ti, slab cracking can be prevented. in this case,
Considering sol.Al, that is, AlN, generated by slab heating and steel pipe normalization before hot rolling, N in steel is equal to Al.
It becomes a Ti compound. Therefore, N that combines with Al is
0.0031% (sol.Al 0.006×N/Al→(0.006×14/
27) → 0.0031%), and since the remaining N combines with Ti, the amount of Ti required for this is 0.010. (0.006-0.0031) x Ti/N → (0.0029 x 48/14) → 0.010) Also, when fixing all N with Ti alone, Ti is
0.021% (0.006・Ti/N→0.006×48/14→0.021
) is required. During melting, Al is added before Ti, so Ti is not fixed alone. Therefore, the lower limit of Ti may be 0.010%. On the other hand, Ti is 0.030%
Exceeding this is not preferable because inclusions increase due to the formation of TiN, TiC, TiS, TiCN, etc., which impairs the cleanliness of the steel. A small amount of N is preferable in order to prevent cracking of the slab, but in consideration of economic efficiency in melting, 0.0060% or less is preferable. Next, when the raw material (slag) of the present invention component is hot-rolled into a coil, the hot-rolled coil is manufactured under hot-rolling conditions of a finishing temperature of 850 to 920°C and a winding temperature of 700 to 800°C. If the finishing temperature is less than 850℃ and the winding temperature is less than 700℃, the strength (tensile strength) of the coil will be significantly higher than 60Kg/ mm2 , so a large amount of power will be required during forming with an electric resistance welding mill, and springback will occur. This is undesirable because it tends to cause cracks in the weld. On the other hand, conditions in which the finishing temperature exceeds 920° C. and the winding temperature exceeds 800° C. are undesirable because the strength of the coil is significantly reduced, but the roll life is shortened due to scale defects on the coil surface and the amount of cooling water is suppressed. The component steel of the present invention is hot-rolled under the hot-rolling conditions of the present invention to form a hot-rolled steel plate, and then the hot-rolled steel plate is formed into a tubular body, and the edge portion of the tubular body is heated and welded. After that, the weld beads on the inner and outer surfaces are cut continuously, the entire steel pipe is cooled to about room temperature, and after being finished to the specified dimensional accuracy with a group of fixed rolls, it is cut with a cutting device (also called a cut-off). and transported to skid. In this production line, the steel pipes are cooled, so the welded parts undergo rapid cooling and become significantly harder than the non-welded parts. Next, the heat treatment method will be explained. Normally, especially when a large amount of C and Mn is contained, the welded part becomes hard, and when the outer diameter and roundness of the steel pipe are improved using regular rolls, cracks may occur in the welded part to give an appropriate outer diameter reduction. , the life of the cut-off blade decreases during the cutting process. As a countermeasure to this problem, the present inventors have developed
This problem was solved by applying the inventive concept described in Publication No. 8565. In other words, in the cooling method for ERW welded steel pipes, the outer surface of the welded steel pipe is cooled to a temperature just above the Ms point behind the welding point, and the outer surface of the welded steel pipe is cooled to a temperature in the vicinity of the Ms point. This is a method in which the entire steel pipe is immediately cooled to room temperature after it becomes almost uniform. Specifically, by changing the amount of cooling water and cooling time on the outer surface of the weld to reduce the hardness of the weld from Hv650 to Hv450, weld cracking can be prevented and the life of the cut-off blade can be reduced to 0.30, which is the normal component. ~0.35%
The lifespan of the blade has been improved to almost the same level as when cutting off C-containing electric resistance welded pipes. The electric resistance welded steel pipe thus produced is then normalized as a whole at a temperature of 750 to 950°C. (Example) Figure 1 shows an as-welded electric resistance welded steel pipe equivalent to API, K-55, with steel composition No. 1 shown in Table 1, outer diameter 114.3φ, wall thickness 6.35mm, at various temperatures. This shows the results of a tensile test performed by heat treatment (normalizing) of holding for 10 minutes and air cooling, and then processing an API arc-shaped tensile test piece from the welded part and base metal part.
【表】【table】
【表】
第１図によれば溶接ままのものを750℃未満で
熱処理すると、引張強さが、API規格を満足せ
ず、又、950℃を超えると降伏点が規格下限ぎり
ぎりである。従つて、750〜950℃が最適焼準範囲
である。一方、保持時間は５分以上あれば問題な
いが、炉温のバラツキを考慮し、10分とした。
次に本発明の実施例の機械的性質について、前
述した方法で製造したAPI、Ｋ−55電縫油井管
（外径114.3φ、肉厚6.35t）の例に従つて説明す
る。
第１表において、本発明のものは、従来法に比
較し、特に円周方向の品質特性に差がないため、
ユーザーに安心して使用してもらうことができる
ほか、ポストアニーラー設備をもたない電縫ミル
において製造可能としたものであり、API、Ｋ−
55電縫油井管の市場ニーズに応えることができ
た。
（発明の効果）
以上、述べたように本発明方法により、従来、
ポストアニーラー設備を有した電縫管造管設備以
外では製造不可能であつた高炭素、高マンガン電
縫鋼管の製造が可能となり、高品質で低コストな
高級管を提供できるようになつたものであり、産
業上稗益するところが極めて大である。
本発明では、適用例を油井管に限つて述べたが
この種のものは、例えば航空機、自動車その他の
機械構造用鋼管として使用することができる。[Table] According to Figure 1, if as-welded products are heat treated at temperatures below 750°C, the tensile strength will not meet the API standard, and if the temperature exceeds 950°C, the yield point will be on the verge of the lower limit of the standard. Therefore, the optimum normalization range is 750 to 950°C. On the other hand, there is no problem if the holding time is 5 minutes or more, but taking into consideration the variation in furnace temperature, it was set to 10 minutes. Next, the mechanical properties of the embodiment of the present invention will be explained using an example of an API, K-55 ERW oil country pipe (outer diameter 114.3φ, wall thickness 6.35t) manufactured by the method described above. In Table 1, the method of the present invention has no difference in quality characteristics in the circumferential direction compared to the conventional method.
In addition to allowing users to use it with peace of mind, it can be manufactured in an electric welding mill without post-annealer equipment, and API, K-
55 We were able to meet the market needs for ERW oil country tubing. (Effects of the Invention) As described above, the method of the present invention allows
It has become possible to manufacture high-carbon, high-manganese ERW steel pipes, which could not be manufactured except by ERW pipe manufacturing equipment equipped with post-annealer equipment, and it has become possible to provide high-quality, low-cost, high-grade pipes. This is a very important industry, and the industrial benefits are extremely large. In the present invention, the application example is limited to oil country tubular goods, but this type of product can be used, for example, as steel pipes for mechanical structures such as aircraft, automobiles, and others.
第１図は本発明の熱処理特性を示す図（×印溶
接部、・印母材部、各温度で10分保持後空冷）、第
２図は第１表のサンプリング位置を示す図であ
る。
FIG. 1 is a diagram showing the heat treatment characteristics of the present invention (welded part marked with x, base metal part marked with *, air cooled after holding at each temperature for 10 minutes), and FIG. 2 is a diagram showing the sampling positions in Table 1.
Claims (1)
1.65％、P0.025％以下、S0.010％以下、T.Al
0.010〜0.035％、Ti0.010〜0.030％、N0.0060％以
下で残部の大部分がFeで、不可避的不純物から
なるスラブを、仕上温度850〜920℃、捲取温度
700〜800℃の熱延条件で熱延鋼板としたのち、該
熱延鋼板を管状体に成形し、該管状体のエツジ部
を加熱して溶接し、鋼管としたのち、750〜950℃
の温度に５〜10分加熱して、焼準することを特徴
とする高炭素、高マンガン電縫鋼管の製造方法。1 C0.38~0.42%, Si0.20~0.30%, Mn1.35~
1.65%, P0.025% or less, S0.010% or less, T.Al
A slab consisting of 0.010 to 0.035%, Ti 0.010 to 0.030%, N 0.0060% or less, with the remainder mostly Fe, and unavoidable impurities, is processed at a finishing temperature of 850 to 920℃ and a rolling temperature.
After making a hot-rolled steel sheet under hot rolling conditions of 700 to 800°C, the hot-rolled steel sheet is formed into a tubular body, and the edge portion of the tubular body is heated and welded to form a steel tube, and then heated to a temperature of 750 to 950°C.
A method for producing a high carbon, high manganese electric resistance welded steel pipe, which comprises normalizing the pipe by heating it to a temperature of 5 to 10 minutes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12199883A JPS6013024A (en) | 1983-07-05 | 1983-07-05 | Production of high-carbon and high-manganese electric welded pipe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12199883A JPS6013024A (en) | 1983-07-05 | 1983-07-05 | Production of high-carbon and high-manganese electric welded pipe |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6013024A JPS6013024A (en) | 1985-01-23 |
| JPS6147884B2 true JPS6147884B2 (en) | 1986-10-21 |
Family
ID=14825024
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12199883A Granted JPS6013024A (en) | 1983-07-05 | 1983-07-05 | Production of high-carbon and high-manganese electric welded pipe |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6013024A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20140140614A (en) | 2012-04-09 | 2014-12-09 | 제이에프이 스틸 가부시키가이샤 | Low-yield-ratio high-strength electric resistance welded steel pipe, steel strip for said electric resistance welded steel pipe, and methods for manufacturing same |
| JP5867474B2 (en) * | 2013-09-25 | 2016-02-24 | Ｊｆｅスチール株式会社 | Manufacturing method of high carbon ERW welded steel pipe with excellent reliability of ERW welds |
| CN109338221B (en) * | 2018-11-07 | 2021-01-26 | 林州凤宝管业有限公司 | Trailer axle tube and production method thereof |
-
1983
- 1983-07-05 JP JP12199883A patent/JPS6013024A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6013024A (en) | 1985-01-23 |
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