JP2672441B2 - Manufacturing method of high strength and high toughness seamless steel pipe with excellent SSC resistance - Google Patents
Manufacturing method of high strength and high toughness seamless steel pipe with excellent SSC resistanceInfo
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- JP2672441B2 JP2672441B2 JP4330656A JP33065692A JP2672441B2 JP 2672441 B2 JP2672441 B2 JP 2672441B2 JP 4330656 A JP4330656 A JP 4330656A JP 33065692 A JP33065692 A JP 33065692A JP 2672441 B2 JP2672441 B2 JP 2672441B2
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Description
【０００１】[0001]
【産業上の利用分野】本発明は、耐ＳＳＣ性の優れた高
強度高靭性シームレス鋼管の製造法に関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a high strength and high toughness seamless steel pipe having excellent SSC resistance.
【０００２】[0002]
【従来の技術】近年、エネルギー資源としてのガス井、
油井開発は硫化水素濃度の高い環境で且つ極北、高深度
化する傾向にあり開発機材として使用されるシームレス
鋼管に対しては、耐水素割れ性、高強度、高靭性（−６
０℃保証）を兼ね備えた性質が要求される。従来より、
このような諸特性を安定して同時に満足するにはＡＳＴ
ＭNo．９未満の結晶粒度では困難であることが本発明者
等によって確かめられている。2. Description of the Related Art In recent years, gas wells as energy resources,
Oil well development is in an environment with a high concentration of hydrogen sulfide, and there is a tendency toward deeper north and deeper depths. For seamless steel pipes used as development equipment, hydrogen cracking resistance, high strength, and high toughness (-6
It is required to have the property that it also has a guarantee of 0 ° C. Conventionally,
To stably satisfy these characteristics at the same time, AST
M No. It has been confirmed by the present inventors that a grain size of less than 9 is difficult.
【０００３】一方、熱間シームレス鋼管の圧延工程は、
鋳造鋼片の穿孔圧延、延伸圧延、仕上圧延工程に分けら
れるが、成型性および表面品位の確保のため通常１１０
０℃以上の高温域で加工が行なわれるため、圧延後の再
結晶γ粒の成長は著しく、その結晶粒度はＡＳＴＭNo．
９より粗粒となる。すなわち、近年の油井開発機材とし
て要求される特性を満足するにはＡＳＴＭNo．９以上の
微細組織を安定して得る必要があるが、ＡＳＴＭNo．９
以上の微細組織を確保し耐ＳＳＣ性の優れた高強度高靭
性シームレス鋼管を得るには熱間シームレス圧延直後に
焼入する直接焼入−焼戻し工程では不十分であった。On the other hand, the rolling process of hot seamless steel pipe is
It can be divided into piercing rolling, drawing rolling, and finish rolling steps of cast steel slabs, but usually 110 to secure formability and surface quality.
Since the processing is performed in a high temperature range of 0 ° C. or higher, the growth of recrystallized γ grains after rolling is remarkable, and the grain size is ASTM No.
It becomes coarser than 9 . In other words, in order to satisfy the characteristics required for oil well development equipment in recent years, ASTM No. It is necessary to stably obtain a fine structure of 9 or more. 9
The direct quenching-tempering step of quenching immediately after hot seamless rolling was not sufficient to secure the above microstructure and obtain a high-strength and high-toughness seamless steel pipe having excellent SSC resistance.
【０００４】そのため、例えば特開昭５２−７７８１３
号公報では熱延粗圧延した中空素管を強制的に一旦鋼の
Ａｒ1 点以下に下げて再度オーステナイト化し引き続き
行う仕上圧延後に焼入−焼戻しするか、或いは通常の仕
上圧延後に再加熱焼入−焼戻しする必要があった。Therefore, for example, Japanese Patent Laid-Open No. 52-77813
According to the publication, the hollow shell that has been hot-rolled and rough-rolled is forcibly lowered to the Ar 1 point or less of the steel and austenized again, followed by quenching-tempering after finish rolling or reheating quenching after ordinary finish rolling. -Need to be tempered.
【０００５】[0005]
【発明が解決しようとする課題】しかしながら、上記の
ような方法はいずれにおいても熱効率上の問題のほかに
製造工程が煩雑となる欠点があった。一方、従来の熱間
シームレス圧延ままで近年の油井開発に要求される特性
を満足できる必要条件である結晶粒度ＡＳＴＭNo．９以
上が得られないため、直接焼入処理などの省工程で耐Ｓ
ＳＣ性の優れた高強度高靭性シームレス鋼管が得られな
い問題があった。However, any of the above-mentioned methods has a drawback that the manufacturing process is complicated in addition to the problem of thermal efficiency. On the other hand, the grain size ASTM No. which is a necessary condition for satisfying the characteristics required for the recent oil well development with the conventional hot seamless rolling. Since 9 or more can not be obtained, S-resistant in a process saving such as direct quenching
There was a problem that a high-strength and high-toughness seamless steel pipe having excellent SC property could not be obtained.
【０００６】本発明は上記した問題点を解消しようとす
るものであり、鋼成分と熱間圧延条件を制約することに
よって、結晶粒度がＡＳＴＭNo．９以上であり、優れた
耐ＳＳＣ性を有する高強度靭性シームレス鋼管の製造法
を提供するものである。[0006] The present invention is intended to solve the above-mentioned problems, and by controlling the steel composition and hot rolling conditions, the grain size can be adjusted to ASTM No. It is 9 or more and provides a method for producing a high-strength tough seamless steel pipe having excellent SSC resistance.
【０００７】[0007]
【課題を解決するための手段】本発明は、上記目的を達
成するために構成したもので、その要旨は、重量％とし
て Ｃ ：０．０３〜０．３５％、 Ｓｉ：０．０１
〜０．５％、Ｍｎ：０．１５〜２．５％、 Ｐ
：０．０２０％以下、Ｓ ：０．０１０％以下、
Ａｌ：０．００５〜０．１％、Ｔｉ：０．００
５〜０．１％、 Ｎｂ：０．００５〜０．１％、
Ｎ ：０．０１％以下 を含有し、更に必要によっては Ｃｒ：０．１〜１．５％、 Ｍｏ：０．０５
〜０．５％、Ｎｉ：０．１〜２．０％、 Ｖ
：０．０１〜０．１％、Ｂ ：０．０００３〜０．０
０３３％、希土類元素：０．００１〜０．０５％、Ｃ
ａ：０．００１〜０．０２％、 Ｃｏ：０．０５〜
０．５％、Ｃｕ：０．１〜０．５％ の１種または２種以上を含有して残部が実質的にＦｅか
らなる鋼片を１１００℃以上に加熱し熱間穿孔圧延した
中空素管をＡｒ3 点〜１１００℃まで冷却し、その直後
の前段傾斜圧延機で肉厚断面減少率が２０〜７０％の成
形加工を施し、更に前段傾斜圧延時の加工発熱によりＡ
ｒ3 点〜１１００℃まで昇温保持された中空粗管をその
直後の最終段の傾斜圧延機で肉厚断面減少率が２０〜７
０％の成形加工を施し、その後、形状矯正連続圧延を行
った後Ａｒ1 点〜９００℃の温度まで降下した中空粗管
を該温度より高い９００〜１１００℃に加熱し、仕上温
度がＡｒ3 点＋５０℃以上の熱間仕上圧延を施した仕上
鋼管を、Ａｒ3 点以上の温度から急冷する焼入処理を施
し、続いてＡｒ1 点以下の温度に加熱して冷却する焼戻
し処理を行う耐ＳＳＣ性の優れた高強度高靭性シームレ
ス鋼管の製造法である。The present invention is configured to achieve the above object, and the gist thereof is as follows: C: 0.03 to 0.35% by weight, Si: 0.01
~ 0.5%, Mn: 0.15 to 2.5%, P
: 0.020% or less, S: 0.010% or less,
Al: 0.005-0.1%, Ti: 0.00
5 to 0.1%, Nb: 0.005 to 0.1%,
N: 0.01% or less is contained, and if necessary, Cr: 0.1 to 1.5%, Mo: 0.05
~ 0.5%, Ni: 0.1-2.0%, V
: 0.01 to 0.1%, B: 0.0003 to 0.0
033%, rare earth elements: 0.001 to 0.05%, C
a: 0.001 to 0.02%, Co: 0.05 to
Hollow steel obtained by hot piercing and rolling a steel slab containing 0.5%, Cu: 0.1 to 0.5%, and one or more of them, and the balance being substantially Fe. The pipe was cooled to Ar 3 point to 1100 ° C., and immediately after that, it was formed by a pre-stage inclined rolling mill with a wall thickness cross-section reduction rate of 20 to 70%.
r The hollow rough tube heated up to 3 ° C to 1100 ° C was held at the final stage of the inclined rolling mill immediately after that, and the reduction rate of the wall thickness was 20 to 7
After performing 0% forming process and then performing shape straightening continuous rolling, the hollow coarse tube which has dropped to a temperature of Ar 1 point to 900 ° C. is heated to 900 to 1100 ° C. higher than the temperature, and the finishing temperature is Ar 3 A tempered steel pipe that has been hot-finished and rolled at a temperature of + 50 ° C or higher is subjected to a quenching treatment by rapidly cooling it from a temperature of Ar 3 points or higher, and then a tempering treatment of heating it to a temperature of 1 point or lower to cool it. This is a method for producing a high-strength, high-toughness seamless steel pipe having excellent SSC properties.
【０００８】以下本発明の製造法について詳細に説明す
る。先ず、本発明において上記のような鋼成分に限定し
た理由について説明する。Ｃ，Ｍｎは、焼入効果を増し
て強度を高め降伏点３０〜８０kgf/mm2 の高張力鋼を安
定して得るためおよび細粒化を図るため重要である。少
な過ぎるとその効果がなく、多過ぎると焼割れの誘発お
よび高硬度化し耐ＳＳＣ性の低下を来すためそれぞれ
０．０３〜０．３５％、０．１５〜２．５％とした。The manufacturing method of the present invention will be described in detail below. First, the reason why the present invention is limited to the above steel components will be described. C and Mn are important in order to enhance the hardening effect to increase the strength, to stably obtain the high tensile strength steel having the yield point of 30 to 80 kgf / mm 2 , and to achieve the grain refinement. If it is too small, the effect is not obtained, and if it is too large, quench cracking is induced and the hardness becomes high, resulting in a decrease in SSC resistance, so the content was made 0.03 to 0.35% and 0.15 to 2.5%, respectively.
【０００９】Ｓｉは、脱酸剤が残存したもので、強度を
高める有効な成分である。少な過ぎるとその効果がな
く、多過ぎると介在物を増加して耐ＳＳＣ性を低下させ
るため０．０１〜０．５％とした。Si is a residual deoxidizer and is an effective component for increasing the strength. If it is too small, the effect is not obtained, and if it is too large, inclusions increase and the SSC resistance decreases, so the content was made 0.01 to 0.5%.
【００１０】Ｐは、粒界偏析を起こして加工の際き裂を
生じ易く有害な成分であり、また低温靭性の劣化をきた
すためその含有量を０．０２０％以下とした。Ｓは、Ｍ
ｎＳ系介在物を形成して熱間連続圧延で延伸し低温靭性
に有害な成分としてその含有量を０．０１０％以下とし
た。[0010] P is a harmful component which easily causes cracks during processing due to segregation of grain boundaries, and since it causes deterioration of low temperature toughness, its content is set to 0.020% or less. S is M
An nS-based inclusion was formed and stretched by hot continuous rolling, and its content was made 0.010% or less as a component harmful to low temperature toughness.
【００１１】Ａｌは、Ｓｉと同様脱酸剤が残存したもの
で、鋼中の不純物成分として含まれるＮと結合して結晶
粒の成長を抑えて耐ＳＳＣ性の向上および低温靭性を改
善する。少な過ぎるとその効果がなく、多過ぎると介在
物を増加して鋼の性質を脆化するため０．００５〜０．
１％とした。Al, like Si, has a deoxidizing agent remaining, and binds with N contained as an impurity component in steel to suppress the growth of crystal grains and improve the SSC resistance and the low temperature toughness. If it is too small, the effect is not obtained, and if it is too large, inclusions increase and the properties of the steel become brittle.
1%.
【００１２】Ｔｉ，Ｎｂは、いずれもシームレス圧延中
の結晶粒径制御元素で、本発明の成分の中で最も重要な
元素である。Ｔｉは、鋼中の不純物成分として含まれる
Ｎと結合して、熱間圧延中の結晶粒制御および熱間圧延
後の結晶粒の成長を抑え耐ＳＳＣ性や低温靭性を改善さ
せると共に、脱酸、脱窒の作用から後述のＢの焼入性を
発揮させ強度を高める。少な過ぎるとその効果がなく、
多過ぎるとＴｉＣを析出して鋼を脆化させるため０．０
０５〜０．１％とした。一方、Ｎｂは、傾斜圧延中の結
晶粒成長抑制および連続圧延後９００℃〜Ａｒ1 点の温
度まで降下した該粗管を該温度より高い９００〜１１０
０℃に加熱した場合のγ粒の異常粗大化を抑制する重要
な元素である。少な過ぎるとその効果がなく、多過ぎて
もその効果が飽和し、しかも非常に高価であるため０．
００５〜０．１％とした。Both Ti and Nb are crystal grain size controlling elements during seamless rolling and are the most important elements among the components of the present invention. Ti combines with N contained as an impurity component in the steel to control the crystal grains during hot rolling and suppress the growth of crystal grains after hot rolling to improve SSC resistance and low-temperature toughness, and deoxidize. From the effect of denitrification, the hardenability of B described later is exerted to enhance the strength. If it is too small, it will have no effect,
If too much, TiC precipitates and the steel becomes brittle, so 0.0
05 to 0.1%. On the other hand, Nb suppresses the crystal grain growth during tilt rolling and after the continuous rolling, the temperature of the crude tube lowered to 900 ° C. to Ar 1 point is 900 to 110 higher than the temperature.
It is an important element that suppresses abnormal coarsening of γ grains when heated to 0 ° C. If the amount is too small, the effect will not be obtained, and if the amount is too large, the effect will be saturated.
It was set to 005 to 0.1%.
【００１３】Ｎは、Ｂの焼入性を低下させる有害な成分
として、その含有量を０．０１％以下とした。N is a harmful component that reduces the hardenability of B, and its content is set to 0.01% or less.
【００１４】上記の成分組成の鋼で更に鋼の強度を高め
る場合Ｃｒなどの成分を必要に応じて選択的に添加す
る。Ｃｒ，Ｍｏ，Ｎｉ，Ｖは、鋼の焼入性を増して、強
度を高めるために添加するものである。少な過ぎるとそ
の効果がなく、多過ぎてもその効果が飽和し、しかも非
常に高価であるため、それぞれ０．０１〜１．５％、
０．０５〜０．５％、０．１〜２．０％、０．０１〜
０．１％とした。Ｂは、焼入性を著しく向上せしめて強
度を高める。少な過ぎるとその効果がなく、多過ぎても
効果は変わらず、靭性や熱間加工性を劣化させるので
０．０００３〜０．００３３％とした。When the strength of the steel is further increased in the steel having the above component composition, components such as Cr are selectively added as needed. Cr, Mo, Ni and V are added to enhance the hardenability of steel and the strength. If the amount is too small, the effect will not be obtained, and if the amount is too large, the effect will be saturated, and since it is very expensive, 0.01 to 1.5% each,
0.05-0.5%, 0.1-2.0%, 0.01-
0.1%. B remarkably improves the hardenability and enhances the strength. If the amount is too small, the effect is not obtained, and if the amount is too large, the effect does not change, and the toughness and hot workability are deteriorated, so the content was made 0.0003 to 0.0033%.
【００１５】更に本発明は、近年のシームレス鋼管の使
用環境に鑑み上記の成分組成で構成される鋼の耐ＳＳＣ
性を改善するために希土類元素などの成分を必要に応じ
て選択的に添加する。希土類元素、Ｃａは、介在物の形
態を球状化させて無害化する有効な成分である。少な過
ぎるとその効果がなく、多過ぎると介在物を増加して耐
ＳＳＣ性を低下させるのでそれぞれ０．００１〜０．０
５％、０．００１〜０．０２％とした。Ｃｏ，Ｃｕは、
鋼中への水素侵入抑制効果があり耐ＳＳＣ性に有効に働
く。少な過ぎるとその効果がなく、多過ぎるとその効果
が飽和するためそれぞれ０．０５〜０．５％、０．１〜
０．５％とした。Further, in view of the use environment of the seamless steel pipe in recent years, the present invention is directed to the SSC resistance of the steel having the above composition.
In order to improve the property, a component such as a rare earth element is selectively added as needed. The rare earth element, Ca, is an effective component that makes the inclusions spherical and harmless. If it is too small, there is no effect, and if it is too large, inclusions increase and SSC resistance decreases, so 0.001 to 0.0, respectively.
5% and 0.001-0.02%. Co and Cu are
It has an effect of suppressing hydrogen invasion into the steel and works effectively for SSC resistance. If the amount is too small, the effect will not be obtained, and if the amount is too large, the effect will be saturated, so 0.05 to 0.5% and 0.1 to 0.1%, respectively.
It was set to 0.5%.
【００１６】次に熱間シームレス圧延条件を上記のよう
に限定した理由について説明する。上記のような成分組
成の鋼は転炉、電気炉などの溶解炉であるいは更に真空
脱ガス処理を経て溶製され、連続鋳造法または造塊分塊
法で鋼片を製造する。鋼片は、直ちにあるいは一旦冷却
された後高温に加熱し熱間穿孔圧延を行う。加熱温度
は、熱間穿孔圧延を容易にするため十分高くしておかね
ばならない。本発明の成分範囲内であれば１１００℃以
上の温度で熱間穿孔加工上なんら支障が生じないのでそ
の温度は１１００℃以上とした。Next, the reason why the hot seamless rolling conditions are limited as described above will be explained. Steel having the above-described composition is melted in a melting furnace such as a converter or an electric furnace or further subjected to vacuum degassing treatment, and a steel slab is manufactured by a continuous casting method or an ingot agglomeration method. The steel slab is immediately or once cooled and then heated to a high temperature for hot piercing and rolling. The heating temperature must be sufficiently high to facilitate hot piercing and rolling. If it is within the range of the components of the present invention, no problem occurs in hot drilling at a temperature of 1100 ° C or higher, so the temperature was set to 1100 ° C or higher.
【００１７】穿孔圧延が行われた中空素管は、前段の傾
斜圧延機前でＡｒ3 点〜１１００℃の温度に冷却し、直
ちに粗加工する傾斜圧延を行う。傾斜圧延機（エロンゲ
ータミルなど）は、シームレス鋼管の圧延に使用される
他の圧延機（マンドレルミル、プラグミルなど）や鋼板
の圧延機と異なり、剪断ひずみの成分が非常に大きい。
したがって、断面積減少率から予測されるひずみ量と比
べて実質的なひずみ量は格段に大きい。このため、傾斜
圧延機では小さな断面積減少率の加工であっても加工発
熱が大きいため直後の最終段の傾斜圧延に必要な温度の
確保が可能となる。前段の傾斜圧延機で圧延された中空
粗管はＡｒ3 点〜１１００℃の温度に昇温保持され、そ
の後、Ａｒ3 点〜１１００℃の温度に昇温保持された中
空粗管は、最終段の傾斜圧延機で鋼管の最終形状に近い
外径、肉厚まで粗加工する傾斜圧延を行う。傾斜圧延機
は、剪断ひずみの成分が非常に大きいため実質的なひず
み量は格段に大きくなり、前述の加工発熱効果に加え
て、低温圧延においても容易に再結晶組織が得られ、図
１で示すように同一断面積減少率であっても剪断ひずみ
の小さい圧延機と比べて細粒が得られる。傾斜圧延機の
圧延温度は、高いと再結晶粒の著しい成長が起こるが、
低過ぎると圧延負荷の増大により鋼の成形性が著しく低
下し、目標とする外径、肉厚が得られにくく再結晶によ
る結晶粒の微細化が図れないため、前段、最終段ともＡ
ｒ3 点〜１１００℃に限定した。The hollow shell that has been pierced and rolled is cooled to a temperature of Ar 3 point to 1100 ° C. in front of the inclined rolling machine in the preceding stage, and is immediately subjected to rough rolling for rough processing. The inclined rolling mill (elongator mill, etc.) has a very large shear strain component, unlike other rolling mills (mandrel mill, plug mill, etc.) and steel plate rolling mills used for rolling seamless steel pipes.
Therefore, the substantial strain amount is much larger than the strain amount predicted from the cross-sectional area reduction rate. For this reason, in the inclined rolling mill, the processing heat generation is large even if the processing is performed with a small cross-sectional area reduction rate, so that it is possible to secure the temperature necessary for the final-stage inclined rolling immediately after. Hollow Arakan which is rolled in front of the inclined rolling mill is heated maintained at a temperature of Ar 3 point C. to 1100 ° C., then, a hollow Arakan which is heated maintained at a temperature of Ar 3 point C. to 1100 ° C., the final stage The slant rolling machine is used to perform slant rolling for rough processing to an outer diameter and wall thickness close to the final shape of the steel pipe. In the inclined rolling mill, since the component of shear strain is very large, the substantial strain amount is remarkably large, and in addition to the above-mentioned processing heat generation effect, a recrystallization structure can be easily obtained even in low temperature rolling. As shown in the figure, even if the cross-sectional area reduction rate is the same, fine grains can be obtained as compared with a rolling mill with small shear strain. When the rolling temperature of the inclined rolling mill is high, a remarkable growth of recrystallized grains occurs,
If it is too low, the formability of steel is significantly reduced due to an increase in rolling load, and it is difficult to obtain the target outer diameter and wall thickness, and it is difficult to refine the crystal grains by recrystallization.
r 3 points to 1100 ° C.
【００１８】また、傾斜圧延機では前段、最終段共に再
結晶は大部分動的に起こるので、結晶粒度は加工量によ
らない。しかし、再結晶する臨界ひずみは超えている必
要がある。圧下率は、再結晶が圧延終了後にも静的に起
こることを考慮して下限を２０％とした。一方、圧下率
が余り大き過ぎると、圧延が困難になりパイプの成形性
や表面品位の低下が起こるため、上限を７０％とした。Further, in the inclined rolling mill, recrystallization mostly occurs dynamically in both the former stage and the final stage, so the grain size does not depend on the processing amount. However, the critical strain for recrystallization needs to be exceeded. The lower limit of the rolling reduction was set to 20% in consideration of the fact that recrystallization statically occurs even after the rolling is completed. On the other hand, if the reduction ratio is too large, rolling becomes difficult and the formability and surface quality of the pipe deteriorate, so the upper limit was made 70%.
【００１９】最終段の傾斜圧延終了後、中空粗管を更に
形状矯正のための連続圧延を行い、Ａｒ1 点〜９００℃
の温度まで降下した該粗管は、該温度より高い９００〜
１１００℃に再加熱される。この再加熱温度は、均一な
材質を得るためパイプ全体を焼入時に完全γの状態にし
ておく必要がある。本発明鋼の範囲であれば９００℃以
上の再加熱で十分γ組織が確保できる。しかし、あまり
高温にするとパイプ表面スケールが多く生成し表面品位
が劣化するため、上限を１１００℃とした。After the final stage of inclined rolling, the hollow rough tube is further continuously rolled to correct the shape, and Ar 1 point to 900 ° C.
The temperature of the rough tube lowered to the temperature of
Reheat to 1100 ° C. This reheating temperature must be in a completely γ state during quenching of the entire pipe in order to obtain a uniform material. Within the range of the steel of the present invention, sufficient γ structure can be secured by reheating at 900 ° C or higher. However, if the temperature is too high, a large amount of pipe surface scale is generated and the surface quality deteriorates, so the upper limit was made 1100 ° C.
【００２０】再加熱後Ａｒ3 ＋５０℃以上の温度で熱間
最終仕上圧延を行う。圧延温度は、あまり低くなると高
強度を得るために必要とされる焼入時の完全γの状態が
確保できないためＡｒ3 ＋５０℃とした。After reheating, hot final finish rolling is performed at a temperature of Ar 3 + 50 ° C. or higher. The rolling temperature was set to Ar 3 + 50 ° C. because if the rolling temperature is too low, the state of perfect γ at the time of quenching required for obtaining high strength cannot be secured.
【００２１】熱間最終仕上圧延後に完全γ状態から焼入
処理を行う。焼入処理開始温度は、十分な焼入組織を確
保し必要とする強度を確保するためＡｒ3 点以上とし
た。焼入時の冷却速度は特に限定しないが空冷より速い
速度とする。焼入後、鋼の性質（強度、靭性、および耐
ＳＳＣ性など）の安定化のため焼戻し処理を行う。焼戻
し温度は、強度および靭性の安定化を確保する必要から
鋼のＡｃ1 点以下とした。その加熱方法については特に
限定しない。以上の製造条件で得られるγは粗大粒を含
むことなく耐ＳＳＣ性の優れた高強度高靭性シームレス
鋼管の製造に有効である。After the hot final finish rolling, quenching treatment is performed from the perfect γ state. The quenching treatment start temperature was set to 3 Ar or higher in order to secure a sufficient quenching structure and the required strength. The cooling rate at the time of quenching is not particularly limited, but it is faster than air cooling. After quenching, tempering treatment is performed to stabilize the properties of the steel (strength, toughness, SSC resistance, etc.). The tempering temperature was set to the Ac 1 point or lower of the steel because it is necessary to ensure the stability of strength and toughness. The heating method is not particularly limited. Γ obtained under the above manufacturing conditions is effective for manufacturing a high-strength and high-toughness seamless steel pipe having excellent SSC resistance without containing coarse grains.
【００２２】[0022]
【実施例】次に本発明の実施例について説明する。表２
は表１に示す成分の鋼を転炉で溶製し連続鋳造を経て製
造された鋼片を熱間シームレス圧延を行って直接焼入焼
戻しした鋼管の強度、靭性、γ粒度および耐ＳＳＣ性を
示す。耐ＳＳＣ性は、ＮＡＣＥ ＴＭ０１−７７に従っ
て定荷重方式によるσｔｈ（Ｔｈｒｅｓｈｏｌｄ Ｓｔ
ｒｅｓｓ）を求めて評価した。本発明によって製造され
た鋼管は、高強度を有し、かつ従来法に比しγ粒度はＡ
ＳＴＭNo. ９以上と微細であり高靭性が得られ耐ＳＳＣ
性はσｔｈで０．２σｙ以上向上することがわかる。Next, an embodiment of the present invention will be described. Table 2
Indicates the strength, toughness, γ grain size and SSC resistance of a steel pipe that is obtained by melting steel in the composition shown in Table 1 in a converter and continuously casting and then directly quenching and tempering the steel slab produced by continuous casting. Show. SSC resistance is σth (Threshold St) according to the constant load method according to NACE TM01-77.
and evaluated. The steel pipe manufactured according to the present invention has high strength and has a γ grain size of A as compared with the conventional method.
STM No. 9 or higher is fine, high toughness is obtained, and SSC resistance
It can be seen that the property is improved by 0.2σy or more in σth.
【００２３】[0023]
【表１】 [Table 1]
【００２４】[0024]
【表２】 [Table 2]
【００２５】[0025]
【発明の効果】上記のような本発明法によって製造され
た鋼管は、高強度を有し更に細粒であるため低温靭性お
よび耐ＳＳＣ性が優れ、極北の寒冷地や硫化物応力腐食
環境において使用できる。The steel pipe produced by the method of the present invention as described above has high strength and fine grains, so that it has excellent low temperature toughness and SSC resistance, and is suitable for cold regions in the far north and sulfide stress corrosion environments. Can be used.
【図１】通常の鋼板圧延法と最終段の傾斜圧延後のγ粒
度と圧延温度の影響を示す。FIG. 1 shows the influence of γ grain size and rolling temperature after a normal steel plate rolling method and the final stage of tilt rolling.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｃ２２Ｃ 38/14 Ｃ２２Ｃ 38/14 (56)参考文献 特開 平２−50916（ＪＰ，Ａ) 特開 平３−64415（ＪＰ，Ａ) 特開 平３−240921（ＪＰ，Ａ) 特開 平３−180427（ＪＰ，Ａ) 特開 平６−172854（ＪＰ，Ａ)─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Internal reference number FI Technical display location C22C 38/14 C22C 38/14 (56) Reference JP-A-2-50916 (JP, A) Special features Kaihei 3-64415 (JP, A) JP 3-240921 (JP, A) JP 3-180427 (JP, A) JP 6-172854 (JP, A)
Claims (4)
℃以上に加熱し熱間穿孔圧延した中空素管をＡｒ3 点〜
１１００℃まで冷却し、その直後の前段傾斜圧延機で肉
厚断面減少率が２０〜７０％の成形加工を施し、更に前
段傾斜圧延時の加工発熱によりＡｒ3 点〜１１００℃ま
で昇温保持された中空粗管をその最終段傾斜圧延機で肉
厚断面減少率で２０〜７０％の成形加工を施し、その
後、形状矯正連続圧延を行った後Ａｒ1 点〜９００℃の
温度まで降下した中空粗管を該温度より高い９００〜１
１００℃に加熱し、仕上温度がＡｒ3 点＋５０℃以上の
熱間仕上圧延を施した仕上鋼管を、Ａｒ3 点以上の温度
から急冷する焼入処理を施し、続いてＡｃ1 点以下の温
度に加熱して冷却する焼戻し処理を行うことを特徴とす
る耐ＳＳＣ性の優れた高強度高靭性シームレス鋼管の製
造法。1. As weight%, C: 0.03 to 0.35%, Si: 0.01 to 0.5%, Mn: 0.15 to 2.5%, P: 0.020% or less, S: 0.010% or less, Al: 0.005 to 0.1%, Ti: 0.005 to 0.1%, Nb: 0.005 to 0.1%, N: 0.01% or less Then, the steel slab consisting essentially of Fe
Ar 3 points for hollow shells that have been hot pierced and rolled by heating above ℃
Immediately after cooling to 1100 ° C., a pre-stage inclined rolling machine is used to perform a forming process with a wall thickness cross-section reduction rate of 20 to 70%, and the temperature of the Ar 3 point to 1100 ° C. is maintained by the heat generated during the pre-stage inclined rolling. The hollow rough tube was subjected to forming processing with a wall thickness cross-section reduction rate of 20 to 70% by the final stage inclined rolling machine, and then shape-correcting continuous rolling was performed, and then the temperature was lowered to a temperature of Ar 1 point to 900 ° C. Coarse tube is higher than the temperature 900 ~ 1
A finished steel tube heated to 100 ° C and subjected to hot finish rolling at an Ar 3 point + 50 ° C or higher is quenched at a temperature of Ar 3 point or higher, followed by a temperature of Ac 1 point or lower. A method for producing a high-strength, high-toughness seamless steel pipe having excellent SSC resistance, which is characterized by performing a tempering treatment in which the steel is heated and cooled.
らなる鋼片を１１００℃以上に加熱し熱間穿孔圧延した
中空素管をＡｒ3 点〜１１００℃まで冷却し、その直後
の前段傾斜圧延機で肉厚断面減少率が２０〜７０％の成
形加工を施し、更に前段傾斜圧延時の加工発熱によりＡ
ｒ3 点〜１１００℃まで昇温保持された中空粗管をその
最終段傾斜圧延機で肉厚断面減少率で２０〜７０％の成
形加工を施し、その後、形状矯正連続圧延を行った後Ａ
ｒ1 点〜９００℃の温度まで降下した中空粗管を該温度
より高い９００〜１１００℃に加熱し、仕上温度がＡｒ
3 点＋５０℃以上の熱間仕上圧延を施した仕上鋼管を、
Ａｒ3 点以上の温度から急冷する焼入処理を施し、続い
てＡｃ1 点以下の温度に加熱して冷却する焼戻し処理を
行うことを特徴とする耐ＳＳＣ性の優れた高強度高靭性
シームレス鋼管の製造法。2. As weight%, C: 0.03 to 0.35%, Si: 0.01 to 0.5%, Mn: 0.15 to 2.5%, P: 0.020% or less, S: 0.010% or less, Al: 0.005 to 0.1%, Ti: 0.005 to 0.1%, Nb: 0.005 to 0.1%, N: 0.01% or less Then, Cr: 0.1 to 1.5%, Mo: 0.05 to 0.5%, Ni: 0.1 to 2.0%, V: 0.01 to 0.1%, B: A hollow steel pipe obtained by heating and hot-rolling a steel slab containing 0.0003 to 0.0033% of 1 type or 2 types and the balance of which consists essentially of Fe at 1100 ° C. or higher is Ar 3 to 1100. Immediately after that, the product was subjected to forming processing with a wall thickness cross-section reduction rate of 20 to 70% in a front-stage inclined rolling machine, and further A due to processing heat during front-stage inclined rolling.
r A hollow rough tube which was heated to 3 points to 1100 ° C was subjected to forming processing with a wall thickness cross-section reduction rate of 20 to 70% by the final stage inclined rolling machine, and then shape-correcting continuous rolling was performed.
r The hollow crude tube that has dropped to a temperature of 1 to 900 ° C is heated to 900 to 1100 ° C, which is higher than the temperature, and the finishing temperature is Ar.
Finished steel pipe that has been subjected to hot finish rolling at 3 points + 50 ° C or higher,
A high-strength, high-toughness seamless steel pipe with excellent SSC resistance, which is characterized by performing quenching treatment by rapidly cooling from a temperature of Ar 3 points or higher, and then performing tempering treatment by heating to a temperature of Ac 1 point or lower and cooling. Manufacturing method.
らなる鋼片を１１００℃以上に加熱し熱間穿孔圧延した
中空素管をＡｒ3 点〜１１００℃まで冷却し、その直後
の前段傾斜圧延機で肉厚断面減少率が２０〜７０％の成
形加工を施し、更に前段傾斜圧延による加工発熱により
Ａｒ3 点〜１１００℃まで昇温保持された中空粗管をそ
の最終段傾斜圧延機で肉厚断面減少率が２０〜７０％の
成形加工を施し、その後、形状矯正連続圧延を行った後
Ａｒ1 点〜９００℃の温度まで降下した中空粗管を該温
度より高い９００〜１１００℃に加熱し、仕上温度がＡ
ｒ3点＋５０℃以上の熱間仕上圧延を施した仕上鋼管
を、Ａｒ3 点以上の温度から急冷する焼入処理を施し、
続いてＡｃ1 点以下の温度に加熱して冷却する焼戻し処
理を行うことを特徴とする耐ＳＳＣ性の優れた高強度高
靭性シームレス鋼管の製造法。3. As a weight%, C: 0.03 to 0.35%, Si: 0.01 to 0.5%, Mn: 0.15 to 2.5%, P: 0.020% or less, S: 0.010% or less, Al: 0.005 to 0.1%, Ti: 0.005 to 0.1%, Nb: 0.005 to 0.1%, N: 0.01% or less Further, rare earth element: 0.001 to 0.05%, Ca: 0.001 to 0.02%, Co: 0.05 to 0.5%, Cu: 0.1 to 0.5%, 1 Type or two or more types of steel, and the balance of which consists essentially of Fe, the steel slab is heated to 1100 ° C or higher and hot pierced and rolled, and the hollow shell is cooled to Ar 3 point to 1100 ° C. thick percent reduction of cross section subjected to molding of 20% to 70% in the rolling mill, until further Ar 3 point C. to 1100 ° C. the process heat generated by the preceding stage inclined rolling The temperature holding hollow crude pipe wall thickness cross-section reduction rate is subjected to molding of 20% to 70% at the final stage inclined rolling mill, then, to a temperature of Ar 1 point to 900 ° C. After straightening continuous rolling The lowered hollow crude tube is heated to 900 to 1100 ° C, which is higher than the temperature, and the finishing temperature is A
r 3 points + 50 ° C or higher is subjected to hot finish rolling, and then the finished steel pipe is subjected to quenching treatment for rapid cooling from a temperature of Ar 3 points or higher,
Next, a method for producing a high-strength, high-toughness seamless steel pipe having excellent SSC resistance, which is characterized by performing a tempering treatment of heating to a temperature of Ac 1 point or lower and cooling.
らなる鋼片を１１００℃以上に加熱し熱間穿孔圧延した
中空素管をＡｒ3 点〜１１００℃まで冷却し、その直後
の前段傾斜圧延機で肉厚断面減少率が２０〜７０％の成
形加工を施し、更に前段傾斜圧延時の加工発熱によりＡ
ｒ3 点〜１１００℃まで昇温保持された中空粗管をその
最終段傾斜圧延機で肉厚断面減少率が２０〜７０％の成
形加工を施し、その後、形状矯正連続圧延を行った後Ａ
ｒ1 点〜９００℃の温度まで降下した中空粗管を該温度
より高い９００〜１１００℃に加熱し、仕上温度がＡｒ
3 点＋５０℃以上の熱間仕上圧延を施した仕上鋼管を、
Ａｒ3 点以上の温度から急冷する焼入処理を施し、続い
てＡｃ1 点以下の温度に加熱して冷却する焼戻し処理を
行うことを特徴とする耐ＳＳＣ性の優れた高強度高靭性
シームレス鋼管の製造法。4. As weight%, C: 0.03 to 0.35%, Si: 0.01 to 0.5%, Mn: 0.15 to 2.5%, P: 0.020% or less, S: 0.010% or less, Al: 0.005 to 0.1%, Ti: 0.005 to 0.1%, Nb: 0.005 to 0.1%, N: 0.01% or less Then, Cr: 0.1 to 1.5%, Mo: 0.05 to 0.5%, Ni: 0.1 to 2.0%, V: 0.01 to 0.1%, B: 0.0003 to 0.0033% of one kind or two or more kinds and rare earth elements: 0.001 to 0.05%, Ca: 0.001 to 0.02%, Co: 0.05 to 0.5%, Cu: 0.1 to 0.5% of one or the balance contains two or more heats the steel strip consisting essentially of Fe above 1100 ° C. hot piercing and rolling the hollow shell Ar 3 It cooled to C. to 1100 ° C., the thickness reduction of area in front inclined rolling mill is subjected to a forming process of 20% to 70% immediately after, further A by the processing heat generated during the previous stage inclined rolling
r The hollow rough tube heated and held at 3 points to 1100 ° C was subjected to forming processing with a wall thickness cross-section reduction rate of 20 to 70% by the final stage inclined rolling machine, and then shape-correcting continuous rolling was performed.
r The hollow crude tube that has dropped to a temperature of 1 to 900 ° C is heated to 900 to 1100 ° C, which is higher than the temperature, and the finishing temperature is Ar.
Finished steel pipe that has been subjected to hot finish rolling at 3 points + 50 ° C or higher,
A high-strength, high-toughness seamless steel pipe with excellent SSC resistance, which is characterized by performing quenching treatment by rapidly cooling from a temperature of Ar 3 points or higher, and then performing tempering treatment by heating to a temperature of Ac 1 point or lower and cooling. Manufacturing method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4330656A JP2672441B2 (en) | 1992-12-10 | 1992-12-10 | Manufacturing method of high strength and high toughness seamless steel pipe with excellent SSC resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4330656A JP2672441B2 (en) | 1992-12-10 | 1992-12-10 | Manufacturing method of high strength and high toughness seamless steel pipe with excellent SSC resistance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06172858A JPH06172858A (en) | 1994-06-21 |
| JP2672441B2 true JP2672441B2 (en) | 1997-11-05 |
Family
ID=18235114
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4330656A Expired - Lifetime JP2672441B2 (en) | 1992-12-10 | 1992-12-10 | Manufacturing method of high strength and high toughness seamless steel pipe with excellent SSC resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2672441B2 (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| MX9702792A (en) * | 1994-10-20 | 1998-02-28 | Sumitomo Metal Ind | Method of manufacturing seamless steel pipes and manufacturing equipment therefor. |
| US5938865A (en) * | 1995-05-15 | 1999-08-17 | Sumitomo Metal Industries, Ltc. | Process for producing high-strength seamless steel pipe having excellent sulfide stress cracking resistance |
| JP4187334B2 (en) * | 1998-01-29 | 2008-11-26 | トピー工業株式会社 | Heat treatment method for hollow cylindrical workpiece |
| JP2003041341A (en) | 2001-08-02 | 2003-02-13 | Sumitomo Metal Ind Ltd | Steel material with high toughness and method for manufacturing steel pipe thereof |
| JP4792778B2 (en) * | 2005-03-29 | 2011-10-12 | 住友金属工業株式会社 | Manufacturing method of thick-walled seamless steel pipe for line pipe |
| CN104438333A (en) * | 2014-12-10 | 2015-03-25 | 西北工业大学 | Tri-roller reciprocating type skew rolling technique of seamless pipes |
| CN104858622B (en) * | 2015-05-20 | 2017-04-05 | 湖州华特不锈钢管制造有限公司 | A kind of stainless steel pipe surface eliminates the production method of hair check |
| CN107217201A (en) * | 2017-06-27 | 2017-09-29 | 包头钢铁（集团）有限责任公司 | A kind of marine drilling platform containing rare earth spud leg 600MPa seamless steel pipes and its production method |
| CN108568644B (en) * | 2018-04-13 | 2020-05-01 | 河南中原特钢装备制造有限公司 | Processing technology of ultra-small specification pipe die |
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| JPH0250916A (en) * | 1988-08-11 | 1990-02-20 | Nippon Steel Corp | Production of low alloy high tension seamless steel pipe having fine grained structure |
| JPH0364415A (en) * | 1989-07-31 | 1991-03-19 | Nippon Steel Corp | Production of high-toughness seamless low alloy steel tube |
| JPH0689398B2 (en) * | 1989-12-08 | 1994-11-09 | 住友金属工業株式会社 | Duplex Stainless Steel Pipe Making Method |
| JP2576254B2 (en) * | 1990-02-15 | 1997-01-29 | 住友金属工業株式会社 | Manufacturing method of seamless steel pipe with ultrafine structure |
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| JPH06172858A (en) | 1994-06-21 |
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