JPS63241116A - Manufacture of high strength resistance welded steel tube having superior sulfide cracking resistance - Google Patents
Manufacture of high strength resistance welded steel tube having superior sulfide cracking resistanceInfo
- Publication number
- JPS63241116A JPS63241116A JP7474987A JP7474987A JPS63241116A JP S63241116 A JPS63241116 A JP S63241116A JP 7474987 A JP7474987 A JP 7474987A JP 7474987 A JP7474987 A JP 7474987A JP S63241116 A JPS63241116 A JP S63241116A
- Authority
- JP
- Japan
- Prior art keywords
- resistance
- less
- steel pipe
- welded
- ssc
- 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.)
- Pending
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 62
- 239000010959 steel Substances 0.000 title claims abstract description 62
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 22
- 238000005336 cracking Methods 0.000 title claims abstract description 12
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 title claims abstract description 11
- 238000010438 heat treatment Methods 0.000 claims abstract description 31
- 238000003466 welding Methods 0.000 claims abstract description 23
- 239000012535 impurity Substances 0.000 claims abstract description 10
- 238000005496 tempering Methods 0.000 claims abstract description 10
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 9
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 8
- 229910052735 hafnium Inorganic materials 0.000 claims abstract description 7
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 7
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 7
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 7
- 229910052726 zirconium Inorganic materials 0.000 claims abstract description 7
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 5
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 3
- 238000010791 quenching Methods 0.000 claims description 17
- 238000000034 method Methods 0.000 claims description 16
- 230000000171 quenching effect Effects 0.000 claims description 15
- 230000001590 oxidative effect Effects 0.000 claims description 7
- 229910052742 iron Inorganic materials 0.000 claims 1
- 229910052698 phosphorus Inorganic materials 0.000 abstract description 2
- 230000001105 regulatory effect Effects 0.000 abstract description 2
- 238000005304 joining Methods 0.000 abstract 2
- 239000010953 base metal Substances 0.000 description 14
- 230000000694 effects Effects 0.000 description 9
- 239000000203 mixture Substances 0.000 description 8
- 239000000126 substance Substances 0.000 description 8
- 230000007547 defect Effects 0.000 description 6
- 239000002994 raw material Substances 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 238000001816 cooling Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 150000001247 metal acetylides Chemical class 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 229910001566 austenite Inorganic materials 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- 238000002791 soaking Methods 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 238000011282 treatment Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000000875 corresponding effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 229910000037 hydrogen sulfide Inorganic materials 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、湿潤な硫化水素を含むいわゆるサワー環境下
で発生する硫化物割れに対して大きな抵抗力を持つ高強
度電縫鋼管の製造方法に関する。Detailed Description of the Invention (Industrial Application Field) The present invention provides a method for manufacturing high-strength electric resistance welded steel pipes that have high resistance to sulfide cracking that occurs in so-called sour environments containing moist hydrogen sulfide. Regarding.
（従来の技術とその問題点）
油田、ガス田の開発に使用されるいわゆる油井管として
、古くから貫層されているシームレス管に代わって、電
縫鋼管が一部に使用されるようになった。電縫油井管は
形状や寸法精度が良く、耐圧壊強度に優れる等の利点が
あるが、反面、溶接部の硫化物割れ（以下、ＳＳＣと略
記する）抵抗性が小さいため、サワー環境下での使用が
制限される。(Conventional technology and its problems) As so-called oil country tubular goods used for the development of oil and gas fields, ERW steel pipes have come to be used in some parts instead of seamless pipes that have been layered for a long time. Ta. ERW oil country tubular goods have advantages such as good shape and dimensional accuracy and excellent crush strength, but on the other hand, they have low resistance to sulfide cracking (hereinafter abbreviated as SSC) in welded parts, so they cannot be used in sour environments. The use of is restricted.
ＳＳＣは、鋼材がＩｂＳを含む湿潤雰囲気下で腐食する
とき発生した水素によって惹起される割れであるが、特
に電縫鋼管においては、その溶接部の耐ＳＳＣ性が問題
になる。SSC is a crack caused by hydrogen generated when steel corrodes in a humid atmosphere containing IbS, but especially in electric resistance welded steel pipes, the SSC resistance of the welded portion becomes a problem.
電縫鋼管の素材（ホットコイル）そのものの耐ＳＳＣ性
改善については、すでにいくつかの提案がなされている
。たとえば、■特開昭５８−２２１２６０号公報■同６
０−８６２１６号公報■同６０−８６２１７号公報に記
載されている発明がそれであって、■はＳＳＣの起点と
なる非金属介在物をできるだけ少なくすること、■、■
は素材となるホットコイルの冷却速度を調整して不均一
組織の生成を防ぐこと、をそれぞれ主たる特徴としてい
る。しかし、これらの提案では、電縫管とした後の溶接
部の耐ＳＳＣに関しては特に述べるところがない。Several proposals have already been made for improving the SSC resistance of the material (hot coil) of the ERW steel pipe itself. For example, ■Japanese Unexamined Patent Publication No. 58-221260 ■No. 6
Publication No. 0-86216 ■ The invention described in Publication No. 60-86217 is that, ■ is to reduce as much as possible nonmetallic inclusions that become the starting point of SSC, ■,
Their main feature is to prevent the formation of non-uniform structures by adjusting the cooling rate of the hot coil material. However, these proposals do not specifically mention the SSC resistance of the welded portion after it is made into an electric resistance welded pipe.
溶接部のＳＳＣを支配する要因は、溶接時に発生する低
温割れやペネトレーシヨンなどの欠陥の存在と溶接部の
組織の不均一である。まず、溶接欠陥の防止策としては
、溶接入熱量やアプセット量の調整、或いは不活性ガス
シールド溶接等が適用され、それ相応の効果をあげてい
る。また、溶接部の組織の均一化についてもシーム部の
後熱処理が種々行われている。しかしながら油井管用の
如き高強度鋼になると上記のような溶接条件の改善だけ
では、溶接欠陥の完全防止は困難であり、また、従来の
後熱処理で溶接部の耐ＳＳＣ性を母材と同一レベルまで
改善することも難しい、サワーガス田、サワー油田を安
全かつ経済的に開発するには、高強度で耐ＳＳＣ性に優
れた鋼管が必要であるが、強度と耐ＳＳＣ性は一般的に
相反する特性であるから、その両者を満足する電縫鋼管
を製造するためには素材鋼帯の化学組成から、製管工程
および得られた電縫管の熱処理まで一貫した綿密な条件
設定が必須である。The factors that govern the SSC of a weld are the presence of defects such as cold cracks and penetration that occur during welding, and the non-uniform structure of the weld. First, as measures to prevent welding defects, adjustment of welding heat input and upset amount, inert gas shield welding, etc., have been applied, and have achieved corresponding effects. In addition, various post-heat treatments of the seam portion are performed to make the structure of the weld portion uniform. However, when it comes to high-strength steels such as those used for oil country tubing, it is difficult to completely prevent weld defects by simply improving the welding conditions as described above, and conventional post-heat treatment can improve the SSC resistance of the welded part to the same level as the base metal. In order to safely and economically develop sour gas fields and sour oil fields, which are difficult to improve, steel pipes with high strength and excellent SSC resistance are required, but strength and SSC resistance are generally contradictory. In order to manufacture ERW steel pipe that satisfies both of these characteristics, it is essential to set consistent and detailed conditions from the chemical composition of the raw steel strip to the pipe manufacturing process and heat treatment of the resulting ERW pipe. .
本発明は、特に油井管として用いるのに好適な高強度電
縫鋼管であって、溶接部の耐ＳＳＣが母材と同程度に優
れたものを製造する新しい方法を提供することを目的と
する。An object of the present invention is to provide a new method for manufacturing high-strength electric resistance welded steel pipes that are particularly suitable for use as oil country tubular goods and whose SSC resistance at welded parts is as excellent as that of the base material. .
（問題点を解決するための手段）
前記目的を達成するための手段としての本発明の要旨は
下記の電縫鋼管の製造方法にある。(Means for Solving the Problems) The gist of the present invention as a means for achieving the above object lies in the following method for manufacturing an electric resistance welded steel pipe.
重量％で、Ｃ：０．１５〜０．３５％、Ｓｉ ： ０．
１〜０．８％、Ｍｎ ： ０．２ 〜０．５ ％、Ｃ
ｒ ： ０．２ 〜０．６ ％、ＭＯ：０．０５〜０
．２５％、ｓｏｌ、 Ａｊ！ ： ０．０１〜０．０６
％、 並びにＺｒ ： ０．０１〜０．１５％とＨｆ
： ０．００１〜０．１５０％の１種または２種、およ
びＮｂ ： ０．０１〜０．１５％、Ｖ：０゜Ｏ２Ｎ２
．１５％、Ｔｉ ： ０．０１〜０．１５％のうちの１
種以上、残部Ｆｅと不可避不純物から成り、不純物とし
てのＰが０．０２％以下、Ｓが０．００５％以下であり
、かつ０．２≦Ｍｏ （χ）／Ｃｒ （Ｘ）≦０．４で
ある鋼帯を、その接合端部を非酸化性雰囲気で加熱し、
アプセット量が肉厚の２５〜１２５％となるように電縫
溶接し、得られた鋼管を９２０〜１０２０℃に加熱した
後焼入れし、次いで焼もどしを行う耐硫化物割れ性に優
れた高強度電縫鋼管の製造方法。In weight%, C: 0.15-0.35%, Si: 0.
1-0.8%, Mn: 0.2-0.5%, C
r: 0.2-0.6%, MO: 0.05-0
．． 25%, sol, Aj! : 0.01~0.06
%, and Zr: 0.01-0.15% and Hf
: 0.001~0.150% of one or two types, and Nb: 0.01~0.15%, V: 0°O2N2
．． 15%, Ti: 1 of 0.01-0.15%
0.02% or less of P as impurities, 0.005% or less of S, and 0.2≦Mo (χ)/Cr (X)≦0.4 The joint end of the steel strip is heated in a non-oxidizing atmosphere,
Electric resistance welding is performed so that the upset amount is 25-125% of the wall thickness, and the resulting steel pipe is heated to 920-1020°C, quenched, and then tempered. High strength with excellent sulfide cracking resistance. Manufacturing method of ERW steel pipe.
上記本発明の方法において、電縫鋼管の素材となる鋼帯
には、上記各成分のばか更に、０．０００１〜０．００
３０％のＢ、０．００１〜０．０１０％のＣａの１種ま
たは２種を含有させてもよい。In the method of the present invention, the steel strip used as the raw material for the electric resistance welded steel pipe contains 0.0001 to 0.00 of the above-mentioned components.
One or both of 30% B and 0.001 to 0.010% Ca may be contained.
かかる本発明方法の特徴は、素材となる鋼帯の化学組成
から製品電縫管の熱処理までの一貫した条件設定にある
が、特にその骨子は０強度と耐ＳＳＣ性とを両立させる
ために合金成分とその含有量を総合的に調整したこと、
■溶接欠陥の発生を防ぐため合金元素、特にＭｎ、 Ｃ
ｒ、およびＭｏの含有量を規制するとともに溶接条件を
適正化したこと、■溶接部の耐ＳＳＣ性を母材と同等に
するため管の熱処理条件を特定したこと、である。The feature of the method of the present invention is the consistent setting of conditions from the chemical composition of the steel strip used as the raw material to the heat treatment of the product ERW pipe. Comprehensive adjustment of ingredients and their contents,
■To prevent welding defects, alloying elements, especially Mn, C
(2) The welding conditions were optimized while regulating the contents of r, and Mo. (2) The heat treatment conditions for the tube were specified in order to make the SSC resistance of the welded part equivalent to that of the base material.
（作用）
以下、本発明の電縫管製造方法における各条件の限定理
由をその作用効果とともに説明する。(Function) Hereinafter, the reason for limiting each condition in the electric resistance welded tube manufacturing method of the present invention will be explained together with its function and effect.
まず、素材鋼帯の化学組成について述べる。First, the chemical composition of the raw steel strip will be described.
Ｃ：強度確保の必要上、０．１５％以上の含有量とする
。しかしＣ含有量が多すぎると靭性、溶接性が劣化し、
熱処理時に焼割れが発生するおそれもあるので、上限を
０．３５％とする。望ましい範囲は０．２０〜０．３０
％である。C: In order to ensure strength, the content should be 0.15% or more. However, if the C content is too high, toughness and weldability will deteriorate,
Since there is a risk of quench cracking occurring during heat treatment, the upper limit is set at 0.35%. Desirable range is 0.20-0.30
%.
Ｓｌ：脱酸効果と焼入れ性向上のため、０．１％以上の
含有を必要とする。しかし、０．８％を超えると結晶粒
の粗大化による耐ＳＳＣ性の低下や靭性劣化を招く、望
ましい範囲は０．２〜０．４％である。Sl: Requires content of 0.1% or more for deoxidizing effect and improving hardenability. However, if it exceeds 0.8%, it causes a decrease in SSC resistance and toughness due to coarsening of crystal grains, so the desirable range is 0.2 to 0.4%.
Ｍｎ：焼入れ性を高めて強度向上に寄与する成分であり
、通常この種の鋼には０．５％以上含有されている。し
かし、本発明では溶接部の耐ＳＳＣ性改善を重視するの
で、その含有量を必要最小限にする。即ち、上記の効果
を得るため下限を０．２％とし、上限は硫化物系介在物
をできるだけ少なくするため０．５％とする。Mn: A component that enhances hardenability and contributes to improved strength, and is normally contained in this type of steel in an amount of 0.5% or more. However, in the present invention, since emphasis is placed on improving the SSC resistance of the welded part, its content is kept to the minimum necessary. That is, the lower limit is set to 0.2% in order to obtain the above effects, and the upper limit is set to 0.5% in order to minimize the amount of sulfide inclusions.
Ｃｒ ： Ｍｎと同じく焼入れ性を高めて強度向上に寄
与する成分である。しかし、Ｃｒの量がふえると溶接時
にＣｒ酸化物が増加するために溶接欠陥が増加し、溶接
部の耐ＳＳＣ性が劣化する。従ってＣｒの含有量も必要
最小限の０．２〜０．６％とする。なお、Ｃｒ含有量は
次に述べるＭｏの含有量と関係づけて調整する必要があ
る。Cr: Like Mn, it is a component that enhances hardenability and contributes to improving strength. However, when the amount of Cr increases, Cr oxide increases during welding, which increases weld defects and deteriorates the SSC resistance of the weld. Therefore, the Cr content is also set to the necessary minimum of 0.2 to 0.6%. Note that the Cr content needs to be adjusted in relation to the Mo content described below.
Ｍｏ：焼入れ性を高めて強度を確保するために０゜０５
％以上の含有量が必要である。一方、ＭＯは粒界炭化物
を粗大化して耐ＳＳＣ性を劣化させるのでその含有量の
上限を０．２５％とする。Mo: 0°05 to improve hardenability and ensure strength
% or more content is required. On the other hand, since MO coarsens grain boundary carbides and deteriorates SSC resistance, the upper limit of its content is set to 0.25%.
ＭｏとＣｒの比（Ｍｏ （％） ／Ｃｒ （％））：第
１図はＭｏ （％） ／Ｃｒ （％）とＳＳＣ発生率と
の関係を調べた結果である。Ratio of Mo and Cr (Mo (%) /Cr (%)): Figure 1 shows the results of investigating the relationship between Mo (%) /Cr (%) and the SSC incidence rate.
なお、この結果は、Ｎｏ （％） ／Ｃｒ （％）を様
々に変えた銅帯について、後述する実施例１同じ鋼帯製
造条件、製管条件、熱処理条件で試験片を作り、実施例
１と同じＳＳＣ試験条件で割れ率をみたものである。Note that this result is based on the test specimens made under the same steel strip manufacturing conditions, pipe manufacturing conditions, and heat treatment conditions as in Example 1, which will be described later, for copper strips with various No (%) / Cr (%) changes. The cracking rate was observed under the same SSC test conditions.
第１図の結果をみれば、母材、溶接部の両方ともに割れ
が発生しないのはＭｏ （％）／Ｃｒ（％）が０．２〜
０．４の範囲である。かかる現象が現れる理由は次のよ
うに考えられる。即ち、Ｍｏ （％）／Ｃｒ（％）が０
．２未満では、高温焼戻し時の炭化物分布の均一性が不
十分で母材および溶接部の耐ＳＳＣ性が劣る。一方、Ｍ
ｏ （％） ／Ｃｒ （％）が０．４を超えると溶接時
に溶接部に粗大な炭化物が形成され、焼入れの加熱時に
も固溶しないため、溶接部の耐ＳＳＣ性が劣るのである
。Looking at the results in Figure 1, it is clear that cracks do not occur in both the base metal and the welded part when Mo (%)/Cr (%) is 0.2 or more.
It is in the range of 0.4. The reason why such a phenomenon appears is considered as follows. That is, Mo (%)/Cr (%) is 0
．． If it is less than 2, the uniformity of carbide distribution during high-temperature tempering is insufficient and the SSC resistance of the base metal and welded part is poor. On the other hand, M
If o (%) /Cr (%) exceeds 0.4, coarse carbides are formed in the weld during welding and do not form a solid solution during heating for quenching, resulting in poor SSC resistance of the weld.
ＺｒおよびＨｆ：それぞれ０．０１％以上、０．００１
％以上で微細窒化物形成により粒界炭化物の粗大化を防
止する効果がある。いずれも０．１５％をこえる含有量
では上記の効果は飽和するのみならず、靭性に悪影響が
ある。Zr and Hf: 0.01% or more, 0.001 respectively
% or more, the formation of fine nitrides has the effect of preventing coarsening of grain boundary carbides. In any case, if the content exceeds 0.15%, not only the above effects are saturated, but also the toughness is adversely affected.
Ｎｂ、 Ｖおよびτｌ：それぞれ０．０１％以上で組織
の微細化と強度向上に寄与する。しかしいずれも０゜１
５％を超えると靭性を劣化させる。Nb, V and τl: each contributes to finer structure and improved strength at 0.01% or more. However, both are 0゜1
If it exceeds 5%, toughness deteriorates.
Ｂ：焼入れ性を上げ強度の向上に効果の大きい成分゛で
ある。特に高強度を必要とするとき０．０００１％以上
含有させる。ただし、０．００３０％を超えると耐ＳＳ
Ｃ性と靭性に悪影響がある。B: A component that is highly effective in increasing hardenability and strength. Particularly when high strength is required, the content is 0.0001% or more. However, if it exceeds 0.0030%, SS resistance
It has a negative effect on carbon properties and toughness.
Ｃａ：Ｂと同じく必要に応じて添加される。 Ｃａの効
果は硫化物系介在物の球状化による耐ＳＳＣ性と耐１）
１Ｃ（水素誘起割れ）性の向上である。この効果が現れ
るのは０．００１％以上である。 ０．０１０％を超え
ると靭性に悪影響がある。Ca: Like B, it is added as necessary. The effect of Ca is on SSC resistance and resistance 1) due to the spheroidization of sulfide inclusions.
This is an improvement in 1C (hydrogen-induced cracking) property. This effect appears at 0.001% or more. If it exceeds 0.010%, toughness will be adversely affected.
上記のＢとＣａは、それぞれ単独で添加してもよく、ま
た複合添加してもよい。The above B and Ca may be added individually or in combination.
次に電縫鋼管の製造工程について説明する。Next, the manufacturing process of the electric resistance welded steel pipe will be explained.
記述のとおり、電縫鋼管溶接部のＳＳＣの一因は酸化物
による溶接欠陥である。その酸化物の生成を防止するた
め、非酸化性雰囲気中で、溶接すべき鋼帯の端部を加熱
し溶接する。雰囲気ガスとしては窒素、アルゴンを使用
し、シールボックスを設けて溶接部を非酸化性に保つ。As described, one cause of SSC in ERW steel pipe welds is weld defects caused by oxides. To prevent the formation of oxides, the ends of the steel strip to be welded are heated and welded in a non-oxidizing atmosphere. Nitrogen or argon is used as the atmospheric gas, and a seal box is provided to keep the welded area non-oxidizing.
接合時のアプセット量を適正な範囲に選ぶことも重要で
ある０本発明者の多数の実験結果によれば、アプセット
量（溶接前後の管外周長の差）が肉厚の２５〜１２５％
のとき、優れた耐ＳＳＣ性が確保される。これが２５％
未満のときは、接合不良が生じることがあり、１２５％
を超えると溶接部のメタルフローが大きくなり非金属介
在物が溶接部の表面に現われ、靭性、耐ＳＳＣ性ともに
劣化する。なお、溶接入熱は通常の４００ＫＶＡ付近で
制御すればよい。It is also important to select the amount of upset during welding within an appropriate range.According to the inventor's numerous experimental results, the amount of upset (difference in the outer circumference of the pipe before and after welding) is 25 to 125% of the wall thickness.
When , excellent SSC resistance is ensured. This is 25%
If it is less than 125%, poor bonding may occur.
If it exceeds this, the metal flow in the weld will increase, non-metallic inclusions will appear on the surface of the weld, and both toughness and SSC resistance will deteriorate. Note that the welding heat input may be controlled at around 400 KVA.
溶接後の熱処理は、溶接部の性能を母材と同等にするた
めの焼入れ焼もどしくＱＴ）処理である。The heat treatment after welding is quenching and tempering (QT) treatment to make the performance of the welded part equivalent to that of the base metal.
焼入れの加熱温度は９２０〜１０２０℃とする０通常の
ＱＴ処理では、焼入れ前の加熱は鋼のオーステナイト変
態点（Ａｒｓ点、本発明の素材鋼帯の場合約８１０〜８
５０℃）以上であればよいとされるが、これを９２０℃
以上とすることによって、溶接部の化学組成が均一化さ
れ、焼入れ後の組織が母材部となり、ひいては焼もどし
後の溶接部の性能も母材と同等のものとなる。しかし、
焼入れ前の加熱温度が１０２０℃を超える高温になると
、溶接部のみならず、母材側もオーステナイト結晶粒が
粗大化し、靭性、耐ＳＳＣ性とも劣化する。焼入れ前の
加熱は、通常のバッチ炉、或いは連続誘導加熱方式を用
いる。また均熱時間は組織均一化のため１分以上とし、
経済性から１時間以内が適当である。The heating temperature for quenching is 920 to 1020°C. In normal QT treatment, the heating before quenching is the austenite transformation point of the steel (Ars point, approximately 810 to 8
50℃) or higher is considered acceptable;
By doing the above, the chemical composition of the welded part is made uniform, the structure after quenching becomes that of the base metal, and the performance of the welded part after tempering becomes equivalent to that of the base metal. but,
When the heating temperature before quenching reaches a high temperature exceeding 1020° C., austenite crystal grains become coarse not only in the weld but also on the base metal side, and both toughness and SSC resistance deteriorate. For heating before quenching, a normal batch furnace or continuous induction heating method is used. In addition, the soaking time should be at least 1 minute to homogenize the structure.
From an economic point of view, it is appropriate to set the time within one hour.
焼入れは、水ジェツトによる連続冷却方式、或いは水槽
への浸漬で行う、焼もどしも、通常のバッチ炉、或いは
連続誘導加熱方式を用いればよい。Quenching may be carried out by continuous cooling using a water jet or by immersion in a water tank, and tempering may be performed using a conventional batch furnace or continuous induction heating method.
温度はＡ１変態点以下でなるべく高温が望ましく、６７
０〜７１０℃が推奨される。均熱時間は焼入れ前の加熱
と同じく１分〜１時間が適当である。The temperature is preferably as high as possible below the A1 transformation point, and 67
A temperature of 0 to 710°C is recommended. The appropriate soaking time is 1 minute to 1 hour, as is the case with heating before quenching.
以上のとおり、鋼帯の化学組成と製管および熱処理工程
を総合して適正な条件とした本発明方法によって製造さ
れる電縫鋼管は、高強度であると同時に優れた耐ＳＳＣ
性を有し、特に腐食条件の厳しい環境下で使用する油井
管用として極めて好適なものとなる。As described above, the electric resistance welded steel pipe manufactured by the method of the present invention under appropriate conditions combining the chemical composition of the steel strip, the pipe manufacturing process, and the heat treatment process has high strength and excellent SSC resistance.
This makes it extremely suitable for oil country tubular goods used particularly in environments with severe corrosive conditions.
（実施例１）
第１表に示す化学組成をもつ２０種の鋼を素材として、
電縫鋼管を製造し、耐ＳＳＣ性を試験した。(Example 1) Using 20 types of steel with the chemical composition shown in Table 1 as raw materials,
Electric resistance welded steel pipes were manufactured and tested for SSC resistance.
素材鋼帯の製造条件、鋼管の製造条件、およびＳＳＣ試
験の条件は次のとおりである。The manufacturing conditions of the raw material steel strip, the manufacturing conditions of the steel pipe, and the conditions of the SSC test are as follows.
（１）鋼帯の製造条件：加熱温度１２５０℃、仕上温度
８５０℃で５腸−厚に熱間圧延し、圧延後６００℃まで
１５℃／秒で冷却、以後炉冷。(1) Manufacturing conditions for steel strip: hot rolling to a thickness of 5 mm at a heating temperature of 1250°C and a finishing temperature of 850°C, cooling at a rate of 15°C/sec to 600°C after rolling, and then cooling in a furnace.
（ｉｉ ）製管条件：窒素ガス雰囲気中で入熱量４００
ＫＶＡの直流通電方式を用いて、アプセット量４ｍｍ（
肉厚の８０％）で溶接し、外径６０＋ｓｍの管とした。(ii) Pipe making conditions: heat input 400 in nitrogen gas atmosphere
Using KVA's direct current method, the upset amount is 4mm (
80% of the wall thickness) to form a tube with an outer diameter of 60+sm.
（ｉｔｉ ）熱処理条件：９５０℃×３０分加熱、水中
焼入れ０次いで、７００℃Ｘ３０分の焼もどしを行った
。(iti) Heat treatment conditions: heating at 950°C for 30 minutes, no quenching in water, then tempering at 700°C for 30 minutes.
（ｉｖ）３５（：試験条件：第２図に示すように、５＋
ｉ＋ｍ厚の試験片に応力集中係数２．５のノツチをつけ
、６０ａｎ＋径のＣリングとして外表面に引張応力を付
加し、１）３ 飽和の０．５％酢酸＋５％食塩の水溶液
に５００時間浸漬し、割れの発生状況を観察した。(iv) 35 (: Test conditions: 5+ as shown in Figure 2)
A notch with a stress concentration factor of 2.5 was made on a test piece with a thickness of i+m, and tensile stress was applied to the outer surface as a C ring with a diameter of 60 an+. The specimen was immersed in water to observe the occurrence of cracks.
試験結果を母材部の引張り試験結果とともに第２表に示
す、なお、耐ＳＳＣ性は、母材部と溶接部に分けて評価
し、数字は各１０ケの試験片のうち割れのあった試験片
の数を示している。The test results are shown in Table 2 together with the tensile test results for the base metal part. The SSC resistance was evaluated separately for the base metal part and the welded part, and the numbers indicate the number of cracks among each 10 test pieces. Indicates the number of test pieces.
第２表に示される如く、本発明で規定する範囲の化学組
成をもつ鋼管（鋼種１〜１０）では、母材、溶接部とも
降伏点を超える応力付加にも関わらず全＜ ＳＳＣは発
生していない、これに対して、Ｍｎ。As shown in Table 2, in steel pipes (steel types 1 to 10) with chemical compositions within the range specified by the present invention, total < SSC did not occur despite the stress applied to both the base metal and the welded part in excess of the yield point. In contrast, Mn.
Ｃｒ、Ｐ ｓ Ｓの高すぎる１２．１３．１７．１８の
鋼管およびＺｒとＩ（ｆのいずれも含まない１６の鋼管
では母材、溶接部双方にＳＳＣが多発している。１）．
１４．１５．２０の鋼管は母材側のＳＳＣは殆んどない
がいずれも溶接部のＳＳＣがはげしい、これらはＭｎ量
又はＡＱ量の過多、Ｍｏ （％） ／Ｃｒ （％）の不
通正によるものである。１９の鋼管は溶接部にはＳＳＣ
が見られないが母材側の耐ＳＳＣ性が劣る。これは、前
述の第１図の試験結果と同じ＜Ｍｏ（％） ／Ｃｒ （
％）が小さすぎて、炭化物の分布が不均一になっている
ものと思われる。In steel pipes 12, 13, 17, and 18 with too high Cr, P s S, and 16 steel pipes containing neither Zr nor I (f), SSC occurs frequently in both the base metal and the weld. 1).
The steel pipes of 14.15.20 have almost no SSC on the base metal side, but all have severe SSC in the welded parts.These are caused by excessive Mn content or AQ content, and failure of Mo (%) / Cr (%). This is due to 19 steel pipes have SSC on welded parts
is not observed, but the SSC resistance of the base metal side is poor. This is the same as the test result shown in Fig. 1 above <Mo (%) /Cr (
%) is too small, and the distribution of carbides is considered to be uneven.
（実施例２）
第１表の３の鋼管を用いて、溶接条件が耐ＳＳＣ性に及
ぼす°影響を調べた。溶接条件以外の製管条件、熱処理
条件および試験条件は、実施例１と同じである。(Example 2) The influence of welding conditions on SSC resistance was investigated using the steel pipe shown in 3 in Table 1. Pipe-making conditions, heat treatment conditions, and test conditions other than welding conditions are the same as in Example 1.
第３表に溶接条件と溶接部の耐ＳＳＣ性とを示す。Table 3 shows the welding conditions and the SSC resistance of the welded parts.
窒素ガス雰囲気中で溶接され、かつアプセット量が本発
明で定める範囲内にある時にだけ、溶接部の耐ＳＳＣが
完全である。The SSC resistance of the welded portion is perfect only when welding is performed in a nitrogen gas atmosphere and the amount of upset is within the range defined by the present invention.
同じく第１表の３の鋼帯から製造した電縫鋼管を用い、
焼入れ前加熱温度の影響をみた。製管までの条件、試験
条件は実施例１と同じである。第４表に示す耐ＳＳＣ性
の試験結果によれば、加熱温度が低すぎる場合溶接部の
耐ＳＳＣ性が劣り、高すぎる場合には母材、溶接部とも
耐ＳＳＣ性が悪い。Similarly, using an electric resistance welded steel pipe manufactured from steel strip 3 in Table 1,
The influence of heating temperature before quenching was examined. The conditions up to pipe making and test conditions are the same as in Example 1. According to the SSC resistance test results shown in Table 4, if the heating temperature is too low, the SSC resistance of the welded part is poor, and if it is too high, the SSC resistance of both the base metal and the welded part is poor.
焼入れ時の加熱温度の選定も耐ＳＳＣ性の改善に極めて
重要であることが分る。It can be seen that selection of the heating temperature during quenching is also extremely important for improving SSC resistance.
（発明の効果）
本発明は特に油井管として用いられることを前提として
、高強度であると同時に耐ＳＳＣ性にも優れた電縫鋼管
の製造方法を提供する。この本発明方法は素材となる鋼
帯の化学組成から製管及び熱処理の条件まで緻密に検討
し、−貫して管理するところに特色があり、それによっ
て電縫鋼管本来の長所を生かしながら、溶接部の耐ＳＳ
Ｃ性が小さいという欠点を克服している。(Effects of the Invention) The present invention provides a method for manufacturing an electric resistance welded steel pipe that has high strength and excellent SSC resistance, especially on the premise that the pipe is used as an oil country tubular product. The method of the present invention is characterized by careful consideration and thorough management of everything from the chemical composition of the raw material steel strip to the tube manufacturing and heat treatment conditions, thereby making full use of the inherent advantages of ERW steel pipe. SS resistance of welded parts
This overcomes the drawback of low C properties.
本発明方法によって得られる電縫鋼管は、油井管として
だけでなく、高強度と優れた耐ＳＳＣ性を必要とするあ
らゆる用途に使用できることは言うまでもない。It goes without saying that the electric resistance welded steel pipe obtained by the method of the present invention can be used not only as oil country tubular goods but also for all kinds of applications requiring high strength and excellent SSC resistance.
第１図は、素材鋼帯のＭｏとＣｒの含有量の比とＳＳＣ
発生率との関係を示す図、
第２図は、耐ＳＳＣ性試験に用いた試験片形状を示す図
、である。Figure 1 shows the ratio of Mo and Cr contents in the raw steel strip and the SSC.
FIG. 2 is a diagram showing the relationship with the incidence rate. FIG. 2 is a diagram showing the shape of the test piece used in the SSC resistance test.
Claims (4)
．１〜０．８％、Ｍｎ：０．２〜０．５％、Ｃｒ：０．
２〜０．６％、Ｍｏ：０．０５〜０．２５％、ｓｏｌ．
Ａｌ：０．０１〜０．０６％、並びにＺｒ：０．０１〜
０．１５％とＨｆ：０．００１〜０．１５０％の１種ま
たは２種、およびＮｂ：０．０１〜０．１５％、Ｖ：０
．０１〜０．１５％、Ｔｉ：０．０１〜０．１５％のう
ちの１種以上、残部Ｆｅと不可避不純物から成り、不純
物としてのＰが０．０２％以下、Ｓが０．００５％以下
であり、かつ０．２≦Ｍｏ（％）／Ｃｒ（％）≦０．４
である鋼帯を、その接合端部を非酸化性雰囲気で加熱し
、アプセット量が肉厚の２５〜１２５％となるように電
縫溶接し、得られた鋼管を９２０〜１０２０℃に加熱し
た後焼入れし、次いで焼もどしを行う耐硫化物割れ性に
優れた高強度電縫鋼管の製造方法。(1) In weight%, C: 0.15-0.35%, Si: 0
．． 1-0.8%, Mn: 0.2-0.5%, Cr: 0.
2-0.6%, Mo: 0.05-0.25%, sol.
Al: 0.01 to 0.06%, and Zr: 0.01 to
0.15%, Hf: 0.001-0.150%, and Nb: 0.01-0.15%, V: 0
．． 01 to 0.15%, Ti: one or more of 0.01 to 0.15%, the balance consisting of Fe and unavoidable impurities, P as impurities is 0.02% or less, S is 0.005% or less and 0.2≦Mo(%)/Cr(%)≦0.4
The joint ends of the steel strips were heated in a non-oxidizing atmosphere, and electrical resistance welding was performed so that the upset amount was 25 to 125% of the wall thickness, and the obtained steel pipe was heated to 920 to 1020 ° C. A method for manufacturing high-strength electric resistance welded steel pipes with excellent sulfide cracking resistance, which involves post-quenching and then tempering.
．１〜０．８％、Ｍｎ：０．２〜０．５％、Ｃｒ：０．
２〜０．６％、Ｍｏ：０．０５〜０．２５％、ｓｏｌ．
Ａｌ：０．０１〜０．０６％、Ｂ：０．０００１〜０．
００３０％、並びにＺｒ：０．０１〜０．１５％とＨｆ
：０．００１〜０．１５０％の１種または２種、および
Ｎｂ：０．０１〜０．１５％、Ｖ：０．０１〜０．１５
％、Ｔｉ：０．０１〜０．１５％のうちの１種以上、残
部Ｆｅと不可避不純物から成り、不純物としてのＰが０
．０２％以下、Ｓが０．００５％以下であり、かつ０．
２≦Ｍｏ（％）／Ｃｒ（％）≦０．４である鋼帯を、そ
の接合端部を非酸化性雰囲気で加熱し、アプセット量が
肉厚の２５〜１２５％となるように電縫溶接し、得られ
た鋼管を９２０〜１０２０℃に加熱した後焼入れし、次
いで焼もどしを行う耐硫化物割れ性に優れた高強度電縫
鋼管の製造方法。(2) In weight%, C: 0.15-0.35%, Si: 0
．． 1-0.8%, Mn: 0.2-0.5%, Cr: 0.
2-0.6%, Mo: 0.05-0.25%, sol.
Al: 0.01-0.06%, B: 0.0001-0.
0030%, and Zr: 0.01 to 0.15% and Hf
: 0.001 to 0.150% of one or two kinds, and Nb: 0.01 to 0.15%, V: 0.01 to 0.15
%, Ti: one or more of 0.01 to 0.15%, the balance consists of Fe and unavoidable impurities, and P as an impurity is 0
．． 0.02% or less, S is 0.005% or less, and 0.02% or less.
A steel strip with 2≦Mo (%)/Cr (%)≦0.4 is heated at its joint end in a non-oxidizing atmosphere, and is electrically welded so that the upset amount is 25 to 125% of the wall thickness. A method for manufacturing a high-strength electric resistance welded steel pipe with excellent sulfide cracking resistance, which comprises welding, heating the obtained steel pipe to 920 to 1020°C, quenching, and then tempering.
．１〜０．８％、Ｍｎ：０．２〜０．５％、Ｃｒ：０．
２〜０．６％、Ｍｏ：０．０５〜０．２５％、ｓｏｌ．
Ａｌ：０．０１〜０．０６％、Ｃａ：０．００１〜０．
０１０％、並びにＺｒ：０．０１〜０．１５％とＨｆ：
０．００１〜０．１５０％の１種または２種、およびＮ
ｂ：０．０１〜０．１５％、Ｖ：０．０１〜０．１５％
、Ｔｉ：０．０１〜０．１５％のうちの１種以上、残部
Ｆｅと不可避不純物から成り、不純物としてのＰが０．
０２％以下、Ｓが０．００５％以下であり、かつ０．２
≦Ｍｏ（％）／Ｃｒ（％）≦０．４である鋼帯を、その
接合端部を非酸化性雰囲気で加熱し、アプセット量が肉
厚の２５〜１２５％となるように電縫溶接し、得られた
鋼管を９２０〜１０２０℃に加熱した後焼入れし、次い
で焼もどしを行う耐硫化物割れ性に優れた高強度電縫鋼
管の製造方法。(3) In weight%, C: 0.15-0.35%, Si: 0
．． 1-0.8%, Mn: 0.2-0.5%, Cr: 0.
2-0.6%, Mo: 0.05-0.25%, sol.
Al: 0.01-0.06%, Ca: 0.001-0.
010%, and Zr: 0.01 to 0.15% and Hf:
0.001 to 0.150% of one or two types, and N
b: 0.01-0.15%, V: 0.01-0.15%
, Ti: 0.01 to 0.15%, the balance is Fe and unavoidable impurities, and P as an impurity is 0.01 to 0.15%.
02% or less, S is 0.005% or less, and 0.2%
Steel strips with ≦Mo (%)/Cr (%)≦0.4 are heated at their joint ends in a non-oxidizing atmosphere, and electrical resistance welding is performed so that the upset amount is 25 to 125% of the wall thickness. A method for manufacturing a high-strength electric resistance welded steel pipe with excellent sulfide cracking resistance, which comprises heating the obtained steel pipe to 920 to 1020°C, quenching it, and then tempering it.
．１〜０．８％、Ｍｎ：０．２〜０．５％、Ｃｒ：０．
２〜０．６％、Ｍｏ：０．０５〜０．２５％、ｓｏｌ．
Ａｌ：０．０１〜０．０６％、Ｂ：０．０００１〜０．
００３０％、Ｃａ：０．００１〜０．０１０％、並びに
Ｚｒ：０．０１〜０．１５％とＨｆ：０．００１〜０．
１５０％の１種または２種、およびＮｂ：０．０１〜０
．１５％、Ｖ：０．０１〜０．１５％、Ｔｉ：０．０１
〜０．１５％のうちの１種以上、残部Ｆｅと不可避不純
物から成り、不純物としてのＰが０．０２％以下、Ｓが
０．００５％以下であり、かつ０．２≦Ｍｏ（％）／Ｃ
ｒ（％）≦０．４である鋼帯を、その接合端部を非酸化
性雰囲気で加熱し、アプセット量が肉厚の２５〜１２５
％となるように電縫溶接し、得られた鋼管を９２０〜１
０２０℃に加熱した後焼入れし、次いで焼もどしを行う
耐硫化物割れ性に優れた高強度電縫鋼管の製造方法。(4) In weight%, C: 0.15-0.35%, Si: 0
．． 1-0.8%, Mn: 0.2-0.5%, Cr: 0.
2-0.6%, Mo: 0.05-0.25%, sol.
Al: 0.01-0.06%, B: 0.0001-0.
0030%, Ca: 0.001-0.010%, Zr: 0.01-0.15%, and Hf: 0.001-0.001%.
150% of one or two types, and Nb: 0.01-0
．． 15%, V: 0.01-0.15%, Ti: 0.01
~0.15%, the balance consists of Fe and unavoidable impurities, P as impurities is 0.02% or less, S is 0.005% or less, and 0.2≦Mo (%) /C
A steel strip with r(%)≦0.4 is heated at its joint end in a non-oxidizing atmosphere, and the upset amount is 25 to 125 of the wall thickness.
%, and the obtained steel pipe is 920~1
A method for producing a high-strength electric resistance welded steel pipe with excellent sulfide cracking resistance, which comprises heating to 020°C, quenching, and then tempering.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7474987A JPS63241116A (en) | 1987-03-28 | 1987-03-28 | Manufacture of high strength resistance welded steel tube having superior sulfide cracking resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7474987A JPS63241116A (en) | 1987-03-28 | 1987-03-28 | Manufacture of high strength resistance welded steel tube having superior sulfide cracking resistance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS63241116A true JPS63241116A (en) | 1988-10-06 |
Family
ID=13556216
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7474987A Pending JPS63241116A (en) | 1987-03-28 | 1987-03-28 | Manufacture of high strength resistance welded steel tube having superior sulfide cracking resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63241116A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5019189A (en) * | 1989-04-13 | 1991-05-28 | Kawasaki Steel Corporation | Steel pipe and a method for welding thereof and pipeline resistant to carbon dioxide corrosion |
-
1987
- 1987-03-28 JP JP7474987A patent/JPS63241116A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5019189A (en) * | 1989-04-13 | 1991-05-28 | Kawasaki Steel Corporation | Steel pipe and a method for welding thereof and pipeline resistant to carbon dioxide corrosion |
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