JP2705946B2 - Manufacturing method of high strength steel sheet with excellent SSC resistance - Google Patents
Manufacturing method of high strength steel sheet with excellent SSC resistanceInfo
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- JP2705946B2 JP2705946B2 JP63156717A JP15671788A JP2705946B2 JP 2705946 B2 JP2705946 B2 JP 2705946B2 JP 63156717 A JP63156717 A JP 63156717A JP 15671788 A JP15671788 A JP 15671788A JP 2705946 B2 JP2705946 B2 JP 2705946B2
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Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は、特に耐SSC性に優れた引張強さ60Kgf/mm2級
の高張力鋼の製造法に関する。DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a method for producing a high-strength steel having a tensile strength of 60 kgf / mm 2 which is particularly excellent in SSC resistance.
（従来の技術） アンモニア、LPGなどの貯蔵タンクや石油、天然ガス
輸送用のラインパイプでは、硫化水素（H2S）によるSSC
（硫化物応力腐食割れ）が大きな問題となっている。SS
Cは、湿潤な硫化水素環境下の腐食反応で生じた水素に
よる水素脆性割れの一種と考えられている。(Conventional technology) Hydrogen sulfide (H 2 S) is used for storage tanks for ammonia and LPG, and for line pipes for oil and natural gas transport.
(Sulfide stress corrosion cracking) is a major problem. SS
C is considered to be a type of hydrogen embrittlement cracking caused by hydrogen generated by a corrosion reaction in a wet hydrogen sulfide environment.
鋼のSSC感受性は、化学成分やミクロ組織、非金属介
在物の有無などによって異なるが、特に硬さの影響が大
きく、ビッカース硬さHv248（HRC22）以下ではSSCは起
こらないとされている。しかし、従来のHT60は特開昭59
−126716号公報で示すように、Ｂ添加鋼の焼入れ・焼戻
し（QT）処理によって製造されており、Ｂの焼入れ性向
上効果を利用しているために、小入熱溶接熱影響部（HA
Z）の硬さが高く、SSC感受性が増大するという欠点を有
していた。SSC susceptibility of steel, chemical composition and microstructure, varies depending on the presence or absence of non-metallic inclusions, in particular the hardness of the impact is large, the following Vickers hardness Hv248 (H R C22) is the SSC does not occur . However, the conventional HT60 is disclosed in
No.-126716, manufactured by quenching and tempering (QT) treatment of B-added steel and utilizing the effect of improving the hardenability of B, the heat affected zone (HA) of small heat input welding
Z) had the disadvantage of high hardness and increased SSC sensitivity.
またＢ無添加のHT60もＣ量をはじめ添加元素や製造法
が適切でなく、母材、HAZの耐SSC性は著しく劣ってい
た。このため新知見に基づく画期的なHT60の開発が強く
望まれていた。Also, HT60 without B added was inadequate in the added element and production method including the C amount, and the SSC resistance of the base material and HAZ was extremely poor. For this reason, the development of epoch-making HT60 based on new findings was strongly desired.
（発明が解決しようとする課題） 本発明は耐SSC性に優れた高張力鋼を安価に製造する
方法を提供するもので、本発明法で製造した鋼は低入熱
溶接時においてもHAZ硬さを低く抑えることが可能とな
り、きわめて優れた耐SSC性を示す。(Problems to be Solved by the Invention) The present invention provides a method for inexpensively producing a high-tensile steel having excellent SSC resistance. The steel produced by the method of the present invention can be used for HAZ hardening even during low heat input welding. It is possible to keep the hardness low, and it shows extremely excellent SSC resistance.
（課題を解決するための手段） 本発明の要旨は、重量％でC:0.02〜0.06％、Si:0.6％
以下、Mn:1.0〜1.6％、P:0.20％以下、S:0.006％以下、
Al:0.001〜0.060％、Mo:0.05〜0.40％、Nb:0.01〜0.05
％、Ti:0.005〜0.030％、N:0.006％以下、必要に応じて
V:0.01〜0.10％、Cr:0.05〜0.50％、Ni:0.05〜1.0％、C
u:0.05〜1.0％、Ca:0.001〜0.006％の一種またはＶ−C
r、Cr−Ni、Ni−Cu、Ｖ−Ca、Ｖ−Cr−Cu、Cr−Ni−C
u、Ｖ−Cr−Ni−Cuの組合せを含有し、残部が鉄および
不可避的不純物からなる実質的にＢを含有しない鋼を連
続鋳造法によってスラブとし、再加熱なしの直送圧延
（HCR、DR）ないしはスラブ冷却後これを1050〜1250℃
の温度で再加熱し、800〜900℃未満の温度で圧延を終了
してただちに焼入れた後Ac1点以下の温度で焼戻し処理
する。(Means for Solving the Problems) The gist of the present invention is as follows: C: 0.02 to 0.06% by weight, Si: 0.6%
Below, Mn: 1.0 to 1.6%, P: 0.20% or less, S: 0.006% or less,
Al: 0.001 to 0.060%, Mo: 0.05 to 0.40%, Nb: 0.01 to 0.05
%, Ti: 0.005-0.030%, N: 0.006% or less, as required
V: 0.01 to 0.10%, Cr: 0.05 to 0.50%, Ni: 0.05 to 1.0%, C
u: 0.05-1.0%, Ca: 0.001-0.006%, or VC
r, Cr-Ni, Ni-Cu, V-Ca, V-Cr-Cu, Cr-Ni-C
u, a steel containing a combination of V-Cr-Ni-Cu, and the balance substantially free of B consisting of iron and unavoidable impurities, is made into a slab by a continuous casting method, and is directly rolled without reheating (HCR, DR ) Or after slab cooling, 1050 ~ 1250 ℃
, And after the rolling is completed at a temperature of less than 800 to 900 ° C, quenched immediately, and then tempered at a temperature of 1 point or less of Ac.
（作用） 以下、本発明について説明する。(Operation) Hereinafter, the present invention will be described.
発明者らの研究によれば、母材強度および耐SSC性に
影響を及ぼすとされるHAZ硬さは鋼の焼入れ性に大きく
依存し、HAZ硬さの低減と母材の高張力化とを同時にバ
ランスよく達成するためには、焼入れ性のみに着目した
鋼成分の適正化だけでは不十分である。According to the study of the inventors, the HAZ hardness, which is considered to affect the base metal strength and SSC resistance, greatly depends on the hardenability of steel, and it is necessary to reduce the HAZ hardness and increase the tensile strength of the base metal. At the same time, in order to achieve a good balance, it is not enough to optimize only the steel components, focusing only on the hardenability.
一方、Ｂフリー・低Ｃ化によって焼入れ性を下げるこ
とは、HAZ硬さ低減の見地からきわめて有効である。そ
こで焼入れ性を下げるためＢフリー・低Ｃをベースとし
てHAZ硬さを抑え、母材強度の不足分はNb（必要に応じ
Ｖ）添加による析出硬化現象を活用することによって補
う方法を発明した。On the other hand, lowering the hardenability by B-free and low C is extremely effective from the viewpoint of reducing the HAZ hardness. In order to reduce the hardenability, the inventors invented a method of suppressing the HAZ hardness based on B-free and low C, and compensating for the lack of base metal strength by utilizing the precipitation hardening phenomenon by adding Nb (V if necessary).
析出硬化は鋼中に析出物を微細に分散させることによ
ってその効果を発揮する。そのため溶鋼の凝固冷却中に
微細析出したNbの析出物が粗大化することのないよう適
切な再加熱、圧延、冷却、熱処理条件を付与する必要が
ある。Precipitation hardening exerts its effect by finely dispersing precipitates in steel. Therefore, it is necessary to provide appropriate reheating, rolling, cooling, and heat treatment conditions so that the precipitate of Nb finely precipitated during solidification and cooling of molten steel does not become coarse.
この析出硬化の活用は、圧延後の直接焼入れによって
可能となったものであり、その理由については後述す
る。またこの直接焼入れ・焼戻し処理を施すことによっ
て組織の均一化がはかられ、耐硫化水素割れ性の面から
も好ましいものとなる。This utilization of precipitation hardening has been made possible by direct quenching after rolling, and the reason will be described later. Further, by performing the direct quenching / tempering treatment, the structure can be made uniform, which is preferable from the viewpoint of resistance to hydrogen sulfide cracking.
しかし、たとえNbの析出物が鋼中に微細に分散してい
ても基本成分が適当でないと、HAZ硬さと母材の高張力
化とのバランスのよい達成は困難である。However, even if Nb precipitates are finely dispersed in steel, it is difficult to achieve a good balance between HAZ hardness and high tensile strength of the base material if the basic components are not appropriate.
以下、この点について説明する。 Hereinafter, this point will be described.
Ｃは焼入れ性に最も顕著に効くものであるが、下限0.
02％は母材および溶接部の強度確保ならびにNbなどの添
加時に、これらの効果を発揮させるための最小量であ
る。しかしＣ量が多過ぎると焼入れ性が上がり、HAZ硬
さを上昇させるため上限を0.06％とした。C has the most remarkable effect on hardenability, but has a lower limit of 0.
02% is the minimum amount for exerting these effects when securing the strength of the base metal and the weld and adding Nb and the like. However, if the C content is too large, the hardenability increases, and the upper limit is made 0.06% in order to increase the HAZ hardness.
Siは脱酸上鋼に含まれる元素であるが、多く添加する
と溶接性、HAZ靭性が劣化するため、上限を0.6％に限定
した。鋼の脱酸はAlのみでも十分可能であり、焼入れ性
の観点から0.25％以下が望ましい。Si is an element contained in the deoxidized upper steel, but if added too much, the weldability and HAZ toughness deteriorate, so the upper limit was limited to 0.6%. Steel can be sufficiently deoxidized with Al alone, and is desirably 0.25% or less from the viewpoint of hardenability.
Mnは強度、靭性を確保する上で不可欠な元素であり、
その下限は1.0％である。しかしMn量が多過ぎると焼入
れ姓が上昇して溶接性、HAZ靭性を劣化させるだけでな
く、スラブの中心偏析を助長するので上限を1.6％とし
た。Mn is an element indispensable for securing strength and toughness,
The lower limit is 1.0%. However, if the amount of Mn is too large, the hardened name increases and not only deteriorates weldability and HAZ toughness, but also promotes center segregation of the slab, so the upper limit was made 1.6%.
本発明鋼において不純物であるＰ、Ｓをそれぞれ0.02
0％以下、0.006％以下とした理由は、母材、溶接部の低
温靭性をより一層向上させるためである。Ｐ量の低減は
HAZにおける粒界破壊を減少させ、またＳ量の低減は粒
界フェライトの生成を抑制する傾向がある。最も好まし
いＰ、Ｓ量は、それぞれ0.01％、0.002％以下である。In the steel of the present invention, the impurities P and S were each reduced to 0.02.
The reason for setting the content to 0% or less and 0.006% or less is to further improve the low-temperature toughness of the base material and the welded portion. Reduction of P amount
Grain boundary fracture in HAZ is reduced, and reduction of S content tends to suppress generation of grain boundary ferrite. The most preferable P and S amounts are 0.01% and 0.002% or less, respectively.
Alは一般に脱酸上鋼に含まれる元素であり、最低0.00
1％の添加含有が必要である。しかし、Alが0.060％を超
えるとHAZ靭性のみならず溶接金属の靭性も著しく劣化
させるためその上限を0.060％とした。Al is an element generally contained in the deoxidized steel and has a minimum content of 0.00
1% additive content is required. However, if Al exceeds 0.060%, not only the HAZ toughness but also the toughness of the weld metal is significantly deteriorated, so the upper limit was made 0.060%.
Moは母材の強度、靭性をともに向上させる。特に本発
明鋼においては強度確保上不可欠の元素であり、その下
限は0.05％である。しかし添加量が多過ぎると母材、溶
接部の靭性、溶接性の劣化を招き好ましくない。そのた
め上限を0.40％とした。Mo improves both strength and toughness of the base material. Particularly, in the steel of the present invention, it is an indispensable element for securing the strength, and the lower limit is 0.05%. However, if the amount is too large, the toughness and weldability of the base material and the welded portion are deteriorated, which is not preferable. Therefore, the upper limit was set to 0.40%.
Nbは本発明鋼において必須元素であり、焼入れ性低下
に伴う強度不足分を析出硬化として補う上で、最低0.01
％が必要である。しかしNbは同時にHAZ硬さ上昇も伴う
ためその上限を0.05％とした。Nb is an essential element in the steel of the present invention, and in order to compensate for insufficient strength due to a decrease in hardenability as precipitation hardening, at least 0.01
%is required. However, since Nb is accompanied by an increase in HAZ hardness at the same time, the upper limit is set to 0.05%.
Tiは母材およびHAZ靭性向上のために必須であり、そ
の下限を0.005％とした。上限は過剰のTiによるTiCの析
出を防止するため0.030％とした。Ti is essential for improving the base material and HAZ toughness, and the lower limit is set to 0.005%. The upper limit is set to 0.030% in order to prevent precipitation of TiC due to excessive Ti.
次にＶ、Cr、Ni、Cu、Caを添加する理由について説明
する。Next, the reason for adding V, Cr, Ni, Cu, and Ca will be described.
基本となる成分に、さらにこれらの元素を添加する主
たる目的は、本発明鋼の優れた特徴を損なうことなく強
度、靭性など特性の向上をはかるためである。したがっ
てその添加量は自ずから制限されるべき性質のものであ
る。The main purpose of adding these elements to the basic components is to improve properties such as strength and toughness without impairing the excellent characteristics of the steel of the present invention. Therefore, the amount of addition is of a nature that should be naturally restricted.
ＶはNbと同様析出硬化に寄与するものであるが、Nbに
比べて母材強度の強化代は小さいため0.01％以下では効
果が少なく、上限は0.10％まで許容できる。またＶはHA
Z硬さをほとんど変化させないためNbとの複合添加が望
ましい。V contributes to precipitation hardening similarly to Nb. However, since the margin for strengthening the base material is smaller than that of Nb, the effect is small at 0.01% or less, and the upper limit is allowable up to 0.10%. V is HA
In order to hardly change the Z hardness, composite addition with Nb is desirable.
Crは母材、溶接部の強度を高めるが、多過ぎると溶接
性や接合部の靭性を劣化させるため上限を0.50％とし
た。下限は材質上への効果が得られるための最小量とす
べきで0.05％である。これは次のNi、Cuについても同様
である。Although Cr increases the strength of the base material and the welded portion, if too much, the weldability and the toughness of the joined portion are deteriorated, so the upper limit was made 0.50%. The lower limit should be the minimum amount for obtaining the effect on the material, and is 0.05%. This is the same for the following Ni and Cu.
Niは溶接性、HAZ靭性に悪影響を及ぼすことなく、母
材の強度、靭性を向上させるが、過剰な添加は溶接性に
好ましくないため上限を1.0％とした。Ni improves the strength and toughness of the base material without adversely affecting the weldability and the HAZ toughness, but the upper limit is set to 1.0% because excessive addition is not preferable for the weldability.
CuはNiとほぼ同様の効果とともに耐食性、耐水素誘起
割れ性などにも効果があるが、1.0％を超えると熱間圧
延時にCu−クラックが発生し製造困難となる。このため
上限を1.0％とした。Cu has almost the same effect as Ni, as well as corrosion resistance and hydrogen-induced cracking resistance. However, if it exceeds 1.0%, Cu-cracks occur during hot rolling, making production difficult. Therefore, the upper limit is set to 1.0%.
Caは硫化物（MnS）の形態を制御し、低温靭性を向上
（シャルピー吸収エネルギーを増加）させるほか、耐水
素誘起割れ性の改善にも効果を発揮する。しかしCa量0.
001％以下では実用上効果がなく、また0.006％を超えて
添加するとCaO、CaSが多量に生成して大型介在物とな
り、鋼の靭性のみならず清浄度も害し、さらには溶接性
にも悪影響を与える。このため添加量の範囲を0.001〜
0.006％に制限した。Ca controls the form of sulfide (MnS), improves low-temperature toughness (increases Charpy absorbed energy), and has an effect on improving hydrogen-induced cracking resistance. However, the amount of Ca is 0.
If it is less than 001%, there is no practical effect, and if it exceeds 0.006%, CaO and CaS are generated in large quantities and become large inclusions, which impair not only the toughness but also the cleanliness of the steel, and also have an adverse effect on weldability. give. Therefore, the range of the addition amount is 0.001 to
Limited to 0.006%.
鋼の成分を上記のように限定しても、製造法が適切で
なければ析出硬化を利用した母材強度の確保およびHAZ
硬さの低減を達成することはできない。このため製造条
件についても限定する必要がある。Even if the composition of steel is limited as described above, if the manufacturing method is not appropriate, securing base metal strength using precipitation hardening and HAZ
No reduction in hardness can be achieved. Therefore, it is necessary to limit the manufacturing conditions.
まず、この鋼は工業的には連続鋳造法で製造すること
が必須である。この理由は、連続鋳造法では溶鋼の凝固
冷却速度が速く、スラブ中に微細なNbの析出物が多量に
得られるためである。大型鋼塊による造塊−分塊法で
は、Nbの析出物をスラブ中に微細分散させることは難し
い。First, it is essential that this steel be manufactured by a continuous casting method industrially. The reason is that the solidification cooling rate of molten steel is high in the continuous casting method, and a large amount of fine Nb precipitates are obtained in the slab. In the ingot-bulking method using a large steel ingot, it is difficult to finely disperse Nb precipitates in the slab.
連続鋳造法の場合、スラブ厚によって冷却速度が異な
るが、その厚みは350mm以下が望ましい。さらにスラブ
の再加熱温度を1250℃以下とする必要がある。なぜなら
これ以上の温度で再加熱すると析出物が粗大化して、析
出硬化現象を期待できないためである。In the case of the continuous casting method, the cooling rate varies depending on the slab thickness, but the thickness is desirably 350 mm or less. Furthermore, the reheating temperature of the slab must be 1250 ° C or less. This is because if reheating is performed at a temperature higher than this, the precipitates become coarse and the precipitation hardening phenomenon cannot be expected.
なお本発明においては、スラブの再加熱は必ずしも実
施する必要はなく、ホットチャージ圧延やダイレクト圧
延を行っても全く問題はない。In the present invention, it is not always necessary to reheat the slab, and there is no problem even if hot charge rolling or direct rolling is performed.
次にスラブ再加熱後の圧延・熱処理条件の限定理由に
ついて述べる。Next, the reasons for limiting the rolling and heat treatment conditions after slab reheating will be described.
圧延終了温度が800℃以下になると、MnS系介在物が残
存した場合に延伸しやすいこと、圧延中にフェライトを
加工する危険性が生ずることなどから800℃以上でなけ
ればならない。しかしあまり高温で圧延を終了した場
合、圧延により細粒化したオーステナイト粒が再び成長
し、鋼の焼入れ性が上昇するためその上限を900℃未満
とした。When the rolling end temperature is 800 ° C. or lower, the temperature must be 800 ° C. or higher because the MnS-based inclusions are likely to be stretched when remaining, and there is a risk of processing ferrite during rolling. However, when the rolling was terminated at an excessively high temperature, the austenite grains refined by the rolling grew again and the hardenability of the steel increased, so the upper limit was set to less than 900 ° C.
また圧延終了後ただちに焼入れする理由は、従来法に
したがい空冷した場合、空冷中にNbの析出物が粗大化し
てしまい、空冷のままの強度はもとよりこれを再加熱し
て焼入れ・焼戻しを行ってもその加熱時にNbが固溶しな
いため、析出物を微細化できず高強度が得られない。The reason for quenching immediately after the end of rolling is that if air cooling is performed according to the conventional method, precipitates of Nb are coarsened during air cooling, and the quenching and tempering is performed by reheating this as well as the strength while maintaining air cooling. However, since Nb does not form a solid solution at the time of heating, precipitates cannot be refined and high strength cannot be obtained.
すなわち圧延後の直接焼入れは組織の微細化をはかる
とともに、析出物の粗大化を防止するために不可欠のも
のであり、これを焼戻すことによって析出物が微細に分
散し、同時に焼入れ後に得られる微細組織の焼戻しによ
って、高張力、高靭性を確保することができる。In other words, direct quenching after rolling aims to refine the structure, and is indispensable for preventing coarsening of the precipitates.Precipitation is finely dispersed by tempering this, and simultaneously obtained after quenching. By tempering the microstructure, high tensile strength and high toughness can be secured.
（実施例） 表１は本発明を実施するにあたって使用に供した鋼の
化学組成である。また表２は各々の鋼に対する製造条件
と母材特性及びHAZ硬さとを示したものである。(Examples) Table 1 shows the chemical composition of steel used for carrying out the present invention. Table 2 shows the manufacturing conditions, base metal properties, and HAZ hardness for each steel.
比較鋼において鋼16はNbが添加されていないため強度
が不足している。また鋼17は直接焼き入れを行っていな
いために析出硬化を活用できておらず、強度が不足して
いる。さらに鋼18ではＣ量が多過ぎる上にＢを含有する
ため、HAZ硬さを低く抑えることができていない。In the comparative steel, steel 16 has insufficient strength because Nb is not added. Further, since steel 17 is not directly quenched, it cannot utilize precipitation hardening and has insufficient strength. Further, since the steel 18 has too much C and contains B, the HAZ hardness cannot be kept low.
これに対して本発明法で製造した鋼板（本発明鋼）は
母材強度とHAZ硬さとをバランスよく達成できている。
また本発明鋼は、４点曲げ応力を付加して行ったが、割
れは全く認められなかった。On the other hand, the steel sheet manufactured by the method of the present invention (the steel of the present invention) achieves a good balance between base material strength and HAZ hardness.
The steel of the present invention was subjected to a four-point bending stress, but no crack was observed.
（発明の効果） 本発明により、母材の高張力化とHAZ硬さの低減とを
同時に達成する鋼を大量かつ安価に製造することが可能
になった。その結果、硫化水素雰囲気にさらされるLP
G、ガス貯蔵用球形タンクなどの溶接鋼構造物の安全性
を大きく向上させることができた。 (Effects of the Invention) According to the present invention, it has become possible to mass-produce steel inexpensively, which achieves both high tensile strength of the base material and reduction of HAZ hardness at the same time. As a result, LP exposed to hydrogen sulfide atmosphere
G. The safety of welded steel structures such as gas storage spherical tanks was greatly improved.
本発明は、厚板ミルに適用することが最も好ましい
が、ホットコイル、形鋼などにも適用可能である。ま
た、この方法で製造した厚鋼板は圧力容器、海洋構造
物、ラインパイプなど厳しい環境下で使用される溶接鋼
構造物を用いることができる。The present invention is most preferably applied to a thick plate mill, but is also applicable to a hot coil, a shaped steel, and the like. In addition, as the thick steel plate manufactured by this method, a welded steel structure used in a severe environment such as a pressure vessel, a marine structure, and a line pipe can be used.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 為広 博 千葉県君津市君津１ 新日本製鐵株式会 社君津製鐵所内 (56)参考文献 特開 昭59−159932（ＪＰ，Ａ) 特開 昭62−86122（ＪＰ，Ａ) 特開 昭60−169517（ＪＰ，Ａ) 特開 昭55−73848（ＪＰ，Ａ) 特開 昭63−7328（ＪＰ，Ａ) 特開 昭59−80752（ＪＰ，Ａ) 特開 平１−96329（ＪＰ，Ａ) ──────────────────────────────────────────────────の Continuation of the front page (72) Inventor Hiroshi Tamehiro 1 Kimitsu, Kimitsu City, Chiba Prefecture Nippon Steel Corporation Kimitsu Works (56) References JP-A-59-159932 (JP, A) JP-A-62-86122 (JP, A) JP-A-60-169517 (JP, A) JP-A-55-73848 (JP, A) JP-A-63-7328 (JP, A) JP-A-59-80752 (JP, A) , A) JP-A-1-96329 (JP, A)
Claims (2)
によってスラブとし、再加熱なしの直送圧延ないしはス
ラブ冷却後これを1050〜1250℃の温度で再加熱し、800
〜900℃未満の温度で圧延を終了してただちに焼入れし
た後Ac1点以下の温度で焼戻し処理することを特徴とす
る耐SSC性の優れた高張力鋼板の製造法。C: 0.02 to 0.06% Si: 0.6% or less Mn: 1.0 to 1.6% P: 0.020% or less S: 0.006% or less Al: 0.001 to 0.060% Mo: 0.05 to 0.40% Nb: 0.01 to 0.05% Ti: 0.005 to 0.030% N: 0.006% or less The remainder is made of steel consisting of iron and unavoidable impurities, converted into a slab by continuous casting, and then directly rolled without reheating or cooled down to 1050 to 1250 ° C. Reheat at temperature, 800
A method for producing a high-strength steel sheet having excellent SSC resistance, characterized in that rolling is completed at a temperature of less than 900 ° C, quenching is performed immediately, and then tempering is performed at a temperature of 1 point or less of Ac.
r−Ni−Cu,V−Cr−Ni−Cuの組合せ 残部が鉄および不可避的不純物からなる鋼を用いること
を特徴とする請求項１に記載する耐SSC性の優れた高張
力鋼板の製造法。2. In% by weight, C: 0.02 to 0.06% Si: 0.6% or less Mn: 1.0 to 1.6% P: 0.020% or less S: 0.006% or less Al: 0.001 to 0.060% Mo: 0.05 to 0.40% Nb: 0.01 to 0.05% Ti: 0.005 to 0.030% N: 0.006% or less V: 0.01 to 0.10% Cr: 0.05 to 0.50% Ni: 0.05 to 1.0% Cu: 0.05 to 1.0% Ca: 0.001 to 0.006% -Cr, Cr-Ni, Ni-Cu, V-Ca, V-Cr-Cu, C
2. The method for producing a high-strength steel sheet having excellent SSC resistance according to claim 1, wherein a combination of r-Ni-Cu and V-Cr-Ni-Cu is made of steel with the balance being iron and unavoidable impurities. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63156717A JP2705946B2 (en) | 1988-06-27 | 1988-06-27 | Manufacturing method of high strength steel sheet with excellent SSC resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63156717A JP2705946B2 (en) | 1988-06-27 | 1988-06-27 | Manufacturing method of high strength steel sheet with excellent SSC resistance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH028322A JPH028322A (en) | 1990-01-11 |
| JP2705946B2 true JP2705946B2 (en) | 1998-01-28 |
Family
ID=15633797
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63156717A Expired - Lifetime JP2705946B2 (en) | 1988-06-27 | 1988-06-27 | Manufacturing method of high strength steel sheet with excellent SSC resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2705946B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2781000B2 (en) * | 1989-04-03 | 1998-07-30 | 新日本製鐵株式会社 | Method for producing high-strength steel sheet excellent in HIC resistance and SSC resistance |
| JPH0428309U (en) * | 1990-06-26 | 1992-03-06 | ||
| JP2596868B2 (en) * | 1992-01-23 | 1997-04-02 | 新日本製鐵株式会社 | Welded structure with excellent HIC resistance and SSC resistance |
| JP7295470B2 (en) | 2020-01-17 | 2023-06-21 | 日本製鉄株式会社 | steel plate and pipe |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5573848A (en) * | 1978-11-22 | 1980-06-03 | Kawasaki Steel Corp | High strength steel for welded structure with superior sulfide stress corrosion cracking resistance |
| JPS5980752A (en) * | 1982-10-28 | 1984-05-10 | Nippon Kokan Kk <Nkk> | Steel material having superior resistance to cracking due to hydrogen embrittlement in hydrogen sulfide environment |
| JPS59159932A (en) * | 1983-03-02 | 1984-09-10 | Sumitomo Metal Ind Ltd | Production of high tensile steel plate having excellent strength and toughness |
| JPS60169517A (en) * | 1984-02-13 | 1985-09-03 | Nippon Steel Corp | Production of high-strength steel having not less than 50kg per milimeter squared tensile strength and uniform hardness in wall thickness direction |
| JPS6286122A (en) * | 1985-09-28 | 1987-04-20 | Kobe Steel Ltd | Production of structural steel having high strength and high weldability |
| JPS637328A (en) * | 1986-06-27 | 1988-01-13 | Nippon Kokan Kk <Nkk> | Production of steel having excellent sulfide corrosion cracking resistance |
-
1988
- 1988-06-27 JP JP63156717A patent/JP2705946B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH028322A (en) | 1990-01-11 |
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