JPS6312925B2 - - Google Patents
Info
- Publication number
- JPS6312925B2 JPS6312925B2 JP54146267A JP14626779A JPS6312925B2 JP S6312925 B2 JPS6312925 B2 JP S6312925B2 JP 54146267 A JP54146267 A JP 54146267A JP 14626779 A JP14626779 A JP 14626779A JP S6312925 B2 JPS6312925 B2 JP S6312925B2
- Authority
- JP
- Japan
- Prior art keywords
- steel
- strength
- temperature
- rolling
- weldability
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- 229910000831 Steel Inorganic materials 0.000 claims description 50
- 239000010959 steel Substances 0.000 claims description 50
- 238000000137 annealing Methods 0.000 claims description 12
- 238000004519 manufacturing process Methods 0.000 claims description 10
- 238000005096 rolling process Methods 0.000 claims description 10
- 238000004804 winding Methods 0.000 claims description 5
- 239000012535 impurity Substances 0.000 claims description 2
- 238000012360 testing method Methods 0.000 description 12
- 238000005098 hot rolling Methods 0.000 description 10
- 239000000463 material Substances 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 238000000034 method Methods 0.000 description 6
- 239000010960 cold rolled steel Substances 0.000 description 5
- 238000005097 cold rolling Methods 0.000 description 5
- 238000001953 recrystallisation Methods 0.000 description 5
- 239000006104 solid solution Substances 0.000 description 5
- 230000006866 deterioration Effects 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 238000011161 development Methods 0.000 description 3
- 230000018109 developmental process Effects 0.000 description 3
- 238000009864 tensile test Methods 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 2
- 230000001965 increasing effect Effects 0.000 description 2
- 150000001247 metal acetylides Chemical class 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- 230000032683 aging Effects 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000008520 organization Effects 0.000 description 1
- 238000004881 precipitation hardening Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 238000003892 spreading Methods 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Sheet Steel (AREA)
- Heat Treatment Of Articles (AREA)
Description
本発明は溶接性のすぐれた高強度薄鋼帯の製造
方法に関するものである。
近年、鋼管はその製造技術の進歩から、従来継
目無鋼管が使用されていた分野にも電縫鋼管が使
用されつつある。しかし、低合金系電縫鋼管では
溶接のままでは溶接部および熱影響部（以下H.
A.Z.と略記する）の硬化という問題があり、造管
ライン内もしくは別途焼なましを施す必要があ
る。
そこで我々はこの問題を解決するため、溶接が
容易で高強度な鋼帯の開発について種々実験検討
を行なつた結果、
(1) 溶接部およびH.A.Z.の硬化を促すＣを可能
な限り低減し、かつMn量を低目に抑えること
により溶接性の改善が計れること、
(2) Siの添加により地鉄の固溶強化を計り、Cr
およびMoをバランス良く複合添加し、これら
の元素によつて形成される炭化物の微細均一分
散化によつて、地鉄の延性を劣化させることな
く溶接性の改善とともに鋼を強化できること、
(3) 熱延条件を適切にコントロールすることによ
り、冷延再結晶焼鈍後の材質特性が適正化され
ること、
等の知見を得、これらを総合的に勘案してさらに
種々実験を重ねた結果、溶接性のすぐれた高強度
薄鋼帯の製造方法を開発するに至つたものであ
る。
すなわち、本発明の要旨とするところは、Ｃ；
0.10〜0.20％、Si；0.60〜1.50％、Mn；0.30〜
0.80％、Cr；0.40〜0.90％、Mo；0.10〜0.20、
sol.Al；0.05％以下で、残部；Feおよび不可避的
不純物よりなる鋼を仕上温度850℃以上920℃以下
で熱間圧延し、捲取温度650℃以下580℃以上で捲
取後、圧下率35％以上75％以下で冷間圧延し、得
られた鋼帯を580℃以上660℃未満の温度で焼鈍
し、次いで調質圧延を施すことからなる溶接性の
すぐれた特に鋼管製造用の高強度薄鋼帯の製造方
法にある。
以下、本方法の詳細を述べる。鋼の溶接性改善
にはＣ量を可能な限り低減することが望ましい
が、そのために生ずる強度不足を他の元素で補う
必要がある。本発明の一つの特徴は、Ｃ量を少量
添加した状態において、従来の高強度鋼に比較的
多量に添加されているMnをやや低い範囲内に制
限し、Si添加により地鉄を固溶強化し、さらに
CrおよびMoを地鉄の延性を阻害しない範囲に適
量複合添加し、これら元素によつて形成される炭
化物の微細分散化を行なう点にある。すなわち、
固溶強化と析出硬化を巧妙に組合わすことにより
溶接性にすぐれかつ延性を阻害することなく高強
度を発現するものである。
しかし、このためには単に組成を選定するだけ
では不十分で、製造条件が重要な要件となる。す
なわち、前記効果をもたらすには、鋼成分ととも
に特に熱延条件の適切なコントロールが必要であ
る。このためには熱延に際し、加熱によつて十分
固溶した炭化物形成元素を熱延によつて微細均一
に析出させ、これにより後続工程の冷延・焼鈍に
おいて冷間成形性に有効な再結晶組織の発達を促
進させるのである。この点も本発明の重要な特徴
をなし、これらの知見が本発明の基礎をなしてい
る。
このような知見事実にもとづき本発明はSi−
Mn−Cr−Mo系鋼により、引張り強さ60Kg／mm2
以上を発現し、しかも従来鋼と同等な溶接性を有
する高強度冷延鋼帯の製造方法の開発に成功した
ものである。
以下、本発明において鋼成分および製造条件を
限定した理由について説明する。
Ｃは微量の添加によつて鋼の強度増加に有効な
元素であるが、反面溶接性および冷間成形性には
著しく有害に作用する。従つて溶接性を重視する
場合には低い方が望ましいが、Ｃ；0.10％未満で
は目標とする強度が得られないのでその下限を
0.10％とした。一方、Ｃが0.20％を超えると溶接
性および冷間成形性が劣化するのでその上限を
0.20％とした。
Siは地鉄中に固溶し、強度向上に有効であるが
溶接性にはあまり大きな影響を及ぼさない。さら
に強度上昇の割に冷間成形性の劣化も少く本発明
で特徴とする元素である。しかしSiが1.50％を超
えると熱延における鋼の表面肌に悪影響を及ぼ
し、冷延・焼鈍後においてもこれが一部残存し、
冷延鋼帯の必須特性の１つである美麗な表面肌を
損うことになる。一方、Siが0.60％未満では目標
とする強度が得られないため、この0.60％を下限
とした。
Mnは鋼に強度と延性を賦与するために必要な
元素であるが、0.80％を超えると溶接性の劣化と
ともに、熱延において帯状組織の発達が著しくな
り、ひいては冷延鋼帯のミクロ偏析による冷間成
形性の劣化を来たすことになるので、この上限を
0.80％とした。下限量0.30％は、これ未満では強
度上昇に殆んど寄与しないため、これを下限とし
た。
Crは強度向上にはあまり寄与しないが、本発
明におけるSi、Mnなど他の元素との適当なバラ
ンスにより、冷間成形性に有害な帯状組織の発達
を抑制することが可能である。しかし、この量が
0.90％を超えると溶接性が劣化するため0.90％を
上限とした。また0.40％未満ではCrの冷間加工性
改善効果が認められないので、Cr；0.40％を下限
とした。
Moは強度上昇効果が非常に大きいが、0.20％
程度までの含有量であれば強度上昇にかかわらず
冷間成形性の劣化は殆んど認められないので、こ
の0.20％をMoの上限とした。一方、Mo；0.10％
未満ではMoの効果が認められないので、0.10％
を下限とした。また、この範囲内のMoの添加は
溶接性の改善という面からも非常に有効であるた
め、Moの添加をこの範囲に限定した。
Alは鋼の脱酸および冷延材の時効現象による
材質の劣化防止などを目的として添加するが、多
量添加ではむしろ冷間成形性および溶接性の劣化
を招き、さらに鋼板表面性状も損う。従つてこれ
らの好ましくない影響を避けるため含有量の上限
はsol.Alで0.05％とした。
上記のように成分限定した鋼を転炉もしくは電
気炉で溶製し、これを連続鋳造または分塊圧延に
よりスラブとし、このスラブを熱延仕上温度850
℃以上920℃以下、捲取温度650℃以下580℃以上
の条件で熱延することが必要である。
すなわち、熱延仕上温度が850℃未満でも、ま
た920℃を超えた場合でも、鋼組織や焼鈍後の材
質特性が本発明で目標とするものに至らない。従
つて本発明における熱延仕上温度の下限を850℃、
上限を920℃に限定している。
また捲取温度が650℃を超えても、580℃未満で
も強度と冷間成形性との兼合において好ましくな
い状態となるので、捲取温度の上限を650℃、下
限を580℃に限定した。
次の冷間圧延においては、圧下率が35％未満で
は冷延による蓄積エネルギーが小さくて再結晶し
にくくなるため再結晶温度を高くとらねばならず
圧下率は少なくとも35％は必要である。一方圧下
率が75％を起えると作業性が劣ることや材質面で
の弊害が生じるので圧下率の上限は75％とする。
再結晶焼鈍は580℃未満の温度では再結晶が不
十分となり、良好な冷間成形性が得られないので
少くとも580℃の温度を必要とする。一方、焼鈍
温度が660℃を超えると目標とする強度が得られ
ず材質的にも好ましくないので、焼鈍温度の上限
を660℃とする必要がある。
次に本発明の実施例を掲げ本発明による効果を
具体的に示す。
実施例
第１表に、本発明範囲の成分組成を有する鋼
（Ａ〜Ｉ）と、本発明範囲外の成分組成を有する
比較鋼（Ｊ〜Ｑ）の化学成分（重量％）を示す。
第１表で示す鋼を溶製し、次の第２表に示す各
種の熱延条件で熱延コイルとし、冷間圧延により
0.8mm厚とし、同じく第２表中に示す焼鈍条件で
焼鈍を行なつた。得られた冷延鋼帯の引張試験お
よび成形性試験を行ない、これらの測定値を第２
表に示す。
但し、第２表における引張試験はJIS5号試験片
によつて行ない、エリクセン値はJIS1号試験片に
よりＡ法で求めた。また限界絞り比（L.D.R.）は
33mmφ平頭ポンチ試験した。さらに穴拡げ試験値
（λ）はブランク径76mmφ、初期穴径10mmφ（打抜
き穴）、ポンチ33mmφ丸頭で穴拡げ比＝Ｄ／D0
（D0は試験前穴径、Ｄは試験後穴径）で表わした
ものである。
The present invention relates to a method for manufacturing a high-strength thin steel strip with excellent weldability. In recent years, due to advances in manufacturing technology for steel pipes, ERW steel pipes are being used in fields where seamless steel pipes have traditionally been used. However, in low-alloy ERW steel pipes, if they are left welded, the weld zone and heat-affected zone (hereinafter referred to as H).
There is a problem of hardening of the pipe (abbreviated as AZ), and it is necessary to perform annealing within the pipe production line or separately. Therefore, in order to solve this problem, we conducted various experiments and studies to develop a steel strip that is easy to weld and has high strength.As a result, we found that (1) we should reduce as much as possible C, which causes hardening of the weld zone and HAZ; (2) Weldability can be improved by keeping the Mn content low; (2) The addition of Si strengthens the base steel as a solid solution, and
(3) By adding Mo and Mo in a well-balanced manner and by finely and uniformly dispersing the carbides formed by these elements, it is possible to improve weldability and strengthen the steel without deteriorating the ductility of the base steel. We obtained the knowledge that the material properties after cold rolling recrystallization annealing can be optimized by appropriately controlling the hot rolling conditions, and as a result of comprehensively taking this into account and conducting various experiments, we found that welding This led to the development of a method for manufacturing high-strength thin steel strips with excellent properties. That is, the gist of the present invention is C;
0.10~0.20%, Si; 0.60~1.50%, Mn; 0.30~
0.80%, Cr; 0.40~0.90%, Mo; 0.10~0.20,
sol.Al: 0.05% or less, balance: Fe and unavoidable impurities. After hot rolling the steel at a finishing temperature of 850℃ or higher and 920℃ or lower, and rolling it at a winding temperature of 650℃ or lower and 580℃ or higher, the rolling reduction ratio A high-quality steel strip with excellent weldability, especially for manufacturing steel pipes, which consists of cold rolling at a temperature of 35% to 75%, annealing the obtained steel strip at a temperature of 580°C to 660°C, and then temper rolling. A method for producing high-strength thin steel strips. The details of this method will be described below. In order to improve the weldability of steel, it is desirable to reduce the amount of C as much as possible, but it is necessary to compensate for the lack of strength resulting from this with other elements. One feature of the present invention is that when a small amount of C is added, Mn, which is added in a relatively large amount to conventional high-strength steel, is limited to a slightly low range, and the base steel is solid solution strengthened by the addition of Si. and further
The point is that Cr and Mo are added in appropriate amounts in combination so as not to inhibit the ductility of the steel base, and the carbides formed by these elements are finely dispersed. That is,
By skillfully combining solid solution strengthening and precipitation hardening, it has excellent weldability and exhibits high strength without impeding ductility. However, for this purpose, simply selecting the composition is not sufficient; manufacturing conditions are an important requirement. That is, in order to bring about the above effect, it is necessary to appropriately control not only the steel components but also the hot rolling conditions. To achieve this, during hot rolling, carbide-forming elements that are sufficiently dissolved in solid solution by heating are precipitated finely and uniformly by hot rolling. It promotes the development of the organization. This point also constitutes an important feature of the present invention, and these findings form the basis of the present invention. Based on such findings, the present invention provides Si-
Made of Mn-Cr-Mo steel, tensile strength 60Kg/mm 2
We have succeeded in developing a method for manufacturing high-strength cold-rolled steel strip that achieves the above and has weldability equivalent to that of conventional steel. The reason why the steel components and manufacturing conditions are limited in the present invention will be explained below. C is an element effective in increasing the strength of steel when added in a small amount, but on the other hand, it has a significant detrimental effect on weldability and cold formability. Therefore, if weldability is important, a lower value is preferable, but if C is less than 0.10%, the target strength cannot be obtained, so the lower limit must be set.
It was set at 0.10%. On the other hand, if C exceeds 0.20%, weldability and cold formability deteriorate, so the upper limit should be
It was set at 0.20%. Si dissolves in solid solution in the steel base and is effective in improving strength, but does not have a great effect on weldability. Furthermore, despite the increase in strength, there is little deterioration in cold formability, making it an element that is featured in the present invention. However, if Si exceeds 1.50%, it will have a negative effect on the surface texture of the steel during hot rolling, and some of this will remain even after cold rolling and annealing.
This will damage the beautiful surface texture, which is one of the essential properties of cold-rolled steel strip. On the other hand, if the Si content is less than 0.60%, the target strength cannot be obtained, so this 0.60% was set as the lower limit. Mn is an element necessary to impart strength and ductility to steel, but if it exceeds 0.80%, weldability deteriorates and a band-like structure develops significantly in hot rolling, which can lead to micro-segregation in cold-rolled steel strips. This upper limit should not be
It was set at 0.80%. The lower limit amount of 0.30% was set as the lower limit because anything less than this hardly contributes to an increase in strength. Although Cr does not contribute much to improving strength, by appropriately balancing it with other elements such as Si and Mn in the present invention, it is possible to suppress the development of band-like structures that are harmful to cold formability. However, this amount
If it exceeds 0.90%, weldability deteriorates, so 0.90% is set as the upper limit. Furthermore, since the effect of Cr on improving cold workability is not observed when the content is less than 0.40%, Cr: 0.40% was set as the lower limit. Mo has a very large strength increasing effect, but 0.20%
If the Mo content is within this range, almost no deterioration in cold formability will be observed despite the increase in strength, so 0.20% was set as the upper limit for Mo. On the other hand, Mo; 0.10%
If it is less than 0.10%, the effect of Mo is not recognized.
was set as the lower limit. Furthermore, the addition of Mo within this range is very effective in terms of improving weldability, so the addition of Mo was limited to this range. Al is added for the purpose of deoxidizing steel and preventing material deterioration due to the aging phenomenon of cold-rolled materials, but when added in large amounts, it actually causes deterioration of cold formability and weldability, and also impairs the surface properties of the steel sheet. Therefore, in order to avoid these undesirable effects, the upper limit of the content was set at 0.05% for sol.Al. Steel with limited composition as described above is melted in a converter or electric furnace, then made into a slab by continuous casting or blooming, and this slab is hot-rolled at a finishing temperature of 850.
It is necessary to hot-roll at a temperature of 650°C or higher and 580°C or higher at the winding temperature. That is, even if the hot rolling finishing temperature is lower than 850°C or higher than 920°C, the steel structure and material properties after annealing will not reach the targets of the present invention. Therefore, the lower limit of the hot rolling finishing temperature in the present invention is 850°C,
The upper limit is limited to 920℃. In addition, even if the winding temperature exceeds 650°C, if it is lower than 580°C, the balance between strength and cold formability will be unfavorable, so we limited the upper limit of the winding temperature to 650°C and the lower limit to 580°C. . In the next cold rolling, if the rolling reduction is less than 35%, the stored energy due to cold rolling will be small and recrystallization will be difficult, so the recrystallization temperature must be high and the rolling reduction must be at least 35%. On the other hand, if the rolling reduction ratio exceeds 75%, workability will be poor and problems will occur in terms of material quality, so the upper limit of the rolling reduction ratio is set at 75%. Recrystallization annealing requires a temperature of at least 580°C, since recrystallization will be insufficient at temperatures below 580°C and good cold formability will not be obtained. On the other hand, if the annealing temperature exceeds 660°C, the target strength cannot be obtained and the material is not preferable, so the upper limit of the annealing temperature needs to be 660°C. Next, examples of the present invention will be presented to specifically demonstrate the effects of the present invention. Examples Table 1 shows the chemical components (% by weight) of steels (A to I) having compositions within the range of the present invention and comparative steels (J to Q) having compositions outside the range of the present invention. The steel shown in Table 1 is melted and made into hot-rolled coils under various hot-rolling conditions shown in Table 2 below, and then cold-rolled.
The thickness was 0.8 mm, and annealing was performed under the same annealing conditions shown in Table 2. The obtained cold-rolled steel strip was subjected to a tensile test and a formability test, and these measured values were
Shown in the table. However, the tensile test in Table 2 was conducted using a JIS No. 5 test piece, and the Erichsen value was determined using method A using a JIS No. 1 test piece. Also, the limiting drawing ratio (LDR) is
A 33mmφ flat head punch test was conducted. Furthermore, the hole expansion test value (λ) is a blank diameter of 76mmφ, an initial hole diameter of 10mmφ (punched hole), a punch with a 33mmφ round head, and a hole expansion ratio of D/D 0.
( D0 is the hole diameter before the test, D is the hole diameter after the test).
【表】【table】
【表】【table】
【表】
第２表から、本発明範囲の鋼を本発明方法に従
つて製造したもの、同等な強度を有する比較鋼
Ｊ、Ｋ、Ｌ、Ｑなどと比較し、延性、張出し性、
深絞り性および伸びフランジ性がすぐれており、
また強度の低い比較鋼Ｎ、Ｏなどとの比較におい
ても遜色のない成形性を示すことが判る。
第３表は本発明実施例の冷延鋼帯Ａ、Ｂ、Ｅ、
Ｇ、Ｉと、比較鋼Ｊ、Ｍ、Ｏについて高周波溶接
により造管したパイプ（28.6φ×0.9×Ｌmm）の造
管条件と材質特性を示す。但し、引張試験は
JISZ2201 11号試験片により行ない、へん平試験
はJISG3441に準じて行なつた。また押し拡げ試
験は先端角度60゜の円錐ポンチにより拡管加工し
割れ発生の認められない限界を加工前の外径(D)と
の比で示した。[Table] Table 2 shows that steels within the scope of the present invention manufactured according to the method of the present invention are compared with comparative steels J, K, L, Q, etc. having the same strength, and the ductility, stretchability,
Excellent deep drawability and stretch flangeability.
Furthermore, it can be seen that the moldability is comparable to that of comparative steels N and O, which have lower strength. Table 3 shows cold rolled steel strips A, B, E,
The pipe-making conditions and material properties of pipes (28.6φ×0.9×Lmm) made by high-frequency welding for G, I, and comparative steels J, M, and O are shown. However, the tensile test
It was conducted using a JISZ2201 No. 11 test piece, and the flattening test was conducted in accordance with JISG3441. In addition, in the expansion test, the pipe was expanded using a conical punch with a tip angle of 60°, and the limit at which no cracking was observed was determined by the ratio to the outside diameter (D) before processing.
【表】
第３表から明らかなように、本発明鋼は同等な
強度を示す比較鋼Ｊ、Ｍにくらべ延性、へん平試
験値、押し拡げ試験値と良好であり、また強度の
低い比較鋼Ｏにも匹敵する加工性を有している。
さらに、造管材のH.A.Z.の硬さ（Hv）を第３
表に示すが、本発明鋼のこれらの値はHv＝395〜
460の範囲にあり、比較鋼でのそれらの値Hv＝
420〜613に比較し、この部分の硬化は軽減されて
いることが判る。なお、比較鋼Ｊは本発明鋼およ
び比較鋼Ｍ、Ｏなどに比較し造管速度を半減すな
わち、入熱量の増加を計つたが、成形性および
H.A.Z.の硬化改善には寄与せず、造管のままで
の使用では上記特性上の問題があり、造管直後も
しくは別途焼鈍により材質改善を計る必要があ
り、これによる費用でのコスト上昇はまぬがれな
い。これに対し本発明各鋼は造管のままでも第３
表に示す特性が得られ、溶接性のすぐれた高強度
パイプ用薄鋼帯として好適である。[Table] As is clear from Table 3, the steel of the present invention has better ductility, flattening test value, and spreading test value than comparative steels J and M, which have the same strength, and the comparative steel has lower strength. It has workability comparable to O. Furthermore, the HAZ hardness (Hv) of the pipe material is
As shown in the table, these values of the steel of the present invention are Hv=395~
460 and their values in comparison steel Hv=
It can be seen that the hardening in this part is reduced compared to 420-613. Comparative Steel J was designed to reduce the pipe forming speed by half, that is, to increase the heat input, compared to the Invention Steel and Comparative Steels M and O, but the formability and
It does not contribute to improving the hardening of the HAZ, and if the tube is used as it is, there are problems with the above characteristics, and it is necessary to improve the material quality immediately after the tube is manufactured or by separately annealing it, and the cost increase due to this can be avoided. do not have. On the other hand, each steel of the present invention has a
It has the properties shown in the table and is suitable as a thin steel strip for high-strength pipes with excellent weldability.
Claims (1)
0.30〜0.80％、Cr；0.40〜0.90％、Mo；0.10〜
0.20％、sol.Al；0.050％以下で、残部；Feおよび
不可避的不純物よりなる鋼を仕上温度850℃以上
920℃以下で熱間圧延し、捲取温度650℃以下580
℃以上で捲取後、圧下率35％以上75％以下で冷間
圧延し、得られた鋼帯を580℃以上660℃未満の温
度で焼鈍し、次いで調質圧延を施すことからなる
溶接性のすぐれた高強度薄鋼帯の製造方法。1 C; 0.10-0.20%, Si; 0.60-1.50%, Mn;
0.30~0.80%, Cr; 0.40~0.90%, Mo; 0.10~
Finishing temperature of steel consisting of 0.20%, sol.Al: 0.050% or less, balance: Fe and unavoidable impurities at 850℃ or higher
Hot rolled at 920℃ or less, winding temperature 650℃ or less580
Weldability consists of rolling the steel strip at a temperature of 35% or more and 75% or less after rolling it at a temperature of 35% or higher, annealing the obtained steel strip at a temperature of 580°C or higher and lower than 660°C, and then subjecting it to temper rolling. A method for producing an excellent high-strength thin steel strip.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14626779A JPS5669326A (en) | 1979-11-12 | 1979-11-12 | Production of high strength thin steel belt excellent in weldability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14626779A JPS5669326A (en) | 1979-11-12 | 1979-11-12 | Production of high strength thin steel belt excellent in weldability |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5669326A JPS5669326A (en) | 1981-06-10 |
| JPS6312925B2 true JPS6312925B2 (en) | 1988-03-23 |
Family
ID=15403867
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14626779A Granted JPS5669326A (en) | 1979-11-12 | 1979-11-12 | Production of high strength thin steel belt excellent in weldability |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5669326A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03291327A (en) * | 1990-04-09 | 1991-12-20 | Kobe Steel Ltd | Production of cold rolled steel sheet excellent in tube making property |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS50136221A (en) * | 1974-04-19 | 1975-10-29 |
-
1979
- 1979-11-12 JP JP14626779A patent/JPS5669326A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS50136221A (en) * | 1974-04-19 | 1975-10-29 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5669326A (en) | 1981-06-10 |
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