JPH05329505A - Method for preventing surface crack of low-alloy steel - Google Patents
Method for preventing surface crack of low-alloy steelInfo
- Publication number
- JPH05329505A JPH05329505A JP16535492A JP16535492A JPH05329505A JP H05329505 A JPH05329505 A JP H05329505A JP 16535492 A JP16535492 A JP 16535492A JP 16535492 A JP16535492 A JP 16535492A JP H05329505 A JPH05329505 A JP H05329505A
- Authority
- JP
- Japan
- Prior art keywords
- surface layer
- steel
- slab
- ingot
- alloy steel
- 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.)
- Granted
Links
- 229910000851 Alloy steel Inorganic materials 0.000 title claims abstract description 17
- 238000000034 method Methods 0.000 title claims description 20
- 239000002344 surface layer Substances 0.000 claims abstract description 29
- 238000009749 continuous casting Methods 0.000 claims abstract description 9
- 238000005336 cracking Methods 0.000 claims description 12
- 229910000831 Steel Inorganic materials 0.000 abstract description 19
- 239000010959 steel Substances 0.000 abstract description 19
- 238000010438 heat treatment Methods 0.000 abstract description 12
- 230000009466 transformation Effects 0.000 abstract description 7
- 238000001816 cooling Methods 0.000 description 24
- 230000007547 defect Effects 0.000 description 9
- 229910001566 austenite Inorganic materials 0.000 description 5
- 238000007711 solidification Methods 0.000 description 4
- 230000008023 solidification Effects 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 238000003303 reheating Methods 0.000 description 3
- 239000007921 spray Substances 0.000 description 3
- 229910000639 Spring steel Inorganic materials 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 229910001562 pearlite Inorganic materials 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000002436 steel type Substances 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 229910000760 Hardened steel Inorganic materials 0.000 description 1
- 229910000655 Killed steel Inorganic materials 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 229910001563 bainite Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Landscapes
- Metal Rolling (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は低合金鋼の表面割れ防止
方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 preventing surface cracking of low alloy steel.
【０００２】[0002]
【従来技術】一般的に、従来から鋳片は可能な限り高温
で加熱炉に装入し、再加熱を行って分塊することが行わ
れてきている。しかし、凝固過程において形成されたオ
ーステナイト結晶粒が粗大であるため、延性が小さく、
分塊中に割れ易いという欠点がある。2. Description of the Related Art Generally, it has been customary to insert a slab into a heating furnace at a temperature as high as possible and reheat it to agglomerate it. However, since the austenite crystal grains formed in the solidification process are coarse, ductility is small,
It has the drawback that it breaks easily during clumping.
【０００３】特に、Ｓｉ含有量の多いバネ鋼は、オース
テナイト粒界から酸素が侵入して粒界酸化を引き起こ
し、さらに割れ易くなり、また、ＡｌおよびＮを含有し
ている鋼では、加熱炉に装入するまでの冷却過程におい
てＡｌＮが粒界に析出し、分塊中の割れ易さを助長して
いる。そして、分塊後の鋼片の表面疵および製品の表面
疵の原因となって歩留りを低下させたり、疵の手入れ等
の作業を行わなければならないという問題がある。In particular, in spring steel having a high Si content, oxygen invades from austenite grain boundaries to cause grain boundary oxidation, which makes cracking easier, and in the case of steel containing Al and N, it is not suitable for heating furnaces. In the cooling process until charging, AlN precipitates at the grain boundaries, which promotes the fragility of the agglomerates. Then, there are problems that the surface defects of the steel slab and the surface defects of the product after the agglomeration are caused, and the yield is reduced, and the work such as the maintenance of the defects must be performed.
【０００４】このような表面欠陥は従来からも問題とな
ってきているが、全ての鋼種に対して完全に防止するこ
とができる効果的な技術は未だ開発されておらず、一部
の鋼種についてのみその対策が行われているのが現状で
ある。Although such surface defects have been problematic in the past, effective techniques capable of completely preventing all steel types have not yet been developed, and some steel types have not been developed yet. The current situation is that only that measure is taken.
【０００５】例えば、ＳｉおよびＣの含有量の多いバネ
鋼、または、合金元素の少ないＡｌ、Ｎを含有している
鋼種においては、凝固過程から冷却されている高温鋳片
の表層部を５００℃〜６８０℃の温度に冷却保持し、変
態を完了させた後、加熱炉に装入して再加熱して分塊を
行って表面疵のない鋼片を製造する方法がある。For example, in the case of a spring steel containing a large amount of Si and C, or a steel containing Al and N containing a small amount of alloying elements, the surface layer portion of the high temperature cast piece cooled from the solidification process is heated to 500 ° C. There is a method of producing a steel slab having no surface flaw by cooling and holding at a temperature of ˜680 ° C. to complete the transformation, and then charging the slab into a heating furnace and reheating to perform lumping.
【０００６】この方法は、オーステナイト相がフェライ
ト＋パーライト相に一度変態し、再加熱によりオーステ
ナイト相に変わるときに、凝固過程において形成された
粒径の数十分の１以下の小さい粒になって、延性が改善
されるのである。According to this method, when the austenite phase is once transformed into a ferrite + pearlite phase and is converted to the austenite phase by reheating, the grains formed in the solidification process become small grains of 1/10 or less. The ductility is improved.
【０００７】しかし、Ｃｒ、Ｍｏ、Ｎｉの１種以上が含
有されている低合金鋼の連続鋳造により製作された鋳片
においては、５００℃〜６８０℃の温度に表層部を冷却
し、保持しても３０分以下の短時間では変態が完了しな
いため、加熱炉に装入して再加熱後、分塊を行うと表面
疵が多数発生し、また、保持時間を３０分以上に長時間
とすると加熱炉の前に鋳片が滞留して、生産性の向上の
障害となっている。However, in a slab produced by continuous casting of a low alloy steel containing at least one of Cr, Mo and Ni, the surface layer portion is cooled and kept at a temperature of 500 ° C to 680 ° C. However, since the transformation is not completed in a short time of 30 minutes or less, many defects are generated when the lump is lumped after being charged in the heating furnace and reheated, and the holding time is longer than 30 minutes. Then, the slab stays in front of the heating furnace, which is an obstacle to improving productivity.
【０００８】[0008]
【発明が解決しようとする課題】本発明は上記に説明し
た、従来技術の低合金鋼鋳片の加工処理における問題点
を解決するために、本発明者が鋭意研究を行った結果、
連続鋳造により製作された低合金鋼鋳片の冷却、保持後
の分塊の際に鋳片表層部に疵が発生して割れる恐れがな
い低合金鋼鋳片の表面割れ防止ほうほうを開発したので
ある。DISCLOSURE OF INVENTION Problems to be Solved by the Invention The present invention has been made by the present inventors as a result of intensive research in order to solve the problems in the processing of the conventional low alloy steel slab described above.
We have developed a method for preventing surface cracking of low alloy steel slabs that is free from the risk of cracks occurring in the surface layer of the slab during cooling and holding of the low alloy steel slabs produced by continuous casting and lumping after holding. Of.
【０００９】本発明に係る低合金鋼の表面割れ防止方法
の特徴とするところは、連続鋳造の鋳型から離れた鋳片
の表層部を３５０℃〜５００℃の温度に１分以上冷却、
保持を行って、表層部を変態させた後、再加熱して圧延
を行うことにある。The feature of the method for preventing surface cracking of low alloy steel according to the present invention is that the surface layer of the slab separated from the continuous casting mold is cooled to a temperature of 350 ° C. to 500 ° C. for 1 minute or more,
After holding, the surface layer portion is transformed, and then reheating is performed for rolling.
【００１０】本発明に係る低合金鋼の表面割れ防止方法
について、以下詳細に声明する。The method for preventing surface cracking of low alloy steel according to the present invention will be described in detail below.
【００１１】連続鋳造により製作された鋳片は、一般的
には凝固した後、加熱炉に高温度で装入されて再加熱が
行われるのであるが、本発明に係る低合金鋼の表面割れ
防止方法においては、鋳型から離れた鋳片の凝固完了
後、スプレー或いはシャワー状の水により鋳片の表層部
を強制冷却するのである。The slab produced by continuous casting is generally solidified and then charged into a heating furnace at a high temperature to be reheated. Surface cracking of the low alloy steel according to the present invention is performed. In the prevention method, after the solidification of the slab separated from the mold is completed, the surface layer of the slab is forcibly cooled by spraying or showering water.
【００１２】この鋳片の強制冷却は加熱炉に装入するの
を円滑にするため、短時間で行う必要があり、急激な冷
却を行うと制御が困難となり、また、熱応力による悪影
響が発生するので、９００℃の温度から５００℃〜３０
０℃の温度の間の表層部の冷却速度は０.３℃／ｓｅｃ
〜５℃／ｓｅｃとするのがよい。This forced cooling of the slab needs to be performed in a short time in order to facilitate charging into the heating furnace, and rapid cooling makes control difficult and adverse effects due to thermal stress occur. Therefore, from the temperature of 900 ℃ to 500 ℃ ~ 30
The cooling rate of the surface layer during the temperature of 0 ° C is 0.3 ° C / sec.
It is preferable to set it to -5 ° C / sec.
【００１３】そして、粗大なオーステナイト相が５００
℃から６８０℃の温度において、パーライト変態をする
ためには長時間の保持時間を必要とするが、３５０℃〜
５００℃の間のベイナイト変態は上記と比較して、非常
に短時間の保持でよい。The coarse austenite phase is 500
At a temperature of from ℃ to 680 ℃, a long holding time is required for the pearlite transformation, but 350 ℃ ~
The bainite transformation between 500 ° C. may be held for a very short time as compared with the above.
【００１４】さらに、Ｃｒ、Ｍｏ、Ｎｉの１種以上を含
有する低合金鋼においては、３５０℃〜５００℃の温度
における保持時間は、１分以上の短時間において全体の
５０％が変態する。また、この変態は１０分以下で完了
するので、保持時間は１分〜１０分とするのがよい。Furthermore, in the low alloy steel containing at least one of Cr, Mo and Ni, 50% of the whole is transformed in a holding time at a temperature of 350 ° C. to 500 ° C. for a short time of 1 minute or more. Further, since this transformation is completed in 10 minutes or less, the holding time is preferably 1 minute to 10 minutes.
【００１５】また、鋳片を強制冷却を行い、かつ、短時
間の保持時間とするので、鋳片内部はまだ高温であり、
そのため、強制冷却を停止すれば復熱してエネルギー損
失は少ない。Further, since the slab is forcibly cooled and held for a short time, the inside of the slab is still at a high temperature,
Therefore, if the forced cooling is stopped, the heat is recovered and the energy loss is small.
【００１６】本発明に係る低合金鋼の表面割れ防止方法
において、使用できる鋼として、 Ｃｒ ０.７５〜１.５ｗｔ％、Ｍｏ ０.１５〜０.３５
ｗｔ％、 Ｎｉ ０.４〜２.０ｗｔ％ の１種以上を含有するＡｌキルド鋼であり、焼入れ性が
改善されており、かつ、ＡｌＮを形成し易いものであ
る。In the method for preventing surface cracking of the low alloy steel according to the present invention, as steels that can be used, Cr 0.75 to 1.5 wt% and Mo 0.15 to 0.35 are used.
It is an Al-killed steel containing at least one of wt% and Ni 0.4 to 2.0 wt%, has improved hardenability, and easily forms AlN.
【００１７】[0017]
【実 施 例】本発明に低合金鋼の表面割れ防止方法の
実施例を説明する。[Example] An example of a method for preventing surface cracking of a low alloy steel according to the present invention will be described.
【００１８】[0018]
【実 施 例】表１に示す含有成分および成分割合の鋼を
溶解後、連続鋳造により鋳片を製作した。この鋳片を鋼
片に分塊する場合の鋳片の冷却温度、保持時間および鋼
片の表面層の疵の割合について表１に示してある。[Examples] After melting the steel having the contained components and component ratios shown in Table 1, a cast slab was produced by continuous casting. Table 1 shows the cooling temperature of the slab, the holding time, and the rate of flaws in the surface layer of the slab when the slab was agglomerated into steel slabs.
【００１９】本発明に係る低合金鋼の表面割れ防止方法
は、加熱炉前において水のスプレーによる強制冷却によ
り鋳片の表面層を冷却した。そして、水スプレーによる
冷却時間は５分間である。In the method for preventing surface cracking of low alloy steel according to the present invention, the surface layer of the slab is cooled by forced cooling with water spray before the heating furnace. The cooling time with water spray is 5 minutes.
【００２０】従来例は強制冷却を行わずに、加熱炉に装
入する場合である。比較例は加熱前で表面層が冷却する
まで装入を止めて待機していた場合である。The conventional example is a case of charging into a heating furnace without performing forced cooling. The comparative example is a case where charging was stopped and waiting was waited until the surface layer was cooled before heating.
【００２１】また、３５０℃〜５００℃の間の保持時間
は、水スプレーによる強制冷却で５００℃の温度になっ
た時から、冷却を停止して復熱により表面層が５００℃
の温度に達する間の時間である。The holding time between 350 ° C. and 500 ° C. is 500 ° C. when cooling is stopped and the surface layer is reheated after the temperature reaches 500 ° C. by forced cooling with water spray.
Time to reach the temperature of.
【００２２】表１から次のことがわかる。Ｎｏ.１は従
来例で炭素鋼の場合において、冷却温度が９５０℃、保
持時間零であってもも鋼片の疵の発生は非常に僅かであ
る。Ｎｏ.２は比較例で、Ｃｒ−Ｍｏ肌焼鋼をＡ1変態点
温度以下に冷却した後、加熱炉に装入するプロセスであ
るが、非常に多くの表面疵が発生して使用できないもの
である。Ｎｏ.４はＣｒ−Ｍｏ肌焼鋼の従来例で、冷却
温度９２０℃であり、保持時間は零で疵の発生がある。
Ｎｏ.５はＣｒ鋼の従来例であり、冷却温度９２０℃で
あり、保持時間は零で疵の発生がある。Ｎｏ.８はＣ含
有量の多い従来例であり、表層部の冷却温度が８８０℃
と高く、かつ、保持時間が零であり疵の発生がある。Ｎ
ｏ.１０はＣｒ−Ｍｏ鋼にＮｂを０.０３５ｗｔ％含有さ
せたもので、冷却温度は８７０℃であり、保持時間は零
で、疵の発生がある。The following can be seen from Table 1. No. 1 is a conventional example, and in the case of carbon steel, even if the cooling temperature is 950 ° C. and the holding time is zero, the occurrence of flaws in the steel slab is very slight. No. 2 is a comparative example, which is a process of cooling Cr-Mo case-hardened steel to a temperature below the A 1 transformation point temperature and then charging it into a heating furnace, but a large number of surface flaws are generated and cannot be used. Is. No. 4 is a conventional example of a Cr-Mo case hardening steel, has a cooling temperature of 920 [deg.] C., has a holding time of zero, and has defects.
No. 5 is a conventional example of Cr steel, the cooling temperature is 920 ° C., the holding time is zero, and defects occur. No. 8 is a conventional example with a large C content, and the cooling temperature of the surface layer is 880 ° C.
And the holding time is zero, and defects occur. N
No. 10 is Cr—Mo steel containing 0.035 wt% of Nb, the cooling temperature is 870 ° C., the holding time is zero, and defects occur.
【００２３】表１の本発明に係る低合金鋼の表面割れ防
止方法（本発明という）について説明する。Ｎｏ.３は
Ｃｒ−Ｍｏ肌焼鋼であり、表層部の冷却温度が３９０℃
で、保持時間が２１０秒であり、鋼片表層部に疵はな
い。Ｎｏ.６はＣｒ鋼であり、表層部の冷却温度４２０
℃であり、保持時間１８０秒であり、鋼片表層部に疵の
発生はない。Ｎｏ.７はＮｉ−Ｃｒ−Ｍｏ鋼であり、表
層部冷却温度は４００℃であり、保持時間は１８０秒
で、鋼片表層部には疵の発生はない。Ｎｏ.９はＣ含有
量が多い鋼であり、表層部の冷却温度は３９０℃であ
り、保持時間は ２１０秒で、鋼片表層部には疵の発生
はない。Ｎｏ.１１はＣｒ−Ｍｏ鋼であり、表層部の冷
却温度は４２０℃であり、保持時間は１８０秒で、鋼片
表層部には疵の発生はない。A method for preventing surface cracking of the low alloy steel according to the present invention (referred to as the present invention) in Table 1 will be described. No. 3 is a Cr-Mo case hardening steel, and the cooling temperature of the surface layer is 390 ° C.
The holding time was 210 seconds, and there was no flaw in the surface layer of the billet. No. 6 is Cr steel, and the cooling temperature of the surface layer is 420
C., the holding time was 180 seconds, and no flaw was generated on the surface layer of the billet. No. 7 is Ni-Cr-Mo steel, the surface layer cooling temperature is 400 ° C., the holding time is 180 seconds, and the steel billet surface layer has no flaws. No. 9 is a steel having a large C content, the cooling temperature of the surface layer portion is 390 ° C., the holding time is 210 seconds, and no flaw is generated in the surface layer portion of the steel slab. No. 11 is Cr-Mo steel, the cooling temperature of the surface layer part is 420 ° C., the holding time is 180 seconds, and no flaw is generated in the surface layer part of the billet.
【００２４】[0024]
【表１】 [Table 1]
【発明の効果】以上説明したように、本発明に係る低合
金鋼の表面割れ防止方法は上記の構成であるから、連続
鋳造により製作された鋳片を分塊を行っても、鋼片表層
部には全く疵のない優れた製品が得られるものである。As described above, since the method for preventing surface cracking of the low alloy steel according to the present invention has the above-mentioned constitution, even if the slab produced by continuous casting is slabbed, the surface layer of the slab is This is an excellent product with no flaws in the part.
Claims (1)
を３５０℃〜５００℃の温度に１分以上冷却、保持を行
って、表層部を変態させた後再加熱して圧延を行うこと
を特徴とする低合金鋼の表面割れ防止方法。1. A surface layer portion of a slab separated from a continuous casting mold is cooled to and held at a temperature of 350 ° C. to 500 ° C. for 1 minute or more to transform the surface layer portion and then reheated to be rolled. A method for preventing surface cracking of low alloy steel, which is characterized by the following.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4165354A JPH07112563B2 (en) | 1992-06-01 | 1992-06-01 | Method for preventing surface cracking of low alloy steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4165354A JPH07112563B2 (en) | 1992-06-01 | 1992-06-01 | Method for preventing surface cracking of low alloy steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05329505A true JPH05329505A (en) | 1993-12-14 |
| JPH07112563B2 JPH07112563B2 (en) | 1995-12-06 |
Family
ID=15810775
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4165354A Expired - Lifetime JPH07112563B2 (en) | 1992-06-01 | 1992-06-01 | Method for preventing surface cracking of low alloy steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07112563B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010005634A (en) * | 2008-06-24 | 2010-01-14 | Kobe Steel Ltd | Method for producing cast metal |
| JP2019155385A (en) * | 2018-03-08 | 2019-09-19 | 日本製鉄株式会社 | Refining device train of continuous casting cast piece |
| JP2020066047A (en) * | 2018-10-26 | 2020-04-30 | 日本製鉄株式会社 | Manufacturing method of steel piece |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS497771A (en) * | 1972-05-11 | 1974-01-23 | ||
| JPS63168260A (en) * | 1986-12-30 | 1988-07-12 | Aichi Steel Works Ltd | Hot working method for continuously cast billet |
| JPH02299701A (en) * | 1989-05-15 | 1990-12-12 | Aichi Steel Works Ltd | Hot working method for base material |
-
1992
- 1992-06-01 JP JP4165354A patent/JPH07112563B2/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS497771A (en) * | 1972-05-11 | 1974-01-23 | ||
| JPS63168260A (en) * | 1986-12-30 | 1988-07-12 | Aichi Steel Works Ltd | Hot working method for continuously cast billet |
| JPH02299701A (en) * | 1989-05-15 | 1990-12-12 | Aichi Steel Works Ltd | Hot working method for base material |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010005634A (en) * | 2008-06-24 | 2010-01-14 | Kobe Steel Ltd | Method for producing cast metal |
| JP2019155385A (en) * | 2018-03-08 | 2019-09-19 | 日本製鉄株式会社 | Refining device train of continuous casting cast piece |
| JP2020066047A (en) * | 2018-10-26 | 2020-04-30 | 日本製鉄株式会社 | Manufacturing method of steel piece |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07112563B2 (en) | 1995-12-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN113106206A (en) | Manufacturing method of 1Cr11Ni2W2MoV heat-resistant steel forging for fastener | |
| US4715905A (en) | Method of producting thin sheet of high Si-Fe alloy | |
| JPH0688125A (en) | Method for hot-working continuously cast slab and steel ingot | |
| JPH05329505A (en) | Method for preventing surface crack of low-alloy steel | |
| KR20010011611A (en) | A Method for Manufacturing Continuously Cast Strands Having Improved Surface Quality from Martensite Stainless Steel | |
| JPH0347918A (en) | Production of b-containing steel | |
| JPS63123556A (en) | Production of cr-ni stainless steel being hard to crack at casting and hot rolling process | |
| JP2843665B2 (en) | Hot work crack prevention method for continuous cast slab. | |
| JP2580936B2 (en) | Method for producing steel with few surface defects | |
| JP3091795B2 (en) | Manufacturing method of steel bars with excellent drawability | |
| JPS63168260A (en) | Hot working method for continuously cast billet | |
| JPH0112561B2 (en) | ||
| JPS6320412A (en) | Hot working method for austenitic stainless steel containing mo and n | |
| JPS58224054A (en) | Method for preventing surface cracking of continuous casting ingot | |
| JPH03223420A (en) | Production of high strength steel | |
| JPS58224055A (en) | Method for preventing surface cracking of continuous casting ingot | |
| JPH0512411B2 (en) | ||
| JPS5852444B2 (en) | Method for suppressing steel billet surface cracking during hot rolling | |
| JPS62253725A (en) | Production of high-toughness non-heattreated bar steel for hot forging | |
| JPS5852443B2 (en) | Method for suppressing steel billet surface cracking during hot rolling | |
| JPS62156056A (en) | Continuous casting method for low alloy steel | |
| JPS61193758A (en) | Production of hot worked steel material having good surface characteristic | |
| JP2583715B2 (en) | Manufacturing method of thick steel plate with excellent low temperature toughness | |
| JPH054169B2 (en) | ||
| CN121592837A (en) | Production method for ML40Cr annealing of automobile cold heading steel wire rod |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 19980120 |