JPH0339421A - Production of cr-ni stainless steel sheet having welding crack resistance - Google Patents
Production of cr-ni stainless steel sheet having welding crack resistanceInfo
- Publication number
- JPH0339421A JPH0339421A JP17298889A JP17298889A JPH0339421A JP H0339421 A JPH0339421 A JP H0339421A JP 17298889 A JP17298889 A JP 17298889A JP 17298889 A JP17298889 A JP 17298889A JP H0339421 A JPH0339421 A JP H0339421A
- Authority
- JP
- Japan
- Prior art keywords
- stainless steel
- slab
- thin sheet
- continuous casting
- crack resistance
- 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
- 229910001220 stainless steel Inorganic materials 0.000 title claims abstract description 28
- 239000010935 stainless steel Substances 0.000 title claims abstract description 28
- 238000004519 manufacturing process Methods 0.000 title claims description 8
- 238000003466 welding Methods 0.000 title abstract description 9
- 238000000034 method Methods 0.000 claims abstract description 17
- 239000000203 mixture Substances 0.000 claims abstract description 15
- 238000009749 continuous casting Methods 0.000 claims abstract description 14
- 238000005096 rolling process Methods 0.000 claims abstract description 11
- 238000001816 cooling Methods 0.000 claims abstract description 9
- 238000005097 cold rolling Methods 0.000 claims abstract description 7
- 238000000137 annealing Methods 0.000 claims abstract description 5
- 238000005336 cracking Methods 0.000 claims description 17
- 229910000831 Steel Inorganic materials 0.000 claims description 9
- 239000010959 steel Substances 0.000 claims description 9
- 238000004804 winding Methods 0.000 claims description 2
- 238000005266 casting Methods 0.000 abstract description 12
- 238000007711 solidification Methods 0.000 abstract description 11
- 230000008023 solidification Effects 0.000 abstract description 11
- 230000001360 synchronised effect Effects 0.000 abstract description 5
- 238000007712 rapid solidification Methods 0.000 abstract description 4
- 230000001105 regulatory effect Effects 0.000 abstract 1
- 229910045601 alloy Inorganic materials 0.000 description 13
- 239000000956 alloy Substances 0.000 description 13
- 230000005496 eutectics Effects 0.000 description 11
- 229910000859 α-Fe Inorganic materials 0.000 description 7
- 239000000047 product Substances 0.000 description 6
- 241000282326 Felis catus Species 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 238000005098 hot rolling Methods 0.000 description 4
- 238000010587 phase diagram Methods 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 230000037303 wrinkles Effects 0.000 description 2
- 229910019590 Cr-N Inorganic materials 0.000 description 1
- 229910019588 Cr—N Inorganic materials 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 229910000963 austenitic stainless steel Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 229910001039 duplex stainless steel Inorganic materials 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Continuous Casting (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、鋳片と鋳型内壁面間に相対速度差の無い、い
わゆる同期式連続鋳造プロセスによって製品厚さに近い
サイズの鋳片を鋳造し、耐溶接割れ性を有するＣｒ−Ｎ
ｉ系ステンレス鋼薄板を製造する方法に関する。[Detailed Description of the Invention] [Industrial Application Field] The present invention casts a slab of a size close to the product thickness by a so-called synchronous continuous casting process in which there is no relative speed difference between the slab and the inner wall surface of the mold. Cr-N with weld cracking resistance
The present invention relates to a method of manufacturing an i-series stainless steel thin plate.
従来、連続鋳造法を用いてＣｒ−Ｎｉ系ステンレス鋼薄
板を製造するには、鋳型を鋳造方向に振動させながら厚
さ１００ｍｍ以上の鋳片に鋳造し、得られた鋳片の表面
手入れを行ない、加熱炉において１０００℃以上に加熱
した後、粗圧延機および仕上げ圧延機列からなるホット
ストリップミルによって熱間圧延を施し、厚さ数ｍＩｌ
＋のホットストリップとしていた。Conventionally, in order to manufacture thin Cr-Ni stainless steel sheets using the continuous casting method, a slab of 100 mm or more in thickness is cast while the mold is vibrated in the casting direction, and the surface of the resulting slab is treated. After heating to 1000°C or higher in a heating furnace, hot rolling is performed using a hot strip mill consisting of a rough rolling mill and a finishing rolling mill row to a thickness of several millimeters.
It was a + hot strip.
こうして得られたホットストリップを冷間圧延するに際
しては、最終製品に要求される形状（平坦さ〉、材質、
表面性状を確保するために、強い熱間加工を受けたホッ
トストリップを軟化させるための熱延板焼鈍を行なうと
ともに、表面のスケール等を酸洗工程の後に研削によっ
て除去していた。When cold rolling the hot strip obtained in this way, the shape required for the final product (flatness, material,
In order to secure the surface quality, hot-rolled sheets were annealed to soften the hot strips that had undergone intense hot working, and scales and the like on the surface were removed by grinding after the pickling process.
溶接材料としてのＣｒ−Ｎｉ系ステンレス鋼薄板も上記
のプロセスで製造されていたが、次のような問題点があ
った。Cr--Ni stainless steel thin plates used as welding materials have also been manufactured by the above process, but they have the following problems.
ステンレス溶接材料は、耐溶接割れ性を付与するために
、オーステナイト中にある程度のδフェライトを分散さ
せた組織とする必要がある。必要なδフエライト量は一
般に５〜１０％以上であることが知られている（たとえ
ば、「ステンレス鋼便覧（初版）」、日刊工業新聞社、
１９７３年８月３０日発行ｐ、 ７２５を参照）。Stainless steel welding materials need to have a structure in which a certain amount of δ ferrite is dispersed in austenite in order to impart weld cracking resistance. It is known that the required amount of δ ferrite is generally 5 to 10% or more (for example, "Stainless Steel Handbook (first edition)", Nikkan Kogyo Shimbun,
(see August 30, 1973, p. 725).
一方、前記従来プロセスでは熱間圧延を行なう必要があ
るが、Ｃｒ−Ｎｉ系ステンレス鋼の熱間加工性は組織中
のδフェライト量ｉこよって大きく影響を受ける。特に
δフエライト量が５〜３０％程度の範囲では熱間加工温
度での絞り値が著しく低下するため、熱延中に表面割れ
が多発し易い（たとえば、「高温変形と高温破壊」 （
鉄鋼基礎共同研究会高温変形部会第３回シンポジウムテ
キスト、１９８１年２月１７日）ｐ、 １８２を参照）
。したがって熱間加工性の面からは、δフエライト量が
この範囲になることを避けることが望ましい。On the other hand, although hot rolling is required in the conventional process, the hot workability of Cr-Ni stainless steel is greatly influenced by the amount of δ ferrite i in the structure. In particular, when the amount of δ ferrite is in the range of about 5 to 30%, the reduction of area at the hot working temperature decreases significantly, and surface cracks are likely to occur frequently during hot rolling (for example, "high temperature deformation and high temperature fracture").
Text of the 3rd Symposium of the Steel Basics Joint Research Group High Temperature Deformation Subcommittee, February 17, 1981) p. 182)
. Therefore, from the viewpoint of hot workability, it is desirable to avoid the amount of δ ferrite falling within this range.
しかし、実用されているステンレス溶接材料には、前記
耐溶接割れ性の観点からこの範囲のδフエライト量を有
するものが多く、歩留りや生産性の向上にとって大きな
障害であった。However, many of the stainless steel welding materials in practical use have an amount of δ ferrite in this range from the viewpoint of the weld cracking resistance, which has been a major obstacle to improving yield and productivity.
最近、１００ｍ以上の厚さの鋳片をホットストリップに
圧延するために長大な熱間圧延設備と多大なエネルギー
や圧延動力を必要とするという問題を解決すべく、連続
鋳造の過程でホットストリップと同等か、或はそれに近
い厚さの鋳片（薄帯）を得るプロセスの研究が進められ
ている。Recently, in order to solve the problem that rolling slabs with a thickness of 100 m or more into hot strips requires a long hot rolling equipment and a large amount of energy and rolling power, hot strip rolling has been developed in the continuous casting process. Research is underway on a process to obtain slabs (thin strips) of the same or similar thickness.
例えば、「鉄と鋼Ｊ ’８５． Ａ１９７〜’ Ａ２５
６やｒＣＡＭＰＩＳＩＪＪ ｖｏｌ、１．１９８８．１
６７０〜１７０５において特集された論文に、ホットス
トリップを連続鋳造によって直接的に得るプロセスが開
示されている。For example, "Tetsu to Hagane J '85. A197~' A25
6 and rCAMPISIJJ vol, 1.1988.1
670-1705 discloses a process for obtaining hot strip directly by continuous casting.
このような連続鋳造プロセスにあっては、得ようとする
鋳片（ストリップ）のゲージが１〜１０叩の水準である
ときは双ロール方式が、また鋳片のゲージが２０〜５０
ｍｍの水準であるときは双ベルト方式が検討されている
。In such a continuous casting process, the twin roll method is used when the gauge of the strip to be obtained is 1 to 10 strokes, and the twin roll method is used when the gauge of the strip to be obtained is 20 to 50 strokes.
At the mm level, a twin belt system is being considered.
ステンレス溶接材料の製造に、連続鋳造によってホット
ストリップと同等の厚さの鋳片を直接得る上記プロセス
を用いれば、熱間加工性に起因する種々の技術的拘束が
なくなるので、極めて有利である。If the above-mentioned process of directly obtaining a slab of thickness equivalent to that of hot strip by continuous casting is used to manufacture stainless steel welding materials, it is extremely advantageous because various technical restrictions due to hot workability are eliminated.
しかし、ホットストリップの形状に近い薄肉鋳片の鋳造
においては、従来の厚い鋳片の鋳造にくらべて著しく急
冷凝固となるため、凝固収縮による鋳片の割れが発生し
やすいという新らたな問題が生じた。However, when casting thin slabs that have a shape similar to hot strips, the cooling and solidification is much more rapid than when casting conventional thick slabs, which creates a new problem in that slabs are more likely to crack due to solidification shrinkage. occurred.
本発明は、鋳片と鋳型内壁面間に相対速度差のない、い
わゆる同期式連続鋳造プロセスによって製品厚さに近い
サイズの鋳片を鋳造する際の急冷凝固による鋳片の割れ
発生を防止した、耐溶接割れ性を有する（：、ｒ−Ｎｉ
系ステンレス鋼薄板を製造方法を提供することを目的と
する。The present invention prevents the occurrence of cracks in slabs due to rapid solidification when casting slabs of a size close to the product thickness by a so-called synchronous continuous casting process in which there is no relative speed difference between the slab and the inner wall surface of the mold. , has weld cracking resistance (:, r-Ni
The purpose of the present invention is to provide a method for manufacturing thin stainless steel sheets.
上記の目的は、本発明によれば、δＦｅ、 ｃａｔ （
％）＝ ３ （Ｃｒ＋ １．５Ｓｉ＋Ｍｏ＋Ｎｂ） −
２，８（Ｎｉ ＋１／２Ｍｎ＋１／２Ｃｕ） −８４（
Ｃ＋Ｎ） −１９，８（％）で定義されるδＦｅ、ｃａ
ｔ（％）が４％以上となる組成のＣｒ−Ｎｉ系ステンレ
ス鋼溶鋼を、鋳型壁面が鋳片に同期して移動する連続鋳
造機によって厚さ１０ｍｍ以下の薄肉鋳片に鋳造し、凝
固温度から１２００℃までを１０℃／ｓｅｅ以上の速度
で冷却し、９５０℃から６００℃までの温度範囲を５℃
／ｓｅｃ以上の速度で冷却し、６００℃以下の温度で巻
き取り、その後通常のデスケール、冷間圧延、最終焼鈍
、および調質圧延を行なうことを特徴とする、耐溶接割
れ性を有するＣｒ−Ｎｉ系ステンレス鋼薄板の製造方法
によって達成される。The above object, according to the invention, is achieved by δFe, cat (
%)=3 (Cr+ 1.5Si+Mo+Nb) −
2,8(Ni+1/2Mn+1/2Cu) -84(
C+N) -19,8 (%) δFe, ca
Molten Cr-Ni stainless steel with a composition of t (%) of 4% or more is cast into a thin slab with a thickness of 10 mm or less using a continuous casting machine in which the mold wall surface moves in synchronization with the slab, and the solidification temperature is to 1200℃ at a rate of 10℃/see or higher, and the temperature range from 950℃ to 600℃ by 5℃
/sec or more, coiled at a temperature of 600°C or less, and then subjected to normal descaling, cold rolling, final annealing, and temper rolling. This is achieved by a method for manufacturing Ni-based stainless steel thin plates.
前記薄肉鋳片の割れ発生を防止するために、本発明者は
、Ｆｅ−Ｃｒ−Ｎｉ系の高温状態図をもとに、各種の成
分糸の合金について鋳型浸漬法で小型の鋳片を作成し、
それらの鋳片表面の収縮状況を調査した。In order to prevent the occurrence of cracks in the thin slab, the present inventor created small slabs using a mold dipping method for alloys of various component threads based on the high temperature phase diagram of the Fe-Cr-Ni system. death,
The shrinkage conditions on the surface of these slabs were investigated.
第２図は、Ｆｅ７０％でＣｒｅｑ＋Ｎ１ｅｑ＝ ３０％
相当の合金の高温状態図である。図中の■、■、■合金
相当合金相当性分作成し、凝固後の表面収縮状況を調査
した。その結果、第１図に示したように、高温で３元共
晶域に相当する合金■の場合に表面の収縮が顕著で凹凸
が大であったが、共晶域外の■と■の合金では表面は平
滑で収縮応力が小さいことが判明した。（厳密には三元
共晶か三元包共晶かは議論がある。ここでは三元共晶あ
るいは三元（包）共晶と表現した。いづれにしてもこの
三相（Ｌ＋δ＋Ｔ）共存域が問題である。〉更にこれら
の合金、■、■、■を双ロール式鋳造試験機で鋳造した
ところ、共晶域外の合金では割れが顕著で、共晶域内の
■は割れと湯じわが顕著であったが、共晶域外の合金で
δ凝固の■は割れもなく、表面性状が良好であった。こ
のように、三元の晶をはずれたδ凝固の組成が急冷凝固
時の割れ抵抗が大きく、かつ表面性状も良好であること
を初めて見出した。Ｆｅ５０％相当域では、三元の共晶
をはずす合金組成はδＦｅ、ｃａｔ（％）＝３ （Ｃｒ
量 １．５ Ｓｉ十Ｍｏ） −２，８（Ｎｉ＋１／２Ｍ
ｎ＋１／２Ｃｕ） −８４（Ｃ＋Ｎ） −１９，８％の
式においてはδＦｅ、ｃａｌ （％）が４％以上に相当
する。したがって４％以上のδＦｅ、ｃａｌ （％）に
おいて良好な鋳造性が得られ、鋳片の割れ発生が防止で
きる。Figure 2 shows Creq+N1eq=30% with Fe70%.
Figure 3 is a high temperature phase diagram of the corresponding alloy. The alloy equivalents of ■, ■, and ■ in the figure were prepared, and the surface shrinkage after solidification was investigated. As a result, as shown in Figure 1, the surface shrinkage was remarkable and the surface unevenness was large in the case of alloy ①, which corresponds to the ternary eutectic region at high temperatures, but It was found that the surface was smooth and the shrinkage stress was small. (Strictly speaking, there is a debate as to whether it is ternary eutectic or ternary envelope eutectic.Here, it is expressed as ternary eutectic or ternary (envelope) eutectic.In any case, this three-phase (L + δ + T) coexistence region Furthermore, when these alloys ■, ■, and ■ were cast using a twin-roll casting tester, alloys outside the eutectic region showed significant cracking, while ■ within the eutectic region showed cracking and wrinkling. However, in alloys outside the eutectic region, there were no cracks in δ solidification, and the surface quality was good.In this way, the composition of δ solidification outside the ternary crystal structure caused cracking during rapid solidification. It was discovered for the first time that the resistance is large and the surface quality is good.In the region equivalent to 50% Fe, the alloy composition that removes the ternary eutectic is δFe, cat (%) = 3 (Cr
Amount 1.5 Si + Mo) -2,8 (Ni + 1/2M
In the formula n+1/2Cu) -84(C+N) -19.8%, δFe, cal (%) corresponds to 4% or more. Therefore, good castability can be obtained when δFe, cal (%) is 4% or more, and cracking of the slab can be prevented.
第３図はＦｅ（ｉＱ％でＣｒｅｑ＋Ｎ１ｅｑ＝ ４０％
相当の高温状態図で、Ｃｒ量やＮｉ量の多い場合である
。Figure 3 shows Fe (iQ%Creq+N1eq=40%
This is a considerably high-temperature phase diagram, in which the amount of Cr and the amount of Ni are large.
この場合にも、高温での三元（包〉共晶組成をはずした
δ凝固組成で鋳片の割れもしわも少なく良好であった。In this case as well, the δ solidification composition, which excludes the ternary (envelope) eutectic composition at high temperatures, was good with few cracks and wrinkles in the slab.
この場合δＦｅ、ｃａｌは１６％以上で良好であった。In this case, δFe and cal were 16% or more, which was good.
（第２図、第３図の高温状態図はいずれもＪ、Ｃ０Ｌ１
ｐｐｏｌｄ ａｎｄ Ｗ、Ｆ、Ｓａｖａｇｅ； Ｗｅｌ
ｄ、Ｊ、５８゜１９７９、３６２Ｓによる。）合金組成
は鋳造性の点からは、δＦｅ、ｃａｔ （％）が大きい
方が良好であるが、δＦｅ、ｃａｔ （％）が余り大き
くなり７０％を越えるようになると、鋳片の巻取り中等
でσに変化しやすく、又、合金の特性的にも特に大きな
効果は認められなくなる。合金組成としては、前記の式
で定義されたδＦｅ、ｃａｔ（％）を適用できるＣｒ−
Ｎｉ系ステンレス鋼でδＦｅ、 ｃａｌ （％）≧４を
満たす範囲であればよい。Ｃ：、ｒ−Ｎｉ系ステンレス
鋼とは、１８Ｃｒ−８Ｎｉステンレス鋼で代表されるオ
ーステナイト・ステンレス鋼および２相ステンレス鋼を
も含む。通常のＣｒ−Ｎｉ系ステンレス鋼においてよく
利用されるような、Ｃｒ、Ｎｉ量はもちろん、Ｓｉ・Ｍ
ｎ、Ｎ、Ｃｕ・Ｍｏ、Ｎｂ、Ｔｉ等を含有してもよい。(The high temperature state diagrams in Figures 2 and 3 are J, C0L1
ppold and W,F,Savage; Wel
d, J, 58° 1979, 362S. ) From the point of view of castability, the larger the δFe, cat (%), the better the alloy composition, but if the δFe, cat (%) becomes too large and exceeds 70%, it may be difficult to roll the slab, etc. σ tends to change easily, and no particularly large effect can be recognized in terms of the properties of the alloy. As for the alloy composition, δFe, cat (%) defined by the above formula can be applied.
Any Ni-based stainless steel may be used as long as δFe, cal (%)≧4 is satisfied. C:, r-Ni stainless steel also includes austenitic stainless steel and duplex stainless steel represented by 18Cr-8Ni stainless steel. In addition to the amounts of Cr and Ni that are often used in ordinary Cr-Ni stainless steel, Si and M
It may contain n, N, Cu/Mo, Nb, Ti, etc.
従来知られているように、溶接性の観点からＳ≦０．０
０６０％、ｌ≦０．０５０％に制限することができる。As is conventionally known, from the viewpoint of weldability, S≦0.0
0.060%, l≦0.050%.
本発明においては、上記δＦｅ、 ｃａｌ （％）≧４
の組成を有するＣｒ−Ｎｉ系ステンレス鋼溶鋼を、鋳型
壁面が鋳片と同期して移動する連続鋳造機（双ロール式
、双ベルト式等）によってホラトス） ＩＪツブ厚さと
同等の厚さ１０ｍｍ以下の薄肉鋳片に鋳造する。鋳造中
、凝固温度から１２００℃までを１０℃／ｓｅｃ以上の
速度で冷却することにより、凝固組織中のδ相の粗大化
を防止する。次に、σ相生成による脆化を防止するため
に、９５０〜６００℃の温度範囲を５℃／ｓｅｃ以上の
速度で冷却し、かつ６００℃以下で巻取る。In the present invention, the above δFe, cal (%)≧4
Molten Cr-Ni stainless steel with a composition of Cast into thin-walled slabs. During casting, by cooling from the solidification temperature to 1200°C at a rate of 10°C/sec or more, coarsening of the δ phase in the solidified structure is prevented. Next, in order to prevent embrittlement due to σ phase formation, it is cooled in a temperature range of 950 to 600°C at a rate of 5°C/sec or more, and wound at a temperature of 600°C or less.
その後、常法通りのデスケール、冷間圧延、最終焼鈍、
および調質圧延を行ないステンレス鋼薄板製品を得る。After that, conventional descaling, cold rolling, final annealing,
and temper rolling to obtain stainless steel thin plate products.
その際、製品形状および表面粗さの観点から、冷間圧延
の合計圧下率を４０％以上とすることが望ましい。最終
焼鈍は、従来一般に行なわれているのと同様に、１００
０〜１２５０℃の温度で保持した後急冷することにより
行なう。In this case, from the viewpoint of product shape and surface roughness, it is desirable that the total reduction ratio of cold rolling is 40% or more. The final annealing was carried out at 100° C.
This is carried out by holding at a temperature of 0 to 1250°C and then rapidly cooling it.
本発明においては、δＦｅ、ｃａｌ （％）を４％以上
としたＣｒ−Ｎｉ系ステンレス鋼を同期式連続鋳造機に
よって厚さ１０ｍｍ以下の薄肉鋳片に鋳造することによ
って、鋳造時の鋳片割れを防止して、耐溶接割れ性を有
するＣｒ−Ｎｉ系ステンレス鋼薄板を製造することがで
きる。In the present invention, by casting Cr-Ni stainless steel with δFe, cal (%) of 4% or more into thin slabs with a thickness of 10 mm or less using a synchronous continuous casting machine, slab cracking during casting is avoided. Thus, it is possible to produce a Cr-Ni stainless steel thin plate having weld cracking resistance.
以下に、実施例により本発明を更に詳細に説明する。EXAMPLES Below, the present invention will be explained in more detail with reference to Examples.
第１表に示した組成のＣｒ−Ｎｉ系ステンレス鋼溶鋼を
、一対の内部水冷式ロールを鋳片と同期移動する鋳型壁
として槽底した双ロール式連続鋳造機によって、厚さ３
． Ｏｍｍの鋳片に鋳造した。第１表中、サンプルＮα
１〜５はδＦｅ、 ｃａｌ （％）≧４とした本発明鋼
であり、サンプルＮα６〜７はδＦｅ、Ｃａ１（％〉く
４％とした比較鋼である。Molten Cr-Ni stainless steel having the composition shown in Table 1 was cast to a thickness of 3.5 mm using a twin-roll continuous casting machine with a pair of internal water-cooled rolls at the bottom of the mold wall that moved in synchronization with the slab.
．． It was cast into a slab of Omm. In Table 1, sample Nα
Samples Nos. 1 to 5 are steels of the present invention in which δFe, cal (%)≧4, and samples Nα6 to 7 are comparative steels in which δFe, Ca1 (%)≧4%.
臥下金白
鋳造後は双ロール出口から鋳片を冷却して、凝固温度か
ら１２００℃までを１０℃／ｓｅｃ以上で冷却してδ相
やＴ相の成長を防止する。After casting, the slab is cooled from the exit of the twin rolls at a rate of 10°C/sec or more from the solidification temperature to 1200°C to prevent the growth of the δ phase and T phase.
更に９５０〜６００℃間は５℃／ｓｅｃ以上で冷却して
、巻取り温度を６００℃以下とし、σ相脆化を防止する
。Furthermore, cooling is performed at a rate of 5° C./sec or more between 950° C. and 600° C., and the winding temperature is set to 600° C. or lower to prevent σ phase embrittlement.
供試溶鋼の内、高温で三元（包〉共晶域外でδ凝固組成
の本発明成分では鋳片割れもなく、鋳片表面の湯じわ発
生もなく良好であったが、比較鋼では割れが発生し、か
つ表面性状も不良であった。Among the sample molten steels, the composition of the present invention with a δ solidification composition outside the ternary (envelope) eutectic region at high temperatures was good with no slab cracking and no hot water wrinkles on the slab surface, but the comparative steel did not exhibit any cracking. occurred, and the surface quality was also poor.
その後、鋳片をデスケールし、常法通り冷間圧延し最終
焼鈍した。これらの製品を使用して、溶接したが、ナメ
付は溶接や、パイプに成形後の溶接、あるいはバンドア
ーク溶接材のいずれにおいても、常法の溶接条件では本
発明鋼は溶接割れを起こさず良好であったが、比較鋼に
はいずれの条件でも溶接割れが発生し不良であった。Thereafter, the slab was descaled, cold rolled and finally annealed in a conventional manner. These products were used for welding, but the steel of the present invention did not cause weld cracking under normal welding conditions, whether welded with a name, welded after forming into a pipe, or band arc welded. However, the comparative steel had weld cracking under all conditions and was poor.
以上説明したように、本発明の方法によれば、本発明は
、鋳片と鋳片内壁面間に相対速度差のない、いわゆる同
期式連続鋳造プロセスによって製品厚さに近いサイズの
鋳片を鋳造する際の急冷凝固による鋳片の割れ発生を防
止して、耐溶接割れ性を有する高δフエライト量のＣｒ
−Ｎｉ系ステンレス鋼薄板を製造することができる。As explained above, according to the method of the present invention, a slab of a size close to the product thickness is produced by a so-called synchronous continuous casting process in which there is no relative speed difference between the slab and the inner wall surface of the slab. Cr with a high δ ferrite content prevents cracking of slabs due to rapid solidification during casting and has weld cracking resistance.
- A Ni-based stainless steel thin plate can be manufactured.
第１図は、第２図の■、■、■の合金組成に相当する溶
鋼を鋳型に浸漬し２叩厚鋳片とした場合の鋳片表面の状
態を示す斜視図、
第２図は、Ｆｅ７０％、 Ｃｒｅｑ＋Ｎ１ｅｑ＝ ３０
％に相当する合金の高温状態図、
および
第３図は、Ｆｅ６０％、 Ｃｒ＋Ｎｉ’＝ ４０％に相
当する合金の高温状態図である。
Ｃｒ、、 （’／１１）
１５
５
２５ ３０
１５ １０
５
４０ｗｔ ０ｔｏｃｒ
○ ｗＬ ’１０ Ｎシ
第３図Figure 1 is a perspective view showing the condition of the slab surface when molten steel corresponding to the alloy compositions of ■, ■, and ■ in Figure 2 is immersed in a mold to form a slab with a thickness of 2. Fe70%, Creq+N1eq=30
Figure 3 is a high temperature phase diagram of an alloy corresponding to 60% Fe, Cr+Ni' = 40%. Cr,, ('/11) 15 5 25 30 15 10 5 40wt 0tocr ○ wL '10 Nshi Figure 3
Claims (1)
ｏ＋Ｎｂ）−２．８（Ｎｉ＋１／２Ｍｎ＋１／２Ｃｕ）
−８４（Ｃ＋Ｎ）−１９．８（％）で定義されるδＦｅ
、ｃａｌ（％）が４％以上となる組成のＣｒ−Ｎｉ系ス
テンレス鋼溶鋼を、鋳型壁面が鋳片に同期して移動する
連続鋳造機によって厚さ１０ｍｍ以下の薄肉鋳片に鋳造
し、凝固温度から１２００℃までを１０℃／ｓｅｃ以上
の速度で冷却し、９５０℃から６００℃までの温度範囲
を５℃／ｓｅｃ以上の速度で冷却し、６００℃以下の温
度で巻き取り、その後通常のデスケール、冷間圧延、最
終焼鈍、および調質圧延を行なうことを特徴とする、耐
溶接割れ性を有するＣｒ−Ｎｉ系ステンレス鋼薄板の製
造方法。1, δFe, cal (%) = 3 (Cr+1.5Si+M
o+Nb)-2.8(Ni+1/2Mn+1/2Cu)
δFe defined as -84(C+N)-19.8(%)
, Cr-Ni stainless steel molten steel with a composition of 4% or more is cast into a thin slab with a thickness of 10 mm or less using a continuous casting machine in which the mold wall surface moves in synchronization with the slab, and then solidified. Cooling from temperature to 1200℃ at a rate of 10℃/sec or more, cooling from 950℃ to 600℃ at a rate of 5℃/sec or more, winding at a temperature of 600℃ or less, then normal A method for producing a Cr-Ni stainless steel thin plate having weld cracking resistance, the method comprising performing descaling, cold rolling, final annealing, and temper rolling.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17298889A JPH0339421A (en) | 1989-07-06 | 1989-07-06 | Production of cr-ni stainless steel sheet having welding crack resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17298889A JPH0339421A (en) | 1989-07-06 | 1989-07-06 | Production of cr-ni stainless steel sheet having welding crack resistance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0339421A true JPH0339421A (en) | 1991-02-20 |
Family
ID=15952095
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17298889A Pending JPH0339421A (en) | 1989-07-06 | 1989-07-06 | Production of cr-ni stainless steel sheet having welding crack resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0339421A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008115437A (en) * | 2006-11-06 | 2008-05-22 | Toshiba Corp | Austenitic-ferritic stainless steel with excellent resistance to deterioration due to thermal aging |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02133529A (en) * | 1988-07-08 | 1990-05-22 | Nippon Steel Corp | Production of cr-ni stainless steel sheet having excellent surface quality and material quality |
-
1989
- 1989-07-06 JP JP17298889A patent/JPH0339421A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02133529A (en) * | 1988-07-08 | 1990-05-22 | Nippon Steel Corp | Production of cr-ni stainless steel sheet having excellent surface quality and material quality |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008115437A (en) * | 2006-11-06 | 2008-05-22 | Toshiba Corp | Austenitic-ferritic stainless steel with excellent resistance to deterioration due to thermal aging |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4713709B2 (en) | Method for producing a strip of iron-carbon-manganese alloy | |
| KR100637790B1 (en) | Method for continuous casting of highly ductile ferritic stainless steel strips between rolls, and resulting thin strips | |
| JP4582916B2 (en) | Method for twin-roll continuous casting of ferritic stainless steel without microcracks | |
| JPH03100124A (en) | Production of cr-ni stainless steel sheet excellent in surface quality | |
| JPS6053726B2 (en) | Method for manufacturing austenitic stainless steel sheets and steel strips | |
| JPH0681036A (en) | Production of ferritic stainless steel sheet excellent in ridging characteristic and workability | |
| JPH01228603A (en) | Manufacture of two-phase stainless steel seamless tube | |
| JPH0730406B2 (en) | Method for producing Cr-Ni stainless steel sheet with excellent surface quality and material | |
| US5030296A (en) | Process for production of Cr-Ni type stainless steel sheet having excellent surface properties and material quality | |
| JPH0339421A (en) | Production of cr-ni stainless steel sheet having welding crack resistance | |
| JPS63123556A (en) | Production of cr-ni stainless steel being hard to crack at casting and hot rolling process | |
| EP0378705B2 (en) | PROCESS FOR PRODUCING THIN Cr-Ni STAINLESS STEEL SHEET EXCELLENT IN BOTH SURFACE QUALITY AND QUALITY OF MATERIAL | |
| JPH02263928A (en) | Production of cr-ni stainless steel sheet excellent in stress corrosion cracking resistance and surface quality | |
| JP2971292B2 (en) | Manufacturing method of austenitic stainless steel with few surface defects | |
| JPH04162943A (en) | Method for preventing hot-working crack in continuously cast slab | |
| WO1991010517A1 (en) | METHOD OF MANUFACTURING Cr-Ni STAINLESS STEEL SHEET EXCELLENT IN SURFACE QUALITY AND MATERIAL THEREOF | |
| JPH0631394A (en) | Production of thin cast slab for non-oriented silicon steel sheet | |
| JPH0670253B2 (en) | Method for producing Cr-Ni type stainless steel thin plate having excellent surface quality and material | |
| JPH0730407B2 (en) | Method for producing Cr-Ni type stainless steel thin plate with excellent surface quality | |
| JP2768527B2 (en) | Method for producing thin Cr-Ni stainless steel sheet with excellent workability | |
| JP3775178B2 (en) | Thin steel plate and manufacturing method thereof | |
| JP2977366B2 (en) | Manufacturing method of austenitic stainless steel sheet | |
| JP2548942B2 (en) | Method for preventing cracking during rapid solidification of Fe-Ni based alloy | |
| JPH07100819B2 (en) | Method for producing Cr-Ni-based stainless steel sheet having excellent mechanical properties and surface properties | |
| KR930000089B1 (en) | Process for production of cr-ni type stainless sheet having excellent surface properties and material quality |