JPS63143219A - Production of austenitic stainless steel - Google Patents
Production of austenitic stainless steelInfo
- Publication number
- JPS63143219A JPS63143219A JP28965486A JP28965486A JPS63143219A JP S63143219 A JPS63143219 A JP S63143219A JP 28965486 A JP28965486 A JP 28965486A JP 28965486 A JP28965486 A JP 28965486A JP S63143219 A JPS63143219 A JP S63143219A
- Authority
- JP
- Japan
- Prior art keywords
- rolling
- stainless steel
- less
- seconds
- temperature range
- 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
- 229910000963 austenitic stainless steel Inorganic materials 0.000 title claims abstract description 21
- 238000004519 manufacturing process Methods 0.000 title claims description 12
- 238000005096 rolling process Methods 0.000 claims abstract description 91
- 238000001816 cooling Methods 0.000 claims abstract description 28
- 238000005098 hot rolling Methods 0.000 claims abstract description 17
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 10
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 10
- 239000010959 steel Substances 0.000 claims abstract description 10
- 239000000243 solution Substances 0.000 claims description 16
- 230000001186 cumulative effect Effects 0.000 claims description 8
- 239000006104 solid solution Substances 0.000 claims description 8
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 6
- 238000001953 recrystallisation Methods 0.000 abstract description 17
- 239000000463 material Substances 0.000 abstract description 14
- 229910001220 stainless steel Inorganic materials 0.000 abstract description 10
- 238000001556 precipitation Methods 0.000 abstract description 9
- 239000010935 stainless steel Substances 0.000 abstract description 7
- 238000003303 reheating Methods 0.000 abstract description 5
- 239000000203 mixture Substances 0.000 abstract description 2
- 238000005260 corrosion Methods 0.000 description 24
- 230000007797 corrosion Effects 0.000 description 24
- 238000000034 method Methods 0.000 description 15
- 150000001247 metal acetylides Chemical class 0.000 description 10
- 230000000694 effects Effects 0.000 description 9
- 238000010438 heat treatment Methods 0.000 description 9
- 238000010586 diagram Methods 0.000 description 7
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 239000002253 acid Substances 0.000 description 2
- 150000007513 acids Chemical class 0.000 description 2
- 229910001566 austenite Inorganic materials 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 239000002436 steel type Substances 0.000 description 2
- 238000005253 cladding Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 238000012360 testing method Methods 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
- C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment of ferrous alloys
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)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明はオーステナイト系ステンレス鋼の製造方法に係
抄、特に熱間圧延のままで従来の固溶化熱処理を施した
と同等の性能を有するオンライン固溶化処理による製造
方法に関する。[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a method for producing austenitic stainless steel, particularly an on-line method that has the same performance as that obtained by subjecting hot-rolled stainless steel to conventional solution heat treatment. This invention relates to a manufacturing method using solid solution treatment.
ステンレス鋼は耐食性、耐熱性に優れた鋼として知られ
ており、そのうちオーステナイト系ステンレス鋼ば５Ｕ
Ｓ３０４．３０４１．、３１６．３１６Ｌ等の鋼種が厚
板、パイプ、クラツド材等として多用されている。Stainless steel is known as a steel with excellent corrosion resistance and heat resistance, and among these, austenitic stainless steel 5U
S304.3041. , 316.316L, etc. are widely used for thick plates, pipes, cladding materials, etc.
オーステナイト系ステンレス鋼材は通常、熱間圧延後１
０１０〜１１５０℃に再加熱して急冷する固溶化熱処理
を施して製造される。固溶化熱処理の目的は加工硬化歪
を除去して均一な再結晶組織を得ることおよびＣｒ炭窒
化物やσ相などの脆化相を固溶化することによって粒界
腐蝕の発生を防止することにある。Austenitic stainless steel materials usually have a
It is manufactured by subjecting it to solution heat treatment, which involves reheating it to 010 to 1150°C and rapidly cooling it. The purpose of solution heat treatment is to remove work hardening strain and obtain a uniform recrystallized structure, and to prevent intergranular corrosion by converting brittle phases such as Cr carbonitrides and σ phase into a solid solution. be.
しかし、再加熱固溶化熱処理は従来、熱間圧延とは別の
オフラインで行わなければならないため、設備コストが
かさむとともに処理能率や省エネルギーの点で好ましく
ない。従って熱間圧延後室温まで冷却することなく、＃
１＃圧延に引き続き固溶化熱処理が実現できれば、熱処
理費用の低減や設備省略、工程短縮等により、従来に比
して大幅にオーステナイト系ステンレス鋼材の製造コス
トを低減できるものと期待されている。However, conventionally, reheating solution heat treatment has to be performed off-line, separate from hot rolling, which increases equipment costs and is unfavorable in terms of processing efficiency and energy saving. Therefore, without cooling to room temperature after hot rolling, #
If solution heat treatment can be realized following 1# rolling, it is expected that the manufacturing cost of austenitic stainless steel materials can be significantly reduced compared to conventional methods by reducing heat treatment costs, omitting equipment, shortening processes, etc.
従来、一般的な固溶化熱処理を省略してオーステナイト
系ステンレス鋼板を製造する方法として特開昭５５−１
０７７２９、特開昭６０−２６６１９等が提案されてい
る。Conventionally, Japanese Patent Application Laid-Open No. 55-1 was proposed as a method for manufacturing austenitic stainless steel sheets by omitting the general solution heat treatment.
07729, JP-A No. 60-26619, etc. have been proposed.
これらの提案の方法は、熱間圧延時の累積圧下率、仕上
げ温度および圧延後の冷却速度をそれぞれ所定の範囲に
規制することによって熱間圧延後に改めて固溶化熱処理
を行うことなく、熱間圧延のままでＣｒ炭窒化物の析出
のないオーステナイト系ステンレス鋼板を得ようとする
ものである。These proposed methods control the cumulative reduction rate during hot rolling, the finishing temperature, and the cooling rate after rolling within predetermined ranges. The purpose is to obtain an austenitic stainless steel sheet without precipitation of Cr carbonitride.
前記提案の方法によれば、確かに熱間圧延のままでＣｒ
炭窒化物の析出のないオーステナイト系ステンレス鋼板
を得ることは可能であるが、軟質化が必ずしも十分では
なく、強度特性のばらつきを生しること、鋼種により合
金元素の多い例えば５ＵＳ３１６．３１６Ｌでは再加熱
固溶化処理材と比較すると強度レベルが高めになってお
り、軟質化が不十分であるなどのｌＩ！ＩＨ点が残され
ていた。According to the method proposed above, it is true that Cr remains hot-rolled.
Although it is possible to obtain an austenitic stainless steel sheet without carbonitride precipitation, the softening is not necessarily sufficient, resulting in variations in strength properties. Compared to heated solution treated materials, the strength level is higher and the softening is insufficient. An IH point was left.
そのため、種々の鋼種に対して再加熱固溶化処理材と同
一の特性をオンライン方式で製造する方法の確立が求め
られていた。Therefore, there has been a need to establish a method for manufacturing various steel types with the same properties as reheated solution treated materials using an online method.
本発明の目的は、上記従来技術に対する要望に応え、オ
ンライン方式で従来の再加熱固溶化処理材と同等の特性
が得られろオーステナイト系ステンレス鋼の製造方法を
提供するにある。An object of the present invention is to provide a method for producing austenitic stainless steel that can obtain properties equivalent to those of conventional reheated solution treated materials using an online method, in response to the above-mentioned demands for the prior art.
〔問題点を解決するための手段および作用〕上記の本発
明の目的は、次の２発明によって達成されろ。[Means and effects for solving the problems] The above objects of the present invention can be achieved by the following two inventions.
第１発明の要旨とするところは次の如くである。The gist of the first invention is as follows.
重量比にて
Ｃ：０．０８％以下
Ｓｉ：１．０％以下
Ｍｎ：２．０％以下
Ｃｒ： １６． ０〜２６．０％
Ｎｉ：６．０〜２２０％
Ｎ：０．３０％以下
を含有するオーステナイト系ステンレス鋼スラブを１０
００℃を越える温度域において累積圧下率が３０％以上
でパス間時間が１θ秒以上の圧延を最終回圧延を含めて
１回以上行う段階と、前記圧延後９００℃以上の温度域
において熱間圧延を完了する段階と、前記圧延完了後９
００〜５００℃の温度域において平均冷却速度Ｖ（’ｅ
／％）が鋼中の炭素含有量Ｃ（％）に応じてＶ≧ｃ３ｘ
ｉ ｏ’を満足する条件で冷却する段階と、を有して
成り、オンライン固溶化処理によることを特徴とするオ
ーステナイト系ステンレス鋼の製造方法である。C: 0.08% or less Si: 1.0% or less Mn: 2.0% or less Cr: 16. 0 to 26.0% Ni: 6.0 to 220% N: 10 austenitic stainless steel slabs containing 0.30% or less
A step of performing rolling at least once in a temperature range exceeding 00°C with a cumulative reduction rate of 30% or more and an interpass time of 1θ seconds or more including the final rolling, and a step of hot rolling in a temperature range of 900°C or more after the rolling. a step of completing rolling; and a step 9 after said rolling is completed.
Average cooling rate V('e
/%) is V≧c3x depending on the carbon content C (%) in the steel.
A method for producing austenitic stainless steel characterized by an online solid solution treatment, comprising a step of cooling under conditions that satisfy io'.
第２発明の要旨とするところは次の如くである。The gist of the second invention is as follows.
すなわち、第１発明と同一成分のオーステナイト系ステ
ンレス鋼スラブを１０００℃を越える温度域において累
積圧下率が３０％以上でパス間時間が１０′４ｊＪ］上
の圧延を最終回圧延を含めて１回以上行う段階と、前記
圧延後９００〜１０００℃の温度域においてパス間時間
が３０秒以上の圧延を最終回圧延を含めて２回以上行う
段階と、前記圧延後９００℃以上の温度域において熱間
圧延を完了する段階と、から成る圧延後第１発明と同一
の冷却を行うオンライン固溶化処理によることを特徴と
するオーステナイト系ステンレス鋼の製造方法である。That is, an austenitic stainless steel slab having the same composition as the first invention is rolled once in a temperature range exceeding 1000°C with a cumulative reduction rate of 30% or more and an interpass time of 10'4jJ], including the final rolling. a step of carrying out rolling with an interpass time of 30 seconds or more in a temperature range of 900 to 1000°C after the rolling two or more times including the final rolling; This is a method for producing austenitic stainless steel, characterized in that it is based on an on-line solution treatment in which the same cooling as in the first invention is performed after rolling, which comprises the step of completing inter-rolling.
本発明者らは、従来技術の問題点を解決するため、種々
の成分のオーステナイト系ステンレス鋼についてスラブ
加熱、熱延（圧延温度圧下率、圧下率／パス、パス間時
間）、冷却等の諸条件について再検討を加え、特に再結
晶挙動について詳細に検討した結果、下記の方法により
十分な再結晶が得られ、オンライン方式で従来の再加熱
固溶化処理材と同一の特性が得られことを見い出だした
。すなわち、具体的には
（イ）熱間圧延中に再結晶を促進し、圧延後に軟質な機
械的性質を得ろため１０００℃を越える温度域の圧延で
パス間時間が１０秒以上となる圧延を１回以上行い、場
合によっては更に９００〜１０００℃の温度域でパス間
時間が３０秒以上となる圧延を２回以上行うこと、
（ロ）冷却中の炭化物の析出を抑制するため９００〜５
００℃の温変域を平均冷却速度Ｖ（’ｅ／秒）が鋼中の
炭素含有量Ｃ（％）に応じてＶ≧Ｃ３Ｘ １０’を満た
す条件で冷却することの２点である。In order to solve the problems of the prior art, the present inventors developed various methods such as slab heating, hot rolling (rolling temperature reduction rate, reduction rate/pass, interpass time), cooling, etc. for austenitic stainless steels of various components. As a result of reexamining the conditions and in particular examining the recrystallization behavior in detail, we found that sufficient recrystallization could be obtained using the method described below, and that the same properties as conventional reheated solution treated materials could be obtained using the online method. I found out. Specifically, (a) rolling is carried out in a temperature range exceeding 1000°C with an interpass time of 10 seconds or more in order to promote recrystallization during hot rolling and obtain soft mechanical properties after rolling. Rolling is performed at least once, and in some cases, rolling is performed at least twice in a temperature range of 900 to 1000°C with an interpass time of 30 seconds or more;
The two points are that the temperature range of 00°C is cooled under the condition that the average cooling rate V ('e/sec) satisfies V≧C3X10' depending on the carbon content C (%) in the steel.
次に本発明における成分限定理由について説明する。Next, the reason for limiting the components in the present invention will be explained.
Ｃ：
Ｃはオーステナイト相を安定化し、強度を増加させるの
に有効であるが、含有量が増大するとＣｒ炭化物が形成
されやすくなり、９００〜５００℃の炭化物析出領域で
の冷却速度を増加させることになるので、Ｃ１，ｔｏ、
０８％以下に限定した。C: C is effective in stabilizing the austenite phase and increasing strength, but as the content increases, Cr carbides are more likely to be formed, increasing the cooling rate in the carbide precipitation region of 900-500°C. Therefore, C1,to,
It was limited to 0.8% or less.
Ｓ ｌ ：
Ｓｉは通常脱酸元素として添加されるが、１０％を越え
る添加は熱間加工性を低下させるので、１．０％以下に
限定した。S 1 :Si is usually added as a deoxidizing element, but addition of more than 10% deteriorates hot workability, so it was limited to 1.0% or less.
Ｍｎ；
Ｍｎは脱酸と熱間加工性の向上のため添加されるが、２
．０％を越えろ添加は耐食性を阻害するので２．０％以
下に限定した。Mn: Mn is added to deoxidize and improve hot workability, but 2
．． Addition of more than 0% impedes corrosion resistance, so it was limited to 2.0% or less.
Ｃｒ：
Ｃｒはステンレス鋼の耐食性を保つのに必須の元素であ
り、オーステナイト系ステンレス鋼においては硫酸、塩
酸等の非酸化性の酸に対する耐食性ζよ１６．０％未満
では不十分である。しかし、２６０％を越える添加は耐
食性が飽和の傾向を示す一方、オーステナイト組織を保
つため高価なＮｉを増加させる必要がありコスト上昇を
招くので、これらの理由からＣｒは１６．０〜２６０％
の範囲に限定した。Cr: Cr is an essential element for maintaining the corrosion resistance of stainless steel, and in austenitic stainless steel, corrosion resistance ζ to non-oxidizing acids such as sulfuric acid and hydrochloric acid is insufficient if it is less than 16.0%. However, if the addition exceeds 260%, the corrosion resistance tends to be saturated, but it is necessary to increase the amount of expensive Ni in order to maintain the austenitic structure, leading to an increase in cost.For these reasons, the Cr content is 16.0-260%
limited to the range of
Ｎ１：
Ｎｉはオーステナイト組織を安定化する作用を有すると
共に硫酸、塩酸等の非酸化性の酸に対する耐食性を改蕎
するが、６．０％未満では十分でない。N1: Ni has the effect of stabilizing the austenite structure and improves corrosion resistance against non-oxidizing acids such as sulfuric acid and hydrochloric acid, but if it is less than 6.0%, it is not sufficient.
しかし、２２．０％を越える添加は耐食性が飽和の傾向
を示しコスト上昇になることから上限を２２．０％とし
、Ｎｉは６０〜２２０％の範囲に限定した。However, if more than 22.0% is added, corrosion resistance tends to be saturated and costs increase, so the upper limit was set at 22.0%, and Ni was limited to a range of 60 to 220%.
Ｎ：
Ｎは強度上昇と耐食性の向上に効果のある元素であるが
、０３０％を越える添加は製造性を低下させるので、０
３０％以下とした。N: N is an element that is effective in increasing strength and improving corrosion resistance, but adding more than 30% reduces manufacturability.
It was set to 30% or less.
上記限定量のＣ，Ｓｉ、Ｍｎ、Ｃｒ、Ｎｉ１Ｎが本発明
の基本成分であるが、更に下記限定量のＭＯｌＣｕｌＮ
ｂ、Ｔｉを添加しても本発明の目的はより有効に達成さ
れる。その添加の効果および限定理由は次のとおりであ
る。The above-mentioned limited amounts of C, Si, Mn, Cr, and Ni1N are the basic components of the present invention, and the following limited amounts of MOlCulN
b. Even if Ti is added, the object of the present invention can be achieved more effectively. The effect of its addition and the reason for its limitation are as follows.
ＭＯ：
ＭＯは耐食性、特に耐孔食性の向上に著しい効果のある
元素であるが、高価な元素であるため多量の添加はコス
ト増加となるので、４％以下に限定した。MO: MO is an element that has a remarkable effect on improving corrosion resistance, especially pitting corrosion resistance, but since it is an expensive element, adding a large amount will increase the cost, so it was limited to 4% or less.
Ｃｕ：
Ｃｕｔ、ｔＭ ｏと同じく耐食性特に耐孔食性の向上に
著しい効果のある元素であるが、高価な元素であろため
多量の添加はコスト増加となるので、２５％以下に限定
した。Cu: Like Cut and tMo, it is an element that has a remarkable effect on improving corrosion resistance, especially pitting corrosion resistance, but since it is an expensive element, adding a large amount will increase the cost, so it was limited to 25% or less.
Ｎｂ：
Ｎｂは炭化物を形成し、Ｃｒ炭化物の生成を抑制して耐
粒界腐蝕性の向上や結晶粒の微細化のために添加される
が、Ｃと有効に結びつ（Ｎｂ量はＣ（％）×１０で十分
であり、多量の添加は製造性の低下を招くので上限を０
，８％とした。Nb: Nb forms carbides and is added to suppress the formation of Cr carbides to improve intergranular corrosion resistance and refine crystal grains, but it combines effectively with C (the amount of Nb is %) x 10 is sufficient, and adding a large amount leads to a decrease in productivity, so the upper limit is set to 0.
, 8%.
Ｔ １：
ＴｉはＮｂと同様にＴｉ炭化物を形成しＣ「炭化物の生
成を抑制して耐粒界腐蝕性を向上させるほか、結晶粒の
微細化のなめに添加するが、Ｃと有効に結びっ＜Ｔｉ量
はＣ（％）×５で十分であ惟、多量の添加は製造性に低
下を招くので上限を０．５％に限定した。T1: Like Nb, Ti forms Ti carbides and suppresses the formation of C carbides to improve intergranular corrosion resistance, and is added to refine grain refinement, but does not effectively combine with C. It is sufficient that the amount of Ti is C (%) x 5, but adding too much leads to a decrease in productivity, so the upper limit was limited to 0.5%.
次に製造条件の限定理由を説明する。Next, the reason for limiting the manufacturing conditions will be explained.
オーステナイト系ステンレス鋼の熱間圧延条件すなわち
圧延温度、圧下率、パス間時間、仕上げ温度等が再結晶
に及ぼす影響を調査し、その結果を第１〜６図に示しな
、第１図は本調査のなめに行った実験の試験方法を示す
例であり、１回の圧下率が１０％で、パス間時間が各パ
ス同一で例えば１秒〜４０秒のパス間時間の繰返し圧延
を行った場合の歪（％）と耐力（ｋｇ／１１１１１”）
との関係を示したものである。軟化度Ｘ５（ｉ）はこの
図から下式で求められる。We investigated the effects of hot rolling conditions of austenitic stainless steel, such as rolling temperature, rolling reduction, interpass time, finishing temperature, etc., on recrystallization, and the results are shown in Figures 1 to 6. This is an example showing the test method of an experiment conducted for the sake of investigation, in which rolling was performed repeatedly with the rolling reduction rate of 10% and the interpass time being the same for each pass, for example, from 1 second to 40 seconds. Strain (%) and yield strength (kg/11111”)
This shows the relationship between The degree of softening X5(i) is determined from this figure using the formula below.
次に第２図はパス間時間がそれぞれ１秒、１０秒、２０
秒、４０秒で５パス圧延を同一パス時間で行った場合に
おける圧延温度と軟化度の関係を示したものである。第
３図は最初から４パス目までのバス間時間はすべて５秒
で最後の５パス目のパス間時間がそれぞれ１０秒、２０
秒、４０秒の場合の圧延温度と軟化度との関係を示した
ものである。Next, Figure 2 shows the interpass times of 1 second, 10 seconds, and 20 seconds, respectively.
This figure shows the relationship between rolling temperature and softening degree when 5-pass rolling is performed at the same pass time for 40 seconds. Figure 3 shows that the inter-bus times from the first to the fourth pass are all 5 seconds, and the inter-pass times for the final fifth pass are 10 seconds and 20 seconds, respectively.
This figure shows the relationship between rolling temperature and softening degree in the case of 40 seconds and 40 seconds.
第２図に示されるようにパス間時間が一定のときは圧延
１度が高い程、また圧延温度が一定のとき、パス間時間
が長い方がより軟化度が太きくなっていることが分る。As shown in Figure 2, when the inter-pass time is constant, the higher the rolling degree, and when the rolling temperature is constant, the longer the inter-pass time, the thicker the degree of softening. Ru.
ところでミクロ組ｌａｗｉ察により軟化度と再結晶率と
の関係を調査すると第５図にように対応のあることが分
る。このように圧延温度が高い程、パス間時間が長いほ
ど、再結晶がより多く生じることが分る。１０００℃を
越す１度で圧下を繰返す場合、１０秒以上のパス間時間
で圧下を行えば軟化度は約０８以上とな９再結晶率で約
８０％以上となる。By the way, when the relationship between the degree of softening and the recrystallization rate is investigated by microscopic observation, it is found that there is a correspondence as shown in FIG. It can thus be seen that the higher the rolling temperature and the longer the interpass time, the more recrystallization occurs. When rolling is repeated once at a temperature exceeding 1000° C., if rolling is performed with an inter-pass time of 10 seconds or more, the softening degree will be about 0.8 or more, and at a recrystallization rate of 9, it will be about 80% or more.
第３図のように途中の圧下におけるパス間時間が１０秒
未満の場合、最終パス１回のみでも１０秒以上のバス間
時間で圧下すると１０００℃を越す温度での圧下で軟化
度が約０．７以上となり再結晶率で約７０％以上となる
。As shown in Figure 3, if the interpass time during the intermediate rolling is less than 10 seconds, if the rolling is done with an interbath time of 10 seconds or more even in just one final pass, the degree of softening will be approximately 0 under rolling at a temperature exceeding 1000°C. .7 or more, and the recrystallization rate is about 70% or more.
次に第４図は、初めの３回のパス間時間が５秒で、後の
４．５回の２回のバス間時間がそれぞれ１０秒、２０秒
、４０秒で圧延した場合の圧延温度と軟化度との関係を
示しているが、同図から明らかな如く、最初のパス間時
間が短かくても、最終２回のパス間時間が３０秒以上で
圧延すると、圧延温度が９００℃以上の場合軟化度が０
７以上すなわち再結晶率が約７０％以上となる。Next, Figure 4 shows the rolling temperatures when rolling was performed with an inter-pass time of 5 seconds for the first three passes and a time of 10 seconds, 20 seconds, and 40 seconds for the latter two passes, respectively. As is clear from the figure, even if the first pass time is short, if the final two passes are rolled with a time of 30 seconds or more, the rolling temperature will rise to 900°C. In the case above, the softening degree is 0
7 or more, that is, the recrystallization rate is about 70% or more.
以上の結果から熱同圧延中に十分な再結晶を達成するた
めには１０００℃を越える温度域での圧延はパス間時間
が１０秒以上となる圧延を１回以上行うことが必要であ
る。また、９００〜１０００℃の温度域での圧延では熱
間圧延中に十分な再結晶を達成するためにはパス間時間
が３０秒以上の圧延を２回以上行うことが必要である。From the above results, in order to achieve sufficient recrystallization during hot rolling, rolling in a temperature range exceeding 1000°C requires rolling with an interpass time of 10 seconds or more at least once. Further, in rolling in a temperature range of 900 to 1000°C, in order to achieve sufficient recrystallization during hot rolling, it is necessary to perform rolling with an interpass time of 30 seconds or more two or more times.
上記圧延における圧下率と再結晶率との関係を調査し、
１０００℃を越す圧延温度における関係を第６図に示し
た。第６図から１０００℃を越す温度域で全圧下率が３
０％以上のとき再結晶率８０％以下が達成される。この
ことから熱間圧延における再結晶を十分に得るには、１
０００℃を越える圧下では３０％以上の圧下率を加えろ
ことが必要である。Investigating the relationship between the rolling reduction rate and recrystallization rate in the above rolling,
The relationship at rolling temperatures exceeding 1000°C is shown in FIG. From Figure 6, the total reduction rate is 3 in the temperature range exceeding 1000℃.
When it is 0% or more, a recrystallization rate of 80% or less is achieved. From this, in order to obtain sufficient recrystallization during hot rolling, 1
When the pressure exceeds 000°C, it is necessary to apply a reduction rate of 30% or more.
次に熱間圧延後の冷却であるが、９００〜５００℃の温
度域での平均冷却速度Ｖ（℃／秒）がＣｒ炭化物の析出
に及ぼす影響を各種のオーステナイト系ステンレス鋼に
ついて調べた結果、炭素量Ｃ（％）に応じて■≧Ｃ３Ｘ
ＩＯ’を満足する場合にはＣ「炭化物の析出による粒界
腐蝕を生じず、上記関係式を満足しない遅い平均冷却速
度Ｖで冷却した場合はＣｒ炭化物が析出して粒界腐蝕を
生じろことが判明した。従って本発明では９００〜５０
０℃の温度域での平均冷却速度をＶ≧１０３Ｘ １０’
と規定した。なお、この場合９００℃を越えろ高温域あ
るいは５００℃未満の低温域における冷却速度はＣ「炭
化物の析出に影響を与えない。従って９００〜５００℃
の温度域についてのみ冷却速度を限定した。Next, regarding cooling after hot rolling, we investigated the effect of the average cooling rate V (°C/sec) in the temperature range of 900 to 500°C on the precipitation of Cr carbides for various austenitic stainless steels. Depending on the carbon content C (%)■≧C3X
If IO' is satisfied, grain boundary corrosion due to the precipitation of carbides will not occur, and if cooling is performed at a slow average cooling rate V that does not satisfy the above relational expression, Cr carbides will precipitate and grain boundary corrosion will occur. Therefore, in the present invention, 900 to 50
The average cooling rate in the temperature range of 0℃ is V≧103X 10'
stipulated. In this case, the cooling rate in the high temperature range exceeding 900°C or the low temperature range below 500°C does not affect the precipitation of carbides.
The cooling rate was limited only to the temperature range of .
［実施例コ
第１表に示す５種のオーステナイト系ステンレス鋼を用
いて第２表に示す圧延条件で熱間圧延を行った。工程（
イ）〜（ネ）は本発明例であり、（ト）〜（ヌ）は比較
例であり、（ト）は１０００℃を越える温度の圧延にお
けろパス間時間が１０秒以上である圧延回数が０回であ
り、（チ）は１０００℃を越丸る温度の圧延の累積圧下
率が３０％未満であり、第１表
（す）は９００〜１０００℃の温度域での圧延パス間時
間が３０秒以上となる圧延回数が１回で、しかも熱間圧
延の仕上げ温度が８９０℃の場合でありＩ富
（ヌ隨延後の冷却速度が遅く本発明の条件を満足しない
例であり、（ル）は従来例であって、現在通常行われて
いるオフライン過熱による固溶化処理を行った例である
。[Example 5] Five types of austenitic stainless steels shown in Table 1 were hot rolled under the rolling conditions shown in Table 2. Process (
A) to (N) are examples of the present invention, (G) to (N) are comparative examples, and (G) is rolling with an interpass time of 10 seconds or more in rolling at a temperature exceeding 1000°C. The number of rolling passes is 0, and (h) is less than 30% in the cumulative rolling reduction at a temperature exceeding 1000°C, and Table 1 (su) shows the number of rolling passes between rolling passes in the temperature range of 900 to 1000°C. This is an example where the number of times of rolling for which the time is 30 seconds or more is 1, and the finishing temperature of hot rolling is 890°C, and the cooling rate after rolling is slow and does not satisfy the conditions of the present invention. , (R) are conventional examples, and are examples in which solid solution treatment by off-line heating, which is currently commonly performed, is performed.
各種の工程で製造された鋼板について機械的性質および
耐食性を調査し、その結果を第３表に示した。なお、第
３表の腐蝕試験においてＯ印は耐食性が良好なものであ
り、Ｘ印は耐食性が劣るものである。The mechanical properties and corrosion resistance of steel plates manufactured through various processes were investigated, and the results are shown in Table 3. In addition, in the corrosion test in Table 3, the mark O indicates good corrosion resistance, and the mark X indicates poor corrosion resistance.
第３表から、（イ）、（ロ）、（Ａ）、（ニ）、（ネ）
で示される本発明例はいずれの鋼種の場合も、（ル）で
示される従来例、すなわち、再加熱固溶化処理材と比較
して全く同等の０２％耐力と伸びならびにシャルピー吸
収エネルギーを有し、しかも耐食性も全く差異が見られ
ず、オンライン方式で固溶化と軟質化が十分達成されて
いることがわかる。From Table 3, (a), (b), (A), (d), (ne)
Regardless of the steel type, the inventive example shown in (1) has exactly the same 02% yield strength, elongation, and Charpy absorbed energy as the conventional example shown in (1), that is, the reheated solution treatment material. Moreover, there was no difference in corrosion resistance at all, indicating that solid solution formation and softening were sufficiently achieved by the online method.
一方、比較例においては、１０００℃を越える温度域の
圧延におけるパス間時間が１０秒以上となる圧延回数が
０回である（ト）の場合、０２％耐力が再加熱固溶化処
理材に比して軟化が著しく不十分で呻び、シャルピー吸
収エネルギーも本発明例より小さい。１０００℃を越え
る温度域の圧延の累積圧下率が３０％未満である（チ）
の場合も同様である。 ９００〜１０００℃の温度域で
の圧延でパス間時間が３０秒以上となる圧延回数が１回
で、しかも熱間圧延の仕上１度が９００℃未満である（
す）の場合は、再結晶が十分ではないため、機械的性質
は比較例（ト）の場合と同様であり、しかも９００℃未
満の温変から冷却を開始し、Ｃｒ炭化物の析出を生じる
ため耐食性も従来の再加熱固溶化処理材より劣る。圧延
後の冷却速度が遅く本発明の条件を満足しない（ヌ）の
場合は、Ｃｒ炭化物の析出が生じるため耐食性が劣化し
ている。On the other hand, in the comparative example, when the number of rolling times at which the inter-pass time is 10 seconds or more in rolling in a temperature range exceeding 1000°C is 0 (G), the 02% yield strength is compared to that of the reheated solution treated material. The softening was extremely insufficient, and the Charpy absorbed energy was also smaller than that of the examples of the present invention. The cumulative reduction rate of rolling in a temperature range exceeding 1000°C is less than 30% (H)
The same applies to the case of . When rolling in a temperature range of 900 to 1000°C, the number of rolling times with an interpass time of 30 seconds or more is 1, and the finishing temperature of hot rolling is less than 900°C (
In the case of (g), recrystallization is not sufficient, so the mechanical properties are the same as in the comparative example (g), and cooling starts from a temperature change of less than 900°C, causing precipitation of Cr carbide. Corrosion resistance is also inferior to conventional reheated solution treated materials. If the cooling rate after rolling is slow and does not satisfy the conditions of the present invention (No), corrosion resistance is deteriorated due to precipitation of Cr carbides.
［発明の効果コ
本発明は上記実施例からも明らかな如く、限定成分のオ
ーステナイト系ステンレス鋼を１０００℃を越える温度
域で累積圧下率が３０％以上で、しかもパス間時間が１
０秒以上となる圧延を１回以上行い、必要の場合は更に
９００〜１０００℃でパス間時間が３０秒以上となる圧
延を２回以上行い、前記熱間圧延を９００℃以上で終了
し、炭素量に応じて９００〜５００℃の平均冷却速度を
限定することによって、従来のオンライン固溶化処理材
では軟質化が不十分であったものが、オンライン方式で
固溶化処理および軟質化が可能となり、従来のオフライ
ン再加熱固溶化処理材と全く同等の性能を得ることがで
きた。[Effects of the Invention] As is clear from the above examples, the present invention can produce austenitic stainless steel with limited components at a cumulative reduction rate of 30% or more in a temperature range exceeding 1000°C, and in addition, the interpass time is 1.
Rolling for 0 seconds or more is performed one or more times, and if necessary, further rolling is performed at 900 to 1000 ° C. for an interpass time of 30 seconds or more two or more times, and the hot rolling is finished at 900 ° C. or more, By limiting the average cooling rate to 900 to 500°C depending on the carbon content, it is now possible to perform solid solution treatment and softening of materials that were insufficiently softened with conventional online solution treatment. , we were able to obtain exactly the same performance as the conventional off-line reheating solid solution treated material.
本発明は厚板圧延ばかりでなく、鋼板、鋼帯、鋼管、鍛
造材等のすべての圧延に適用できる広範な技術である乙
とも、その効果として挙げることができる。The present invention can be cited as an effect of B, which is a wide range of techniques that can be applied not only to thick plate rolling but also to all types of rolling such as steel plates, steel strips, steel pipes, and forged materials.
第１図は軟化度を求めるための圧延における歪と耐力と
の関係を示す線図、第２図はそれぞれ１．１０．２０．
４０秒の同一パス間時間で５パス圧延を行った場合の圧
延温度と軟化度の関係を示す線図、第３図は初めの４パ
スを５秒の同一パス間時間で、最後の５パス目をそれぞ
れ１０．２０．４０秒のパス間時間で圧延した場合の圧
延温度と軟化度との関係を示す線図、第４図は初めの３
バスを５秒の同一バス間時間で、後の２パスをそれぞれ
１０，２０，４０秒のパス間時間で圧延した場合の圧延
温度と軟化度との関係を示す線図、第５図は再結晶率と
軟化度との関係を示す相関図、第６図は１０００℃を越
える温度域における全圧下率と再結晶率との関係を示す
線図である。Fig. 1 is a diagram showing the relationship between strain and yield strength during rolling to determine the degree of softening, and Fig. 2 is a diagram showing the relationship between strain and yield strength in rolling to determine the degree of softening.
A diagram showing the relationship between rolling temperature and softening degree when rolling is performed for 5 passes with the same interpass time of 40 seconds. Figure 3 shows the relationship between rolling temperature and softening degree when rolling is performed for 5 passes with the same interpass time of 40 seconds. Figure 4 is a diagram showing the relationship between rolling temperature and softening degree when rolling with interpass times of 10, 20, and 40 seconds, respectively.
Figure 5 is a diagram showing the relationship between rolling temperature and softening degree when the bus is rolled with the same inter-bath time of 5 seconds and the latter two passes with inter-pass times of 10, 20, and 40 seconds, respectively. FIG. 6 is a correlation diagram showing the relationship between crystallinity and softening degree. FIG. 6 is a diagram showing the relationship between total rolling reduction and recrystallization rate in a temperature range exceeding 1000°C.
Claims (2)
００℃を越える温度域において累積圧下率が３０％以上
でパス間時間が１０秒以上の圧延を最終回圧延を含めて
１回以上行う段階と、前記圧延後９００℃以上の温度域
において熱間圧延を完了する段階と、前記圧延完了後９
００〜５００℃の温度域において平均冷却速度Ｖ（℃／
秒）が鋼中の炭素含有量Ｃ（％）に応じてＶ≧Ｃ＾３×
１０＾４を満足する条件で冷却する段階と、を有して成
りオンライン固溶化処理によることを特徴とするオース
テナイト系ステンレス鋼の製造方法。(1) Weight ratio C: 0.08% or less Si: 1.0% or less Mn: 2.0% or less Cr: 16.0 to 26.0% Ni: 6.0 to 22.0% N: 10 austenitic stainless steel slabs containing 0.30% or less
A step of performing rolling at least once in a temperature range exceeding 00°C with a cumulative reduction rate of 30% or more and an interpass time of 10 seconds or more including the final rolling, and a step of hot rolling in a temperature range of 900°C or more after the rolling. a step of completing rolling; and a step 9 after said rolling is completed.
Average cooling rate V (°C/
V≧C^3× depending on the carbon content C (%) in the steel
1. A method for producing austenitic stainless steel, comprising a step of cooling under conditions satisfying 10^4, and using online solid solution treatment.
００℃を越える温度域において累積圧下率が３０％以上
でパス間時間が１０秒以上の圧延を最終回圧延を含めて
１回以上行う段階と、前記圧延後９００〜１０００℃の
温度域においてパス間時間が３０秒以上の圧延を最終回
圧延を含めて２回以上行う段階と、前記圧延後９００℃
以上の温度域において熱間圧延を完了する段階と、前記
圧延完了後９００〜５００℃の温度域において平均冷却
速度Ｖ（℃／秒）が鋼中の炭素含有量Ｃ（％）に応じて
Ｖ≧Ｃ＾３×１０＾４を満足する条件で冷却する段階と
、有して成り、オンライン固溶化処理することを特徴と
するオーステナイト系ステンレス鋼の製造方法。(2) Weight ratio C: 0.08% or less Si: 1.0% or less Mn: 2.0% or less Cr: 16.0 to 26.0% Ni: 6.0 to 22.0% N: 10 austenitic stainless steel slabs containing 0.30% or less
A step of rolling at least once in a temperature range exceeding 00°C with a cumulative reduction rate of 30% or more and an interpass time of 10 seconds or more including the final rolling, and a step in a temperature range of 900 to 1000°C after the rolling. A step of rolling with a rolling time of 30 seconds or more twice or more including the final round of rolling, and a step of rolling at 900° C. after the rolling.
At the stage of completing hot rolling in the above temperature range and in the temperature range of 900 to 500°C after the completion of the rolling, the average cooling rate V (°C/sec) varies depending on the carbon content C (%) in the steel. A method for producing austenitic stainless steel, comprising a step of cooling under conditions satisfying ≧C^3x10^4, and performing an on-line solution treatment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28965486A JPS63143219A (en) | 1986-12-04 | 1986-12-04 | Production of austenitic stainless steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28965486A JPS63143219A (en) | 1986-12-04 | 1986-12-04 | Production of austenitic stainless steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS63143219A true JPS63143219A (en) | 1988-06-15 |
Family
ID=17746032
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28965486A Pending JPS63143219A (en) | 1986-12-04 | 1986-12-04 | Production of austenitic stainless steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63143219A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55107729A (en) * | 1979-02-13 | 1980-08-19 | Sumitomo Metal Ind Ltd | Solution-treating method for austenitic stainless steel |
| JPS60208459A (en) * | 1984-03-30 | 1985-10-21 | Aichi Steel Works Ltd | High strength stainless steel and its manufacture |
| JPS62124220A (en) * | 1985-07-17 | 1987-06-05 | Nippon Steel Corp | Manufacture of stainless steel plate |
-
1986
- 1986-12-04 JP JP28965486A patent/JPS63143219A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55107729A (en) * | 1979-02-13 | 1980-08-19 | Sumitomo Metal Ind Ltd | Solution-treating method for austenitic stainless steel |
| JPS60208459A (en) * | 1984-03-30 | 1985-10-21 | Aichi Steel Works Ltd | High strength stainless steel and its manufacture |
| JPS62124220A (en) * | 1985-07-17 | 1987-06-05 | Nippon Steel Corp | Manufacture of stainless steel plate |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPH01172524A (en) | Production of complex phase structure chromium stainless strip having excellent corrosion resistance and high ductility and strength | |
| JPH06248339A (en) | Production of steel sheet for vessel with high rigidity | |
| JP3823338B2 (en) | Manufacturing method of high strength hot-rolled steel sheet | |
| JPH0313524A (en) | Production of thick high-toughness high tensile steel plate having excellent toughness on steel plate surface and in central part of thickness | |
| JP3455047B2 (en) | Ferritic stainless steel sheet excellent in workability and roping properties and method for producing the same | |
| JPH0257634A (en) | Manufacture of high-strength steel plate and heat treatment for worked product of same | |
| JPS63143219A (en) | Production of austenitic stainless steel | |
| JPH04276042A (en) | Austenitic stainless steel and its production | |
| JPS63213620A (en) | Manufacture of high strength steel pipe joint | |
| JP4494653B2 (en) | Manufacturing method of ferritic stainless steel sheet | |
| JPH05255738A (en) | Production of steel for machine structural use excellent in delayed fracture resistance | |
| JPS63162818A (en) | Manufacture of ferritic stainless steel sheet extremely excellent in press formability | |
| JPS624825A (en) | Manufacture of austenitic stainless thick steel plate | |
| JP5228994B2 (en) | Manufacturing method of ferritic stainless steel material and manufacturing method of ferritic stainless steel pipe | |
| JPS62267419A (en) | Manufacture of austenitic stainless steel plate | |
| JPH0841546A (en) | Production of high chromium cold rolled steel strip excellent in ridging resistance and workability and production of hot rolled steel strip for the same stock | |
| JPH0688129A (en) | Production of high strength steel pipe as welded low in residual stress | |
| JPH02247330A (en) | Production of austenitic stainless steel excellent in strength at high temperature and ductility | |
| JPS5845318A (en) | Production of high tensile steel having weldability and >=50kg/mm2 strength | |
| JPH027368B2 (en) | ||
| JPS62267418A (en) | Manufacture of high strength austenitic stainless steel | |
| JPH01205029A (en) | Manufacture of high-cr ferritic steel stock for high-temperature use | |
| JPH06248338A (en) | Production of starting sheet for vessel | |
| JPH0310051A (en) | High-carbon and high-nitrogen stainless steel having high strength and high toughness and its production | |
| JPH03277717A (en) | Manufacture of hot-rolled steel plate and method for heat-treating processed product thereof |