JP3124045B2 - Method for producing hot-rolled steel strip of austenitic stainless steel containing B - Google Patents
Method for producing hot-rolled steel strip of austenitic stainless steel containing BInfo
- Publication number
- JP3124045B2 JP3124045B2 JP03015974A JP1597491A JP3124045B2 JP 3124045 B2 JP3124045 B2 JP 3124045B2 JP 03015974 A JP03015974 A JP 03015974A JP 1597491 A JP1597491 A JP 1597491A JP 3124045 B2 JP3124045 B2 JP 3124045B2
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- Prior art keywords
- hot
- austenitic stainless
- rolling
- steel strip
- stainless steel
- Prior art date
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- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は，Ｂ含有オーステナイト
系ステンレス鋼の熱延鋼帯の製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hot-rolled steel strip of B-containing austenitic stainless steel.
【０００２】[0002]
【従来の技術】Ｂ含有オーステナイト系ステンレス鋼は
熱中性子吸収断面積が大きいという特質があり且つ耐食
性にも優れることから, 熱中性子遮蔽材料として好適で
ある。しかしＢを含有すると鋼中のＢがＣrやＦeと化合
した融点の低い脆弱な硼化物が生成するので熱間圧延に
おいて鋼帯耳部に割れ疵が発生しやすい。このため品質
の良好な熱延鋼帯を製造するのが難しい。本発明者らは
特開昭63-96221号公報において, Ｂを0.2〜1.2重量％含
有するオーステナイト系ステンレス鋼のスラブまたは鋼
塊を1150〜1200℃の温度に加熱し，粗圧延機と仕上圧延
機を用いて圧延終了温度が1000℃以上となるように熱間
圧延を行うことからなるＢ含有オーステナイト系ステン
レス鋼の熱延鋼帯の製造法を提案した。しかし，この方
法では熱延鋼帯に割れ疵が発生することがあり, 品質の
良好な熱延鋼帯を提供するという観点からは必ずしも満
足できるものではなかった。2. Description of the Related Art B-containing austenitic stainless steel is suitable as a thermal neutron shielding material because it has the characteristic of having a large thermal neutron absorption cross-sectional area and has excellent corrosion resistance. However, when B is contained, a fragile boride having a low melting point, in which B in the steel is combined with Cr or Fe, is formed, so that cracks are likely to occur at the steel strip ears in hot rolling. Therefore, it is difficult to produce a hot-rolled steel strip of good quality. The present inventors disclosed in JP-A-63-96221 that a slab or ingot of austenitic stainless steel containing 0.2 to 1.2% by weight of B was heated to a temperature of 1150 to 1200 ° C. A method for producing a hot-rolled steel strip of B-containing austenitic stainless steel, which comprises performing hot rolling so that the rolling end temperature is 1000 ° C. or higher using a mill. However, this method may cause cracks in the hot-rolled steel strip, which is not always satisfactory from the viewpoint of providing a hot-rolled steel strip of good quality.
【０００３】そこで発明者らはＢ含有オーステナイト系
ステンレス鋼の熱間加工性についての詳細な研究を行
い，特開平1-195243号公報において，Ｂを0.2〜1.2重量
％含有するオーステナイト系ステンレス鋼の鋼塊を製造
し，この鋼塊を1150℃〜1200℃の温度に加熱し20〜70％
の圧下を行う分塊スラブ製造工程と, 得られた分塊スラ
ブを1150℃〜1200℃の温度に加熱して20〜70％の圧下を
行う中間スラブ製造工程とを経たうえ, この中間スラブ
を1150℃〜1200℃の温度に加熱して鋼帯にまで熱延する
ことからなる熱延鋼帯の製造方法を提案し，この方法に
よって割れ疵のない熱延鋼帯が得られることを示した。
すなわちＢ含有オーステナイト系ステンレス鋼の熱間割
れは硼化物を起点として或いは硼化物とマトリクスの境
界において生じることが明らかにされたのであるが，途
中に中間スラブ製造工程を追加することにより硼化物を
微細化することができ, このような状態のスラブを熱間
圧延に供することにより, 割れ疵のない熱延鋼帯を製造
することが可能となった。Accordingly, the present inventors have conducted a detailed study on the hot workability of a B-containing austenitic stainless steel, and have disclosed in Japanese Patent Application Laid-Open No. 1-195243 that the austenitic stainless steel containing 0.2-1.2% by weight of B is not disclosed. The steel ingot is manufactured, and the steel ingot is heated to a temperature of 1150 ° C to 1200 ° C and is heated to 20 to 70%
And a middle slab manufacturing process in which the obtained slab is heated to a temperature of 1150 ° C to 1200 ° C and reduced by 20 to 70%. A method for manufacturing a hot-rolled steel strip, which is hot-rolled to a steel strip by heating to a temperature between 1150 ° C and 1200 ° C, was proposed, and it was shown that a hot-rolled steel strip without cracks can be obtained by this method. .
That is, it has been clarified that hot cracking of B-containing austenitic stainless steel starts from boride or at the boundary between boride and matrix, but boride is added by adding an intermediate slab manufacturing process in the middle. By subjecting the slab in such a state to hot rolling, it was possible to produce a hot-rolled steel strip without cracks.
【０００４】[0004]
【発明が解決しようとする課題】しかし, 中間スラブ製
造工程を追加することは多大なエネルギーと時間を必要
とし生産性を低下させる要因となる。そこでより大量生
産に適した製造方法が望まれていた。本発明は, この問
題点を改善し，耳部の割れ疵のない品質の良好なＢ含有
オーステナイト系ステンレス鋼の熱延鋼帯を一層生産性
よく製造する方法の開発を目的としたものである。However, adding an intermediate slab manufacturing process requires a great deal of energy and time, and is a factor that lowers productivity. Therefore, a manufacturing method more suitable for mass production has been desired. An object of the present invention is to improve this problem and to develop a method for producing a hot-rolled steel strip of B-containing austenitic stainless steel of good quality without cracks in the ears with higher productivity. .
【０００５】[0005]
【課題を解決するための手段】上記目的は, Ｂを0.2〜
1.2重量％含有するオーステナイト系ステンレス鋼の鋼
塊を製造し, この鋼塊を1150℃〜1200℃の温度に加熱し
て20〜80％の圧下率について分塊圧延し，次いで得られ
た分塊スラブを1150℃〜1200℃の温度に加熱して最終仕
上圧延速度Ｖ(m/sec)が Ｖ≦20−9.5Ｂ％ を満足しかつ圧延終了温度が1000℃以上となるように鋼
帯にまで熱間圧延することによって達成することができ
る。The object of the present invention is to set B to 0.2 to
A steel ingot of austenitic stainless steel containing 1.2% by weight is manufactured, and the steel ingot is heated to a temperature of 1150 ° C to 1200 ° C and slab-rolled to a rolling reduction of 20 to 80%. The slab is heated to a temperature of 1150 ° C to 1200 ° C to reach a steel strip so that the final finish rolling speed V (m / sec) satisfies V ≦ 20-9.5B% and the rolling end temperature is 1000 ° C or more. This can be achieved by hot rolling.
【０００６】[0006]
【作用】特開平1-195243号公報に示されるように, Ｂを
0.2〜1.2重量％含有するオーステナイト系ステンレス鋼
においては, 分塊圧延の後, 中間スラブ製造工程を経て
脆弱な硼化物を微細化したうえで熱間圧延を行うという
方法で耳部に割れ疵のない熱延鋼帯を得ることができ
る。しかし, 発明者らはＢ含有オーステナイト系ステン
レス鋼の熱間加工方法の検討をさらに続けた結果, 中間
スラブ製造工程を省略した場合においても, 後の熱間圧
延工程での最終仕上圧延速度と圧延終了温度を適切に制
御すれば耳部に割れ疵のない良好な熱延鋼帯が得られる
ことを見出した。以下にその内容を説明する。[Action] As shown in JP-A-1-195243, B is
For austenitic stainless steel containing 0.2 to 1.2 wt%, after slab rolling, the brittle boride is refined through an intermediate slab manufacturing process, and then hot-rolled. No hot rolled steel strip can be obtained. However, the inventors continued their studies on the hot working method for B-containing austenitic stainless steel.As a result, even when the intermediate slab manufacturing process was omitted, the final finishing rolling speed and rolling speed in the subsequent hot rolling process were reduced. It has been found that if the end temperature is appropriately controlled, a good hot-rolled steel strip having no cracks in the lugs can be obtained. The details will be described below.
【０００７】まず本発明はＢ（硼素）含有量が0.2〜1.2
％のオーステナイト系ステンレス鋼を対象とする。Ｂ添
加による熱中性子遮蔽効果を得るには少なくとも0.2％
のＢ含有を必要とするからである。他方，Ｂ含有量が1.
2％を超えるような鋼では加工性及び靭性が極度に悪く
なり，また1.2％を超える多量のＢの添加を要せずとも
熱中性子遮蔽効果が十分に満足される場合が多いからで
ある。なお，Ｂ以外に一般的な商用オーステナイト系ス
テンレス鋼に含有される諸元素が鋼中に含有されること
は差し支えない。また基質たるオーステナイト系ステン
レス鋼としては商用の各種の鋼が本発明の対象となり得
る。First, according to the present invention, the B (boron) content is 0.2 to 1.2.
% Austenitic stainless steel. At least 0.2% to obtain thermal neutron shielding effect by adding B
Is required. On the other hand, when the B content is 1.
This is because the workability and toughness of steel exceeding 2% are extremely deteriorated, and the thermal neutron shielding effect is often sufficiently satisfied without the necessity of adding a large amount of B exceeding 1.2%. In addition, various elements contained in general commercial austenitic stainless steel other than B may be contained in the steel. As the austenitic stainless steel as a substrate, various commercially available steels can be an object of the present invention.
【０００８】本発明において分塊圧延に供する鋼塊およ
び熱間圧延に供するスラブの加熱温度はいずれも1150℃
〜1200℃の範囲とするが，上限を1200℃に限定するの
は, 特開平1-195243号公報に示した理由による。すなわ
ち, Ｂ含有オーステナイト系ステンレス鋼の変形能は12
00℃を超えると極端に低下しほとんど加工ができないか
らである。また下限を1150℃に限定するのは, 1150℃未
満の抽出温度では加工中の温度低下により割れ疵が発生
する場合があるからである。In the present invention, the heating temperature of the steel ingot to be subjected to slab rolling and the slab to be subjected to hot rolling are both 1150 ° C.
The upper limit is limited to 1200 ° C. for the reason described in JP-A-1-195243. That is, the deformability of B-containing austenitic stainless steel is 12
This is because if the temperature exceeds 00 ° C., the temperature is extremely lowered and almost no processing is possible. In addition, the lower limit is limited to 1150 ° C. because at an extraction temperature lower than 1150 ° C., cracks may occur due to a decrease in temperature during processing.
【０００９】熱間圧延工程での製造条件は本発明の特徴
的な事項である。図１に，Ｂ含有量が0.38重量％および
0.74重量％のオーステナイト系ステンレス鋼の分塊圧延
スラブと，分塊圧延スラブを経て製造した中間スラブの
両者から切り出した直径10mmの丸棒試験片を供試材とし
て，これらを1100℃で引張破断させた場合の歪速度と断
面収縮率の関係を示した。図１から明らかなように，分
塊スラブは中間スラブと比べ変形能が低いことがわか
る。また, 歪速度が大きくなる程いずれのスラブも変形
能は低下し，さらに同じ歪速度で比較するとＢ含有量の
高い程変形能は低くなる。このことは熱間圧延に際して
圧延速度 (歪速度) を高くしすぎると変形能が低下して
割れ疵が発生しやすくなり, 特に中間スラブ製造工程を
省略した分塊スラブを直接熱間圧延する場合には圧延速
度に対する制約がより厳しくなることを示している。そ
してＢ含有量によって制限すべき圧延速度の上限が異な
ることを示している。[0009] The manufacturing conditions in the hot rolling step are characteristic of the present invention. Figure 1 shows that the B content is 0.38% by weight and
A 10 mm-diameter round bar specimen cut from both a 0.74 wt% austenitic stainless steel bulk slab and an intermediate slab produced through the bulk slab was used as a test material. The relationship between the strain rate and the cross-sectional shrinkage rate in the case where the strain was applied was shown. As is clear from FIG. 1, it can be seen that the bulk slab has a lower deformability than the intermediate slab. In addition, as the strain rate increases, the deformability of any slab decreases, and when the strain rate is compared, the deformability decreases as the B content increases. This is because if the rolling speed (strain rate) is too high during hot rolling, the deformability is reduced and cracks are likely to occur, especially when directly hot rolling a slab without intermediate slab manufacturing process. Shows that the restriction on the rolling speed becomes more severe. And it shows that the upper limit of the rolling speed to be restricted differs depending on the B content.
【００１０】図２は，Ｂ含有量が0.36重量％, 0.52重量
％，0.76重量％および1.12重量％の鋼塊を1150℃〜1200
℃の温度に加熱して分塊圧延を行い, 得られた分塊スラ
ブを中間スラブ製造工程を経ることなく1150℃〜1200℃
の温度に加熱して製造ラインにて熱間圧延し，圧延速度
および圧延終了温度と鋼帯耳部の割れ疵の発生の関係に
ついて詳しく調べた結果を示したものである。図中○印
のプロットは鋼帯耳部に割れ疵の発生しなかったもの
（良好なもの），×印のプロットは鋼帯耳部に割れ疵の
発生したものを表す。また，図中の数字は圧延終了温度
（℃）を表す。図２の結果に見られるように，圧延終了
温度が1000℃未満の場合は耳部に割れ疵を生じた。圧延
終了温度が1000℃以上の場合には最終仕上圧延速度が或
る上限値以下であれば耳部割れ疵が発生しなかった。こ
の最終仕上圧延速度の上限値Ｖmax(m/sec）はＢ含有量
によって異なり，次式で表されることが分かった。 Ｖmax＝20−9.5Ｂ％ したがって，中間スラブ製造工程を省略した場合にあっ
ても， 最終仕上圧延速度Ｖ(m/sec) ≦20−9.5Ｂ％ の関係を満足しかつ圧延終了温度が1000℃以上となるよ
うに熱間圧延すれば耳部に割れ疵のない良好な熱延鋼帯
が得られることがわかった。FIG. 2 shows that steel ingots having a B content of 0.36% by weight, 0.52% by weight, 0.76% by weight and 1.12% by weight
The lumped slab is heated to a temperature of ℃ and the obtained lumped slab is heated to 1150 ℃ ~ 1200 ℃ without going through the intermediate slab manufacturing process
This figure shows the results of a detailed examination of the relationship between the rolling speed, the rolling end temperature, and the occurrence of cracks in the steel strip ears, after being heated to a temperature of and subjected to hot rolling in a production line. In the figure, the plots marked with ○ indicate those where cracks did not occur at the steel strip ears (good), and the plots indicated with X indicated those where cracks occurred at the steel strip ears. The numbers in the figure represent the rolling end temperature (° C.). As can be seen from the results in FIG. 2, when the rolling end temperature was lower than 1000 ° C., cracks were formed at the ears. When the rolling end temperature was 1000 ° C. or higher, no crack at the edge portion occurred when the final finish rolling speed was lower than a certain upper limit. Upper limit value V max of the final finish rolling speed (m / sec) depends on the B content, were found to be expressed by the following equation. V max = 20-9.5B% Therefore, even if the intermediate slab manufacturing process is omitted, the relationship of final finish rolling speed V (m / sec) ≤20-9.5B% is satisfied and the rolling end temperature is 1000 It was found that a hot-rolled steel strip having no cracks in the lugs can be obtained by hot rolling at a temperature of at least ℃.
【００１１】[0011]
【実施例】表１に示す化学成分を有するＢ含有オーステ
ナイト系ステンレス鋼の鋼塊を製造し，この鋼塊を1150
℃〜1200℃の温度に加熱して分塊圧延を行った。得られ
たスラブを1150℃〜1200℃の温度に加熱して熱間圧延を
行い, 板厚4.5〜5.0mmの熱延鋼帯を得た。分塊圧延の途
中では中間加熱は実施せず, また中間スラブ製造工程も
省略した。表２にこれらの製造条件と，得られた熱延鋼
帯における耳部の割れ疵の有無を示した。表２から明ら
かなように，最終仕上速度Ｖ(m/sec) について，Ｖ≦20
−9.5Ｂ％の関係を満足し，かつ圧延終了温度が1000℃
以上となるように熱間圧延を行った場合 (本発明例Ａ〜
Ｇ）は，耳部の割れ疵のない品質の良好な熱延鋼帯が得
られた。EXAMPLE A steel ingot of B-containing austenitic stainless steel having the chemical components shown in Table 1 was produced, and this steel ingot was
The slab was heated to a temperature of from 1C to 1200C to perform slab rolling. The obtained slab was heated to a temperature of 1150 ° C to 1200 ° C and hot rolled to obtain a hot rolled steel strip with a thickness of 4.5 to 5.0 mm. No intermediate heating was performed during the slab rolling, and the intermediate slab manufacturing process was omitted. Table 2 shows these manufacturing conditions and the presence or absence of cracks in the ears of the obtained hot rolled steel strip. As is clear from Table 2, the final finishing speed V (m / sec) was V ≦ 20.
Satisfies the relationship of -9.5B% and the rolling end temperature is 1000 ℃
When hot rolling is performed as described above (Examples A to
In G), a hot-rolled steel strip of good quality without cracks in the ears was obtained.
【００１２】これに反し，最終仕上圧延速度Ｖ(m/sec)
≦20−9.5Ｂ％の関係を満足しない場合（比較例Ｉ，
Ｊ，Ｌ，Ｎ）および圧延終了温度が1000℃より低い場合
(比較例Ｈ，Ｋ，Ｍ）は，いずれも熱延鋼帯耳部に割れ
疵が発生し，品質の良好な熱延鋼帯は得られなかった。On the other hand, the final finish rolling speed V (m / sec)
≦ 20−9.5B% (Comparative Example I,
J, L, N) and when the rolling end temperature is lower than 1000 ° C
In each of Comparative Examples H, K, and M, cracks were generated at the edge of the hot-rolled steel strip, and a hot-rolled steel strip of good quality could not be obtained.
【００１３】[0013]
【表１】 [Table 1]
【００１４】[0014]
【表２】 [Table 2]
【００１５】[0015]
【発明の効果】本発明の方法により，中性子吸収能と耐
食性に優れかつ耳部の割れ疵のない品質の良好なＢ含有
オーステナイト系ステンレス鋼の熱延鋼帯を工業的に安
定して製造することができる。Industrial Applicability According to the method of the present invention, a hot-rolled steel strip of B-containing austenitic stainless steel having excellent neutron absorption capacity and corrosion resistance and good quality without cracks in the ears can be industrially manufactured. be able to.
【図１】 Ｂ含有オーステナイト系ステンレス鋼の1100
℃での引張試験における歪速度と断面収縮率の関係を示
す図である。Fig. 1 1100 of B-containing austenitic stainless steel
It is a figure which shows the relationship between the strain rate and the cross-sectional shrinkage rate in the tensile test in ° C.
【図２】 Ｂ含有オーステナイト系ステンレス鋼の熱間
圧延における最終仕上速度, 圧延終了温度と鋼帯耳部の
割れ疵の発生の関係を示す図である。FIG. 2 is a diagram showing a relationship between a final finishing speed, a rolling end temperature, and the occurrence of cracks in a steel strip ear in hot rolling of a B-containing austenitic stainless steel.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭63−256243（ＪＰ，Ａ) 特開 昭63−50429（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C21D 9/46 ────────────────────────────────────────────────── (5) References JP-A-63-256243 (JP, A) JP-A-63-50429 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) C21D 9/46
Claims (1)
イト系ステンレス鋼の鋼塊を製造し，この鋼塊を1150℃
〜1200℃の温度に加熱して20〜80％の圧下率で分塊圧延
し，次いで，得られた分塊スラブを1150℃〜1200℃の温
度に加熱して最終仕上圧延速度Ｖ(m/sec)が Ｖ≦20−9.5Ｂ％ の関係を満足しかつ圧延終了温度が1000℃以上となるよ
うに鋼帯にまで熱間圧延することからなるＢ含有オース
テナイト系ステンレス鋼の熱延鋼帯の製造方法。An austenitic stainless steel ingot containing 0.2 to 1.2% by weight of B is produced, and the ingot is heated to 1150 ° C.
To a temperature of ~ 1200 ° C and slab rolling at a rolling reduction of 20 to 80%, and then heating the obtained slab to a temperature of 1150 ° C to 1200 ° C to obtain a final finish rolling speed V (m / m sec) satisfies the relationship of V ≦ 20−9.5B% and the hot-rolled steel strip of the B-containing austenitic stainless steel is hot-rolled to a steel strip such that the rolling end temperature is 1000 ° C. or higher. Production method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03015974A JP3124045B2 (en) | 1991-01-14 | 1991-01-14 | Method for producing hot-rolled steel strip of austenitic stainless steel containing B |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03015974A JP3124045B2 (en) | 1991-01-14 | 1991-01-14 | Method for producing hot-rolled steel strip of austenitic stainless steel containing B |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04236716A JPH04236716A (en) | 1992-08-25 |
| JP3124045B2 true JP3124045B2 (en) | 2001-01-15 |
Family
ID=11903679
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03015974A Expired - Fee Related JP3124045B2 (en) | 1991-01-14 | 1991-01-14 | Method for producing hot-rolled steel strip of austenitic stainless steel containing B |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3124045B2 (en) |
-
1991
- 1991-01-14 JP JP03015974A patent/JP3124045B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04236716A (en) | 1992-08-25 |
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