JPH10280035A - Production of high purity ferritic stainless hot rolled steel strip excellent in workability and heat resistance - Google Patents
Production of high purity ferritic stainless hot rolled steel strip excellent in workability and heat resistanceInfo
- Publication number
- JPH10280035A JPH10280035A JP9379197A JP9379197A JPH10280035A JP H10280035 A JPH10280035 A JP H10280035A JP 9379197 A JP9379197 A JP 9379197A JP 9379197 A JP9379197 A JP 9379197A JP H10280035 A JPH10280035 A JP H10280035A
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- Prior art keywords
- rolling
- hot
- steel strip
- ferritic stainless
- workability
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、自動車排気系材料
や電気器具などとして使用される、比較的安価で加工性
と耐熱性に優れた高純フェライト系ステンレス熱延鋼帯
を冷延・焼鈍を行うことなく省工程で製造する方法に関
する。BACKGROUND OF THE INVENTION The present invention relates to a cold-rolled and annealed high-purity ferritic stainless steel strip which is relatively inexpensive and has excellent workability and heat resistance, and is used as an automobile exhaust system material or electric appliance. And a method for manufacturing in a reduced number of steps without performing the method.
【０００２】[0002]
【従来の技術】Ｃｒを１３〜１５％、Ｍｏを０．３〜
１．０％含有し、ＴｉおよびＮｂで炭窒化物を固定した
いわゆる高純フェライト系ステンレス鋼帯は、ステンレ
ス鋼としては比較的安価で、かつ、６００〜９００℃の
中高温で優れた耐熱性を有することから、自動車の排気
系材料のうち、エキゾーストマニホールドなど高温域で
使用される材料として用途が広がりつつある フェライト系ステンレス鋼は、一般的には、熱延後、熱
延板焼鈍、酸洗、冷延、焼鈍、酸洗の工程を経て製造さ
れている。Ｃｒを１３〜１５％含有する高純フェライト
系ステンレス鋼は、ＳＵＳ４３０に代表される通常のフ
ェライト系ステンレス鋼やさらに高Ｃｒの耐熱フェライ
ト系ステンレス鋼に比較して安価であることが市場から
強く要求されるため、従来より、高い生産性をもって製
造する様々な工夫が凝らされている。2. Description of the Related Art Cr is 13% to 15%, Mo is 0.3% or less.
The so-called high-purity ferritic stainless steel strip containing 1.0% and fixing carbonitride with Ti and Nb is relatively inexpensive for stainless steel and has excellent heat resistance at medium to high temperatures of 600 to 900 ° C. Ferrite-based stainless steel, which is being used in high-temperature areas such as exhaust manifolds among exhaust system materials for automobiles, is generally used after hot-rolling, hot-rolled sheet annealing, It is manufactured through the steps of washing, cold rolling, annealing, and pickling. Highly pure ferritic stainless steel containing 13 to 15% of Cr is strongly demanded by the market to be inexpensive as compared with ordinary ferritic stainless steel represented by SUS430 and further high-temperature heat-resistant ferritic stainless steel. Therefore, various devices for manufacturing with high productivity have been conventionally devised.
【０００３】例えば、加工性を損なうことなく製造工程
を簡略化する目的で、熱延板焼鈍を省略する方法とし
て、熱延後鋼帯を高温で巻き取る方法が既に開示されて
いる（特開昭５２−９５５２７号公報）。本従来方法に
よれば、熱延板焼鈍を省略することが可能となるが、良
好な加工性を得るためには、引き続いて冷延、焼鈍が必
要である。上記従来方法によって熱延板焼鈍を省略した
だけでは、熱延鋼帯の金属組織は、熱間圧延工程で充分
に再結晶していないため、冷延・焼鈍して得られた再結
晶組織に比ベ、延性、深絞り性が低下する。従って、熱
延に引き続き、冷延・焼鈍による金属組織の調整が必要
となる。For example, a method of winding a steel strip at a high temperature after hot rolling has already been disclosed as a method of omitting hot-rolled sheet annealing for the purpose of simplifying a manufacturing process without impairing workability (Japanese Patent Application Laid-Open (JP-A) no. JP-A-52-95527). According to this conventional method, it is possible to omit hot rolled sheet annealing, but in order to obtain good workability, it is necessary to continuously perform cold rolling and annealing. Omitting the hot-rolled sheet annealing by the above-mentioned conventional method, the metallographic structure of the hot-rolled steel strip is not sufficiently recrystallized in the hot rolling step. The specificity, ductility and deep drawability decrease. Therefore, subsequent to hot rolling, it is necessary to adjust the metal structure by cold rolling and annealing.
【０００４】[0004]
【発明が解決しようとする課題】本発明の目的は、冷延
・焼鈍を行うことなく熱延・焼鈍ままの鋼帯で、良好な
加工性と耐熱性を得るための成分、熱間圧延、熱延板焼
鈍に関する条件を特定したフェライト系ステンレス鋼の
製造方法を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide a steel strip which is hot-rolled and annealed without performing cold-rolling and annealing. An object of the present invention is to provide a method for producing a ferritic stainless steel in which conditions relating to hot-rolled sheet annealing are specified.
【０００５】[0005]
【課題を解決するための手段】本発明は、高純フェライ
ト系ステンレス鋼帯の熱延に際し、熱延のいわゆる粗圧
延において圧延温度、圧下率、粗圧延終了後の保熱温度
および時間を設定した上、熱延後熱延板焼鈍を行うこと
により、熱延・焼鈍ままで良好な加工性と耐熱性を有す
る高純フェライト系ステンレス鋼を得るものである。SUMMARY OF THE INVENTION The present invention sets a rolling temperature, a reduction ratio, and a heat retention temperature and time after the completion of rough rolling in hot rolling of hot pure ferritic stainless steel strip in so-called rough rolling of hot rolling. In addition, by performing hot-rolled sheet annealing after hot-rolling, a high-purity ferritic stainless steel having good workability and heat resistance as hot-rolled and annealed is obtained.
【０００６】すなわち、本発明の要旨とするところは、
重量％で、Ｃ：０．０３％以下、Ｓｉ：１．２％以下、
Ｍｎ：１．２％以下、Ｃｒ：１３〜１５％、Ａｌ：０．
０１〜０．１％、Ｔｉ：０．１〜０．３５％、Ｎ：０．
０１％以下を含み、残部がＦｅおよび不可避的不純物か
らなるフェライト系ステンレス鋼帯を熱間圧延するに際
し、１１００℃以下、１０００℃以上の温度域で圧下率
８０％以上の圧延を行い、９５０℃以上、１０５０℃以
下で５分以上保熱後、仕上げ圧延した鋼帯を９００℃以
上、１１００℃以下で焼鈍することを特徴とする加工性
と耐熱性に優れた高純フェライト系ステンレス熱延鋼帯
の製造方法である。That is, the gist of the present invention is as follows.
By weight%, C: 0.03% or less, Si: 1.2% or less,
Mn: 1.2% or less, Cr: 13 to 15%, Al: 0.
01-0.1%, Ti: 0.1-0.35%, N: 0.
When hot rolling a ferritic stainless steel strip containing not more than 01% and the balance consisting of Fe and unavoidable impurities, rolling is performed at a rolling reduction of 80% or more in a temperature range of 1100 ° C or less and 1000 ° C or more, and 950 ° C. A hot rolled high pure ferritic stainless steel excellent in workability and heat resistance, characterized in that the steel strip which has been heat-treated at 1050 ° C or lower for 5 minutes or more and then finish-rolled is annealed at 900 ° C or higher and 1100 ° C or lower It is a method of manufacturing a belt.
【０００７】[0007]
【発明の実施の形態】本発明者らは、高純フェライト系
ステンレス鋼を冷延する前の、熱延ままの金属組織を観
察し、鋳片で生じた粗大なフェライト粒が熱延過程でほ
とんど再結晶することなく、粗大な延伸フェライト粒と
なったフェライト単相組織であることを観察した。この
ような粗大な変形フェライト粒の組織では、加工硬化に
より強度が高く、伸び、ｒ値が低く、良好な加工性は得
られない。熱延板焼鈍を行っても、延性は改善するが、
ｒ値が低く、リジングも大きく、良好な加工性は得られ
ないことを確認した。BEST MODE FOR CARRYING OUT THE INVENTION The present inventors observed the metal structure of hot-rolled ferritic stainless steel before cold-rolling, and found that coarse ferrite grains generated in the cast slab during the hot-rolling process. It was observed that the ferrite had a single-phase structure of coarse expanded ferrite grains with almost no recrystallization. In the structure of such coarse deformed ferrite grains, the strength is increased by work hardening, the elongation and the r value are low, and good workability cannot be obtained. Even if hot-rolled sheet annealing is performed, ductility is improved,
The r value was low, the ridging was large, and it was confirmed that good workability could not be obtained.
【０００８】以上の観察、試験結果に基づき、本発明者
らは、鋳片に存在するフェライトを熱延過程で再結晶さ
せれば、熱延板の加工性を改善し得ると考えた。本発明
者らは熱延工程の中でも、いわゆる粗圧延と仕上げ圧延
の間の保熱効果に着目し、この間で再結晶が生じる粗圧
延条件および保熱条件を検討した。その結果、１４％Ｃ
ｒ−Ｍｏ−Ｎｂ−Ｔｉ鋼を粗圧延後１０００℃で保熱し
た場合、図１に示すように、１１００〜１０００℃にお
けるトータル圧下率を８０％以上とすれば、保熱後に６
０％以上の再結晶が得られ、さらにＣ，Ｎの低減が再結
晶の進行を促進するという知見を得た。[0008] Based on the above observations and test results, the present inventors thought that the workability of the hot rolled sheet could be improved by recrystallizing the ferrite present in the slab during the hot rolling process. The present inventors paid attention to the heat retention effect between so-called rough rolling and finish rolling in the hot rolling process, and examined rough rolling conditions and heat retention conditions in which recrystallization occurs during this process. As a result, 14% C
When the r-Mo-Nb-Ti steel is kept at 1000 ° C after rough rolling, as shown in Fig. 1, if the total draft at 1100 to 1000 ° C is 80% or more, 6% after the heat retention.
It was found that recrystallization of 0% or more was obtained, and that the reduction of C and N promoted the progress of recrystallization.
【０００９】図１は表１の鋼Ａ，Ｂ，Ｃを実験室で溶解
し、厚さ１１０mmのインゴットを作製し、これを１１７
５℃に加熱後、１１００〜１０００℃で、仕上げ厚さを
変えることにより圧下率を変化させた熱間圧延を行い、
圧延終了後１０００℃で１０分間保熱し、直ちに水冷し
た鋼板の金属組織中の再結晶率と圧下率の関係を示した
ものである。圧下率８０％以上ですべて、再結晶率６０
％以上となる。また、Ｃ＋Ｎを低減することにより再結
晶が上昇し、Ｃ＋Ｎ＜０．０１５％ならば、７５％以上
の再結晶が得られる。FIG. 1 shows that steels A, B, and C shown in Table 1 were melted in a laboratory to produce an ingot having a thickness of 110 mm.
After heating to 5 ° C, hot rolling was performed at 1100 to 1000 ° C to change the rolling reduction by changing the finished thickness,
This figure shows the relationship between the recrystallization rate and the rolling reduction in the metal structure of a steel sheet which was kept at 1000 ° C. for 10 minutes after the completion of rolling and immediately cooled with water. All with a reduction of 80% or more, a recrystallization rate of 60
% Or more. In addition, recrystallization increases by reducing C + N, and if C + N <0.015%, recrystallization of 75% or more can be obtained.
【００１０】図１に示した検討に加え、保熱温度、時間
の影響を検討した結果、粗圧延のトータル圧下率を８０
％以上にし、粗圧延後９５０℃以上、１０５０℃以下で
５分以上保熱すれば、６０％以上の再結晶組織が得られ
ることが判明した。また、本発明者らは、上記のように
６０％以上の再結晶組織とした場合、熱延・焼鈍ままで
も、伸び、ｒ値が大きく、またリジングが小さくなり、
良好な加工性が得られることも確認し、本発明の完成に
至った。[0010] In addition to the examination shown in FIG. 1, the influence of the heat retention temperature and time was examined.
% Or more, and after the rough rolling, heat retention at 950 ° C. or more and 1050 ° C. or less for 5 minutes or more revealed that a recrystallized structure of 60% or more was obtained. In addition, when the present inventors have a recrystallized structure of 60% or more as described above, the elongation, the r value are large, and the ridging is small even as hot rolled and annealed,
It was also confirmed that good workability was obtained, and the present invention was completed.
【００１１】次に、本発明の成分限定理由を述べる。Ｃ
は、深絞り性を表す指標であるｒ値を低下させる。ま
た、耐食性を低下させる。特に、溶接熱影響によりＣｒ
の炭化物を形成し、粒界腐食感受性が高くなり鋭敏化の
原因となる。従って、Ｃは低いほど望ましい。Ｃの低減
は、一般にＶＯＤなどの二次精錬で行うが、極端にＣを
下げることはいたずらに精錬コストを上昇させるだけな
ので、本発明ではＣの上限を０．０３％とする。さら
に、本発明においては、熱延の粗圧延後に粗大なフェラ
イト粒の再結晶を図る目的からＣはＮとともに低い方が
望ましく、保熱後７５％以上の再結晶率を得るために
は、Ｃ＋Ｎ≦０．０１５％に低減することが必要であ
る。Next, the reasons for limiting the components of the present invention will be described. C
Reduces the r value, which is an index representing the deep drawability. Also, it reduces the corrosion resistance. In particular, Cr
Forms carbides, thereby increasing the susceptibility to intergranular corrosion and causing sensitization. Therefore, the lower the C, the better. In general, the reduction of C is performed by secondary refining such as VOD. However, since extremely lowering C only unnecessarily increases the refining cost, the upper limit of C is set to 0.03% in the present invention. Further, in the present invention, it is desirable that C is lower together with N for the purpose of recrystallizing coarse ferrite grains after rough rolling of hot rolling. In order to obtain a recrystallization ratio of 75% or more after heat retention, C + N It is necessary to reduce it to ≦ 0.015%.
【００１２】Ｓｉは耐酸化性を高めるために有効な元素
であり、望ましくは１．０％程度の添加が効果的である
が、過度に添加すると靭性を低下するので、上限を１．
２％とする。Si is an element effective for improving the oxidation resistance. Desirably, the addition of about 1.0% is effective. However, excessive addition lowers the toughness.
2%.
【００１３】Ｍｎは脱酸元素として用いるだけでなく、
耐酸化性を高めるために添加するが、多量に添加すると
加工性を損なうために、上限を１．２％とする。Mn is used not only as a deoxidizing element,
It is added to increase the oxidation resistance, but if added in a large amount, the workability is impaired, so the upper limit is made 1.2%.
【００１４】Ｃｒは耐熱性、耐酸化性、耐食性を得るた
めに必須の元素である。本発明では、６００〜９００℃
の中高温における耐熱性、および常温の加工性を勘案し
て、１３〜１５％とする。Cr is an essential element for obtaining heat resistance, oxidation resistance and corrosion resistance. In the present invention, 600-900 ° C
In consideration of heat resistance at medium and high temperatures and workability at room temperature, the content is set to 13 to 15%.
【００１５】Ａｌは脱酸生成物が残存したものであり、
脱酸の目的で０．０１％以上添加するが、過剰に添加す
ると、鋼の清浄度を低下し、加工性に悪影響をもたらす
ので上限を０．１％とする。Al is a residue of a deoxidized product,
Although 0.01% or more is added for the purpose of deoxidation, if it is added excessively, the cleanliness of the steel is reduced and the workability is adversely affected, so the upper limit is made 0.1%.
【００１６】Ｔｉは溶接熱影響部の耐食性低下を防止す
る目的で、安定化元素として添加する。また、Ｔｉは中
高温域での強度確保を目的として添加するＮｂの効果を
有効に得るためにも添加する。Ｎｂ添加による中高温域
での強化は固溶Ｎｂの作用で得られるが、この温度域で
はＮｂの炭窒化物が析出しやすい。そこでＮｂよりも炭
窒化物を形成しやすいＴｉをＮｂとともに複合添加して
固溶Ｎｂが低下するのを防止する。以上の効果を発現せ
しめるために本発明では、Ｔｉを０．１％以上添加す
る。しかし、多量に添加すると、固溶Ｔｉにより靭性が
低下するので上限を０．３５％とする。[0016] Ti is added as a stabilizing element for the purpose of preventing the corrosion resistance of the heat affected zone from deteriorating. Also, Ti is added to effectively obtain the effect of Nb added for the purpose of securing strength in a medium-high temperature range. Strengthening in the medium and high temperature range by the addition of Nb is obtained by the action of solid solution Nb, but Nb carbonitride tends to precipitate in this temperature range. Therefore, Ti, which forms carbonitride more easily than Nb, is added together with Nb to prevent the solid solution Nb from lowering. In the present invention, Ti is added in an amount of 0.1% or more in order to exert the above effects. However, if added in a large amount, the toughness is reduced by solid solution Ti, so the upper limit is made 0.35%.
【００１７】ＮはＣと同じ理由で低いほど望ましいが、
粗圧延後の再結晶挙動に及ぼす影響および精錬コストを
勘案して、上限を０．０１５％とする。Although N is preferably lower for the same reason as C,
The upper limit is made 0.015% in consideration of the effect on the recrystallization behavior after rough rolling and the refining cost.
【００１８】次に、本発明における、圧延条件の限定理
由を述べる。本発明では、熱延粗圧延の歪を利用して、
粗圧延後の保熱中に粗大なフェライトの再結晶化を図る
ために、粗大なフェライト粒でも再結晶し得るだけの歪
を付加する必要がある。粗圧延温度が１１００℃を超え
ると、圧延後にフェライトは回復するだけで、再結晶に
必要な歪が蓄積しない。一方、粗圧延温度が低すぎて、
１０００℃を下回ると、保熱温度まで昇温するのに時間
がかかる。従って、圧延温度を１１００〜１０００℃と
する。ここで言う圧延温度は、粗圧延の内で再結晶に寄
与する圧延に関するもので、粗圧延温度全部を規定する
のではない。形状を得るために粗圧延開始を１１００℃
を超える温度で行っても全く問題ない。Next, the reasons for limiting the rolling conditions in the present invention will be described. In the present invention, utilizing the strain of hot rolling rough rolling,
In order to recrystallize the coarse ferrite during the heat retention after the rough rolling, it is necessary to apply a strain enough to recrystallize the coarse ferrite grains. When the rough rolling temperature exceeds 1100 ° C., the ferrite only recovers after rolling, and the strain required for recrystallization does not accumulate. On the other hand, the rough rolling temperature is too low,
If the temperature is lower than 1000 ° C., it takes time to raise the temperature to the heat retention temperature. Therefore, the rolling temperature is set to 1100 to 1000 ° C. The rolling temperature mentioned here relates to the rolling that contributes to recrystallization in the rough rolling, and does not specify the entire rough rolling temperature. Start rough rolling at 1100 ° C to obtain shape
It does not matter at all if the temperature is exceeded.
【００１９】本発明の圧延温度で、本発明に関わる成分
を有する鋼組成において、粗大なフェライトの再結晶率
６０％以上を得るためには、上述のようにトータルの圧
下率で８０％以上の歪の付加が必要である。圧下率の上
限は、スラブ厚、熱延仕上げ厚により決めればよいの
で、特に規定しない。また、本発明では粗圧延後保熱
し、再結晶を行わせるが、再結晶の進行に少なくとも９
５０℃、５分以上の保熱が必要である。しかし、１０５
０℃を超えて保熱するとスケール生成量が増し、仕上圧
延で表面疵の原因となるので、保熱温度の上限を１０５
０℃とする。保熱時間の上限も、スラブ厚、熱延仕上げ
厚等を考慮して決めればよいので、特に規定しない。At the rolling temperature of the present invention, in order to obtain a recrystallization rate of coarse ferrite of 60% or more in a steel composition having a component related to the present invention, as described above, the total reduction rate is 80% or more. It is necessary to add distortion. The upper limit of the rolling reduction is not particularly defined because it may be determined by the slab thickness and the hot-rolled finished thickness. Further, in the present invention, after the rough rolling, heat is retained and recrystallization is performed.
Heat retention at 50 ° C for 5 minutes or more is required. However, 105
When the heat is retained at more than 0 ° C., the amount of scale generated increases, which causes surface flaws in finish rolling.
0 ° C. The upper limit of the heat retention time is not particularly defined because it may be determined in consideration of the slab thickness, the hot rolled finished thickness, and the like.
【００２０】粗圧延後再結晶した鋼板は、仕上げ圧延に
より再び加工を受けるため、その加工の影響を除き必要
な加工性を得るために、本発明では、熱延後焼鈍を行
う。焼鈍温度の下限は、ほぼ完全な再結晶組織が得られ
る下限の９００℃とする。また、焼鈍温度が高すぎる
と、結晶粒が粗大化し、製品加工時の肌荒れの原因とな
るので焼鈍の上限温度は、１１００℃とする。焼鈍方法
は、いわゆる箱焼鈍、連続焼鈍いずれでもよく、従っ
て、加熱、保持、冷却方法は間わない。Since the steel sheet recrystallized after the rough rolling is processed again by the finish rolling, in order to obtain necessary workability without the influence of the processing, in the present invention, annealing after hot rolling is performed. The lower limit of the annealing temperature is 900 ° C., which is a lower limit at which a substantially complete recrystallized structure can be obtained. On the other hand, if the annealing temperature is too high, the crystal grains become coarse and the surface becomes rough at the time of product processing. Therefore, the upper limit temperature of the annealing is set to 1100 ° C. The annealing method may be so-called box annealing or continuous annealing, and therefore, heating, holding, and cooling methods are not required.
【００２１】[0021]
【実施例】表１に示す成分の鋼を実験室で溶製し、５０
kgのインゴットを作製した。１１７５℃に加熱後、タン
デム式の熱間圧延機で表２に示す条件で１１００〜１０
００℃で圧延を行い、保熱後、仕上圧延を行った。圧延
仕上温度は、８６０〜８４０℃、仕上板厚は２mmとし
た。圧延後、直ちに巻取を再現するための電気炉に挿入
し、７５０℃に１時間保持後炉冷した。炉冷後の鋼板に
ついて、表２の条件で熱延板焼鈍を行った。得られた鋼
板から圧延方向に平行に、ＪｌＳ１３Ｂ号引張試験片、
ＪｌＳ５号引張試験片および高温引張試験片を作製し
た。高温引張試験片は、平行部幅１０mm、標点間距離５
０mmの平板状試験片とした。ＪｌＳ１３Ｂ号引張試験片
を用い引張試験を行い、降伏応力、伸びを測定した。ま
た、ＪｌＳ５号引張試験片を用い、１５％，２０％まで
の引張を行い、それぞれ、ｒ値、リジング高さを測定し
た。さらに、高温引張試験片を用い、ＪｌＳＧ０５６７
に準拠した高温引張試験を６００℃で行った。EXAMPLE Steels having the components shown in Table 1 were melted in a laboratory, and 50
kg ingots were produced. After heating to 1175 ° C., the temperature was 1100 to 10
Rolling was performed at 00 ° C., and after heat retention, finish rolling was performed. The rolling finishing temperature was 860 to 840 ° C., and the finished plate thickness was 2 mm. Immediately after rolling, the roll was inserted into an electric furnace for reproducing winding, kept at 750 ° C. for 1 hour, and cooled in the furnace. The steel sheet after the furnace cooling was subjected to hot-rolled sheet annealing under the conditions shown in Table 2. From the obtained steel sheet, in parallel to the rolling direction, Jls13B tensile test piece,
JLS No. 5 tensile test pieces and high temperature tensile test pieces were prepared. The high-temperature tensile test specimen has a parallel part width of 10 mm and a gauge length of 5
The test piece was a 0 mm flat test piece. A tensile test was performed using a JLS13B tensile test piece, and the yield stress and elongation were measured. In addition, a tensile test was performed to 15% or 20% using a JIS5 tensile test piece, and the r value and the ridging height were measured, respectively. Further, using a high temperature tensile test piece, JlSG0567
Was performed at 600 ° C.
【００２２】[0022]
【表１】 [Table 1]
【００２３】[0023]
【表２】 [Table 2]
【００２４】本発明の条件に従う場合、伸び、ｒ値に優
れ、リジング高さも低く、良好な加工性を有している。
また、６００℃でも優れた強度を有している。しかし比
較例１，２，３では、それぞれ、１１００〜１０００℃
の圧下率、１１００〜１０００℃の圧延後の保熱温度、
保熱時間が本発明の範囲を逸脱するため、本発明による
場合に比ベ、伸び、ｒ値およびリジング高さに劣る。比
較例４は熱延板焼鈍温度が本発明の範囲より低いため、
ｒ値に劣り、リジング高さが大きい。比較例５は熱延板
焼鈍温度が本発明の範囲より高過ぎる結果、焼鈍後の冷
却過程でＮｂが析出して高温強度が低下してしまう。According to the conditions of the present invention, elongation and r-value are excellent, ridging height is low, and good workability is obtained.
Also, it has excellent strength even at 600 ° C. However, in Comparative Examples 1, 2, and 3, 1100 to 1000 ° C., respectively.
Reduction rate, heat retention temperature after rolling at 1100 to 1000 ° C.,
Since the heat retention time deviates from the range of the present invention, the heat retention time is inferior to the case of the present invention in elongation, r value and ridging height. In Comparative Example 4, since the hot-rolled sheet annealing temperature was lower than the range of the present invention,
Inferior in r value and large ridging height. In Comparative Example 5, as a result of the hot-rolled sheet annealing temperature being higher than the range of the present invention, Nb precipitates in the cooling process after annealing, and the high-temperature strength decreases.
【００２５】[0025]
【発明の効果】本発明により、自動車排気系材料や電気
器具などとして使用される、比較的安価で加工性と耐熱
性に優れた高純フェライト系ステンレス熱延鋼帯を冷延
・焼鈍を行うことなく省工程で製造できるため工業的効
果は非常に大きい。According to the present invention, a relatively inexpensive high-purity ferritic stainless steel hot-rolled steel strip which is used as an automobile exhaust system material or electric appliance and has excellent workability and heat resistance is cold rolled and annealed. The industrial effect is very large because it can be manufactured in a reduced number of processes without any need.
【図１】１４％Ｃｒ−Ｍｏ−Ｎｂ−Ｔｉ鋼を１１７５℃
に加熱後、１１００〜１０００℃で、仕上げ厚さを変え
ることにより圧下率を変化させた熱間圧延を行い、圧延
終了後１０００℃で１０分間保熱後、直ちに水冷した鋼
板の金属組織中の再結晶率とＣ＋Ｎ量、圧下率の関係を
示し、１１００〜１０００℃のトータル圧下率を８０％
以上にすれば、６０％以上の再結晶組織が得られ、ま
た、再結晶率は、Ｃ＋Ｎ量を下げるほど大きくなること
を示す図である。FIG. 1 shows that a 14% Cr—Mo—Nb—Ti steel is 1175 ° C.
After heating at 1100 to 1000 ° C., hot rolling was performed with the rolling reduction changed by changing the finished thickness. After the completion of the rolling, the sheet was kept at 1000 ° C. for 10 minutes, and immediately thereafter, in the metallographic structure of the water-cooled steel sheet. It shows the relationship between the recrystallization rate, the C + N amount, and the rolling reduction. The total rolling reduction at 1100 to 1000 ° C. is 80%.
This is a diagram showing that a recrystallized structure of 60% or more can be obtained, and that the recrystallization ratio increases as the C + N amount decreases.
Claims (1)
ライト系ステンレス鋼帯を熱間圧延するに際し、１１０
０℃以下、１０００℃以上の温度域で圧下率８０％以上
の圧延を行い、９５０℃以上、１０５０℃以下で５分以
上保熱後、仕上げ圧延した鋼帯を９００℃以上、１１０
０℃以下で焼鈍することを特徴とする加工性と耐熱性に
優れた高純フェライト系ステンレス熱延鋼帯の製造方
法。C: 0.03% or less, Si: 1.2% or less, Mn: 1.2% or less, Cr: 13 to 15%, Al: 0.01 to 0.1% by weight% , Ti: 0.1-0.35%, N: 0.01% or less, with the balance being 110% when hot-rolling a ferritic stainless steel strip comprising Fe and unavoidable impurities.
Rolling is performed at a rolling rate of 80% or more in a temperature range of 0 ° C. or less and 1000 ° C. or more, and after keeping the heat at 950 ° C. or more and 1050 ° C. or less for 5 minutes or more, the finish-rolled steel strip is heated to 900 ° C.
A method for producing a hot rolled high-purity ferritic stainless steel strip having excellent workability and heat resistance, characterized by annealing at 0 ° C. or lower.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9379197A JPH10280035A (en) | 1997-04-11 | 1997-04-11 | Production of high purity ferritic stainless hot rolled steel strip excellent in workability and heat resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9379197A JPH10280035A (en) | 1997-04-11 | 1997-04-11 | Production of high purity ferritic stainless hot rolled steel strip excellent in workability and heat resistance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH10280035A true JPH10280035A (en) | 1998-10-20 |
Family
ID=14092248
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9379197A Withdrawn JPH10280035A (en) | 1997-04-11 | 1997-04-11 | Production of high purity ferritic stainless hot rolled steel strip excellent in workability and heat resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH10280035A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011122513A1 (en) * | 2010-03-29 | 2011-10-06 | 新日鐵住金ステンレス株式会社 | Ferritic stainless steel sheet superior in surface glossiness and corrosion resistance and method for producing same |
| CN102912213A (en) * | 2012-11-21 | 2013-02-06 | 齐齐哈尔市精铸良铸造有限责任公司 | Preparation method of bainite-martensite automobile gear nodular cast iron |
| JP2016164309A (en) * | 2015-02-27 | 2016-09-08 | ポスコ | Ferritic stainless steel sheet excellent in intergranular corrosion resistance |
-
1997
- 1997-04-11 JP JP9379197A patent/JPH10280035A/en not_active Withdrawn
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011122513A1 (en) * | 2010-03-29 | 2011-10-06 | 新日鐵住金ステンレス株式会社 | Ferritic stainless steel sheet superior in surface glossiness and corrosion resistance and method for producing same |
| CN102822373A (en) * | 2010-03-29 | 2012-12-12 | 新日铁住金不锈钢株式会社 | Ferritic stainless steel sheet superior in surface glossiness and corrosion resistance and method for producing same |
| JP5709845B2 (en) * | 2010-03-29 | 2015-04-30 | 新日鐵住金ステンレス株式会社 | Ferritic stainless steel sheet with excellent surface gloss and weather resistance and method for producing the same |
| KR101536291B1 (en) * | 2010-03-29 | 2015-07-13 | 닛폰 스틸 앤드 스미킨 스테인레스 스틸 코포레이션 | Ferritic stainless steel sheet superior in surface glossiness and corrosion resistance and method for producing same |
| CN102912213A (en) * | 2012-11-21 | 2013-02-06 | 齐齐哈尔市精铸良铸造有限责任公司 | Preparation method of bainite-martensite automobile gear nodular cast iron |
| JP2016164309A (en) * | 2015-02-27 | 2016-09-08 | ポスコ | Ferritic stainless steel sheet excellent in intergranular corrosion resistance |
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