JPS6249325B2 - - Google Patents
Info
- Publication number
- JPS6249325B2 JPS6249325B2 JP4753283A JP4753283A JPS6249325B2 JP S6249325 B2 JPS6249325 B2 JP S6249325B2 JP 4753283 A JP4753283 A JP 4753283A JP 4753283 A JP4753283 A JP 4753283A JP S6249325 B2 JPS6249325 B2 JP S6249325B2
- Authority
- JP
- Japan
- Prior art keywords
- steel strip
- scale
- low
- pickling
- scale 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.)
- Expired
Links
- 229910000831 Steel Inorganic materials 0.000 claims description 31
- 239000010959 steel Substances 0.000 claims description 31
- 238000005554 pickling Methods 0.000 claims description 13
- 229910001220 stainless steel Inorganic materials 0.000 claims description 13
- 238000000137 annealing Methods 0.000 claims description 12
- 239000010935 stainless steel Substances 0.000 claims description 12
- 238000005098 hot rolling Methods 0.000 claims description 10
- 238000004519 manufacturing process Methods 0.000 claims description 9
- 238000000034 method Methods 0.000 description 18
- 239000002344 surface layer Substances 0.000 description 10
- 230000003647 oxidation Effects 0.000 description 8
- 238000007254 oxidation reaction Methods 0.000 description 8
- 238000007796 conventional method Methods 0.000 description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 239000012467 final product Substances 0.000 description 5
- 238000012733 comparative method Methods 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 230000004584 weight gain Effects 0.000 description 4
- 235000019786 weight gain Nutrition 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 239000010410 layer Substances 0.000 description 3
- 238000005498 polishing Methods 0.000 description 3
- 230000001603 reducing effect Effects 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000004576 sand Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- -1 SUS410 Substances 0.000 description 1
- 238000005422 blasting Methods 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007730 finishing process Methods 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
- 239000000126 substance Substances 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
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips 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 Sheet Steel (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
- Preventing Corrosion Or Incrustation Of Metals (AREA)
Description
本発明は耐スケール性にすぐれた低Cr系ステ
ンレス鋼帯の製造方法に係り、特にNo.１仕上鋼帯
の製造方法に関する。
低Cr系ステンレス鋼例えばSUS410，
SUS420J1，SUS420J2，AISI409の如き鋼は、Ｃ
含有量が少ないものは器物用、数百度程度の低温
度域における耐酸化性が要求される用途、あるい
は腐食環境が厳しくない用途に、一方Ｃ含有量が
多いものは刃物用に使用されることが多い。
これらの低Cr系ステンレス鋼帯の最終製品ま
での製造工程は、熱間圧延後の熱延鋼帯に熱処理
酸洗またはこれに準ずる処理を施すいわゆるNo.１
仕上工程と、その後の熱処理、冷間加工、酸洗、
研磨等を行い最終製品とするそれ以後の工程に大
別できる。
熱延鋼帯からNo.１仕上鋼帯への従来の代表的な
方法はHNX（約N2：95％，H2：５％）ガス雰囲
気下で焼鈍して酸洗する方法である。しかし、こ
の方法では製造工程中においてもスケールが発生
しやすく、いわゆる耐スケール性が悪く、最終製
品に到るまでの脱スケール負荷が大きく更に
AISI409の如き鋼は最終製品においても本来具備
すべきすぐれた耐スケール性という品質特性が失
われてしまう問題点があつた。
これらの低Cr系ステンレス鋼帯の耐スケール
性の良否は鋼表面層のCr濃度に依存し、Cr濃度
が高いと耐スケール性は良好で低いと耐スケール
性は劣化する。Crの含有量が16％以上のSUS430
に代表されるステンレス鋼においては、鋼表面層
のCr濃度が板厚中央部に比較して低くともこの
ような耐スケール性の劣化はみられない。
また、これらの製造工程中および最終製品の耐
スケール性は熱延鋼帯の焼鈍、酸洗後のNo.１仕上
鋼帯の耐スケール性に大きく影響される。このた
め、従来No.１仕上表面層に生じた低Cr濃度層を
除去し耐スケール性を向上させるため、研摩ある
いはNo.１仕上製造時の酸洗における浸漬時間の延
長、あるいはこれらの両者を併用する等の方法が
あるが十分な効果が得られず、また大幅なコスト
アツプをきたす等の問題点があつた。
本発明の目的は、上記従来技術の問題点を解決
し、低コストの耐スケール性にすぐれた低Cr系
ステンレス鋼帯の製造方法を提供するにある。
No.１仕上あるいはそれ以降に加工を受けた状態
において耐スケール性を改善するには鋼帯表面の
低Cr濃度域を除去する必要があるが、熱延時の
スケールを除去せずに熱延鋼帯をH2雰囲気で焼
鈍した後でスケールを除去しても効果はない。こ
れは熱延時に生成したスケールが付着したまま
H2雰囲気で熱延鋼帯を焼鈍すると次のような現
象がおこるためである。
(イ) スケールと地鉄が反応して新たなCr酸化を
生じる。
(ロ) 従つて表層へのCr拡散が十分にできない。
本発明者らは、種々検討の結果、熱延時のスケ
ールをまず除去し、次に酸化を抑制しながら焼鈍
し表層へのCr拡散を行う方法を見い出した。
本発明の要旨とするところは次のとおりであ
る。すなわち、重量比でCrを10.5％以上、14％未
満の範囲で含有する低Cr系ステンレス熱延鋼帯
を熱延時に生成したスケールを機械的に除去する
工程と、前記スケール除去鋼帯を100％H2もしく
は10％以上のH2とArの混合雰囲気下でバツチ焼
鈍する工程と、前記焼鈍鋼帯を酸洗する工程と、
を有することを特徴とする耐スケール性にすぐれ
た低Cr系ステンレス鋼帯の製造方法である。
本発明において、Cr含有量を限定したのは、
Crが10.5％未満では十分な耐スケール性が得られ
ず、また14％以上では鋼表面層のCr濃度が若干
低下しても、耐スケール性の劣下が見られず本発
明を必要としないので、Crの含有量を10.5％以
上、14％未満の範囲に限定した。
熱延時に生成したスケールを機械的に除去する
手段としては通常行われているシヨツトブラスト
の使用、あるいは高圧水に砂鉄スラリーを混入し
砂鉄を加速して鋼表面衝突させる方法で十分であ
るが、これらの後に更にベルト研摩によつてスケ
ールを完全に除去しても差支えない。
次に熱延鋼帯を焼鈍するのであるが、雰囲気ガ
スとしては酸化防止と環元性の両方を備える必要
があり、従来のHNXガスでは還元作用が不十分
で所期の目的が達せられず、H2：100％もしくは
10％以上のH2と完全な不活性ガスであるArとの
混合ガスとする必要がある。焼鈍温度、時間につ
いては従来と同様でよい。
焼鈍によりCrが表層まで拡散された焼鈍鋼帯
の酸洗は熱延時のスケールが機械的に除去され、
焼鈍は還元雰囲気なので容易に実施できる。
上記の本発明法により、鋼帯表面層にCr欠乏
層が存在しないので、耐スケール性のすぐれた低
Cr系ステンレス鋼帯を得ることができる。
実施例
第１表に化学組成を示したSUS410，SUS420J2
およびAISI409の熱延鋼帯を第２表の工程で処理
してNo.１仕上とした。本発明法の他に本発明法の
The present invention relates to a method for producing a low Cr stainless steel strip with excellent scale resistance, and particularly to a method for producing a No. 1 finished steel strip. Low Cr stainless steel such as SUS410,
Steels such as SUS420J 1 , SUS420J 2 , and AISI409 are C
Those with a low C content are used for utensils, applications that require oxidation resistance in the low temperature range of several hundred degrees, or applications that are not subject to harsh corrosive environments, while those with a high C content are used for cutlery. There are many. The manufacturing process for these low Cr stainless steel strips up to the final product is the so-called No. 1 process in which the hot rolled steel strip is subjected to heat treatment pickling or similar treatment after hot rolling.
Finishing process and subsequent heat treatment, cold working, pickling,
It can be roughly divided into subsequent processes that include polishing and other steps to produce the final product. The typical conventional method for converting hot-rolled steel strip to No. 1 finished steel strip is annealing and pickling in a HNX (about 95% N 2 , 5% H 2 ) gas atmosphere. However, with this method, scale easily occurs during the manufacturing process, so-called scale resistance is poor, and the descaling load required to reach the final product is large.
Steels such as AISI409 have the problem that even in the final product, the quality characteristic of excellent scale resistance that should originally be possessed is lost. The quality of the scale resistance of these low Cr stainless steel strips depends on the Cr concentration of the steel surface layer; when the Cr concentration is high, the scale resistance is good, and when the Cr concentration is low, the scale resistance is deteriorated. SUS430 with Cr content of 16% or more
In stainless steels such as the above, such deterioration of scale resistance is not observed even though the Cr concentration in the steel surface layer is lower than that in the center of the plate thickness. In addition, the scale resistance during these manufacturing processes and of the final product is greatly influenced by the scale resistance of the No. 1 finished steel strip after annealing and pickling of the hot rolled steel strip. Therefore, in order to remove the low Cr concentration layer that has conventionally formed on the surface layer of No. 1 finish and improve its scale resistance, it is necessary to increase the immersion time during polishing or pickling during the production of No. 1 finish, or both. Although there are methods such as using them in combination, there are problems such as insufficient effects and a significant increase in costs. An object of the present invention is to solve the problems of the prior art described above and to provide a low-cost method for manufacturing a low-Cr stainless steel strip with excellent scale resistance. In order to improve the scale resistance of the steel strip after No. 1 finishing or after processing, it is necessary to remove the low Cr concentration region on the surface of the steel strip. Descaling after annealing the strip in an H2 atmosphere has no effect. This is because the scale generated during hot rolling remains attached.
This is because the following phenomenon occurs when hot-rolled steel strip is annealed in an H2 atmosphere. (b) Scale and base iron react to produce new Cr oxidation. (b) Therefore, Cr cannot diffuse sufficiently into the surface layer. As a result of various studies, the present inventors have discovered a method of first removing scale during hot rolling, then annealing while suppressing oxidation, and diffusing Cr into the surface layer. The gist of the present invention is as follows. That is, a step of mechanically removing scale generated during hot rolling of a low Cr stainless steel hot rolled steel strip containing Cr in a range of 10.5% or more and less than 14% by weight, and a process of mechanically removing scale generated during hot rolling of a low Cr stainless steel hot rolled steel strip containing Cr in a range of 10.5% or more and less than 14% by weight; % H2 or a mixed atmosphere of 10% or more H2 and Ar, and pickling the annealed steel strip;
This is a method for producing a low Cr stainless steel strip having excellent scale resistance. In the present invention, the Cr content is limited by
If Cr is less than 10.5%, sufficient scale resistance cannot be obtained, and if it is 14% or more, even if the Cr concentration in the steel surface layer decreases slightly, no deterioration in scale resistance is observed and the present invention is not required. Therefore, the Cr content was limited to a range of 10.5% or more and less than 14%. As a means of mechanically removing scale generated during hot rolling, it is sufficient to use shot blasting, which is the usual method, or to mix iron sand slurry with high-pressure water and accelerate the iron sand so that it collides with the steel surface. After this, the scale may be completely removed by belt polishing. Next, the hot-rolled steel strip is annealed, but the atmospheric gas must have both oxidation prevention and cyclic properties, and conventional HNX gas has insufficient reducing action and cannot achieve the intended purpose. , H 2 : 100% or
The gas must be a mixture of 10% or more H 2 and Ar, which is a completely inert gas. The annealing temperature and time may be the same as conventional ones. Pickling of an annealed steel strip in which Cr has been diffused to the surface layer through annealing mechanically removes scale during hot rolling.
Annealing can be easily performed in a reducing atmosphere. By using the above-mentioned method of the present invention, there is no Cr-depleted layer on the surface layer of the steel strip, so it has excellent scale resistance and low
Cr stainless steel strip can be obtained. Example SUS410, SUS420J 2 whose chemical composition is shown in Table 1
and AISI409 hot-rolled steel strips were treated with the steps shown in Table 2 to give No. 1 finish. In addition to the method of the present invention, the method of the present invention
【表】
条件を一部変更した比較法および従来法について
も参考のため実施した。なお第２表の焼鈍は第２
表で表示した雰囲気中で800℃×2hrの均熱後更に
750℃×5hrの均熱を行つたものであ[Table] Comparative methods with partially modified conditions and conventional methods were also conducted for reference. Note that the annealing in Table 2 is
After soaking for 2 hours at 800℃ in the atmosphere shown in the table,
It was soaked at 750℃ for 5 hours.
【表】
ある。また酸洗は次の３段階の酸洗を行い水洗し
たものである。
従来法Ｅの酸洗→酸洗とあるのは上記の３段階
の酸洗を２回繰返したものである。
第２表の工程でNo.１仕上とした鋼帯を大気中で
800℃×10minの熱処理を行い、耐スケール性の
目安の一つである酸化増量値を調査し、その結果
を第１図に示した。
第１図において、本発明法Ａ，Ｂはいずれも酸
化増量値が低く耐スケール性がすぐれているのが
わかる。一方、熱延時のスケールを除去しない比
較法Ｃ、およびスケールを最初に除去しても焼鈍
中の雰囲気の還元性が不十分な比較法Ｄ、あるい
はHNX焼鈍の従来法E.F等はいずれも酸化増量値
が高く耐スケール性が十分ではないことを示して
いる。
また、第２表の本発明法Ｂおよび従来法Ｆによ
るSUS410のNo.１仕上鋼帯の表面層のCrの濃度を
イオンマスマイクロアナライザーで測定し、その
結果を第２図に示した。第２図から本発明法Ｂは
従来法Ｆに比較して表面のCr欠乏層の少ないこ
とがわかる。
上記実施例からも明らかな如く、本発明法は低
Cr系ステンレス熱延鋼帯の熱延時のスケールを
機械的に除去し、100H2もしくは10％以上のH2と
Arの混合雰囲気でバツチ焼鈍を行い、ついで酸
洗することにより、耐スケール性にすぐれた低
Cr系ステンレス鋼帯を低コストで製造すること
ができる。[Table] Yes. Further, the pickling was carried out in the following three steps and then washed with water. The phrase "pickling→pickling" in conventional method E means that the above three stages of pickling are repeated twice. A steel strip with No. 1 finish in the process shown in Table 2 is placed in the atmosphere.
Heat treatment was performed at 800°C for 10 minutes, and the oxidation weight gain value, which is one of the indicators of scale resistance, was investigated. The results are shown in Figure 1. In FIG. 1, it can be seen that both methods A and B of the present invention have low oxidation weight gain values and excellent scale resistance. On the other hand, Comparative Method C, which does not remove scale during hot rolling, Comparative Method D, in which the atmosphere during annealing has insufficient reducing properties even if scale is removed first, and conventional method EF, which uses HNX annealing, all have oxidation weight gain. The value is high, indicating that the scale resistance is not sufficient. In addition, the Cr concentration in the surface layer of the No. 1 finished steel strip of SUS410 obtained by the method B of the present invention and the conventional method F shown in Table 2 was measured using an ion mass microanalyzer, and the results are shown in FIG. From FIG. 2, it can be seen that the method B of the present invention has less Cr-depleted layer on the surface than the conventional method F. As is clear from the above examples, the method of the present invention has a low
Mechanically removes the scale during hot rolling of Cr-based stainless steel hot rolled steel strip and processes it with 100H2 or more than 10% H2
By batch annealing in an Ar mixed atmosphere and then pickling, the
Cr stainless steel strip can be manufactured at low cost.
第１図は本発明法、比較法および従来法による
No.１仕上鋼帯を大気中で800℃×10minの熱処理
行つた時の酸化増量値を示すグラフ、第２図はイ
オンマスマイクロアナライザでSUS410No.１仕上
鋼帯の表層のCr濃度を分析した結果を示す線図
である。
Figure 1 shows results obtained using the present invention method, comparative method, and conventional method.
A graph showing the oxidation weight gain when No. 1 finished steel strip was heat-treated at 800°C for 10 minutes in the air. Figure 2 shows the Cr concentration in the surface layer of SUS410 No. 1 finished steel strip analyzed using an ion mass microanalyzer. FIG. 3 is a diagram showing the results.
Claims (1)
含有する低Cr系ステンレス熱延鋼帯を熱延時に
生成したスケールを機械的に除去する工程と、前
記スケール除去鋼帯を100％H2もしくは10％以上
のH2とArの混合雰囲気下でバツチ焼鈍する工程
と、前記焼鈍鋼帯を酸洗する工程と、を有するこ
とを特徴とする耐スケール性にすぐれた低Cr系
ステンレス鋼帯の製造方法。1. A step of mechanically removing scale generated during hot rolling of a low Cr stainless hot rolled steel strip containing Cr in a range of 10.5% or more and less than 14% by weight, and 100% of the scale removed steel strip. A low Cr stainless steel with excellent scale resistance, characterized by comprising a step of batch annealing in a mixed atmosphere of H 2 or 10% or more H 2 and Ar, and a step of pickling the annealed steel strip. Method of manufacturing steel strip.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4753283A JPS59173224A (en) | 1983-03-22 | 1983-03-22 | Preparation of low cr-type stainless steel strip excellent in scale resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4753283A JPS59173224A (en) | 1983-03-22 | 1983-03-22 | Preparation of low cr-type stainless steel strip excellent in scale resistance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59173224A JPS59173224A (en) | 1984-10-01 |
| JPS6249325B2 true JPS6249325B2 (en) | 1987-10-19 |
Family
ID=12777731
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4753283A Granted JPS59173224A (en) | 1983-03-22 | 1983-03-22 | Preparation of low cr-type stainless steel strip excellent in scale resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59173224A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59185727A (en) * | 1983-04-07 | 1984-10-22 | Kawasaki Steel Corp | Manufacture of cold rolled ferritic stainless steel plate having superior surface luster |
| JPH0756045B2 (en) * | 1988-09-08 | 1995-06-14 | 新日本製鐵株式会社 | Method for producing stainless steel sheet with excellent surface selection and high rust resistance |
-
1983
- 1983-03-22 JP JP4753283A patent/JPS59173224A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59173224A (en) | 1984-10-01 |
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