JPH0625817A - Production of hot-dip galvanized cold rolled steel sheet having high strength and excellent in adhesion of plating film - Google Patents
Production of hot-dip galvanized cold rolled steel sheet having high strength and excellent in adhesion of plating filmInfo
- Publication number
- JPH0625817A JPH0625817A JP18422492A JP18422492A JPH0625817A JP H0625817 A JPH0625817 A JP H0625817A JP 18422492 A JP18422492 A JP 18422492A JP 18422492 A JP18422492 A JP 18422492A JP H0625817 A JPH0625817 A JP H0625817A
- Authority
- JP
- Japan
- Prior art keywords
- hot
- steel sheet
- adhesion
- dip galvanized
- high strength
- 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
Landscapes
- Coating With Molten Metal (AREA)
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、Siを0.2%以上含
み、めつき被膜の密着性にすぐれる溶融亜鉛めつき高強
度冷延鋼板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 high-strength cold-rolled steel sheet with hot dip galvanizing, which contains Si in an amount of 0.2% or more and has excellent adhesion of the galvanized coating.
【0002】[0002]
【従来の技術】近年、自動車用部材や建設用に使用され
る冷延鋼板は、高強度と耐食性とが要求されている。こ
のような要求を満たすために、冷延鋼板の表面に溶融亜
鉛めつきが施されるが、Si添加量が0.2%を越えると
きは、めつき密着性が劣化する問題がある。そこで、現
状では、溶融亜鉛めつきを必要とする高強度冷延鋼板に
は、Siの代わりに、Mnを添加することによつて強度
向上を図り、Si量を抑えて、上記問題を回避してい
る。2. Description of the Related Art In recent years, cold-rolled steel sheets used for automobile members and construction are required to have high strength and corrosion resistance. In order to meet such requirements, the surface of the cold rolled steel sheet is plated with molten zinc, but when the amount of Si added exceeds 0.2%, there is a problem that the plating adhesion deteriorates. Therefore, at present, in a high-strength cold-rolled steel sheet that requires hot-dip galvanizing, strength is improved by adding Mn instead of Si, and the amount of Si is suppressed to avoid the above problems. ing.
【0003】高強度鋼板は、一般に、Mn及びSiを添
加することによつて、必要な強度を得ているが、高強度
で、しかも高靱性を満たすためには、Si添加の方がM
n添加よりも有利であり、めつきを必要としない鋼板に
おいては、Siが多く添加されている。しかし、めつき
を必要とする場合には、上記問題から、Siを0.2%以
下に抑え、Mnにて強度を得ているために、延性にやや
問題があり、且つ、焼鈍条件も複雑となつている。High strength steel sheets generally have the required strength by adding Mn and Si. However, in order to attain high strength and high toughness, addition of Si gives M
In a steel sheet which is more advantageous than the addition of n and does not require plating, a large amount of Si is added. However, when plating is required, due to the above problems, since the Si content is suppressed to 0.2% or less and the strength is obtained with Mn, ductility is somewhat problematic and the annealing conditions are complicated. It is said.
【0004】[0004]
【発明が解決しようとする課題】そこで、本発明者ら
は、上記した問題を解決するために鋭意研究を重ねた結
果、冷間圧延した鋼板を一酸化炭素を含む還元雰囲気中
で再結晶焼鈍することによつて、めつき被膜の密着性に
すぐれた溶融亜鉛めつき高強度冷延鋼板を得ることがで
きることを見出して、本発明に至つたものである。Therefore, as a result of intensive studies to solve the above problems, the present inventors have found that cold-rolled steel sheets are recrystallized and annealed in a reducing atmosphere containing carbon monoxide. By doing so, it was found that a high-strength cold-rolled steel sheet with hot-dip galvanized steel having excellent adhesion of the plating film can be obtained, and the present invention has been completed.
【0005】[0005]
【課題を解決するための手段】本発明によるめつき被膜
の密着性にすぐれる溶融亜鉛めつき高強度冷延鋼板の製
造方法は、重量%にて C 0.05〜0.3%、 Si 0.2〜1.5%、 Mn 0.5〜2.0%、及び sol Al 0.005〜0.05% を含有し、残部鉄及び不可避的不純物よりなる鋼を熱間
圧延し、酸洗し、冷間圧延した後、一酸化炭素0.1〜1.
0%、水素5〜10%、残部窒素、露点が−30℃以下
なる雰囲気中において、750〜900℃の温度に加熱
して、再結晶連続焼鈍を行なつた後、溶融亜鉛めつき処
理を施すことを特徴とする。According to the present invention, a method for producing a high strength cold rolled steel sheet with a hot dip galvanized steel having excellent adhesion of a galvanized coating is performed in a weight percentage of C 0.05 to 0.3%, Si Steel containing 0.2-1.5%, Mn 0.5-2.0%, and sol Al 0.005-0.05%, with the balance iron and unavoidable impurities is hot-rolled and acid-treated. After washing and cold rolling, carbon monoxide 0.1-1.
In an atmosphere of 0%, 5 to 10% hydrogen, the balance of nitrogen, and a dew point of -30 ° C or less, heating is performed at a temperature of 750 to 900 ° C, continuous recrystallization annealing is performed, and then hot dipping of molten zinc is performed. It is characterized by applying.
【0006】先ず、本発明の方法において用いる鋼の化
学成分について説明する。Cは、鋼板の引張強さを支配
する重要な元素であり、マルテンサイト組織を得るため
には、少なくとも0.05%の添加を必要とし、強度を高
めるためには多いほどよいが、しかし、延性を確保し難
くなるので、添加量の上限は、0.3%とする。First, the chemical composition of steel used in the method of the present invention will be described. C is an important element that controls the tensile strength of the steel sheet, and in order to obtain a martensitic structure, it is necessary to add at least 0.05%, and it is better to increase C to increase the strength, but Since it becomes difficult to secure ductility, the upper limit of the amount added is 0.3%.
【0007】Siは、鋼の延性を劣化させずに、強度を
上げると共に、Ac1点以上の加熱後の冷却過程でのフエ
ライトの生成を促進し、必要な材質を得るための必須元
素である。しかし、1.5%を越えて添加するときは、め
つき密着性が劣化するので、添加量の上限を1.5%とす
る。また、添加量が0.2%未満では、必要な強度を得る
ことができない。[0007] Si is an essential element for increasing the strength without deteriorating the ductility of the steel, promoting the formation of ferrite in the cooling process after heating at the Ac 1 point or higher, and obtaining the required material. . However, if the addition amount exceeds 1.5%, the plating adhesion deteriorates, so the upper limit of the addition amount is made 1.5%. If the amount added is less than 0.2%, the required strength cannot be obtained.
【0008】Mnは、オーステナイト相を安定化し、冷
却過程における低温変態生成物の生成を容易にするが、
0.5%よりも少ないときは、冷却開始温度が高くなり、
製造上問題がある。また、2.0%を越えるときは、Si
のオーステナイト相へ濃縮によつて第2相の体積率が増
加し、Cの濃縮が弱まることから、その添加量を2.0%
以下とする。[0008] Mn stabilizes the austenite phase and facilitates the formation of low temperature transformation products in the cooling process.
When it is less than 0.5%, the cooling start temperature becomes high,
There is a manufacturing problem. When it exceeds 2.0%, Si
To the austenite phase, the volume ratio of the second phase increases and the concentration of C weakens, so the addition amount is 2.0%.
Below.
【0009】Alは、溶鋼の脱酸を目的に添加される
が、その含有量がsol Alとして、0.005%よりも少
ないときは、その目的が達成されず、他方、0.05%を
越えるときは、脱酸効果が飽和すると共に、Al2O3 介在
物が増加して、加工成形性を劣化させる。本発明によれ
ば、再結晶焼鈍温度及び雰囲気組成を規定することによ
つて、溶融亜鉛めつき密着性にすぐれた鋼板を製造する
ことができる。これら条件について、以下に詳しく説明
する。Al is added for the purpose of deoxidizing molten steel. When the content of sol Al is less than 0.005%, the purpose is not achieved, while 0.05% is added. When it exceeds, the deoxidizing effect is saturated, and Al 2 O 3 inclusions increase to deteriorate the workability. According to the present invention, by regulating the recrystallization annealing temperature and the atmosphere composition, it is possible to manufacture a steel sheet having excellent hot-dip galvanizing adhesion. These conditions will be described in detail below.
【0010】Si量が多い鋼板のめつき密着性が悪いの
は、焼鈍により鋼板表面でSiが選択酸化され、その結
果、Siの濃化層が形成され、溶融亜鉛めつきの密着性
を阻害するとされている。本発明によれば、通常、水素
及び窒素の雰囲気下での焼鈍で生じる脱炭を、雰囲気中
に一酸化炭素を混合し、防止することによつて、Si濃
化を低減させることができることを見い出し、その結果
として、めつき密着性にすぐれる高強度溶融亜鉛めつき
用鋼板を得ることができるのである。A steel sheet having a large amount of Si has poor plating adhesion, because the Si is selectively oxidized on the surface of the steel sheet by annealing and, as a result, a concentrated layer of Si is formed, which impairs the adhesion of molten zinc plating. Has been done. According to the present invention, it is possible to reduce the Si concentration by mixing carbon monoxide in the atmosphere to prevent decarburization that normally occurs in annealing in an atmosphere of hydrogen and nitrogen. As a result, it is possible to obtain a high-strength hot-dip galvanized steel sheet having excellent plating adhesion.
【0011】本発明においては、再結晶焼鈍時の鋼板表
面での脱炭を防止し、鋼板表面直下のC濃度の低下を防
ぐことにより、Siの表面への拡散を抑え、Si濃化を
低減させることにより、めつき密着性を改善するもので
あつて、加熱後の冷却、過時効処理の条件は、めつき密
着性に何ら影響を与えるものではない。但し、めつき層
の合金化を行なう場合は、500〜600℃で10〜3
0秒の範囲で行なうことが、めつき密着性の観点から望
ましい。In the present invention, decarburization on the surface of the steel sheet during recrystallization annealing is prevented, and a decrease in the C concentration immediately below the surface of the steel sheet is prevented, thereby suppressing diffusion of Si to the surface and reducing Si concentration. By doing so, the adhesive adhesion is improved, and the conditions of cooling after heating and overaging do not affect the adhesive adhesion at all. However, when alloying the plating layer, it is 10 to 3 at 500 to 600 ° C.
It is desirable to perform the treatment within the range of 0 seconds from the viewpoint of the plating adhesion.
【0012】次に、雰囲気の組成について説明する。一
酸化炭素は、これを従来の雰囲気に加えることにより、
露点が低下し、更に、鋼板表面からの脱炭を防止するこ
とができる。しかし、雰囲気において、0.1%よりも少
ないときは、その作用効果が十分でなく、他方、1.0%
を越えるときは、鋼種によつては浸炭性が強すぎて、表
面汚れの原因となる。Next, the composition of the atmosphere will be described. Carbon monoxide, by adding it to a conventional atmosphere,
The dew point is lowered, and further decarburization from the steel plate surface can be prevented. However, in the atmosphere, when it is less than 0.1%, its action and effect are not sufficient, while on the other hand, it is 1.0%.
If it exceeds the range, the carburizing property is too strong depending on the steel type, which causes surface contamination.
【0013】また、雰囲気の露点は、水素濃度及び一酸
化炭素濃度と共に、雰囲気の性質に対して重要な役割を
果たし、本発明にて規定する範囲にすることにより、本
発明で規定する成分鋼に対して、雰囲気の還元性及び浸
炭性を維持することができる。Further, the dew point of the atmosphere plays an important role with respect to the properties of the atmosphere together with the hydrogen concentration and the carbon monoxide concentration, and by making it within the range specified by the present invention, the composition steel specified by the present invention can be obtained. In contrast, the reducing property and carburizing property of the atmosphere can be maintained.
【0014】[0014]
【発明の効果】以上のように本発明の方法によれば、所
定の化学成分、特に、Siを0.2%以上含む鋼を冷間圧
延した後、一酸化炭素を含み、所定の露点を有する水素
−窒素雰囲気下で再結晶連続焼鈍を行なつた後、溶融亜
鉛めつき処理を施すことによつて、めつき被膜の密着性
にすぐれる溶融亜鉛めつき高強度冷延鋼板を得ることが
できる。As described above, according to the method of the present invention, after cold rolling a steel containing a predetermined chemical component, particularly 0.2% or more of Si, it contains carbon monoxide and has a predetermined dew point. Obtaining a high-strength cold-rolled steel sheet with hot-dip galvanized steel having excellent adhesion to the plating film by performing hot-dip galvanizing treatment after performing continuous recrystallization annealing in a hydrogen-nitrogen atmosphere. You can
【0015】[0015]
【実施例】以下に実施例を挙げて本発明を説明するが、
本発明はこれら実施例により何ら限定されるものではな
い。The present invention will be described below with reference to examples.
The present invention is not limited to these examples.
【0016】実施例1 表1に示す化学成分を有する鋼板を仕上げ温度800〜
900℃、巻取温度500〜600℃にて、厚さ2.8mm
に熱間圧延し、酸洗した後、厚さ0.8mmに冷間圧延し
た。次に、800〜850℃の温度範囲に90秒の再結
晶焼鈍を行なつた後、冷却速度15℃/秒にて強制空冷
し、600〜700℃の温度から200℃/秒にて50
0℃まで冷却し、浴温470℃の溶融亜鉛浴に浸漬し
た。結果を表2に示す。Example 1 A steel sheet having the chemical composition shown in Table 1 was finished at a finishing temperature of 800-
Thickness of 2.8mm at 900 ℃ and winding temperature of 500-600 ℃
After hot rolling, pickling, and cold rolling to a thickness of 0.8 mm. Next, after performing recrystallization annealing for 90 seconds in a temperature range of 800 to 850 ° C., forced air cooling is performed at a cooling rate of 15 ° C./second, and a temperature of 600 to 700 ° C. is set to 50 ° C. at 200 ° C./second.
It was cooled to 0 ° C. and immersed in a molten zinc bath having a bath temperature of 470 ° C. The results are shown in Table 2.
【0017】実施例2 表1に示す鋼種3の化学成分を有する鋼板を仕上げ温度
800〜900℃、巻取温度500〜600℃にて、厚
さ2.8mmに熱間圧延し、酸洗した後、厚さ0.8mmに冷間
圧延した。次に、800〜850℃の温度範囲に90秒
間、加熱保持した後、冷却速度10℃/秒にて強制空冷
し、600〜700℃の温度から100℃/秒にて50
0℃まで冷却し、浴温470℃の溶融亜鉛浴に浸漬し、
その後、600℃で10秒間、亜鉛めつき層の合金化処
理を行なつた。結果を表3に示す。Example 2 A steel sheet having the chemical composition of steel type 3 shown in Table 1 was hot-rolled to a thickness of 2.8 mm at a finishing temperature of 800 to 900 ° C. and a winding temperature of 500 to 600 ° C. and pickled. Then, it was cold-rolled to a thickness of 0.8 mm. Next, after heating and holding in a temperature range of 800 to 850 ° C. for 90 seconds, forced air cooling is performed at a cooling rate of 10 ° C./second, and a temperature of 600 to 700 ° C. is set to 100 ° C./second for 50 seconds.
Cool to 0 ° C and immerse in a molten zinc bath with a bath temperature of 470 ° C.
Then, the zinc plating layer was alloyed at 600 ° C. for 10 seconds. The results are shown in Table 3.
【0018】実施例1及び実施例2共に、再結晶焼鈍時
の雰囲気は、以下に示す5条件のいずれかで行なつた。 A:10%水素−窒素、露点−30℃ B:10%水素−0.05%一酸化炭素−窒素 露点−3
0℃ C:10%水素−0.1%一酸化炭素−窒素 露点−30
℃ D:10%水素−0.5%一酸化炭素−窒素 露点−30
℃ E:10%水素−0.8%一酸化炭素−窒素 露点−30
℃ めつき密着性は、V曲げ試験後、表面をテープ剥離し、
テープ付着した剥離量を目視で3段階に分類し、評価し
た。In both Example 1 and Example 2, the atmosphere during recrystallization annealing was performed under any of the following five conditions. A: 10% hydrogen-nitrogen, dew point -30 ° C B: 10% hydrogen-0.05% carbon monoxide-nitrogen dew point -3
0 ° C C: 10% hydrogen-0.1% carbon monoxide-nitrogen dew point -30
C D: 10% hydrogen-0.5% carbon monoxide-nitrogen dew point -30
C E: 10% hydrogen-0.8% carbon monoxide-nitrogen dew point -30
℃ adhesiveness is measured by V-bending test, tape peeling the surface,
The amount of peeled tape was visually classified into 3 levels and evaluated.
【0019】表2及び表3に示すように、本発明の方法
によつて、めつき被膜の密着性にすぐれた溶融亜鉛めつ
き高強度冷延鋼板を得ることができる。As shown in Tables 2 and 3, according to the method of the present invention, it is possible to obtain a high strength cold-rolled steel sheet with hot dip galvanizing which is excellent in adhesion of the galling film.
【0020】[0020]
【表1】 [Table 1]
【0021】[0021]
【表2】 [Table 2]
【0022】[0022]
【表3】 [Table 3]
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.5 識別記号 庁内整理番号 FI 技術表示箇所 C22C 38/06 ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 5 Identification code Internal reference number FI technical display location C22C 38/06
Claims (1)
圧延し、酸洗し、冷間圧延した後、一酸化炭素0.1〜1.
0%、水素5〜10%、残部窒素、露点が−30℃以下
なる雰囲気中において、750〜900℃の温度に加熱
して、再結晶連続焼鈍を行なつた後、溶融亜鉛めつき処
理を施すことを特徴とするめつき被膜の密着性にすぐれ
る溶融亜鉛めつき高強度冷延鋼板の製造方法。1. By weight%, C 0.05 to 0.3%, Si 0.2 to 1.5%, Mn 0.5 to 2.0%, and sol Al 0.005 to 0.05%. After hot rolling, steel containing the balance iron and unavoidable impurities, pickling and cold rolling, carbon monoxide 0.1 to 1.
In an atmosphere of 0%, 5 to 10% hydrogen, the balance of nitrogen, and a dew point of -30 ° C or less, heating is performed at a temperature of 750 to 900 ° C, continuous recrystallization annealing is performed, and then hot dipping of molten zinc is performed. A method for producing a high-strength cold-rolled steel sheet with hot dip galvanized, which is excellent in the adhesion of the galvanized coating.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP18422492A JPH0625817A (en) | 1992-07-10 | 1992-07-10 | Production of hot-dip galvanized cold rolled steel sheet having high strength and excellent in adhesion of plating film |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP18422492A JPH0625817A (en) | 1992-07-10 | 1992-07-10 | Production of hot-dip galvanized cold rolled steel sheet having high strength and excellent in adhesion of plating film |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0625817A true JPH0625817A (en) | 1994-02-01 |
Family
ID=16149546
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP18422492A Pending JPH0625817A (en) | 1992-07-10 | 1992-07-10 | Production of hot-dip galvanized cold rolled steel sheet having high strength and excellent in adhesion of plating film |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0625817A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006037130A (en) * | 2004-07-23 | 2006-02-09 | Nippon Steel Corp | Method for producing plated steel sheet for hot press |
WO2007043273A1 (en) * | 2005-10-14 | 2007-04-19 | Nippon Steel Corporation | Method of continuous annealing/hot-dipping of steel sheet containing silicon and apparatus for continuous annealing/hot-dipping |
WO2013157146A1 (en) * | 2012-04-17 | 2013-10-24 | Jfeスチール株式会社 | Method for producing alloyed hot-dip galvanized steel sheet having excellent adhesion to plating and excellent sliding properties |
JP2016117921A (en) * | 2014-12-18 | 2016-06-30 | 株式会社神戸製鋼所 | Steel sheet and manufacturing method therefor |
-
1992
- 1992-07-10 JP JP18422492A patent/JPH0625817A/en active Pending
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006037130A (en) * | 2004-07-23 | 2006-02-09 | Nippon Steel Corp | Method for producing plated steel sheet for hot press |
JP4500124B2 (en) * | 2004-07-23 | 2010-07-14 | 新日本製鐵株式会社 | Manufacturing method of hot-pressed plated steel sheet |
WO2007043273A1 (en) * | 2005-10-14 | 2007-04-19 | Nippon Steel Corporation | Method of continuous annealing/hot-dipping of steel sheet containing silicon and apparatus for continuous annealing/hot-dipping |
WO2013157146A1 (en) * | 2012-04-17 | 2013-10-24 | Jfeスチール株式会社 | Method for producing alloyed hot-dip galvanized steel sheet having excellent adhesion to plating and excellent sliding properties |
JP2016117921A (en) * | 2014-12-18 | 2016-06-30 | 株式会社神戸製鋼所 | Steel sheet and manufacturing method therefor |
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