JP2006009116A - Steel sheet for hot pressing - Google Patents
Steel sheet for hot pressing Download PDFInfo
- Publication number
- JP2006009116A JP2006009116A JP2004190827A JP2004190827A JP2006009116A JP 2006009116 A JP2006009116 A JP 2006009116A JP 2004190827 A JP2004190827 A JP 2004190827A JP 2004190827 A JP2004190827 A JP 2004190827A JP 2006009116 A JP2006009116 A JP 2006009116A
- Authority
- JP
- Japan
- Prior art keywords
- steel sheet
- strength
- hot pressing
- steel
- hot
- 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.)
- Granted
Links
Images
Landscapes
- Heat Treatment Of Sheet Steel (AREA)
Abstract
Description
本発明は、プレス成形と焼き入れによる部材の強度向上を同時に行う熱間プレス用鋼板、特に自動車ボデーの骨格部品、補強部品や足回り部品などの製造に使用される熱間プレス用鋼板に関する。 The present invention relates to a steel sheet for hot pressing that simultaneously improves the strength of a member by press forming and quenching, and more particularly, to a steel sheet for hot pressing used for manufacturing a frame part, a reinforcing part, a suspension part, and the like of an automobile body.
近年、地球環境の観点から自動車の軽量化が強く望まれており、ボデー等の鋼板が使用される部品では、高強度鋼板を適用し鋼板の板厚を薄くして軽量化が図られている。しかしながら、鋼板の高強度化は部品製造時の加工性、プレス成形性の低下を招き、特にスプリングバック等の製品精度の確保がより難しくなってくる。
これらの課題解決のために加工性に優れた鋼板の開発や製品精度を高める加工方法が提案されているが、自動車に適用される鋼板の高強度化も進み、特に引張り強度（TS：Tensile Strength ）が１１８０ＭＰａを越える高強度鋼板においては、上記の加工性、製品精度の観点から適用可能な部品に制限があるのが実情である。
In recent years, weight reduction of automobiles has been strongly demanded from the viewpoint of the global environment, and in parts where steel plates such as bodies are used, high-strength steel plates are used to reduce the thickness of the steel plates and reduce the weight. . However, increasing the strength of the steel sheet causes a decrease in workability and press formability at the time of manufacturing parts, and in particular, it becomes more difficult to ensure product accuracy such as spring back.
In order to solve these problems, the development of steel plates with excellent workability and processing methods that improve product accuracy have been proposed. However, the strength of steel plates applied to automobiles has been increasing, especially in terms of tensile strength (TS: Tensile Strength). In the case of high-strength steel sheets exceeding 1180 MPa, there is a limit to the parts that can be applied from the viewpoints of workability and product accuracy.
近年、鋼板の高強度化と加工性、製品精度を同時に満足する手法として熱間プレス工法（プレスクエンチ工法）が実用技術として使用されるようになってきた。例えば特許文献１に開示されている。これは、鋼板を約８００℃以上のオーステナイト域まで加熱した後、プレス成形を行い、同時に成形後の冷却により焼き入れを行い高強度の材質を得るものである。この熱間プレス工法により、プレス成形時に導入される残留応力も減少するため、ＴＳで１１８０ＭＰａを越える高強度鋼板で問題となる遅れ破壊の感受性も低下する。この技術により、高強度の自動車用部品製造における成形時の割れ発生等の不具合が抑制され、比較的良好な製品精度の部品の製造が可能となったが、以下の不具合が残った。 In recent years, the hot press method (press quench method) has come to be used as a practical technique as a method of simultaneously satisfying the high strength, workability, and product accuracy of steel sheets. For example, it is disclosed in Patent Document 1. In this method, a steel sheet is heated to an austenite region of about 800 ° C. or higher, and then press forming is performed, and at the same time, quenching is performed by cooling after forming to obtain a high-strength material. This hot pressing method also reduces the residual stress introduced at the time of press forming, thereby reducing the susceptibility to delayed fracture, which is a problem with high-strength steel sheets with a TS exceeding 1180 MPa. With this technology, problems such as the occurrence of cracks during molding in the manufacture of high-strength automotive parts can be suppressed and parts with relatively good product accuracy can be manufactured, but the following problems remain.
すなわち、自動車部品の製造においては、上記の熱間プレス後のプレス成形品を所定の製品寸法に仕上げる切断や他部品を取り付けるための穴をあける打ち抜きが実施され、所望の部品となる。また、さらに製造された部品は、他部品と接合されて最終的に自動車の形態となる。このように、自動車の部品は多くの工程を経て製造されているが、熱間プレス後の焼き入れによって高強度化された部品は、切断や打抜きが難しく、微細なクラックを発生させ、このクラックが起点となって遅れ破壊が生じる場合がある。これは、従来の高強度鋼板を適用した場合と同様である。また、他部品との接合は通常、自動車の製造においてはスポット溶接が使用されるが、熱間プレスに使用されている鋼板は、焼き入れ性を確保するため添加成分が多いので、スポット溶接部は高硬度化され、スポット溶接部の接合の信頼性（破断形態）を低下させているのが実情である。すなわち、熱間プレス工法において、熱間プレス、焼き入れ後の部品強度、部品の切断性や打抜き性、さらには遅れ破壊特性、スポット溶接性が考慮された鋼板は未だ無い状況である。
本発明者らは、上記のような課題を克服し、熱間プレス、焼き入れ後の部品強度、部品の切断性や打抜き性、さらには遅れ破壊特性、スポット溶接性を満足する熱間プレス用鋼板を提供することにある。 The present inventors have overcome the above-mentioned problems, and for hot presses that satisfy hot press, strength of parts after quenching, cutability and punchability of parts, delayed fracture characteristics, and spot weldability. It is to provide a steel sheet.
本発明の要旨は以下の通りである。
（１）質量％にて、
Ｃ ：０．１５〜０．３％、
Ｓｉ：０．００５〜１．０％、
Ｍｎ：０．０１〜３．０％、
Ｐ ：０．００５〜０．１％、
Ｓ ：０．０２％以下、
Ａｌ：０．０１％〜３．０％、
Ｎ ：０．０１％以下、
Ｃｒ：０．０２〜０．５％、
Ｖ：０．００２〜０．５％、
Ｂ：０．０００２〜０．０１％、
Ｍｇ：０．０００２％〜０．０１％
を含有し、残部が鉄および不可避的不純物からなる鋼で、鋼中に平均粒径が０．０１〜５．０μｍの範囲にあるＭｇの酸化物、硫化物、複合晶出物および複合析出物のいずれか１種もしくは２種以上の複合酸化物を、１平方ｍｍ当り１×１０2 個〜１×１０7 個含み、かつ、下記式（Ａ）を満足することを特徴とする熱間プレス用高強度鋼板、
０．３５≧Ｃ＋Si/30+Mn/20+Cr/20+Mo/15+V/10＋４・Ｂ＋２・Ｐ＋４・Ｓ ……（Ａ）（２）更に、質量％にて、
Ｔｉ：０．００２〜０．５％、
Ｎｂ：０．００２〜０．５％、
Ｚｒ: ０．００２〜０．５％
の１種または２種以上を含有し、残部が鉄および不可避的不純物からなる鋼であることを特徴とする前記（１）に記載の熱間プレス用高強度鋼板、
（３）更に、質量％にて、
Ｍｏ：０．００５〜１％、
Ｗ ：０．００５〜１％
の１種または２種以上を含有し、残部が鉄および不可避的不純物からなる鋼であることを特徴とする前記（１）または（２）に記載の熱間プレス用高強度鋼板、
（４）更に、質量％にて、
Ｃｕ：０．００５〜２．０％
を含有し、残部が鉄および不可避的不純物からなる鋼であることを特徴とする前記（１）〜（３）に記載の熱間プレス用高強度鋼板、
（５）更に、質量％にて、
Ｎｉ：０．００５〜２．０％、
Ｃｏ：０．００５〜２．０％
の１種または２種以上を含有し、残部が鉄および不可避的不純物からなる鋼であることを特徴とする前記（１）〜（４）に記載の熱間プレス用高強度鋼板、
（６）更に、質量％にて、
ＲＥＭ：０．０００５〜０．０１％、
Ｃａ：０．０００５〜０．０１％、
Ｙ ：０．０００５〜０．０１％
の１種または２種以上を含有し、残部が鉄および不可避的不純物からなる鋼であることを特徴とする前記（１）〜（５）に記載の熱間プレス用高強度鋼板、
（７）前記（１）〜（６）に記載の高強度鋼板が熱延鋼板または冷延鋼板であることを特徴とする、熱間プレス用高強度鋼板、
（８）前記高強度薄鋼板が、高強度表面処理鋼板であることを特徴とする前記（１）〜（７）に記載の熱間プレス用高強度鋼板、
（９）前記高強度表面処理鋼板が亜鉛めっきされた鋼板であることを特徴とする前記（８）記載の熱間プレス用高強度鋼板、
にある。
The gist of the present invention is as follows.
(1) In mass%,
C: 0.15-0.3%
Si: 0.005 to 1.0%,
Mn: 0.01 to 3.0%,
P: 0.005-0.1%,
S: 0.02% or less,
Al: 0.01% to 3.0%,
N: 0.01% or less,
Cr: 0.02 to 0.5%,
V: 0.002 to 0.5%,
B: 0.0002 to 0.01%
Mg: 0.0002% to 0.01%
Mg, oxides, sulfides, composite crystallized products, and composite precipitates containing steel and the balance being iron and inevitable impurities, and having an average particle size in the range of 0.01 to 5.0 μm in the steel A hot press characterized by containing 1 × 10 2 to 1 × 10 7 complex oxides per square mm and satisfying the following formula (A): High strength steel plate,
0.35 ≧ C + Si / 30 + Mn / 20 + Cr / 20 + Mo / 15 + V / 10 + 4 · B + 2 · P + 4 · S (A) (2) Furthermore, in mass%,
Ti: 0.002 to 0.5%,
Nb: 0.002 to 0.5%,
Zr: 0.002 to 0.5%
A high-strength steel sheet for hot pressing as set forth in (1) above, wherein the steel is one or more of the following, the balance being steel consisting of iron and inevitable impurities,
(3) Furthermore, in mass%,
Mo: 0.005 to 1%,
W: 0.005 to 1%
A high-strength steel sheet for hot pressing as set forth in (1) or (2) above, wherein the steel is one or more of the following, the balance being steel consisting of iron and inevitable impurities,
(4) Furthermore, in mass%,
Cu: 0.005 to 2.0%
High-strength steel sheet for hot pressing as described in (1) to (3) above, wherein the balance is steel composed of iron and inevitable impurities,
(5) Furthermore, in mass%,
Ni: 0.005 to 2.0%,
Co: 0.005 to 2.0%
A high-strength steel sheet for hot pressing as described in (1) to (4) above, wherein the steel is one or more of the following, the balance being steel consisting of iron and inevitable impurities,
(6) Furthermore, in mass%,
REM: 0.0005 to 0.01%,
Ca: 0.0005 to 0.01%,
Y: 0.0005 to 0.01%
A high-strength steel sheet for hot pressing as described in (1) to (5) above, wherein one or more of the above are contained, and the balance is steel composed of iron and inevitable impurities,
(7) The high-strength steel sheet for hot pressing, wherein the high-strength steel sheet according to (1) to (6) is a hot-rolled steel sheet or a cold-rolled steel sheet,
(8) The high-strength steel sheet for hot pressing according to (1) to (7), wherein the high-strength thin steel sheet is a high-strength surface-treated steel sheet,
(9) The high-strength steel sheet for hot pressing according to (8), wherein the high-strength surface-treated steel sheet is a galvanized steel sheet,
It is in.
本発明の熱間プレス用高強度鋼板は、打抜き部の遅れ破壊特性、スポット溶接性に優れた鋼板を提供することができ、本発明の鋼板により製造された部材を使用すれば自動車の軽量化、安全性向上に大きく貢献できるものと考えられ、産業上の寄与は大きい。 The high-strength steel sheet for hot pressing according to the present invention can provide a steel sheet excellent in delayed fracture characteristics and spot weldability of a punched portion, and if a member manufactured using the steel sheet of the present invention is used, the weight of the automobile can be reduced. Therefore, it is thought that it can greatly contribute to safety improvement, and the industrial contribution is great.
発明者らは、熱間プレス、焼き入れ後の部品強度、部品の切断性や打抜き性、さらには遅れ破壊特性、スポット溶接性を満足するために様々な添加成分、添加量、また、添加成分相互の影響について調査を行った。まず、打抜き性について調査したところ、Ｍｇを添加することで打抜き断面に発生するクラックを微細均一化することが可能であることがわかった。そして鋼板中に存在する酸化物とこれらを核とした複合晶出・析出物を均一分散させることにより打抜き時の粗大なクラックの発生が抑制されることがわかった。加えてこれらの酸化物とこれらを核とした複合晶出・析出物は、遅れ破壊の要因と考えられている拡散性水素のトラップサイトとなり、その部分に水素がトラップされるため拡散性水素濃度が下がり、遅れ破壊の感受性が下がる効果も確認された。 The inventors have various additive components, additive amounts, and additive components in order to satisfy hot pressing, strength of parts after quenching, cutting and punching properties of parts, delayed fracture characteristics, and spot weldability. We investigated the mutual effects. First, as a result of investigating the punchability, it was found that the crack generated in the punched section can be made fine and uniform by adding Mg. It was also found that the generation of coarse cracks during punching is suppressed by uniformly dispersing oxides present in the steel sheet and composite crystallization / precipitates having these as nuclei. In addition, these oxides and their combined crystallization and precipitates become diffusible hydrogen trap sites, which are considered to be a cause of delayed fracture, and hydrogen is trapped there, so the diffusible hydrogen concentration The effect of lowering the susceptibility to delayed fracture was also confirmed.
次にスポット溶接性について調査したところ、熱間プレス・焼き入れした鋼板をスポット溶接した場合、溶接部の熱履歴によって、母材の強度に対して溶接部及び熱影響部の強度が変化するため、接合強度を評価した場合、スポット溶接部の破断形態は、溶接部（ナゲット）が残らない剥離破断やナゲットが残存するナゲット外破断を呈する場合があることが判明した。そして、鋼中にＣ、Ｓｉ、Ｍｎ、Ｐ、Ｓ、Ａｌ、Ｎ、Ｃｒ、Ｖ、Ｂ、Ｍｇ、Ｔｉ、Ｎｂ、Ｚｒ、Ｍｏ、Ｗ、Ｃｕ、Ｎｉ、Ｃｏ、ＲＥＭ、Ｃａ、Ｙを含有する場合において、これらの中でＣ、Ｓｉ、Ｍｎ、Ｃｒ、Ｍｏ、Ｖ、Ｂ、Ｐ、Ｓが所定の関係式を満たした場合にスポット溶接部の破断形態がナゲット外破断を呈しやすくなることを見出した。 Next, when the spot weldability was investigated, when the hot-pressed and hardened steel plate was spot-welded, the strength of the welded part and the heat-affected zone changes with respect to the strength of the base metal due to the thermal history of the welded part. When the joint strength was evaluated, it was found that the fracture form of the spot welded part may exhibit a peeling rupture in which the welded part (nugget) does not remain or an external nugget rupture in which the nugget remains. And C, Si, Mn, P, S, Al, N, Cr, V, B, Mg, Ti, Nb, Zr, Mo, W, Cu, Ni, Co, REM, Ca, Y are contained in the steel In this case, when C, Si, Mn, Cr, Mo, V, B, P, and S satisfy a predetermined relational expression, the fracture form of the spot welded portion is likely to exhibit an outer nugget fracture. I found.
以上の知見を元に鋼板の添加成分を最適化し、かつ相互の添加量比を所定の範囲にすることで、所望の特性を有する熱間プレス用鋼板が得られる。 以下に本発明を詳細に説明する。
まず、以下に鋼の各成分を、所定の範囲に限定する理由について述べる。
Based on the above knowledge, a steel sheet for hot pressing having desired characteristics can be obtained by optimizing the additive components of the steel sheet and setting the mutual additive amount ratio within a predetermined range. The present invention is described in detail below.
First, the reason why each component of steel is limited to a predetermined range will be described below.
Ｃは、熱間プレス、焼き入れ後の部品強度に影響を及ぼす重要な元素であり、０．１５％未満では、十分な強度が確保できない。また、０．３％を超えると打抜き時のクラック発生の起点となるセメンタイトを増加させるため、遅れ破壊を生じやすくするため、０．１５〜０．３％とした。 C is an important element that affects the strength of parts after hot pressing and quenching, and if it is less than 0.15%, sufficient strength cannot be secured. Further, if it exceeds 0.3%, the cementite that becomes the starting point of crack generation at the time of punching is increased, so that it is easy to cause delayed fracture, so the content was made 0.15 to 0.3%.
Ｓｉは、熱間プレス、焼き入れ性に影響する元素であり、かつセメンタイト析出を抑制する元素であるが、０．００５％未満では十分な効果を得ることができない。また、１．０％を超えると鋼板製造工程における熱間圧延でのスケール除去にコストがかかり経済的に不利となり、まためっき、特に亜鉛めっきのめっき濡れ性が低下し、外観が劣化するため、１．０％を上限とした。 Si is an element that affects hot pressing and hardenability, and is an element that suppresses cementite precipitation, but if it is less than 0.005%, a sufficient effect cannot be obtained. Also, if it exceeds 1.0%, the scale removal in hot rolling in the steel sheet manufacturing process is costly and economically disadvantageous, and the plating wettability of plating, particularly galvanizing, decreases, and the appearance deteriorates. The upper limit was 1.0%.
Ｍｎは、熱間プレス、焼き入れ性に影響する元素であり、鋼板の強度上昇に有効である。しかし、０．０１％未満ではこの効果が得られないので、下限値を０．０１％とした。また、３．０％を超えるとＰ、Ｓとの共偏析を助長し、スポット溶接部の脆化を招き破断形態を悪化させるため３．０％を上限値とする。 Mn is an element that affects hot press and hardenability, and is effective in increasing the strength of the steel sheet. However, since this effect cannot be obtained if the content is less than 0.01%, the lower limit is set to 0.01%. On the other hand, if it exceeds 3.0%, co-segregation with P and S is promoted, leading to embrittlement of the spot weld and worsening of the fracture form, so 3.0% is made the upper limit.
Ｐは、粒界偏析による粒界破壊の助長をする元素であり、低い方が望ましいが、０．００５％未満にしようとすると、製造工程における製鋼でのコスト上昇を招くため好ましくない。また０．１％を超えると粒界破壊の助長、スポット溶接部の脆化を招くため、上限を０．１％とする。 P is an element that promotes intergranular fracture due to intergranular segregation, and a lower value is desirable. However, if it is attempted to make it less than 0.005%, it is not preferable because it causes an increase in the cost of steelmaking in the production process. On the other hand, if it exceeds 0.1%, intergranular fracture will be promoted and spot welds will become brittle, so the upper limit is made 0.1%.
Ｓは、ＭｎＳ等の非金属介在物を生成し、打抜き性を劣化させたり、腐食環境下での水素吸収を助長する元素であり、低い方が望ましいが、極低化は製造コスト上好ましくないため０．０２％以下とする。 S is an element that generates non-metallic inclusions such as MnS, deteriorates punchability, or promotes hydrogen absorption in a corrosive environment, and is preferably low, but extremely low is not preferable in terms of manufacturing cost. Therefore, it is made 0.02% or less.
Ｍｇは、添加により酸化物等の複合化合物を形成するが、これらの複合化合物が遅れ破壊の要因となるＨのトラップサイトとなるため、耐遅れ破壊性の向上に効果的である。また同時に形成されたＭｇの化合物は微細なため、打抜き面の粗大なクラックの発生を抑制するのに有効となる。ただし、０．０００２％未満の添加ではその効果が不十分である。また、０．０１％を超えると粗大な化合物を形成し添加量に対する効果代が飽和させるため上限を０．０１％とした。 Mg forms complex compounds such as oxides when added, but these complex compounds serve as H trap sites that cause delayed fracture, which is effective in improving delayed fracture resistance. Further, since the Mg compound formed at the same time is fine, it is effective in suppressing the occurrence of coarse cracks on the punched surface. However, if less than 0.0002% is added, the effect is insufficient. On the other hand, if it exceeds 0.01%, a coarse compound is formed, and the effect on the amount added is saturated, so the upper limit was made 0.01%.
Ａｌは、脱酸のため０．０１％以上を添加するが、添加量が増加するとアルミナ等の介在物が増加し、打抜き面の粗大クラック発生の要因となるため上限を３．０％とした。 Al is added in an amount of 0.01% or more for deoxidation. Increasing the addition amount increases inclusions such as alumina, which causes generation of coarse cracks on the punched surface, so the upper limit was made 3.0%. .
Ｎは、添加量が多くなると粗大化合物を生成するため、打抜き面の粗大クラックの発生を招いたり、後述のＢと結合してＢＮを生成し、Ｂ添加の効果を低下させるため、添加は少ない方が望ましい。特に０．０１％を越えるとその影響が顕著となるため、上限を０．０１％とした。 Since N produces a coarse compound when the amount of addition increases, it causes the occurrence of coarse cracks on the punched surface, or forms BN by combining with B described later, thereby reducing the effect of B addition, so the addition is small. Is preferable. In particular, when the content exceeds 0.01%, the effect becomes significant, so the upper limit was made 0.01%.
Ｃｒは、鋼板の焼き入れ性を高める元素であり、熱間プレス、焼き入れ後の強度確保のために必要である。しかし、０．０２％未満ではこれらの効果が得られないため、下限値を０．０２％とした。また、多量の添加は焼き入れ性が飽和するだけでなく、耐食性（孔食性）を悪化させ、遅れ破壊感受性を高める恐れがあるため、０．５％を上限とする。 Cr is an element that enhances the hardenability of the steel sheet, and is necessary for ensuring the strength after hot pressing and quenching. However, since these effects cannot be obtained if the content is less than 0.02%, the lower limit is set to 0.02%. Further, addition of a large amount not only saturates the hardenability but also deteriorates the corrosion resistance (pitting corrosion property) and may increase the delayed fracture susceptibility, so the upper limit is made 0.5%.
Ｂは、焼き入れ性を向上させるのに有効な元素であり、耐遅れ破壊性やスポット溶接性を劣化させる傾向にあるＣの多量な添加を抑制するのに有効である。このような効果を有効にするためには、０．０００２％以上の添加が必要ある。しかし、過多に添加してもその効果は飽和するので、０．０１％を上限とした。 B is an element effective for improving the hardenability, and is effective for suppressing the addition of a large amount of C which tends to deteriorate delayed fracture resistance and spot weldability. In order to make such an effect effective, 0.0002% or more must be added. However, the effect is saturated even if added excessively, so 0.01% was made the upper limit.
Ｖ、Ｔｉ、Ｎｂ、Ｚｒは強炭化物生成元素であり、析出物や介在物を生成させて熱間プレス、焼き入れした部材の強度を確保するとともに鋼中に侵入する拡散性水素のトラップサイトとなり耐遅れ破壊性を改善するために必要な元素である。 V, Ti, Nb, and Zr are strong carbide-forming elements, which form precipitates and inclusions to ensure the strength of hot-pressed and quenched parts and serve as trapping sites for diffusible hydrogen that penetrates into steel. It is an element necessary for improving delayed fracture resistance.
Ｖは、０．００２％未満の添加ではこの効果が得られないために、下限値を０．００２％とした。また、０．５％を超えると炭窒化物の析出が顕著になり、打抜き面の粗大クラック発生の要因となるため、上限を０．５％とした。 Since this effect cannot be obtained when V is added in an amount of less than 0.002%, the lower limit is set to 0.002%. On the other hand, if the content exceeds 0.5%, the precipitation of carbonitrides becomes prominent and causes coarse cracks on the punched surface, so the upper limit was made 0.5%.
Ｔｉ、Ｎｂ、Ｚｒは、０．００２％未満では析出物の個数が少なくなり遅れ破壊性改善の効果が得られないため、下限値を０．００２％とした。また、０．５％を超えると粗大析出または昇出物が生成するために、打抜き面の粗大クラック発生の要因となるため、上限を０．５％とした。 If Ti, Nb, and Zr are less than 0.002%, the number of precipitates decreases and the effect of improving delayed fracture property cannot be obtained. Therefore, the lower limit is set to 0.002%. On the other hand, if it exceeds 0.5%, coarse precipitates or extrudates are produced, which causes generation of coarse cracks on the punched surface, so the upper limit was made 0.5%.
Ｍｏは、焼入れ性を向上させるのに有効でかつ、粒界を強化して遅れ破壊発生を抑制する効果がある。しかし、０．００５％未満ではこれらの効果が得られないため、下限を０．００５％とした。また、添加量が１．０％を超えると効果が飽和するため、上限値を１．０％とした。 Mo is effective in improving hardenability and has the effect of strengthening grain boundaries and suppressing delayed fracture. However, since these effects cannot be obtained at less than 0.005%, the lower limit was made 0.005%. Moreover, since an effect will be saturated when the addition amount exceeds 1.0%, the upper limit is set to 1.0%.
Ｗは、水溶液中で溶解して生じたタングステン酸イオンの吸着作用により、耐食性（孔食性）を高める効果があり、耐遅れ破壊特性の改善に有効な元素である。しかし、０．００５％未満ではこれらの効果が得られないため、下限を０．００５％とした。また、１％を超えるとその効果が飽和するのみであるので、上限を１．０％とした。 W is an element that has an effect of improving corrosion resistance (pitting corrosion resistance) due to the action of adsorbing tungstate ions generated by dissolution in an aqueous solution, and is effective in improving delayed fracture resistance. However, since these effects cannot be obtained at less than 0.005%, the lower limit was made 0.005%. Moreover, since the effect will only be saturated if it exceeds 1%, the upper limit was made 1.0%.
Ｃｕは、生成錆を緻密化して腐食環境下における腐食速度を著しく低減し、かつ、Ｃｕの微細析出は遅れ破壊の向上にも寄与する元素である。しかし、０．００５％未満の低下ではこれらの効果が得られないので下限を０．００５％とした。また、過剰の添加は製造工程における熱間圧延時の脆化を引き起こし、また表面欠陥（Ｃｕヘゲ）が生じる可能性があるため、添加量の上限を２．０％とした。また、Ｃｕの熱間圧延時の脆化や表面欠陥を抑制するためには、後述するようにＮｉと併せて添加するのが望ましい。 Cu is an element that densifies the generated rust and significantly reduces the corrosion rate in a corrosive environment, and the fine precipitation of Cu contributes to the improvement of delayed fracture. However, since these effects cannot be obtained with a decrease of less than 0.005%, the lower limit was made 0.005%. Further, excessive addition causes embrittlement during hot rolling in the manufacturing process and may cause surface defects (Cu hege), so the upper limit of the addition amount was set to 2.0%. Further, in order to suppress embrittlement and surface defects during hot rolling of Cu, it is desirable to add together with Ni as described later.
Ｎｉは、Ｎｉ硫化物が拡散性水素の侵入を抑制し耐遅れ破壊特性を向上させる効果や前述のＣｕ添加した場合に生じる脆化や表面欠陥（Ｃｕヘゲ）の抑制するのに有効な元素である。しかし、添加量が０．００５％未満ではこれらの効果が得られないため、下限を０．００５％とした。また、２．０％を超える添加は効果が飽和するとともに、コストアップを招くため、上限を２．０％とした。なお、熱間圧延時の脆化や表面欠陥に対するＮｉ添加の効果はＣｕの添加量に応じて発揮されるため、ＮｉはＮｉ／Ｃｕ：０．２５〜０．６０の範囲で添加することが望ましい。 Ni is an element effective for Ni sulfide to suppress diffusion of diffusible hydrogen and improve delayed fracture resistance, and to suppress embrittlement and surface defects (Cu heges) that occur when Cu is added. It is. However, if the addition amount is less than 0.005%, these effects cannot be obtained, so the lower limit was made 0.005%. Moreover, since addition exceeding 2.0% will saturate the effect and increase the cost, the upper limit was made 2.0%. In addition, since the effect of Ni addition with respect to the embrittlement and surface defect at the time of hot rolling is exhibited according to the addition amount of Cu, Ni may be added in the range of Ni / Cu: 0.25-0.60. desirable.
Ｃｏは耐食性を高める効果を有した元素であり、耐遅れ破壊性の向上に寄与する。しかし、０．００５％未満ではその効果が得られないため、下限を０．００５％とした。また、過剰の添加はＣｏが高価な元素であることからコストアップを招くため、上限を２．０％とした。 Co is an element having an effect of improving corrosion resistance, and contributes to improvement of delayed fracture resistance. However, since the effect cannot be obtained if it is less than 0.005%, the lower limit was made 0.005%. Further, excessive addition causes cost increase because Co is an expensive element, so the upper limit was made 2.0%.
ＲＥＭ、Ｃａ、Ｙは、鋼中の介在物の形態制御に有効で、耐遅れ破壊性に寄与することから、０．０００５％以上の添加とした。一方、過剰添加は熱間加工性を劣化させるため、０．０１％以下の添加とする。 REM, Ca, and Y are effective for controlling the form of inclusions in steel and contribute to delayed fracture resistance, so 0.0005% or more was added. On the other hand, excessive addition deteriorates hot workability, so 0.01% or less is added.
次にＭｇを含む酸化物または硫化物と、それらと複合晶出または析出した化合物について説明する。本発明では、鋼板中に存在する酸化物とこれらを核とした複合晶出・析出物を均一分散させることにより打抜き時の粗大なクラックの発生を抑制し、かつこれらの酸化物とこれらを核とした複合晶出・析出物が、遅れ破壊の要因と考えられている拡散性水素のトラップサイトとなり、その部分に水素がトラップされるため拡散性水素濃度が下がることにより遅れ破壊の感受性が下がる効果を発揮するために、鋼板中に存在する酸化物とこれらを核とした複合晶出・析出物のサイズ（平均粒径）と存在状態（密度）が重要となる。 Next, an oxide or sulfide containing Mg and a compound crystallized or precipitated with them will be described. In the present invention, the generation of coarse cracks at the time of punching is suppressed by uniformly dispersing oxides present in the steel sheet and composite crystallization / precipitates having these as nuclei, and these oxides and these are nucleated. The combined crystallization and precipitates become a diffusible hydrogen trap site that is considered to be a cause of delayed fracture, and hydrogen is trapped in that part, so the susceptibility to delayed fracture decreases as the concentration of diffusible hydrogen decreases. In order to exert an effect, the size (average particle diameter) and the presence state (density) of the oxides present in the steel sheet, and the composite crystallization / precipitate with these as nuclei are important.
平均粒径は、水素のトラップサイトとしてはある程度の大きさが必要であり、かつ、微細な粒子を多量に存在させることは困難となることから下限を０．０１μｍとした。また、粗大な粒子は拡散性水素のトラップサイトとしての作用がなくなる上、打抜き破断面の粗大クラックの起点となり得るので上限を５．０μｍとした。 The average particle diameter needs to be a certain size as a hydrogen trap site, and since it is difficult to make a large amount of fine particles present, the lower limit is set to 0.01 μm. In addition, the coarse particles have no action as trapping sites for diffusible hydrogen, and can be the starting point of coarse cracks in the punched fracture surface, so the upper limit was set to 5.0 μm.
粒子の密度は、１×１０2 個〜１×１０7 個／ｍｍ2 とした。粒子密度が低いと、拡散性水素のトラップサイト数が少なくなり、耐遅れ破壊性を確保できないため、下限を１×１０2 個／ｍｍ2 とした。また、粒子密度が高くなると、打抜き加工面に粗大クラックが発生し、耐遅れ破壊性を確保できなくなる可能性があるので、上限を１×１０7 個／ｍｍ2 とした。 The density of the particles was 1 × 10 2 to 1 × 10 7 particles / mm 2 . When the particle density is low, the number of diffusible hydrogen trap sites decreases, and delayed fracture resistance cannot be ensured, so the lower limit was set to 1 × 10 2 particles / mm 2 . Further, when the particle density is increased, coarse cracks are generated on the punched surface, and delayed fracture resistance may not be ensured. Therefore, the upper limit is set to 1 × 10 7 pieces / mm 2 .
Ｍｇ化合物を含む粒子の状態は、例えば以下の方法により定量的に測定される。鋼板の任意の場所から抽出レプリカのサンプルを作成し、透過型電子顕微鏡（ＴＥＭ）にて、５０００〜１０００００倍の倍率で観察を行い、最低３０視野を測定することで得られる値とする。粒子径は、画像解析による円相当径にて評価する。また、密度を求める際には、複合析出または晶出物は１ヶとして数える。化合物の組成同定は、ＴＥＭに付属のエネルギー分散型Ｘ線分光法（ＥＤＳ）を用いて行う。各複合化合物は、Ｍｇの他合金添加元素（例えばＴｉ, Ｎｂ, Ｖ，Ｃｒ, Ｍｏ, ＲＥＭ, Ｃａなど）を含有した化合物（炭化物、窒化物、酸化物や硫化物など) である。 The state of the particles containing the Mg compound is quantitatively measured by, for example, the following method. A sample of an extracted replica is prepared from an arbitrary place on the steel plate, and observed with a transmission electron microscope (TEM) at a magnification of 5000 to 100000 times to obtain a value obtained by measuring at least 30 fields of view. The particle diameter is evaluated by the equivalent circle diameter by image analysis. Moreover, when calculating | requiring a density, a composite precipitation or a crystallization thing is counted as one piece. The composition of the compound is identified using energy dispersive X-ray spectroscopy (EDS) attached to the TEM. Each composite compound is a compound (a carbide, a nitride, an oxide, a sulfide, or the like) containing an alloy addition element (for example, Ti, Nb, V, Cr, Mo, REM, Ca, etc.) in addition to Mg.
さらに本発明においては、上記各成分のうち、Ｃ、Ｓｉ、Ｍｎ、Ｃｒ、Ｍｏ、Ｖ、Ｂ、Ｐ、Ｓの各添加量が下記式（Ａ）を満足することが重要となる。
０．３５≧Ｃ＋Si/30+Mn/20+Cr/20+Mo/15+V/10＋４・Ｂ＋２・Ｐ＋４・Ｓ ……（Ａ）
Furthermore, in the present invention, among the above components, it is important that the addition amounts of C, Si, Mn, Cr, Mo, V, B, P, and S satisfy the following formula (A).
0.35 ≧ C + Si / 30 + Mn / 20 + Cr / 20 + Mo / 15 + V / 10 + 4 ・ B + 2 ・ P + 4 ・ S ...... (A)
式（Ａ）の値が０．３５を超えるとスポット溶接部のピール試験（ＪＩＳ Ｚ３１４４）にて破断形態を評価した場合、スポット溶接部の破断形態が、溶接部（ナゲット）が残らない剥離破断する場合が多くなる。本発明者らは、実験室にて鋼中成分としてＣ、Ｓｉ、Ｍｎ、Ｐ、Ｓ、Ａｌ、Ｎ、Ｃｒ、Ｖ、Ｂ、Ｍｇ、Ｔｉ、Ｎｂ、Ｚｒ、Ｍｏ、Ｗ、Ｃｕ、Ｎｉ、Ｃｏ、ＲＥＭ、Ｃａ、Ｙを含有する鋼板において、これらの中でＣ、Ｓｉ、Ｍｎ、Ｃｒ、Ｍｏ、Ｖ、Ｂ、Ｐ、Ｓの量を変化させた種々の成分組成を有する鋼板を用いて、スポット溶接部の破断形態と上記式（Ａ）の右辺の値との関係を調査した。その結果を図１に示した。 When the value of the formula (A) exceeds 0.35, when the fracture form is evaluated by a peel test (JIS Z3144) of the spot welded part, the fracture form of the spot welded part does not leave the welded part (nugget). There are many cases to do. In the laboratory, we have C, Si, Mn, P, S, Al, N, Cr, V, B, Mg, Ti, Nb, Zr, Mo, W, Cu, Ni, In steel plates containing Co, REM, Ca, and Y, steel plates having various component compositions in which the amounts of C, Si, Mn, Cr, Mo, V, B, P, and S are changed are used. The relationship between the fracture form of the spot weld and the value on the right side of the above formula (A) was investigated. The results are shown in FIG.
横軸は、上記式（Ａ）のうち、Ｃ、Ｓｉ、Ｍｎ、Ｃｒ、Ｍｏ、Ｖ、Ｂに関する値の和であり、縦軸は、上記式（Ａ）のうちＰ、Ｓに関する値の和である。図１より、式（Ａ）が成り立つ場合、すなわち、Ｃ、Ｓｉ、Ｍｎ、Ｃｒ、Ｍｏ、Ｖ、Ｂ、Ｐ、Ｓの添加量が本発明に従う場合には、破断形態はナゲット外破断あるいは、一部ナゲット内破断であることが判明した。これは、Ｃ、Ｓｉ、Ｍｎ、Ｃｒ、Ｍｏ、Ｖ、Ｂ、は、溶接部および熱影響部の強度を高めるため、またＰ、Ｓは、溶接時の入熱により粒界への偏析を生じやすくなるため、過剰に添加されると溶接部を脆化させ、剥離破断の傾向となるものと考えられる。剥離破断は溶接部の接合強度が母材の強度より低くなる場合もあるため、部品の性能の信頼性を損なう可能性もある。このため、部品性能の信頼性を確保するためには、上記式（Ａ）を満足することが重要となる。式（Ａ）を満足する場合、破断形態は一部ナゲット内破断もしくは、ナゲット外破断となり、溶接部（ナゲット）が一方の鋼板に残存する破断形態となる。 The horizontal axis is the sum of values related to C, Si, Mn, Cr, Mo, V, and B in the above formula (A), and the vertical axis is the sum of values related to P and S in the above formula (A). It is. From FIG. 1, when the formula (A) is satisfied, that is, when the addition amount of C, Si, Mn, Cr, Mo, V, B, P, S is in accordance with the present invention, the fracture mode is the nugget fracture or Part of the nugget was found to break. This is because C, Si, Mn, Cr, Mo, V, and B increase the strength of the welded part and heat-affected zone, and P and S cause segregation to the grain boundary due to heat input during welding. Therefore, it is considered that when added excessively, the welded portion becomes brittle and tends to peel and break. In the case of peeling fracture, since the joint strength of the welded portion may be lower than the strength of the base material, the reliability of the performance of the component may be impaired. For this reason, in order to ensure the reliability of the component performance, it is important to satisfy the above formula (A). When the expression (A) is satisfied, the fracture mode is a partial fracture in the nugget or an external nugget fracture, and a fracture mode in which the welded portion (nugget) remains in one of the steel plates.
本発明の高強度鋼板の製造方法は、その各種条件が、用途や必要特性に応じて、適宜選択され得るものである。
例えば、以下の方法に従って高強度鋼板を製造することができる。まず、転炉で上記成分組成の範囲で調整された鋼を溶製し、連続鋳造法によりスラブとなす。このスラブを高温状態のまま、あるいは、室温まで冷却した後、加熱炉に挿入し、１０００〜１２５０℃の温度範囲で仕上圧延を行い、次いで７００℃以下の温度で巻き取って熱延鋼板とする。次いで、酸洗、冷延後、焼鈍を行い冷延鋼板とする。高強度表面処理鋼板の場合は、さらに、熱延鋼板または冷延鋼板にめっきを施す。焼鈍は、７００℃以上９００℃未満が好ましい。７００℃未満では、十分な再結晶が行われず、母材の均一性が安定的に得られ難い。このため、焼鈍温度は７００℃を下限とする。また、９００℃を超えると通板性等の製造上の問題が生じる可能性があるため、９００℃を上限とする。
In the method for producing a high-strength steel sheet according to the present invention, various conditions can be appropriately selected according to the use and required characteristics.
For example, a high-strength steel plate can be manufactured according to the following method. First, steel adjusted in the range of the above-mentioned component composition is melted in a converter and made into a slab by a continuous casting method. After this slab is kept in a high temperature state or cooled to room temperature, it is inserted into a heating furnace, finish-rolled in a temperature range of 1000 to 1250 ° C., and then wound up at a temperature of 700 ° C. or less to obtain a hot-rolled steel sheet. . Next, after pickling and cold rolling, annealing is performed to obtain a cold rolled steel sheet. In the case of a high-strength surface-treated steel sheet, the hot-rolled steel sheet or the cold-rolled steel sheet is further plated. The annealing is preferably 700 ° C or higher and lower than 900 ° C. If it is less than 700 degreeC, sufficient recrystallization will not be performed but the uniformity of a base material will be hard to be obtained stably. For this reason, the annealing temperature has a lower limit of 700 ° C. Further, if it exceeds 900 ° C., production problems such as plate-through property may occur, so 900 ° C. is the upper limit.
自動車用として使用される高強度表面処理鋼板は、その多くが溶融亜鉛めっき鋼板である。鋼板に溶融亜鉛めっきを施す場合は、通常、焼鈍と同じ設備（又は同一設備列）で同時に行う。鋼板表面に施すメッキは３５ｍｇ／ｍ2 〜８００ｍｇ／ｍ2 である。３５ｍｇ／ｍ2 未満では、熱間プレス焼き入れ工程にて亜鉛めっきの一部が蒸発してしまい、防食作用が無くなり、めっきの目的を果たすことができない。また、８００ｍｇ／ｍ2 を超えると、溶接時にブローホール等の欠陥が著しく発生しやすくなる。それ故、めっき量は３５ｍｇ／ｍ2 〜８００ｍｇ／ｍ2 の範囲とする。
また、焼鈍の後、電気めっきを施した場合にも溶融亜鉛めっきを焼鈍と同時に行った場合と同様に、本発明の効果は損なわれない。
次に実施例について述べる。
Many of the high-strength surface-treated steel sheets used for automobiles are hot-dip galvanized steel sheets. When hot dip galvanizing is applied to a steel sheet, it is usually performed simultaneously with the same equipment (or the same equipment row) as annealing. Plating applied to the steel sheet surface is 35mg / m 2 ~800mg / m 2 . If it is less than 35 mg / m < 2 >, a part of zinc plating will evaporate in a hot press hardening process, corrosion protection will be lose | eliminated, and the objective of plating cannot be achieved. Moreover, when it exceeds 800 mg / m < 2 >, defects, such as a blowhole, will generate | occur | produce remarkably at the time of welding. Therefore, the plating amount is in the range of 35mg / m 2 ~800mg / m 2 .
In addition, even when electroplating is performed after annealing, the effect of the present invention is not impaired as in the case where hot dip galvanizing is performed simultaneously with annealing.
Next, examples will be described.
表１に示す成分組成の鋼を転炉で溶製し、常法に従い連続鋳造でスラブとした。これらのスラブを加熱炉中で１１４０℃〜１２５０℃の温度で加熱し、８１０℃〜８８０℃の仕上げ温度で熱間圧延を行い、６００℃〜６６０℃にて巻き取り、高強度熱延鋼板（板厚：１．８ｍｍ）とした。さらに、一部のものについては、酸洗後に冷間圧延、焼鈍（焼鈍温度：７２０℃）を施し、高強度冷延鋼板（板厚：１．２ｍｍ）とした。その後、一部の鋼板については、溶融亜鉛めっき（目付け量：９０ｇ／ｍ2 ）を施した。製造された鋼板中の析出化合物の平均粒径、密度を透過電子顕微鏡により測定した。これらの結果を表１に示す。 Steels having the component compositions shown in Table 1 were melted in a converter and slabs were obtained by continuous casting according to a conventional method. These slabs are heated in a heating furnace at a temperature of 1140 ° C to 1250 ° C, hot-rolled at a finishing temperature of 810 ° C to 880 ° C, wound up at 600 ° C to 660 ° C, and a high-strength hot-rolled steel sheet ( (Plate thickness: 1.8 mm). Furthermore, about some, after pickling, cold rolling and annealing (annealing temperature: 720 degreeC) were given, and it was set as the high intensity | strength cold-rolled steel plate (plate thickness: 1.2 mm). Thereafter, some of the steel plates were hot dip galvanized (weight per unit area: 90 g / m 2 ). The average particle diameter and density of the precipitated compound in the produced steel plate were measured with a transmission electron microscope. These results are shown in Table 1.
上記の鋼板を用い、加熱炉にて９５０℃×５ｍｉｎの条件にて加熱を行い、ハット形状品の熱間プレスを実施し、部材強度１４７０ＭＰａクラスの部品を採取した。（ハット形状：幅１００ｍｍ、長さ：３００ｍｍ、高さ：６０ｍｍ）このプレス品より、評価サンプルを切り出し、熱間プレス、焼き入れ後の引っ張り強度、遅れ破壊特性、スポット溶接性を評価した。引っ張り試験は、ＪＩＳ Ｚ ２２０１に従って実施した。 Using the above steel plate, heating was performed in a heating furnace under the condition of 950 ° C. × 5 min, and a hat-shaped product was hot-pressed, and a component having a member strength of 1470 MPa class was collected. (Hat shape: width 100 mm, length: 300 mm, height: 60 mm) An evaluation sample was cut out from this press product, and hot press, tensile strength after quenching, delayed fracture characteristics, and spot weldability were evaluated. The tensile test was performed according to JIS Z 2201.
遅れ破壊特性は、自動車部品の切断工程に準じるように、８０ｍｍ×３０ｍｍのサイズにシャー切断したサンプルを曲げ加工し、応力を開放した状態でサンプル曲げ加工部の外側表面に耐水性を有するひずみゲージを張った。この後、サンプルにキリ穴を開け、このキリ穴にボルトを通し、該ボルトを締め、曲げ部に応力を負荷した。負荷応力は５９０ＭＰａとした。鋼板のヤング率を２０５８００ＭＰａとし、応力σは、σ＝Ｅ・εなる式がσが５９０ＭＰａとなる歪を与えた。この後、該サンプルを０．５mol/l の硫酸中に漬け、電解チャージ（電流密度40mA/cm2）を行って水素を発生させ、割れ発生の状況を調査した。割れの判定は、応力を負荷するときに使用したひずみゲージをそのまま使用し、電解チャージ中のひずみの変化を測定した。割れが発生していない場合にはひずみの値に変化はないが、割れが発生すると歪が変化する。電解チャージ時間は最大１２０ｍｉｎとし、割れ発生の有無を評価した。結果を表２に示した。 Delayed fracture characteristics are strain gauges that have a water resistance on the outer surface of the sample bending part after bending the sheared sample to a size of 80 mm x 30 mm and releasing the stress in accordance with the cutting process of automobile parts. I stretched. Thereafter, a drill hole was made in the sample, a bolt was passed through the drill hole, the bolt was tightened, and a stress was applied to the bent portion. The load stress was 590 MPa. The Young's modulus of the steel sheet was 205800 MPa, and the stress σ was given a strain such that σ = E · ε was σ = 590 MPa. Thereafter, the sample was immersed in 0.5 mol / l sulfuric acid and subjected to electrolytic charging (current density 40 mA / cm 2 ) to generate hydrogen, and the occurrence of cracks was investigated. For the determination of cracking, the strain gauge used when applying stress was used as it was, and the change in strain during electrolytic charging was measured. When no crack is generated, there is no change in the strain value, but when the crack is generated, the strain changes. The electrolytic charging time was set to 120 min at maximum, and the presence or absence of cracking was evaluated. The results are shown in Table 2.
スポット溶接性の評価は、ＪＩＳ Ｚ ３１４４に従うピール試験によって行った。溶接には、定置式スポット溶接機を使用い、加圧力：４．４ｋＮ、通電時間：０．３ｓ、保持時間：０．０８ｓとし、電流値は、各鋼種にてナゲット径が４√ｔ（ｔ：板厚ｍｍ）の大きさになるように設置した。結果を表２に示した。 The spot weldability was evaluated by a peel test according to JIS Z 3144. For the welding, a stationary spot welder is used. The applied pressure is 4.4 kN, the energization time is 0.3 s, the holding time is 0.08 s, and the current value is 4√t ( t: plate thickness mm). The results are shown in Table 2.
表１結果から、本発明鋼の範囲では、焼き入れ後の引っ張り強度が約１４７０ＭＰａ程度以上となっており、所望の部品強度を有することが確認された。これに対し、本発明の範囲から外れた場合には、引っ張り強度が低くなった。表２の結果から、本発明鋼の範囲では、遅れ破壊特性、スポット溶接性をともに満足するが、本発明の範囲から外れた場合には、両者の特性を同時に満足することができず、本発明鋼が所望の特性を満足することがわかる。 From the results of Table 1, the tensile strength after quenching was about 1470 MPa or more in the range of the steel of the present invention, and it was confirmed that the steel had the desired component strength. On the other hand, when it was outside the scope of the present invention, the tensile strength was low. From the results of Table 2, both the delayed fracture characteristics and the spot weldability are satisfied within the range of the steel of the present invention. However, if they are outside the range of the present invention, both characteristics cannot be satisfied at the same time. It can be seen that the inventive steel satisfies the desired properties.
Claims (9)
Ｃ ：０．１５〜０．３％、
Ｓｉ：０．００５〜１．０％、
Ｍｎ：０．０１〜３．０％、
Ｐ ：０．００５〜０．１％、
Ｓ ：０．０２％以下、
Ａｌ：０．０１％〜３．０％、
Ｎ ：０．０１％以下、
Ｃｒ：０．０２〜０．５％、
Ｖ：０．００２〜０．５％、
Ｂ：０．０００２〜０．０１％、
Ｍｇ：０．０００２％〜０．０１％
を含有し、残部が鉄および不可避的不純物からなる鋼で、鋼中に平均粒径が０．０１〜５．０μｍの範囲にあるＭｇの酸化物、硫化物、複合晶出物および複合析出物のいずれか１種もしくは２種以上の複合酸化物を、１平方ｍｍ当り１×１０2 個〜１×１０7 個含み、かつ、下記式（Ａ）を満足することを特徴とする熱間プレス用高強度鋼板。
０．３５≧Ｃ＋Si/30+Mn/20+Cr/20+Mo/15+V/10＋４・Ｂ＋２・Ｐ＋４・Ｓ ……（Ａ）
In mass%
C: 0.15-0.3%
Si: 0.005 to 1.0%,
Mn: 0.01 to 3.0%,
P: 0.005-0.1%,
S: 0.02% or less,
Al: 0.01% to 3.0%,
N: 0.01% or less,
Cr: 0.02 to 0.5%,
V: 0.002 to 0.5%,
B: 0.0002 to 0.01%
Mg: 0.0002% to 0.01%
Mg, oxides, sulfides, composite crystallized products, and composite precipitates containing steel and the balance being iron and inevitable impurities, and having an average particle size in the range of 0.01 to 5.0 μm in the steel A hot press characterized by containing 1 × 10 2 to 1 × 10 7 complex oxides per square mm and satisfying the following formula (A): High strength steel plate.
0.35 ≧ C + Si / 30 + Mn / 20 + Cr / 20 + Mo / 15 + V / 10 + 4 ・ B + 2 ・ P + 4 ・ S ...... (A)
Ｔｉ：０．００２〜０．５％、
Ｎｂ：０．００２〜０．５％、
Ｚｒ: ０．００２〜０．５％
の１種または２種以上を含有し、残部が鉄および不可避的不純物からなる鋼であることを特徴とする請求項１に記載の熱間プレス用高強度鋼板。 Furthermore, in mass%,
Ti: 0.002 to 0.5%,
Nb: 0.002 to 0.5%,
Zr: 0.002 to 0.5%
The high-strength steel sheet for hot pressing according to claim 1, wherein the steel is one or more of the following, and the balance is iron and iron unavoidable impurities.
Ｍｏ：０．００５〜１％、
Ｗ ：０．００５〜１％
の１種または２種以上を含有し、残部が鉄および不可避的不純物からなる鋼であることを特徴とする請求項１または２に記載の熱間プレス用高強度鋼板。 Furthermore, in mass%,
Mo: 0.005 to 1%,
W: 0.005 to 1%
The high-strength steel sheet for hot pressing according to claim 1 or 2, wherein the steel is made of iron and unavoidable impurities.
Ｃｕ：０．００５〜２．０％
を含有し、残部が鉄および不可避的不純物からなる鋼であることを特徴とする請求項１〜３に記載の熱間プレス用高強度鋼板。 Furthermore, in mass%,
Cu: 0.005 to 2.0%
The high-strength steel sheet for hot press according to claim 1, wherein the balance is steel made of iron and inevitable impurities.
Ｎｉ：０．００５〜２．０％、
Ｃｏ：０．００５〜２．０％
の１種または２種以上を含有し、残部が鉄および不可避的不純物からなる鋼であることを特徴とする請求項１〜４に記載の熱間プレス用高強度鋼板。 Furthermore, in mass%,
Ni: 0.005 to 2.0%,
Co: 0.005 to 2.0%
The high-strength steel sheet for hot press according to claim 1, wherein the steel is made of iron and unavoidable impurities.
ＲＥＭ：０．０００５〜０．０１％、
Ｃａ：０．０００５〜０．０１％、
Ｙ ：０．０００５〜０．０１％
の１種または２種以上を含有し、残部が鉄および不可避的不純物からなる鋼であることを特徴とする請求項１〜５に記載の熱間プレス用高強度鋼板。 Furthermore, in mass%,
REM: 0.0005 to 0.01%,
Ca: 0.0005 to 0.01%,
Y: 0.0005 to 0.01%
The high-strength steel sheet for hot pressing according to claim 1, wherein the steel is made of iron and inevitable impurities.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004190827A JP4317491B2 (en) | 2004-06-29 | 2004-06-29 | Steel sheet for hot press |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004190827A JP4317491B2 (en) | 2004-06-29 | 2004-06-29 | Steel sheet for hot press |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2006009116A true JP2006009116A (en) | 2006-01-12 |
| JP4317491B2 JP4317491B2 (en) | 2009-08-19 |
Family
ID=35776676
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2004190827A Active JP4317491B2 (en) | 2004-06-29 | 2004-06-29 | Steel sheet for hot press |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4317491B2 (en) |
Cited By (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007308745A (en) * | 2006-05-17 | 2007-11-29 | Nissan Motor Co Ltd | High strength member and its manufacturing method |
| JP2008308732A (en) * | 2007-06-14 | 2008-12-25 | Sumitomo Metal Ind Ltd | Hardened steel plate member, steel plate for hardening, and their manufacturing methods |
| JP2010174298A (en) * | 2009-01-28 | 2010-08-12 | Jfe Steel Corp | Steel sheet to be die-quenched superior in hot-punchability |
| JP2010174297A (en) * | 2009-01-28 | 2010-08-12 | Jfe Steel Corp | Steel sheet to be die-quenched superior in hot-punchability |
| JP2010174291A (en) * | 2009-01-28 | 2010-08-12 | Jfe Steel Corp | Steel sheet to be die-quenched superior in hot-punchability |
| JP2010174290A (en) * | 2009-01-28 | 2010-08-12 | Jfe Steel Corp | Steel sheet to be die-quenched superior in hot-punchability |
| JP2010174306A (en) * | 2009-01-28 | 2010-08-12 | Jfe Steel Corp | Steel sheet for die quenching |
| WO2012120692A1 (en) | 2011-03-09 | 2012-09-13 | 新日本製鐵株式会社 | Steel sheets for hot stamping, method for manufacturing same, and method for manufacturing high-strength parts |
| EP2527481A1 (en) * | 2009-12-30 | 2012-11-28 | Hyundai Steel Company | Quenched steel sheet having excellent hot press formability, and method for manufacturing same |
| JP2012237048A (en) * | 2011-05-13 | 2012-12-06 | Nippon Steel Corp | Hot stamping steel plate excellent in hot composite molding property and delayed fracture resistance in punched part thereof, method for manufacturing the same and method for smelting the same |
| WO2013133270A1 (en) | 2012-03-07 | 2013-09-12 | 新日鐵住金株式会社 | Steel sheet for hot stamping, method for producing same, and hot-stamped steel material |
| WO2014142238A1 (en) | 2013-03-14 | 2014-09-18 | 新日鐵住金株式会社 | High strength steel plate with excellent delayed destruction resistance characteristics and low temperature toughness, and high strength member manufactured using same |
| EP2708612A4 (en) * | 2011-05-12 | 2015-08-05 | Nhk Spring Co Ltd | Steel for automotive suspension spring component, automotive suspension spring component, and manufacturing method for same |
| CN105385939A (en) * | 2015-12-15 | 2016-03-09 | 安徽楚江特钢有限公司 | Manufacturing method of high-strength high-tenacity alloy steel |
| CN106834941A (en) * | 2017-01-20 | 2017-06-13 | 唐山钢铁集团有限责任公司 | A kind of hot press-formed steel and its production method |
| CN108411195A (en) * | 2018-03-27 | 2018-08-17 | 本钢板材股份有限公司 | A kind of the hot forming steel plate and preparation method of cold environment punching production |
| WO2019003540A1 (en) * | 2017-06-30 | 2019-01-03 | Ｊｆｅスチール株式会社 | Hot-press member and method for manufacturing same, and cold-rolled steel sheet for hot pressing and method for manufacturing same |
| US10829840B2 (en) | 2014-12-10 | 2020-11-10 | Voestalpine Stahl Gmbh | Steel sheet for hot pressing and hot pressed article using the same |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6733585B2 (en) | 2000-02-01 | 2004-05-11 | Komatsu Denshi Kinzoku Kabushiki Kaisha | Apparatus for pulling single crystal by CZ method |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001207235A (en) * | 2000-01-25 | 2001-07-31 | Kawasaki Steel Corp | High tensile strength hot dip galvanized steel plate and producing method therefor |
| JP2003147499A (en) * | 2001-11-07 | 2003-05-21 | Sumitomo Metal Ind Ltd | Steel sheet for hot press, and production method therefor |
| JP2003166035A (en) * | 2001-11-28 | 2003-06-13 | Nippon Steel Corp | High-strength thin steel sheet superior in delayed fracture resistance after being formed, manufacturing method therefor, and high strength component for automobile made of the high-strength thin steel sheet |
-
2004
- 2004-06-29 JP JP2004190827A patent/JP4317491B2/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001207235A (en) * | 2000-01-25 | 2001-07-31 | Kawasaki Steel Corp | High tensile strength hot dip galvanized steel plate and producing method therefor |
| JP2003147499A (en) * | 2001-11-07 | 2003-05-21 | Sumitomo Metal Ind Ltd | Steel sheet for hot press, and production method therefor |
| JP2003166035A (en) * | 2001-11-28 | 2003-06-13 | Nippon Steel Corp | High-strength thin steel sheet superior in delayed fracture resistance after being formed, manufacturing method therefor, and high strength component for automobile made of the high-strength thin steel sheet |
Cited By (27)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007308745A (en) * | 2006-05-17 | 2007-11-29 | Nissan Motor Co Ltd | High strength member and its manufacturing method |
| JP2008308732A (en) * | 2007-06-14 | 2008-12-25 | Sumitomo Metal Ind Ltd | Hardened steel plate member, steel plate for hardening, and their manufacturing methods |
| JP2010174291A (en) * | 2009-01-28 | 2010-08-12 | Jfe Steel Corp | Steel sheet to be die-quenched superior in hot-punchability |
| JP2010174298A (en) * | 2009-01-28 | 2010-08-12 | Jfe Steel Corp | Steel sheet to be die-quenched superior in hot-punchability |
| JP2010174297A (en) * | 2009-01-28 | 2010-08-12 | Jfe Steel Corp | Steel sheet to be die-quenched superior in hot-punchability |
| JP2010174290A (en) * | 2009-01-28 | 2010-08-12 | Jfe Steel Corp | Steel sheet to be die-quenched superior in hot-punchability |
| JP2010174306A (en) * | 2009-01-28 | 2010-08-12 | Jfe Steel Corp | Steel sheet for die quenching |
| EP2527481A1 (en) * | 2009-12-30 | 2012-11-28 | Hyundai Steel Company | Quenched steel sheet having excellent hot press formability, and method for manufacturing same |
| EP2527481A4 (en) * | 2009-12-30 | 2013-08-14 | Hyundai Steel Co | Quenched steel sheet having excellent hot press formability, and method for manufacturing same |
| WO2012120692A1 (en) | 2011-03-09 | 2012-09-13 | 新日本製鐵株式会社 | Steel sheets for hot stamping, method for manufacturing same, and method for manufacturing high-strength parts |
| US10344360B2 (en) | 2011-03-09 | 2019-07-09 | Nippon Steel & Sumitomo Metal Corporation | Steel sheet for hot stamping use, method of production of same, and method of production of high strength part |
| EP2708612A4 (en) * | 2011-05-12 | 2015-08-05 | Nhk Spring Co Ltd | Steel for automotive suspension spring component, automotive suspension spring component, and manufacturing method for same |
| JP2012237048A (en) * | 2011-05-13 | 2012-12-06 | Nippon Steel Corp | Hot stamping steel plate excellent in hot composite molding property and delayed fracture resistance in punched part thereof, method for manufacturing the same and method for smelting the same |
| WO2013133270A1 (en) | 2012-03-07 | 2013-09-12 | 新日鐵住金株式会社 | Steel sheet for hot stamping, method for producing same, and hot-stamped steel material |
| US10161023B2 (en) | 2012-03-07 | 2018-12-25 | Nippon Steel & Sumitomo Metal Corporation | Steel sheet for hot stamping, method for production thereof, and hot stamping steel material |
| KR20140138829A (en) | 2012-03-07 | 2014-12-04 | 신닛테츠스미킨 카부시키카이샤 | Steel sheet for hot stamping, method for producing same, and hot-stamped steel material |
| WO2014142238A1 (en) | 2013-03-14 | 2014-09-18 | 新日鐵住金株式会社 | High strength steel plate with excellent delayed destruction resistance characteristics and low temperature toughness, and high strength member manufactured using same |
| US9353424B2 (en) | 2013-03-14 | 2016-05-31 | Nippon Steel & Sumitomo Metal Corporation | High strength steel sheet excellent in delayed fracture resistance and low temperature toughness, and high strength member manufactured using the same |
| KR20150119072A (en) | 2013-03-14 | 2015-10-23 | 신닛테츠스미킨 카부시키카이샤 | High strength steel plate with excellent delayed destruction resistance characteristics and low temperature toughness, and high strength member manufactured using same |
| US10829840B2 (en) | 2014-12-10 | 2020-11-10 | Voestalpine Stahl Gmbh | Steel sheet for hot pressing and hot pressed article using the same |
| CN105385939A (en) * | 2015-12-15 | 2016-03-09 | 安徽楚江特钢有限公司 | Manufacturing method of high-strength high-tenacity alloy steel |
| CN106834941A (en) * | 2017-01-20 | 2017-06-13 | 唐山钢铁集团有限责任公司 | A kind of hot press-formed steel and its production method |
| WO2019003540A1 (en) * | 2017-06-30 | 2019-01-03 | Ｊｆｅスチール株式会社 | Hot-press member and method for manufacturing same, and cold-rolled steel sheet for hot pressing and method for manufacturing same |
| JP6501045B1 (en) * | 2017-06-30 | 2019-04-17 | Ｊｆｅスチール株式会社 | Hot pressed member, method for producing the same, cold rolled steel sheet for hot pressing, and method for producing the same |
| CN110799661A (en) * | 2017-06-30 | 2020-02-14 | 杰富意钢铁株式会社 | Hot-pressed member, method for manufacturing same, cold-rolled steel sheet for hot pressing, and method for manufacturing same |
| US11293074B2 (en) | 2017-06-30 | 2022-04-05 | Jfe Steel Corporation | Hot-pressed member and method for manufacturing same, and cold-rolled steel sheet for hot pressing and method for manufacturing same |
| CN108411195A (en) * | 2018-03-27 | 2018-08-17 | 本钢板材股份有限公司 | A kind of the hot forming steel plate and preparation method of cold environment punching production |
Also Published As
| Publication number | Publication date |
|---|---|
| JP4317491B2 (en) | 2009-08-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR102400445B1 (en) | High-strength galvanized steel sheet, high-strength member and manufacturing method thereof | |
| JP6040753B2 (en) | Hot stamping molded article excellent in strength and hydrogen embrittlement resistance and method for producing the same | |
| JP5020572B2 (en) | High strength thin steel sheet with excellent delayed fracture resistance after forming | |
| JP5541421B2 (en) | Hot stamping steel plate, manufacturing method thereof, and hot stamping steel material | |
| JP4317491B2 (en) | Steel sheet for hot press | |
| JP4317384B2 (en) | High-strength galvanized steel sheet with excellent hydrogen embrittlement resistance, weldability and hole expansibility, and its manufacturing method | |
| CN109154045B (en) | Plated steel sheet and method for producing same | |
| KR102119373B1 (en) | Steel sheet for hot press and method of manufacturing same, and hot-press forming part and method of manufacturing same | |
| TW201332673A (en) | High-strength hot-dip galvanized steel sheet with excellent mechanical cutting characteristics, high-strength alloyed hot-dip galvanized steel sheet, and method for producing said sheets | |
| EP2508640A1 (en) | HIGH-STRENGTH STEEL SHEET HAVING EXCELLENT HYDROGEN EMBRITTLEMENT RESISTANCE AND MAXIMUM TENSILE STRENGTH OF 900 MPa OR MORE, AND PROCESS FOR PRODUCTION THEREOF | |
| JP3924159B2 (en) | High-strength thin steel sheet with excellent delayed fracture resistance after forming, its manufacturing method, and automotive strength parts made from high-strength thin steel sheet | |
| JP2004332099A (en) | High-strength thin steel sheet superior in hydrogen embrittlement resistance, weldability, hole-expandability, and ductility and manufacturing method therefor | |
| CN111386358A (en) | High-strength galvanized steel sheet and method for producing same | |
| TW201337003A (en) | Steel plate, plated steel plate, and method of manufacturing the same | |
| JP6825747B2 (en) | Hot-pressed members, cold-rolled steel sheets for hot-pressed members, and their manufacturing methods | |
| JP4495064B2 (en) | Steel sheet for hot press | |
| EP1637618B1 (en) | Method for manufacturing high strength steel sheets with excellent resistance to delayed fracture after forming | |
| JPWO2020162509A1 (en) | Steel members, steel sheets, and their manufacturing methods | |
| KR20210120089A (en) | Hot-pressed member, cold-rolled steel sheet for hot-pressing, and manufacturing method thereof | |
| JP2022095819A (en) | Joint component, and production method of the same | |
| JP6460239B2 (en) | Steel sheet, hot-dip galvanized steel sheet, alloyed hot-dip galvanized steel sheet, and methods for producing them | |
| JP6460238B2 (en) | Steel sheet, hot-dip galvanized steel sheet, alloyed hot-dip galvanized steel sheet, and methods for producing them | |
| JP2010235989A (en) | High strength zn-al-mg based plated steel sheet excellent in liquid metal embrittlement resistant characteristics and production method therefor | |
| JPWO2020203979A1 (en) | Covered steel members, coated steel sheets and their manufacturing methods | |
| JP2010174293A (en) | Steel sheet to be die-quenched superior in hot-punchability |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20060905 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20081218 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20090106 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20090306 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20090515 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20090522 |
|
| R151 | Written notification of patent or utility model registration |
Ref document number: 4317491 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R151 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120529 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130529 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130529 Year of fee payment: 4 |
|
| S531 | Written request for registration of change of domicile |
Free format text: JAPANESE INTERMEDIATE CODE: R313531 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130529 Year of fee payment: 4 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130529 Year of fee payment: 4 |
|
| S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130529 Year of fee payment: 4 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140529 Year of fee payment: 5 |
|
| S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |