JPH108188A - Steel sheet for working excellent in high speed destruction resistance in heated zone - Google Patents
Steel sheet for working excellent in high speed destruction resistance in heated zoneInfo
- Publication number
- JPH108188A JPH108188A JP18680496A JP18680496A JPH108188A JP H108188 A JPH108188 A JP H108188A JP 18680496 A JP18680496 A JP 18680496A JP 18680496 A JP18680496 A JP 18680496A JP H108188 A JPH108188 A JP H108188A
- Authority
- JP
- Japan
- Prior art keywords
- pearlite
- steel sheet
- group
- hardness
- high speed
- 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.)
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- Heat Treatment Of Sheet Steel (AREA)
Abstract
Description
【0001】[0001]
【発明が属する技術分野】本発明は、点溶接やアーク溶
接などの溶接処理を施した周辺などの加熱部に優れた耐
高速破壊特性を付与することができる加工用鋼板に関す
るものであり、自動車の衝突緩衝部品用鋼板等として好
適に用いられる。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel sheet for processing capable of imparting excellent high-speed fracture resistance to a heated portion such as a periphery subjected to a welding treatment such as spot welding or arc welding. It is suitably used as a steel plate for impact buffering parts.
【0002】[0002]
【従来の技術】自動車の衝突緩衝部品などは、成形加工
後にスポット溶接等の溶接が施されて所定形状の部品に
製造される。これらの部品には、衝突吸収エネルギーの
向上が望まれる。2. Description of the Related Art Impact-absorbing parts of automobiles are manufactured into parts having a predetermined shape by performing spot welding or other welding after forming. It is desired that these components have improved collision absorption energy.
【0003】かかる用途に好適な鋼板としては、例え
ば、特開昭52−86919号公報に開示されているよ
うに、鋳造過程で注入操作を調整すると共に、鋳型内の
溶鋼中に合金元素を添加し、特定の成分組成を持つ内外
2層を有する高強度鋼板があり、良好な表面性状、加工
性及び溶接性を持ち、車対車事故による衝撃エネルギー
(高速破壊エネルギー)の吸収量も大きい。この鋼板で
は、溶接部の酸化物組成を低融点化し、溶接部に生じた
溶融金属の流動性を改善することで、スポット溶接のナ
ゲットの接着力を改善し、引いてはナゲットで破壊する
ことを抑制して、吸収エネルギーの改善が図られてい
る。[0003] As a steel sheet suitable for such use, for example, as disclosed in Japanese Patent Application Laid-Open No. 52-86919, the casting operation is adjusted during the casting process and the alloy element is added to the molten steel in the mold. In addition, there is a high-strength steel plate having two layers of inner and outer layers having a specific component composition, has good surface properties, workability and weldability, and also has a large absorption amount of impact energy (high-speed fracture energy) due to a car-to-car accident. In this steel plate, the oxide composition of the weld is reduced in melting point and the fluidity of the molten metal generated in the weld is improved, thereby improving the adhesive strength of the spot weld nugget and breaking it with the nugget. Is suppressed, and the absorption energy is improved.
【0004】[0004]
【発明が解決しようとする課題】近年、溶接技術の進歩
により、アルミキルド鋼板等を用いても、溶接部の溶着
性は改善されており、前記2層鋼板と同様、衝突等にお
ける耐高速破壊特性は向上している。In recent years, due to the progress of welding technology, the weldability of a welded portion has been improved even when an aluminum-killed steel plate or the like is used. Is improving.
【0005】しかし、溶接の際、溶接部周辺が加熱され
るため、通常、この部分が軟化し、軟化部で破壊しやす
い。特に、スポット溶接では応力が集中しやすいので軟
化していなくても破壊しやすい。近年、乗用車の衝突時
の安全規制が厳しくなりつつあることを考慮すると、溶
接技術の向上を考慮しても、衝突時の吸収エネルギーが
十分とは言えず、十分な耐高速破壊特性が得られていな
いのが実情である。[0005] However, since the periphery of the weld is heated during welding, this portion is usually softened and easily broken at the softened portion. In particular, in spot welding, stress is easily concentrated, so that it is easily broken even if it is not softened. In recent years, considering that the safety regulations at the time of collision of passenger cars are becoming stricter, the energy absorbed at the time of collision cannot be said to be sufficient, and sufficient high-speed fracture resistance can be obtained even if the welding technology is improved. It is not the fact.
【0006】尚、合金元素の量を多くすれば、ナゲット
部周辺の強度が向上し、耐高速破壊特性も向上するが、
同時に母材自体が硬化するので、プレス成形性が劣化す
るという問題が併発する。When the amount of the alloy element is increased, the strength around the nugget portion is improved, and the high-speed fracture resistance is also improved.
At the same time, since the base material itself is cured, the problem that the press formability is deteriorated also occurs.
【0007】本発明はかかる課題に鑑みなされたもの
で、プレス加工前には軟質で加工しやすく、一方溶接等
の加熱加工後の成形品が耐高速破壊特性に優れる加工用
鋼板を提供する。The present invention has been made in view of the above problems, and provides a working steel sheet which is soft and easy to work before press working, and on the other hand, a formed article after heating such as welding is excellent in high-speed fracture resistance.
【0008】[0008]
【課題を解決するための手段】本発明の加工用鋼板は、
パーライトと残部実質的にフェライトからなる2相組織
を有する鋼板であって、前記パーライト分率が0.05
〜0.2であり、かつパーライトにおける平均C濃度が
0.5wt%以上、パーライトの硬さが300Hv以下で
あることを特徴とする。The steel sheet for processing according to the present invention comprises:
A steel sheet having a two-phase structure consisting of pearlite and the balance substantially ferrite, wherein the pearlite fraction is 0.05
0.20.2, the average C concentration in pearlite is 0.5 wt% or more, and the hardness of pearlite is 300 Hv or less.
【0009】発明者等はCを十分濃縮させたパーライト
組織を有する鋼のパーライトを軟質化させることで、プ
レス加工性を損なうことなく、しかもプレス成形部材を
点溶接等により接合一体化した成形品において、高速破
壊時の吸収エネルギーが向上することを知見し、かかる
知見に基づいて本発明をなすに至った。ここでいうパー
ライトとは、ラメラー組織を有する典型的なものだけで
なく、疑似パーライトの様な粒状セメンタイトを内有す
るものも含む。The present inventors softened the pearlite of steel having a pearlite structure in which C was sufficiently concentrated, so that the press-formed member was joined and integrated by spot welding or the like without impairing the press workability. In the above, it was found that the absorbed energy at the time of high-speed destruction was improved, and the present invention was accomplished based on such knowledge. The term “pearlite” as used herein includes not only a typical one having a lamellar structure but also one having a granular cementite like pseudo perlite.
【0010】高速破壊時の吸収エネルギーの向上理由に
ついては必ずしも明らかではないが、本発明の鋼板はパ
ーライト中にCが十分に濃縮しているため、炭化物間の
距離が短くなり、点溶接などの短時間の加熱でも炭化物
同士が結合して、ナゲット周辺のHAZ部か硬化し、引
いては加熱部の周辺の強度が向上し、耐高速破壊特性が
向上するものと推定される。勿論、パーライトを軟質化
させているため、鋼板自体が軟質であり、プレス加工性
は良好である。尚、加熱方法は、点溶接に限らず、その
他の溶接や部分強化のための加熱でも本発明の効果を期
待することができる。Although the reason for the improvement in the absorbed energy at the time of high-speed fracture is not always clear, the steel sheet of the present invention has a sufficient concentration of C in the pearlite, so that the distance between carbides becomes short, and spot welding and the like become difficult. It is presumed that the carbides are bonded to each other even by heating for a short time, and the HAZ around the nugget is hardened, whereby the strength around the heated portion is improved and the high-speed fracture resistance is improved. Of course, since the pearlite is softened, the steel sheet itself is soft and the press workability is good. The heating method is not limited to spot welding, and the effects of the present invention can be expected with other welding and heating for partial strengthening.
【0011】ここで、本発明鋼板の組織限定理由につい
て説明する。本発明の鋼板は、良好なプレス加工性を得
るために、基本的にはパーライトと残部実質的にフェラ
イトからなる2相組織を有する。パーライト量は、体積
率で0.05〜0.2(体積%で5〜20%)とされ
る。0.05未満では、後述のようにC濃度を高めたパ
ーライトを生成しても、量的に過少であるため、十分な
加熱硬化性を得ることができない。一方、0.2を越え
ると、加工性が劣化するようになる。このため、下限を
0.05以上、好ましくは0.1とし、上限を0.2と
する。尚、パーライト量、言い換えるとフェライト量の
調整は、例えば鋼のC含有量を調整することにより行う
ことができる。Here, the reasons for limiting the structure of the steel sheet of the present invention will be described. The steel sheet of the present invention basically has a two-phase structure composed of pearlite and the balance substantially ferrite in order to obtain good press workability. The pearlite amount is 0.05 to 0.2 in volume ratio (5 to 20% in volume%). If it is less than 0.05, even if pearlite having an increased C concentration is generated as described below, sufficient heat curability cannot be obtained because the amount is too small. On the other hand, if it exceeds 0.2, the workability will deteriorate. Therefore, the lower limit is 0.05 or more, preferably 0.1, and the upper limit is 0.2. The amount of pearlite, in other words, the amount of ferrite can be adjusted, for example, by adjusting the C content of steel.
【0012】パーライト中のC濃度は、溶接部周辺等の
加熱部の硬さの向上に寄与する。0.5%未満では、そ
の硬化作用が過少である。このため、0.5%以上、好
ましくは1.0%以上とする。尚、パーライト中のC量
を調整するには、鋼中のC含有量を調整するほか、例え
ば圧延仕上温度や熱延後の600〜700℃間の滞留時
間を調整することにより、フェライト析出のための時間
を制御すればよい。[0012] The C concentration in the pearlite contributes to the improvement of the hardness of the heated portion such as around the welded portion. If it is less than 0.5%, the curing effect is too small. For this reason, it is 0.5% or more, preferably 1.0% or more. In addition, in order to adjust the C content in the pearlite, in addition to adjusting the C content in the steel, for example, by adjusting the rolling finishing temperature or the residence time between 600 and 700 ° C. after hot rolling, ferrite precipitation can be prevented. The time for this may be controlled.
【0013】パーライトの硬さは、加熱硬化性と加熱前
の加工性に影響を及ぼす。パーライトの硬さが300H
vを越えると、高速破壊時の吸収エネルギーが低下す
る。その理由は、必ずしも明らかでないが、HAZ部等
の加熱部の周辺における硬化が少なく、溶接部で破壊す
るようになるためと考えられる。また、鋼板自体が硬く
なるため、加工性も劣化する。このため、パーライトの
硬さを300Hv以下、好ましくは250Hv以下とす
る。尚、パーライトを軟質化させるには、例えば熱延あ
るいは冷延後、600〜700℃で所定時間再加熱(焼
鈍)すればよい。かかる熱処理により、パーライトにお
けるセメンタイトの形態が変化し、これにより硬さを調
整することができる。The hardness of pearlite affects heat curability and workability before heating. Perlite hardness is 300H
When v exceeds v, the absorbed energy at the time of high-speed destruction decreases. Although the reason is not necessarily clear, it is considered that hardening around the heating portion such as the HAZ portion is small and the weld portion is broken. Further, since the steel plate itself becomes hard, workability is also deteriorated. For this reason, the hardness of pearlite is set to 300 Hv or less, preferably 250 Hv or less. In order to soften the pearlite, for example, after hot rolling or cold rolling, reheating (annealing) at 600 to 700 ° C. for a predetermined time may be performed. Such heat treatment changes the form of cementite in pearlite, thereby making it possible to adjust the hardness.
【0014】本発明の鋼板は、前記組織を有すればよ
く、化学組成は特に限定されないが、代表的な鋼種とし
て下記基本成分を有するアルミキルド鋼を上げることが
できる。単位はwt%である。The steel sheet of the present invention may have the above-mentioned structure, and its chemical composition is not particularly limited. As a typical steel type, an aluminum-killed steel having the following basic components can be used. The unit is wt%.
【0015】C :0.05〜0.25%、Mn:0.
8〜3.0%、P :0.01〜0.20%、S :
0.01%未満、残部:Fe及び不可避的不純物C: 0.05-0.25%, Mn: 0.1%
8 to 3.0%, P: 0.01 to 0.20%, S:
Less than 0.01%, balance: Fe and inevitable impurities
【0016】成分限定理由は次の通りである。 C :0.05〜0.25% 加熱処理後の強度上昇量を確保するため、0.05%以
上、好ましくは0.10%以上は必要である。一方、
0.25%を越えて添加するとプレス加工性、特に延び
フランジ性が劣化する。The reasons for limiting the components are as follows. C: 0.05 to 0.25% In order to secure an increase in strength after the heat treatment, 0.05% or more, preferably 0.10% or more is required. on the other hand,
If added in excess of 0.25%, the press workability, especially the stretch flangeability, is degraded.
【0017】Mn:0.8〜3.0% 加熱処理後の強度上昇量を確保するため、0.8%以上
は必要である。0.8%未満とMnが少なくなると、パ
ーライトが加熱の際にオーステナイトに逆変態するため
の温度か高くなり、加熱部の強度上昇が困難になる。一
方、3.0%を越えて添加するとプレス加工性が劣化す
る。Mn: 0.8 to 3.0% In order to secure an increase in strength after the heat treatment, 0.8% or more is required. If the Mn content is less than 0.8%, the temperature for reverse transformation of pearlite into austenite during heating becomes high, and it becomes difficult to increase the strength of the heated part. On the other hand, if added in excess of 3.0%, the press workability will deteriorate.
【0018】P :0.01〜0.20% 固溶強化により、鋼板を強化するために添加する。0.
01%未満では効果が過少となり、またコスト高とな
る。一方、0.20%を越えて添加すると、ナゲット部
が脆化して吸収エネルギーの劣化を引き起こす。好まし
くは0.08%以下とするのがよい。尚、Pの添加によ
り、耐食性の向上も期待できる。P: 0.01 to 0.20% P is added to strengthen the steel sheet by solid solution strengthening. 0.
If it is less than 01%, the effect is too small and the cost is high. On the other hand, if it is added in excess of 0.20%, the nugget portion is embrittled and the absorbed energy is deteriorated. Preferably, the content is 0.08% or less. The addition of P can also be expected to improve corrosion resistance.
【0019】S :0.01%未満 Sを添加することにより切削性の向上が期待できるが、
0.01%以上添加すると延びフランジ性が劣化するよ
うになる。S: less than 0.01% Improvement of machinability can be expected by adding S,
When added in an amount of 0.01% or more, the stretch flangeability is deteriorated.
【0020】以上の成分のほか、機械的性質を向上させ
るため、補助的成分として、必要に応じて更に下記A
群、B群、C群、D群のいずれかの群に含まれる元素の
内から1種以上を添加することができる。尚、C群の元
素は他の群の元素と併用することができる。In addition to the above components, as an auxiliary component for improving the mechanical properties, if necessary, the following A
One or more of the elements included in any of the group, group B, group C, and group D can be added. In addition, the element of group C can be used together with the element of another group.
【0021】Ti,Nb,V,MoからなるA群 これらの元素は、析出強化や組織強化により、鋼板の高
強度化に有効である。しかし、これらの元素の1種以上
の合計が0.4%を越えると、強度が高くなりすぎて延
性が劣化する。Group A consisting of Ti, Nb, V, and Mo These elements are effective in increasing the strength of a steel sheet by strengthening precipitation and strengthening the structure. However, if the total of one or more of these elements exceeds 0.4%, the strength becomes too high and the ductility deteriorates.
【0022】Cr,Ni,Cu,SiからなるB群 これらの元素は固溶強化により、鋼板の高強度化に寄与
する。しかし、これらの元素の1種以上の合計が4.0
%を越えると、強度が高くなりすぎて、延性が劣化する
ようになる。尚、CuやNiの添加は耐食性の向上にも
寄与する。Group B consisting of Cr, Ni, Cu and Si These elements contribute to the strengthening of the steel sheet by solid solution strengthening. However, the sum of one or more of these elements is 4.0
%, The strength becomes too high and the ductility deteriorates. The addition of Cu or Ni also contributes to the improvement of corrosion resistance.
【0023】Ca,REM (希土類元素)からなるC群 CaやREMは、硫化物析出物の形態を制御するために
用いられ、加工性向上に寄与する。しかし、これらの元
素の1種以上の合計が50ppmを越えると、加工性を
劣化させるので、合計で50ppm以下とする。Group C consisting of Ca and REM (rare earth element) Ca and REM are used to control the form of sulfide precipitates and contribute to the improvement of workability. However, if the total of one or more of these elements exceeds 50 ppm, the workability is degraded, so the total is set to 50 ppm or less.
【0024】B,NからなるD群 BやNは綱の強度向上に寄与するが、これらの元素の1
種以上の合計が50ppmを越えると、加工性を劣化さ
せるので、合計で50ppm以下とする。D group consisting of B and N B and N contribute to the improvement of the strength of the rope.
If the sum of the species exceeds 50 ppm, the workability is deteriorated. Therefore, the total is set to 50 ppm or less.
【0025】尚、上記基本成分又は、及び補助的成分の
ほか、Alを脱酸のために添加してもよい。過少である
と脱酸不良となり、連鋳の場合では製造困難になる。一
方、過多になると介在物による延性劣化を招来し、また
表面品質も劣化する。このため、0.01〜0.05%
の含有が好ましい。Incidentally, in addition to the above-mentioned basic component or auxiliary component, Al may be added for deoxidation. If the amount is too small, deoxidation becomes poor, and in the case of continuous casting, production becomes difficult. On the other hand, if it is excessive, ductility deterioration due to inclusions is caused, and surface quality is also deteriorated. For this reason, 0.01-0.05%
Is preferred.
【0026】[0026]
【実施例】下記表1〜表3に示す成分の鋼を、表4の条
件で製造し、パーライト中のC濃度、パーライト分率、
パーライトの硬さの異なる種々の鋼板を製造した。尚、
パーライト中のC濃度は、(平均C濃度/パーライト分
率)により算出した。また、パーライト分率は体積率を
示し、パーライトの硬さは、通常のマイクロビッカース
硬さ計(加重:50g)により測定した。EXAMPLES Steels having the components shown in Tables 1 to 3 below were produced under the conditions shown in Table 4, and the C concentration in pearlite, the pearlite fraction,
Various steel plates with different pearlite hardness were manufactured. still,
The C concentration in pearlite was calculated by (average C concentration / pearlite fraction). In addition, the pearlite fraction indicates a volume ratio, and the hardness of pearlite was measured by a normal micro Vickers hardness meter (weight: 50 g).
【0027】各表において、試料No. A1〜9(Aグル
ープ)は、鋼板成分を変えずにパーライト中のC濃度を
変化させたものであり、試料No. B1〜6(Bグルー
プ)はC含有量を変えてパーライト中のC濃度を変化さ
せたものである。試料No. C1〜3(Cグループ)はM
nの影響、試料No. D1〜3(Dグループ)はPの影響
を調査したものである。試料No. E1〜12(Eグルー
プ)は、種々の添加元素の影響を調べたものである。
尚、BグループとEグループとは、熱延後に冷間加工を
実施したものである。試料No. F1〜6(Fグループ)
はパーライト分率の影響、No. G1〜5(Gグループ)
はパーライトの硬さの影響を調査したものである。In each table, Sample Nos. A1 to 9 (Group A) were obtained by changing the C concentration in pearlite without changing the steel sheet components, and Sample Nos. The content was changed to change the C concentration in pearlite. Sample No. C1-3 (C group) is M
The influence of n and the sample Nos. D1 to D3 (D group) were obtained by investigating the influence of P. Sample Nos. E1 to E12 (E group) were obtained by examining the effects of various additional elements.
The B group and the E group are obtained by performing cold working after hot rolling. Sample No. F1-6 (F group)
No. G1-5 (G group)
Is an investigation of the effect of pearlite hardness.
【0028】上記各鋼板を用いて、高速圧壊試験を行っ
た。試験結果を表1〜3に併せて示した。試験要領は、
1.4mm厚の鋼板を断面U字形に折り曲げ、その開口部
を同厚の平板で塞ぎ、U字部の端部と平板周縁とを50
mmピッチで点溶接して高さ450mm、横断面外形寸法1
20×80mmの中空の角柱部材を作製し、この角柱部材
の両端部に端板を付設して立設し、その上面に500k
gの物体を時速50kmで落下させ、その際、角柱部材
にかかる加重と変形量を刻々測定し、変位量が150mm
に達するまでの吸収エネルギー(高速圧壊吸収エネルギ
ー)を算出した。A high-speed crush test was performed using each of the above steel plates. The test results are also shown in Tables 1 to 3. The test procedure is
A steel plate having a thickness of 1.4 mm is bent into a U-shaped cross section, and its opening is closed with a flat plate having the same thickness.
Spot welding at a pitch of mm, height 450mm, cross-sectional dimension 1
A hollow prism member having a size of 20 × 80 mm is manufactured, and end plates are attached to both ends of the prism member to stand upright.
g object is dropped at a speed of 50 km / h. At this time, the load and deformation on the prism member are measured every moment, and the displacement is 150 mm.
Absorbed energy (high-speed collapse absorbed energy) up to the maximum was calculated.
【0029】また、試料F及びGグループについては、
伸びフランジ性を調査するため、穴拡げ試験を行った。
試験要領は、10mmφの打抜き穴を開けて、頂角60度
の円錐ポンチで穴を拡大し、亀裂が生じ始めた時点での
穴径(限界穴径:mm)を求め、下記式により穴拡げ率を
求めた。これらの試験結果を表3に併せて示す。 穴拡げ率(%)=(限界穴径−10)×100/10For the samples F and G,
A hole expansion test was performed to investigate stretch flangeability.
The test procedure is as follows: Drill a 10mmφ punched hole, expand the hole with a conical punch with a vertical angle of 60 °, find the hole diameter (crack hole diameter: mm) when cracking starts, and expand the hole by the following formula. The rate was determined. These test results are shown in Table 3. Hole expansion rate (%) = (critical hole diameter−10) × 100/10
【0030】[0030]
【表1】 [Table 1]
【0031】[0031]
【表2】 [Table 2]
【0032】[0032]
【表3】 [Table 3]
【0033】[0033]
【表4】 [Table 4]
【0034】表1のA及びBグループより、パーライト
中のC量が本発明範囲内の実施例ではで高い吸収エネル
ギー値を示すが、比較例の試料No. A9のようにC量が
過多になるとパーライト部の硬さも338Hvと上昇
し、吸収エネルギーが減少することが分かる。これはC
量が大きくなると、ナゲットで割れやすくなるためと推
定される。試料No. A1〜8のデータについて、高速圧
壊吸収エネルギーに及ぼすパーライト中のC濃度(wt
%)の影響を図1に示すが、実施例では、吸収エネルギ
ーが5KJ以上と良好な値を示している。From the groups A and B in Table 1, the C content in pearlite shows a high absorption energy value in the examples within the scope of the present invention, but the C content is excessive as in the comparative sample No. A9. It turns out that the hardness of the pearlite part also increases to 338 Hv, and the absorbed energy decreases. This is C
It is presumed that the larger the amount, the easier it is to break with a nugget. Regarding the data of sample Nos. A1 to A8, the C concentration in pearlite (wt.
FIG. 1 shows the effect of (%), but in the example, the absorbed energy shows a good value of 5 KJ or more.
【0035】Bグループはパーライトを軟質化させるた
めの焼鈍処理の前に冷間圧延を行っており、一方Fグル
ープは冷間圧延を行っていないが、成分が近似している
No.B2とNo. F2、No. B4とNo. F4を比較する
と、両実施例とも特に吸収エネルギーに違いは見られ
ず、良好な値を示している。Group B performs cold rolling before annealing to soften pearlite, while Group F does not perform cold rolling, but has similar components.
Comparing No. B2 and No. F2, and No. B4 and No. F4, there is no particular difference in the absorbed energy in both examples, showing good values.
【0036】CグループとDグループの実施例は5KJ
以上の良好な吸収エネルギーを有しているが、比較例の
No. C3やNo. D3では、吸収エネルギーが低下する傾
向が見られる。これは、MnやPが多くなりすぎると、
ナゲット部の硬質化と脆化のため、ナゲットで割れやす
くなるためと推定される。The embodiment of group C and group D is 5KJ
Although it has the above good absorption energy,
In No. C3 and No. D3, the tendency that absorption energy falls is seen. This is because if Mn or P becomes too large,
It is presumed that the nugget part is hardened and embrittled, so that the nugget is easily broken.
【0037】実施例のEグループは、補助的元素が添加
されているが、全て本発明の組織条件を満足しており、
高い吸収エネルギーを有していることが分かる。Fグル
ープでは、パーライト分率が本発明範囲よりも低いNo.
F1を除き、良好な吸収エネルギー値を示している。一
方、パーライト分率が本発明範囲よりも高いNo. F6
は、吸収エネルギー値は高いものの、伸びフランジ性が
55%と、劣化が著しい。伸びフランジ性は、通常の加
工の場合、ばらつきを考慮して平均80%程度は欲しい
ところである。試料No. F1〜F5について、吸収エネ
ルギーに及ぼすパーライト分率の影響を図2に示す。In the group E of the examples, auxiliary elements are added, but all satisfy the structural conditions of the present invention.
It turns out that it has high absorption energy. In the F group, the pearlite fraction was lower than the range of the present invention.
Except for F1, good absorption energy values are shown. On the other hand, No. F6 having a pearlite fraction higher than the range of the present invention.
Although the absorption energy value is high, the stretch flangeability is 55%, and the deterioration is remarkable. In the case of ordinary processing, the stretch flangeability is desired to be about 80% on average in consideration of variation. FIG. 2 shows the effect of the pearlite fraction on the absorbed energy for Sample Nos. F1 to F5.
【0038】Gグループでは、実施例では良好な吸収エ
ネルギー値と伸びフランジ性を示しているが、パーライ
トの硬さが本発明範囲を越えるNo. G5では、吸収エネ
ルギーが低下し、また伸びフランジ性の劣化も大きい。
Gグループについて、吸収エネルギーと伸びフランジ性
に及ぼすパーライトの硬さの影響を図3に示す。In the group G, the examples show good absorbed energy value and stretch flangeability. However, in the case of No. G5 where the hardness of pearlite exceeds the range of the present invention, the absorbed energy decreases and the stretch flangeability decreases. Degradation is large.
FIG. 3 shows the effect of the pearlite hardness on the absorbed energy and the stretch flangeability for the G group.
【0039】[0039]
【発明の効果】以上説明した通り、本発明の加工用鋼板
は、パーライト分率、パーライトにおけるC濃度および
パーライトの硬さを所定の範囲に規定したので、溶接等
の加熱加工を行うと加熱部周辺が硬質化し、溶接後の成
形品の破壊時に溶接部周辺の加熱部での破壊が抑制さ
れ、引いては高速破壊時の吸収エネルギーを向上させる
ことができ、耐高速破壊特性に優れる。しかも、加熱加
工前には、軟質であるので、成形加工性を損なうことが
ない。As described above, in the steel sheet for processing according to the present invention, the pearlite fraction, the C concentration in the pearlite and the hardness of the pearlite are defined within predetermined ranges. The periphery is hardened, the fracture in the heated part around the welded part is suppressed when the molded product is destroyed after welding, the absorbed energy at the time of high-speed fracture can be improved, and the high-speed fracture resistance is excellent. Moreover, since the material is soft before the heat processing, the formability is not impaired.
【図1】高速圧壊吸収エネルギーに及ぼすパーライト中
のC濃度の影響を示す。FIG. 1 shows the effect of C concentration in pearlite on high-speed crush absorption energy.
【図2】高速圧壊吸収エネルギーに及ぼすパーライト分
率の影響を示す。FIG. 2 shows the effect of pearlite fraction on high-speed collapse absorption energy.
【図3】高速圧壊吸収エネルギーと伸びフランジ性に及
ぼすパーライトの硬さの影響を示す。FIG. 3 shows the effect of pearlite hardness on high-speed crush absorption energy and stretch flangeability.
Claims (2)
らなる2相組織を有する鋼板であって、 前記パーライト分率が0.05〜0.2であり、かつパ
ーライトにおける平均C濃度が0.5wt%以上、パーラ
イトの硬さが300Hv以下であることを特徴とする加
熱部の耐高速破壊特性に優れた加工用鋼板。1. A steel sheet having a two-phase structure composed of pearlite and the balance substantially of ferrite, wherein the pearlite fraction is 0.05 to 0.2 and the average C concentration in pearlite is 0.5 wt%. As described above, a processing steel sheet excellent in high-speed fracture resistance of a heating portion, wherein the hardness of pearlite is 300 Hv or less.
0.25%、Mn:0.8〜3.0%、P :0.01
〜0.20%、S :0.01%未満、あるいは更に、
Ti,Nb,V,Moからなりかつこれらの元素の1種
以上の合計が0.4wt%以下からなるA群、Cr,N
i,Cu,Siからなりかつこれらの元素の1種以上の
合計が4.0wt%以下からなるB群、Ca,REM から
なりかつこれらの元素の1種以上の合計が50ppm以
下からなるC群、B,Nからなりかつこれらの元素の1
種以上の合計が50ppm以下からなるD群の内のいず
れかの群から選ばれた1種以上の元素を含み、残部Fe
及び不可避的不純物よりなる請求項1に記載した加熱部
の耐高速破壊特性に優れた加工用鋼板。2. The chemical composition in which C: 0.05-% by weight.
0.25%, Mn: 0.8 to 3.0%, P: 0.01
~ 0.20%, S: less than 0.01%, or further,
Group A consisting of Ti, Nb, V, Mo and containing at least 0.4 wt% of one or more of these elements; Cr, N
Group B consisting of i, Cu, Si and the total of one or more of these elements is 4.0 wt% or less, and Group C consisting of Ca, REM and the total of one or more of these elements is 50 ppm or less. , B, N and one of these elements
Containing at least one element selected from any of the groups D having a total of 50 ppm or less, the balance being Fe
2. The steel sheet for processing according to claim 1, wherein said steel sheet is excellent in high-speed fracture resistance.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP18680496A JPH108188A (en) | 1996-06-26 | 1996-06-26 | Steel sheet for working excellent in high speed destruction resistance in heated zone |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP18680496A JPH108188A (en) | 1996-06-26 | 1996-06-26 | Steel sheet for working excellent in high speed destruction resistance in heated zone |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH108188A true JPH108188A (en) | 1998-01-13 |
Family
ID=16194884
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP18680496A Pending JPH108188A (en) | 1996-06-26 | 1996-06-26 | Steel sheet for working excellent in high speed destruction resistance in heated zone |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH108188A (en) |
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---|---|---|---|---|
JP2006299344A (en) * | 2005-04-20 | 2006-11-02 | Nippon Steel Corp | High-strength hot-dip galvanized steel sheet with excellent formability, and its manufacturing method |
JP2011001599A (en) * | 2009-06-18 | 2011-01-06 | Kobe Steel Ltd | Steel for machine structure suitable to friction pressure welding, method for producing the same, and friction pressure-welded component |
JP2012057213A (en) * | 2010-09-09 | 2012-03-22 | Kobe Steel Ltd | Steel for machine structure for friction pressure welding and friction pressure welding component |
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WO2018043067A1 (en) * | 2016-08-29 | 2018-03-08 | 株式会社神戸製鋼所 | Thick steel sheet and production method therefor |
JP2018193605A (en) * | 2016-08-29 | 2018-12-06 | 株式会社神戸製鋼所 | Thick steel plate and manufacturing method therefor |
-
1996
- 1996-06-26 JP JP18680496A patent/JPH108188A/en active Pending
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006299344A (en) * | 2005-04-20 | 2006-11-02 | Nippon Steel Corp | High-strength hot-dip galvanized steel sheet with excellent formability, and its manufacturing method |
JP4644028B2 (en) * | 2005-04-20 | 2011-03-02 | 新日本製鐵株式会社 | High-strength hot-dip galvanized steel sheet with excellent formability and method for producing the same |
JP2011001599A (en) * | 2009-06-18 | 2011-01-06 | Kobe Steel Ltd | Steel for machine structure suitable to friction pressure welding, method for producing the same, and friction pressure-welded component |
JP2012057213A (en) * | 2010-09-09 | 2012-03-22 | Kobe Steel Ltd | Steel for machine structure for friction pressure welding and friction pressure welding component |
WO2013031105A1 (en) * | 2011-08-31 | 2013-03-07 | Jfeスチール株式会社 | Hot-rolled steel sheet for cold-rolled steel sheet, hot-rolled steel sheet for hot-dipped galvanized steel sheet, method for producing hot-rolled steel sheet for cold-rolled steel sheet, and method for producing hot-rolled steel sheet for hot-dipped galvanized steel sheet |
JP2013049901A (en) * | 2011-08-31 | 2013-03-14 | Jfe Steel Corp | Hot-rolled steel sheet for cold-rolled steel sheet and hot-rolled steel sheet for hot-dipped galvanized steel sheet superior in processability and material stability, and method for producing the same |
US11098392B2 (en) | 2011-08-31 | 2021-08-24 | Jfe Steel Corporation | Hot rolled steel sheet for cold rolled steel sheet, hot rolled steel sheet for galvanized steel sheet, and method for producing the same |
WO2018043067A1 (en) * | 2016-08-29 | 2018-03-08 | 株式会社神戸製鋼所 | Thick steel sheet and production method therefor |
JP2018193605A (en) * | 2016-08-29 | 2018-12-06 | 株式会社神戸製鋼所 | Thick steel plate and manufacturing method therefor |
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