摘要:
A hot-dip galvanized steel sheet which is produced from a cold-rolled steel sheet, as a base steel sheet, consisting essentially of C: 0.010-0.06 wt %, Si: no more than 0.5 wt %, Mn: no less than 0.5 wt % and less than 2.0 wt %, P: no more than 0.20 wt %, S: no more than 0.01 wt %, Al: 0.005-0.10 wt %, N: no more than 0.005 wt %, Cr: no more than 1.0 wt %, Mn+1.3Cr: 1.9-2.3 wt %, Fe: remainder, and having a structure composed of ferrite and a second phase containing martensite, said second phase in the structure accounting for no more than 20% in terms of area and martensite in the second phase accounting for no less than 50%, and which has a zinc-plated layer formed on the surface thereof by hot-dip galvanizing or hot-dip galvannealing. A process for production of said hot-dip galvanized steel sheet. This steel sheet has a composite structure containing martensite and yet it has a low strength (no higher than 500 MPa) and also has good strength-ductility balance.
摘要:
A P- and Ti-added galvannealed steel sheet superior in ductility, and a process for production thereof. It is made of a cold-rolled steel sheet and has alloyed hot-dip galvanizing on the surface thereof, said cold-rolled steel sheet having the chemical composition (in terms of wt %) of C: less than 0.010%, Si: no more than 0.5%, Mn: 1.0˜3.0%, P: no more than 0.20%, S: no more than 0.01%, Al: 0.005˜0.10%, N: no more than 0.0050%, Ti/48−(C/12+N/14+S/32): 0.0003˜0.0018 with the remainder being chiefly Fe, and said cold-rolled steel sheet being characterized by &rgr;1≦107 and &rgr;2≦5×105, where &rgr;1 is the number of precipitates whose particle diameter (D) is in the range of 10 nm≦D
摘要翻译:具有优异延性的P型和Ti型合金化热镀锌钢板及其制造方法。 由冷轧钢板制成,其表面具有合金化的热浸镀锌,所述冷轧钢板的化学组成(按重量%计)C:小于0.010%,Si:不 大于0.5%,Mn:1.0〜3.0%,P:不大于0.20%,S:0.01%以下,Al:0.005〜0.10%,N:不大于0.0050%Ti / 48-(C / 12 + N / 14 + S / 32):0.0003〜0.0018,余量主要为Fe,所述冷轧钢板的特征在于rho1 <= 107且rho2 = 5×105,其中rho1是其颗粒 直径(D)在10nm <= D <100nm的范围内,rho2是其粒径(D)在100nm
摘要:
A high-strength cold rolled steel sheet contains:0.10 to 0.28% of C,1.0 to 2.0% of Si,1.0 to 3.0% of Mn, and0.03 to 0.10% of Nb in terms of % by mass,Al is controlled to 0.5 or less, P is controlled to 0.15% or less, and S is controlled to 0.02% or less, and residual austenite accounts for 5 to 20%, bainitic ferrite accounts for 50% or more, and polygonal ferrite accounts for 30% or less (containing 0%), of the entire structure, and a mean number of residual austenite blocks is 20 or more as determined when the random area (15 μm×15 μm) is observed by EBSP (electron back scatter diffraction pattern).
摘要:
To provide a high-strength cold rolled steel sheet that has well-balanced tensile strength and elongation as well as well-balanced tensile strength and stretch-flangeability, and a plated steel sheet manufactured by plating the steel sheet. The high-strength cold rolled steel sheet contains: 0.10 to 0.28% of C, 1.0 to 2.0% of Si, 1.0 to 3.0% of Mn, and 0.03 to 0.10% of Nb in terms of % by mass, wherein the content of Al is controlled to 0.5 or less, the content of P is controlled to 0.15% or less, and the content of S is controlled to 0.02% or less, and wherein residual austenite accounts for 5 to 20%, bainitic ferrite accounts for 50% or more, and polygonal ferrite accounts for 30% or less (containing 0%), of the entire structure, and wherein a mean number of residual austenite blocks is 20 or more as determined when the random area (15 μm×15 μμm) is observed by EBSP (electron back scatter diffraction pattern).
摘要:
Disclosed is a dual-phase steel sheet having low yield ratio, excellent in the balance for strength-elongation and for strength-stretch flange formability, and also excellent in bake hardening property containing (on the mass % basis). C: 0.01-0.20%, Si: 0.5% or less, Mn: 0.5-3%, sol.Al: 0.06% or less (inclusive 0%), P: 0.15% or less (exclusive 0%), and S: 0.02% or less (inclusive 0″), and in which the matrix phase contains tempered martensite; tempered martensite and ferrite; tempered bainite; or tempered bainite and ferrite, and the second phase comprises 1 to 30% of martensite at an area ratio based on the entire structure.
摘要:
Disclosed is a dual-phase steel sheet having low yield ratio, excellent in the balance for strength-elongation and for strength-stretch flange formability, and also excellent in bake hardening property containing (on the mass % basis). C: 0.01-0.20%, Si: 0.5% or less, Mn: 0.5-3%, sol.Al: 0.06% or less (inclusive 0%), P: 0.15% or less (exclusive 0%), and S: 0.02% or less (inclusive 0″), and in which the matrix phase contains tempered martensite; tempered martensite and ferrite; tempered bainite; or tempered bainite and ferrite, and the second phase comprises 1 to 30% of martensite at an area ratio based on the entire structure.
摘要:
A high strength steel sheet having (2-1) a base phase structure, the base phase structure being tempered martensite or tempered bainite and accounting for 50% or more in terms of a space factor relative to the whole structure, or the base phase structure comprising tempered martensite or tempered bainite which accounts for 15% or more in terms of a space factor relative to the whole structure and further comprising ferrite, the tempered martensite or the tempered bainite having a hardness which satisfies the relation of Vickers hardness (Hv)≧500[C]+30[Si]+3[Mn]+50 where [ ] represents the content (mass %) of each element, and (2-2) a second phase structure comprising retained austenite which accounts for 3 to 30% in terms of a space factor relative to the whole structure and optionally further comprising bainite and/or martensite, the retained austenite having a C concentration (CγR) of 0.8% or more.
摘要:
A high-strength forged part is disclosed which comprises a base phase structure, comprising 30% or more of ferrite in terms of a space factor, and a second phase structure, comprising bainite and/or martensite, and retained austenite having an average gain diameter of 5 μm or less and a content represented by 50X[C]
摘要:
To provide a high strength and low yield ratio cold rolled steel sheet having high elongation property and high flange drawing property, or a plated steel sheet made by plating the same. The high strength and low yield ratio cold rolled steel sheet or the plated steel sheet made by plating the same has such a constitution as 0.10 to 0.25% of C, 1.0 to 2.0% of Si and 1.5 to 3.0% of Mn, are contained in terms of weight percentage, while other elements are controlled such as Al within 0.2%, P within 0.15% and S within 0.02%, with residual austenite occupying at least 5%, bainitic ferrite occupying at least 60% (preferably 80% or more), and polygonal ferrite within 20% (containing 0%), so that a tensile strength is 980 MPa or higher, while an elongation (El in %), a flange drawing property (λin %), a tensile strength (TS in MPa) and a yield strength (YP in MPa) satisfy the following inequality (1): [(El ×λ×TS)/YP]≧645.
摘要:
A high-strength forged part is disclosed which comprises a base phase structure, comprising 30% or more of ferrite in terms of a space factor, and a second phase structure, comprising bainite and/or martensite, and retained austenite having an average grain diameter of 5 μm or less and a content represented by 50X[C]