The invention relates to an ultrahigh strength multiphase steel having a minimum tensile strength of 980 MPa containing (in wt. %): C0.075 to 0.115; Si0.400 to 0.500; Mn1.900 to 2.350; Cr0.250 to 0.400; Al0.010 to 0.060; N0.0020 to 0.0120; P0.020; S0.0020; Ti0.005 to 0.060; Nb0.005 to 0.060; V0.005 to 0.020; B0.0005 to 0.0010; Mo0.200 to 0.300; Ca0.0010 to 0.0060; Cu0.050; Ni0.050; Sn0.040; H0.0010; and residual iron, including customary steel-accompanying smelting-related impurities, wherein the total content of Mn+Si+Cr is 1.750 to 2.250 wt. % with a view to a processing window which is as wide as possible during the annealing process, in particular during the continuous annealing process, of cold strips of said steel.

The invention relates to a stainless steel. The stainless steel consists of in weight % (wt. %):

TABLE-US-00001 C 0.32-0.50 Si 0.1-1.0 Mn 0.1-0.8 Cr11-14 Mo 1.8-2.6 V 0.35-0.70 N 0.05-0.19 optional elements, balance Fe and impurities.

The invention relates to a stainless steel. The stainless steel consists of in weight % (wt. %):

TABLE-US-00001 C 0.32-0.50 Si 0.1-1.0 Mn 0.1-0.8 Cr11-14 Mo 1.8-2.6 V 0.35-0.70 N 0.05-0.19 optional elements, balance Fe and impurities.

A method of making a small diameter elongated steel article such as wire or strip is disclosed. The method includes the step of melting a steel alloy having the following weight percent composition TABLE-US-00001 C 0.88-1.00 Mn 0.20-0.80 Si 0.50 max. P 0.050 max. S 0.010-0.100 Cr 0.15-0.90 Ni 0.10-0.50 Mo 0.25 max. Cu 0.08-0.23 V 0.025-0.15 N 0.060 max. O 0.040 max.
and the balance is iron and usual impurities. The method includes melting the alloy, atomizing the molten alloy to make a pre-alloyed metal powder, consolidating the metal powder to substantially full density, and then hot working the consolidated metal powder to form an intermediate elongated article. The method further includes a multi-step heat treating process. A small diameter, elongated steel article having enhanced machinability is also disclosed.

A method of making a small diameter elongated steel article such as wire or strip is disclosed. The method includes the step of melting a steel alloy having the following weight percent composition TABLE-US-00001 C 0.88-1.00 Mn 0.20-0.80 Si 0.50 max. P 0.050 max. S 0.010-0.100 Cr 0.15-0.90 Ni 0.10-0.50 Mo 0.25 max. Cu 0.08-0.23 V 0.025-0.15 N 0.060 max. O 0.040 max.
and the balance is iron and usual impurities. The method includes melting the alloy, atomizing the molten alloy to make a pre-alloyed metal powder, consolidating the metal powder to substantially full density, and then hot working the consolidated metal powder to form an intermediate elongated article. The method further includes a multi-step heat treating process. A small diameter, elongated steel article having enhanced machinability is also disclosed.

The steel material for a carburized bearing part according to the present invention contains, by mass %, C: 0.25 to 0.45%, Si: 0.15 to 0.45%, Mn: 0.40 to 1.50%, P: 0.015% or less, S: 0.005% or less, Cr: 0.60 to 2.00%, Mo: 0.10 to 0.35%, V: 0.20 to 0.40%, Al: 0.005 to 0.100%, Ca: 0.0002 to 0.0010%, N: 0.0300% or less and O: 0.0015% or less, with the balance being Fe and impurities, and satisfies Formulae (1) to (3).

1.20<0.4Cr+0.4Mo+4.5V<2.75(1)

A1/A2>0.50(2)

2.7C+0.4Si+Mn+0.45Ni+0.8Cr+Mo+V>2.55(3)

Formula (2) shows an area fraction of sulfides containing Ca in an amount of 1 mol % or more among sulfides having an equivalent circular diameter of 1 m or more.

The steel material for a carburized bearing part according to the present invention contains, by mass %, C: 0.25 to 0.45%, Si: 0.15 to 0.45%, Mn: 0.40 to 1.50%, P: 0.015% or less, S: 0.005% or less, Cr: 0.60 to 2.00%, Mo: 0.10 to 0.35%, V: 0.20 to 0.40%, Al: 0.005 to 0.100%, Ca: 0.0002 to 0.0010%, N: 0.0300% or less and O: 0.0015% or less, with the balance being Fe and impurities, and satisfies Formulae (1) to (3).

1.20<0.4Cr+0.4Mo+4.5V<2.75(1)

A1/A2>0.50(2)

2.7C+0.4Si+Mn+0.45Ni+0.8Cr+Mo+V>2.55(3)

Formula (2) shows an area fraction of sulfides containing Ca in an amount of 1 mol % or more among sulfides having an equivalent circular diameter of 1 m or more.

Provided are a high-strength galvanized steel sheet and a method for producing the high-strength galvanized steel sheet. The high-strength galvanized steel sheet includes a base steel sheet having a specific composition and a microstructure including ferrite and carbide-free bainite, martensite and carbide-containing bainite, and retained austenite, the total area fraction of ferrite and carbide-free bainite being 0% to 65%, the total area fraction of martensite and carbide-containing bainite being 35% to 100%, and the area fraction of retained austenite being 0% to 15%, the content of diffusible hydrogen in the base steel sheet being 0.00008% by mass or less (including 0%) and a galvanizing layer disposed on the base steel sheet. The density of gaps in the galvanizing layer, that the gaps cutting across the entire thickness of the galvanizing layer, is 10 gaps/mm or more.

[Object] To provide a steel sheet for carburizing that demonstrates improved ductility, and a method for manufacturing the same.

[Solution] A steel sheet consisting of, in mass %, C: more than or equal to 0.02%, and less than 0.30%, Si: more than or equal to 0.005%, and less than 0.5%, Mn: more than or equal to 0.01%, and less than 3.0%, P: less than or equal to 0.1%, S: less than or equal to 0.1%, sol. Al: more than or equal to 0.0002%, and less than or equal to 3.0%, N: less than or equal to 0.2%, Ti: more than or equal to 0.010%, and less than or equal to 0.150%, and the balance: Fe and impurities, in which the number of carbides per 1000 m.sup.2 is 100 or less, percentage of number of carbides with an aspect ratio of 2.0 or smaller is 10% or larger relative to the total carbides, average equivalent circle diameter of carbide is 5.0 m or smaller, and average crystal grain size of ferrite is 10 m or smaller.

[Object] To provide a steel sheet for carburizing that demonstrates improved extreme deformability prior to carburizing, and a method for manufacturing the same.

[Solution] A steel sheet consisting of, in mass %, C: more than or equal to 0.02%, and less than 0.30%, Si: more than or equal to 0.005%, and less than 0.5%, Mn: more than or equal to 0.01%, and less than 3.0%, P: less than or equal to 0.1%, S: less than or equal to 0.1%, sol. Al: more than or equal to 0.0002%, and less than or equal to 3.0%, N: less than or equal to 0.2%, and the balance: Fe and impurities, in which average value of X-ray random intensity ratio, assignable to an orientation group of ferrite crystal grain ranging from {100}<011> to {223}<110>, is 7.0 or smaller, average equivalent circle diameter of carbide is 5.0 m or smaller, percentage of number of carbides with an aspect ratio of 2.0 or smaller is 80% or larger relative to the total carbides, and percentage of number of carbides present in the ferrite crystal grain is 60% or larger relative to the total carbides.