A method for manufacturing a crankshaft for an internal combustion engine with a plurality of journals having a hardened case with a first microstructure. The crankshaft is comprised of a steel comprising between about 0.3 wt % and 0.77 wt % Carbon. The first microstructure of the hardened case of the journals comprises between about 15% and 30% ferrite and a balance of martensite and the resultant subsurface residual stress between 310 MPa and 620 MPa.

A forged component having a chemical composition including, by mass %, C: 0.30 to 0.45%, Si: 0.05 to 0.35%, Mn: 0.50 to 0.90%, P: 0.030 to 0.070%, S: 0.040 to 0.070%, Cr: 0.01 to 0.50%, Al: 0.001 to 0.050%, V: 0.25 to 0.35%, Ca: 0 to 0.0100%, N: 0.0150% or less, and the balance being Fe and unavoidable impurities, and satisfying formula 1. Metal structure is a ferrite pearlite structure, and a ferrite area ratio is 30% or more. Vickers hardness is in the range of 320 to 380 HV. 0.2% yield strength is 800 MPa or more. A Charpy V-notch impact value is in the range of 7 to 15 J/cm.sup.2.

A bearing component including a first metallic material and a second metallic material. The first metallic material provides a first carbon content and the second metallic material presents a second carbon content. The first metallic material and the second metallic material have been joined by a diffusion welding process. The diffusion welding process results in a transition zone with a varying carbon content between the first metallic material and the second metallic material. Varying carbon content in the transition zone is within an interval and the interval end points are defined by the carbon contents of the first metallic material and the second metallic material.

A carburized shaft part having a predetermined composition, a C content at a surface layer part of a mass % of 0.60 to 1.00%, at least one hole at an outer circumferential surface, a total volume ratio of martensite and retained austenite of 97% or more at a structure at a position of a 1 mm depth from the outer circumferential surface in an axial direction of the hole and a position of a 20 m depth from the surface of the hole, a maximum retained austenite volume ratio (R1) of 10.0 to 30.0% at a position of a 1 mm depth from the outer circumferential surface in the axial direction of the hole and a range up to a 200 m depth from the surface of the hole, and a retained austenite reduction ratio of 20% or more found from R1 and the retained austenite volume ratio (R2) at a position of a 1 mm depth from the outer circumferential surface in the axial direction of the hole and a position of a 20 m depth from the surface of the hole by the formula (A): =(R1R)/R1100.

A bearing component such as a bearing ring includes a metallic base body and at least one alloy steel coating on the base body, the coating being applied to the base body by deposition welding. The base body is preferably non-alloy steel or cast iron, and the alloy includes at least one carbide-forming transition metal such as niobium, tantalum, zirconium, titanium, hafnium, tungsten, molybdenum, vanadium, or manganese. The coating can form a raceway of the bearing component or a structural element such as a flange. Also a method of forming such a bearing component is provided.

Steel for a crankshaft includes 0.37 to 0.42 wt % of carbon (C), 0.55 to 0.70 wt % of silicon (Si), 1.45 to 1.65 wt % of manganese (Mn), 0.025 wt % or less (excluding 0 wt %) of phosphorus (P), 0.020 to 0.035 wt % of sulfur (S), 0.15 to 0.30 wt % of chromium (Cr), 0.035 to 0.055% of vanadium (V), and the remainder of Fe and other inevitable impurities. The steel for a crankshaft has strength that is maintained high even when reducing the amount of vanadium.

A rolling-sliding member that is high in hardness and continues to have a passivation film reliably even after being subjected to a process that does not require any processing for removal of scale, etc., as well as a rolling bearing using the same and a method for manufacturing the rolling-sliding member.

A steel alloy and automotive components, such as crankshafts, produced therefrom are provided. The steel alloy includes iron, about 0.34 to about 0.40 weight percent carbon, about 0.8 to about 1.2 weight percent manganese, about 0.40 to about 0.60 weight percent silicon, about 0.04 to about 0.07 weight percent sulfur, about 0.9 to about 1.2 weight percent chromium, about 0.20 to about 0.35 weight percent molybdenum, about 0.08 to about 0.15 weight percent vanadium, and about 0.02 to about 0.06 weight percent aluminum. The steel alloy may also include up to 0.03 weight percent phosphorus, up to 0.25 weight percent nickel, up to 0.20 weight percent copper, up to 0.03 weight percent titanium, up to 0.03 weight percent nitrogen, and up to 0.002 weight percent boron.

A bushing formed of different alloys selected to accommodate different operating conditions is provided. For example, the bushing could include an iron-based alloy in a portion of the bushing exposed to lower temperatures, and a cobalt-based alloy in a portion of the bushing exposed to higher temperatures. The first and second alloys could be axially or radially aligned. The iron based alloy includes 10 to 30 wt % Cr, 0 to 21 wt % Ni, 0 to 10 wt % Mo, 0 to 5 wt % W, 0 to 3 wt % C, 0 to 4 wt % V, 0 to 20 wt % Co, and a balance of Fe; and the cobalt based alloy includes 10 to 30 wt % Cr, 5 to 21 wt % Ni, 0 to 10 wt % Mo, 0 to 10 wt % W, 0 to 3 wt % V, 0.5 to 3 wt % C, and a balance of Co.

A method for manufacturing a crankshaft for an internal combustion engine with a plurality of journals having a hardened case with a first microstructure. The crankshaft is comprised of a steel comprising between about 0.3 wt % and 0.77 wt % Carbon. The first microstructure of the hardened case of the journals comprises between about 15% and 30% ferrite and a balance of martensite and the resultant subsurface residual stress between 310 MPa and 620 MPa.