A steel alloy providing from 0.05 to 0.25 wt. % carbon, from 10 to 14 wt. % chromium, from 1.5 to 4 wt. % molybdenum, from 0.3 to 1.2 wt. % vanadium, from 0.3 to 3 wt. % nickel, from 6 to 11 wt. % cobalt from 0.05 to 0.4 wt. % silicon, from 0.1 to 1 wt. % manganese, from 0.02 to 0.06 wt. % niobium, optionally one or more of the following elements from 0 to 2.5 wt. % copper from 0 to 0.1 wt. % aluminum, from 0 to 250 ppm nitrogen, from 0 to 30 ppm boron, and the balance iron, together with any unavoidable impurities, wherein the alloy has a Ni.sub.eq of greater than 11.5, the Ni.sub.eq being defined by the formula Ni.sub.eq=Ni+Co+(0.5Mn)+(30C), in wt. %.

A linear motion guide device having a long-life slider is provided. The linear motion guide device includes a guide rail, a plurality of rolling elements, and a slider. The material of the slider body 11 is alloy steel containing 0.1 mass % or more and less than 0.3 mass % of C, 0.5 mass % or more and 1.5 mass % or less of Cr, and 0.1 mass % or more and 0.4 mass % or less of Si, with the balance being Fe and inevitable impurities. An amount of retained austenite in a surface layer 14F of a slider-side rolling groove 14 subjected to a carburizing heat treatment is 15 vol % or more and 45 vol % or less. The surface hardness of the slider-side rolling groove 14 is Hv 650 or more.

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 crankshaft with improved fatigue strength is provided. A crankshaft 10 includes journals 11, pins 12, and fillets 14, each fillet 14 having a residual stress distribution where the residual stresses are compressive residual stresses from the surface down to a depth of at least 300 m, the maximum value of the compressive residual stress being not lower than 1000 MPa, the surface roughness Rz being lower than 3.00 m.

An inner-flanged bushing for a hydraulic breaker is a tubular shape having an inner flange and is made of a steel containing at least 0.55% and less than 0.70% by mass of carbon, at least 0.15% and less than 0.35% by mass of silicon, at least 0.4% and less than 0.9% by mass of manganese, at least 0.4% and less than 1.3% by mass of chromium, and at least 0.10% and less than 0.55% by mass of molybdenum, with the balance being iron and unavoidable impurities. The bushing includes a base region having a hardness of at least 30 HRC and less than 45 HRC, and a quench hardened layer formed on an inner periphery side of the base region to include an inner peripheral surface of a region including the inner flange, the quench hardened layer having a hardness of at least 55 HRC and less than 63 HRC.

A carburisable steel alloy suitable for bearing components comprising, in percent by weight: C 0.05-0.5 wt. % Cr 2.5-5.0 wt. %, Mo 4-6 wt. %, W 2-4.5 wt. %, V 1-3 wt. %, Ni 2-4 wt. %, Co 2-8 wt. %, optionally one or more of the following elements: Nb 0-2 wt. % N 0-0.5 wt. % Si 0-0.7 wt. %, Mn 0-0.7 wt. %, Al 0-0.1 5 wt. %, wherein the combined amount of Nb+V is within the range 1-3.5 wt. %, the combined amount of C+N is within the range 0.05-0.5 wt. %, the balance being Fe and unavoidable impurities.

Provided is a sliding member including: a back-metal layer and a sliding layer including a copper alloy. The back-metal layer includes a hypoeutectoid steel including 0.07 to 0.35 mass % of carbon and has a structure including a ferrite phase and pearlite. The back-metal layer has a high ferrite phase portion at a bonding surface between the back-metal layer and the sliding layer. A volume ratio Pc and a volume ratio Ps satisfy Ps/Pc0.4, where the volume ratio Pc is a volume ratio of pearlite in the structure at a center portion in a thickness direction of the back-metal layer, and the volume ratio Ps is a volume ratio of pearlite in the high ferrite phase portion.

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 is disclosed that provides a unique combination of strength, toughness, and fatigue life. The steel alloy has the following composition in weight percent:

TABLE-US-00001 C about 0.15 to about 0.30 Mn about 1.7 to about 2.3 Si about 0.7 to about 1.1 Cr about 1.85 to about 2.35 Ni about 0.5 to about 0.9 Mo + W about 0.1 to about 0.3 Cu about 0.3 to about 0.7 V + 5/9 Nb about 0.2 to about 0.5
The balance of the alloy is iron, usual impurities, and residual amounts of other elements added during melting for deoxidizing and/or desulfurizing the alloy. A hardened and tempered steel article made from the alloy is also disclosed.

A non-heat treated steel for a crankshaft of the present invention comprises iron (Fe) as a main component and also comprises 0.37 to 0.43 mass % of carbon (C), 0.15 to 0.35 mass % of silicon (Si), 0.90 to 1.30 mass % of manganese (Mn), 0.08 to 0.15 mass % of vanadium (V); and the content of phosphorous (P) is 0.030 mass % or less, the content of copper (Cu) is 0.300 mass % or less, the content of nickel (Ni) is 0.30 mass % or less, and the content of chromium (Cr) is 0.35 mass % or less.

The non-heat treated steel also comprises 0.010 to 0.035 mass % of sulfur (S) and 0.02 to 0.05 mass % of bismuth (Bi), which are machinability-improving elements. Thus, the non-heat treated steel has a high fatigue strength and a high yield strength and also has an excellent machinability.