摘要:
A bearing steel having long rolling life comprising, by weight, 0.65 to 0.90% of C, 0.15 to 0.50% of Si, 0.15 to 1.0% of Mn and 2.0 to 5.0% of Cr, and the balance of Fe. Austenite grain size can be prevented from becoming coarser to make hardening in high temperature possible by further adding one or more of 0.0090 to 0.0200% of N, 0.010 to 0.050% of Al and 0.005 to 0.500% of Nb as optional elements to the steel. Further, rolling fatigue life can be improved by further adding one or more of 0.20 to 0.50% of Ni, 0.10 to 2.00% Of Mo and 0.05 to 1.00% of V as optional elements, and machinability can be improved by further adding one or more of 0.02 to 0.05% of S, 0.005 to 0.10% of rare earth elements, 0.02 to 0.30% of Pb, 0.0005 to 0.0100% of Ca, 0.001 to 0.200% of Bi, 0.005 to 0.20% of Se and 0.005 to 0.100% of Te in the steel as optional elements.
摘要:
For extension of service lives of rollers and discs of a toroidal continuously variable transmission, input discs, output discs and rollers are formed of a heat-resisting bearing steel. At least a roller has its peripheral surface subjected to a shot peening for achieving a compressive residual stress of 0.6 to 1.2 GPa and a hardness of HRC 63 to 66 at the outermost surface.
摘要:
A steel part having a long rolling contact fatigue life and capable of further increasing the life of a bearing under severer using condition than usual conditions. The steel part includes steel having a composition containing 0.7% by mass to 1.1% by mass of C, 0.5% by mass to 2.0% by mass of Si, 0.4% by mass to 2.5% by mass of Mn, 1.6% by mass to 5.0% by mass of Cr, 0.1% by mass to less than 0.5% by mass of Mo, 0.010% by mass to 0.050% by mass of Al, less than 0.0015% by mass of Sb as an impurity, and the balance composed of Fe and inevitable impurities, the steel being hardened and tempered. In the steel structure of a portion from the surface to a depth of 5 mm, residual cementite has a grain diameter of 0.05 to 1.5 μm, prior austenite has a grain diameter of 30 μm or less, and the ratio by volume of the residual austenite is less than 25%.
摘要:
A roller member comprising high carbon chromium bearing steel having a carburization treatment. The bearing steel comprising a surface portion defined as a range between a surface of a rolling face of the roller member to a depth where a maximum shearing stress acts thereon, the surface portion containing carbon in a total amount comprising a range of 1.0 to 1.6 wt % and an amount of residual austenite comprising a range of 20 vol % to 35 vol % wherein a compression residual stress of the surface portion comprises a range of 150 to 1000 MPa, wherein a surface hardness of the surface portion comprises a range of 64 or higher in Rockwell C hardness, wherein an amount of carbide precipitate on the surface portion comprises a range of 10% to 25% in an area rate and each carbide particle size comprises a range of 3 μm or less.
摘要:
Coal particles can be agglomerated with simultaneous ash removal therefrom by adding an oil fraction to an aqueous slurry of coal particles which contains a surfactant and optionally an inorganic electrolyte.
摘要:
A steel part having a long rolling contact fatigue life and capable of further increasing the life of a bearing under severer using condition than usual conditions. The steel part includes steel having a composition containing 0.7% by mass to 1.1% by mass of C, 0.5% by mass to 2.0% by mass of Si, 0.4% by mass to 2.5% by mass of Mn, 1.6% by mass to 5.0% by mass of Cr, 0.1% by mass to less than 0.5% by mass of Mo, 0.010% by mass to 0.050% by mass of Al, less than 0.0015% by mass of Sb as an impurity, and the balance composed of Fe and inevitable impurities, the steel being hardened and tempered. In the steel structure of a portion from the surface to a depth of 5 mm, residual cementite has a grain diameter of 0.05 to 1.5 μm, prior austenite has a grain diameter of 30 μm or less, and the ratio by volume of the residual austenite is less than 25%.
摘要:
In a power amplifier driven by a pulse width modulation (PWM) signal, a first pair of drive pulses opposite in level to each other is formed from a first pulse width modulation signal whose quantization level corresponds to its pulse width and supplied to a first push-pull circuit (15). A second pair of drive pulses opposite in level to each other is formed from a second pulse width modulation signal whose two's complement of quantization level corresponds to its pulse width, and supplied to a second push-pull circuit (16). A speaker (19) is connected between the first and second push-pull circuits (15 and 16). A deviation between potentials at the output terminals of the first and second push-pull circuits (15 and 16), respectively, is detected. When a deviation is detected, the push-pull circuits are substantially stopped from operating.
摘要:
Provided are a steel having excellent rolling contact fatigue life and the manufacturing method thereof. The steel consists essentially of 0.7 to 1.1% C, 0.2 to 2.0% Si, 0.4 to 2.5% Mn, 1.6 to 4.0% Cr, 0.1% or more and less than 0.5% Mo, 0.010 to 0.050% Al, bymass, and balance of Fe and inevitable impurities, is treated by quenching and tempering, has residual cementite grain sizes ranging from 0.05 to 1.5 μm, and has prior-austenite grain sizes of 30 μm or smaller. When the steel is used to bearing steel, the bearing life extends even under service in more severe environments.
摘要:
An optical system moving apparatus having first and second driving motors, transmitting screws coupled to the first and second driving motors, and a moving table on which an optical system is mounted and which is coupled through the transmitting screws to the first and second driving motors, wherein the moving table is driven by a combined output of the first and second driving motors.
摘要:
Provided are a steel having excellent rolling contact fatigue life and the manufacturing method thereof. The steel consists essentially of 0.7 to 1.1% C, 0.2 to 2.0% Si, 0.4 to 2.5% Mn, 1.6 to 4.0% Cr, 0.1% or more and less than 0.5% Mo, 0.010 to 0.050% Al, bymass, and balance of Fe and inevitable impurities, is treated by quenching and tempering, has residual cementite grain sizes ranging from 0.05 to 1.5 μm, and has prior-austenite grain sizes of 30 μm or smaller. When the steel is used to bearing steel, the bearing life extends even under service in more severe environments.