457 results about "Contact fatigue" patented technology

The invention belongs to the alloy steel field, particularly relating to steel for a fine grain carburization gear and a preparation method thereof. The steel comprises the following chemical compositions in weight percentage: 0.15 to 0.25 percent of C, less than or equal to 0.35 percent of Si, 0.60 to 0.90 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.010 percent of S, 0.80 to 1.20 percent of Cr, 0.15 to 0.35 percent of Mo, 0.02 to 0.08 percent of Nb, 0.0005 to 0.0035 percent of B, 0.02 to 0.06 percent of Al, 0.01 to 0.04 percent of Ti, less than or equal to 0.015 percent of [N], less than or equal to 0.0015 percent of [O], the balance being Fe and inevitable impurities. Meanwhile, Ti is more than or equal to 2[N] and B is more than or equal to ([N] minus Ti / 3.4) / 1.4 plus 0.001; and the rolling production process with the finish-to-gage temperature below 900 DEG C is adopted. Compared with the prior carburization gear steel 20CrMoH, the grain size of the steel after carburizing and quenching exceeds ten grade, the bending fatigue resistance(sigama-1) is improved by more than 15 percent and the contact fatigue life(L10) is improved by more than 30 percent.

The invention discloses a semi high speed steel cold-rolling intermediate roll and a manufacturing method thereof. The semi high speed steel cold-rolling intermediate roll comprises the following chemical components in percentage by weight: 0.50 to 0.90 percent of C, 0.5 to 2.00 percent of Si, 0.20 to 1.00 percent of Mn, 4.50 to 6.00 percent of Cr, 0.50 to 2.00 percent of Mo, 0.20 to 1.00 percent of V, less than or equal to 0.80 percent of Ni, less than or equal to 0.025 percent of S and less than or equal to 0.025 percent of P. The manufacturing method comprises: manufacturing a steel blank of the cold-rolling roll; roughly turning and tempering; quenching at 940 to 1,000 DEG C; and tempering at 450 to 550 DEG C for 30 to 120 hours. The surface hardness of the cold-rolling intermediate roll made of the material is 75 to 85HSD; the mechanical stress resistance, thermal stress resistance, tissue stress resistance, contact fatigue resistance, wear resistance, hot impact resistance and roll shape retaining performance of the semi high speed steel cold-rolling intermediate roll are high, and the comprehensive service performance of the semi high speed steel cold-rolling intermediate roll is high.

Steels having a pearlitic structure and containing 0.65 to 0.80 weight percent carbon, 0.90 to 1.10 weight percent silicon, 0.85 to 1.15 weight percent manganese, 0.001 to 0.030 weight percent phosphorus, 0.009 to 0.013 weight percent niobium, 0.05 to 0.15 nickel, 0.20 to 0.30 weight percent molybdenum, 0.10 to 0.30 weight percent vanadium and 0.005 to 0.040 weight percent sulfur with the remainder of said steel being iron and incidental impurities, can be used to make railway wheels that are particularly resistant to rolling contact fatigue and, hence, shelling.

The invention relates to a bidirectional micro motion test fixture and a bidirectional micro motion test method thereof. The fixture is mainly in the structure that: a planar test-piece fixture (2) is in an inversed V shape, the opposite surfaces of the left and right sides of the lower part are all opened with a groove (4) fit to a planar test-piece (13), and the wall of the groove (4) is provided with a puller screw (3); a spherical test-piece fixture (8) is opened with a spherical test-piece cavity (7) fit to a spherical test-piece (5), and the wall of the spherical test-piece cavity (7) is provided with a puller screw (6); and the vertical axes of the spherical test-piece cavity (7), a piston (9) and the planar test-piece fixture (2) are coincided. One side of the upper part of the planar test-piece fixture (2) is connected with an upper vertical screw (10) while the spherical test-piece fixture (8) is connected with a lower vertical screw (12), and a displacement sensor is connected with the upper vertical screw (10) and the lower vertical screw (12). The test fixture can effectively simulate bidirectional fretting under spherical / surface contact condition, test tribology properties and estimate contact fatigue life of a coating under spherical / surface bidirectional micro motion condition on the existing hydraulic servo micro motion test platform.

The invention discloses a heat treatment method of a wheel rim surface of the train wheel with high carbon steel. The method is carried out as follows: during the cooling process, the wheel tread of train wheel is firstly cooled by spraying water with small flow in short time, then large flow in long time. The invention also discloses a heat treatment device of using the method. An water feed tubular tube comprises a water feed tubular tube with large flow and a water feed tubular tube with small flow, the water feed tubular tube with large flow is communicated with a plurality of nozzles with large flow, and the water feed tubular tube with small flow is communicated with a plurality of nozzles with small flow. Adopting the technical proposal can improve the contacting fatigue resistance of train wheel, reduces the tread spalling of train wheel; obtains the appropriate geometric matching relation between wheels and rails as soon as possible, increases the contact area, decreases the contact stress level; promotes the wear resistance of the internal part of wheel rim, thereby promoting the service life of wheel; can not increase the operation difficulty of the heat treatment and cooling technology of wheels.

Steels having a pearlitic structure and containing 0.65 to 0.80 weight percent carbon, 0.90 to 1.10 weight percent silicon, 0.85 to 1.15 weight percent manganese, 0.001 to 0.030 weight percent phosphorus, 0.009 to 0.013 weight percent niobium, 0.05 to 0.15 nickel, 0.20 to 0.30 weight percent molybdenum, 0.10 to 0.30 weight percent vanadium and 0.005 to 0.040 weight percent sulfur with the remainder of said steel being iron and incidental impurities, can be used to make railway wheels that are particularly resistant to rolling contact fatigue and, hence, shelling.

The invention provides a rolling piston used for a rotary refrigeration compressor and the manufacture method thereof. The material of the rolling piston is a precise steel pipe made of GCr15 bearing steal cold rolled; the manufacture method of the invention is that (1) the GCr15 bearing steal is selected to be cold rolled to the steel pipe meeting required internal diameter, external diameter and thickness of the rolling piston; (2) the steel pipe is cut according to the length of the rolling piston material; (3) the cut steel pipe is disposed by hot controllable gas; (4) all surfaces of the steel pipe are kibbled; (5) the steel pipe is disposed by heat stabilization; (6) all surfaces of the steel pipe are finely grinded. The invention has the advantages that the made rolling piston has obvious predominance on the anti-wear performance and high contact fatigue life. The work load of the cutting process can be reduced by 50%, and the utilization ratio of the steel material can reach more than 90%, thus reducing the manufacture cost. The invention saves the casting method, avoids the environmental pollution and high energy consumption, and is a good energy-saving method with environmental protection.

The invention discloses a diesel engine cam thermal treatment method comprising a carburizing step, a quenching step and a tempering step.After the carburizing step, a pit cooling method is adopted for reducing the deformation of the cam because of the heat treatment process, two times of alkaline bath quenching are adopted for not only reducing thermal stress and deformation, but also having functions of thinning heart crystal grains and eliminating network carbide for satisfying metallography requirement in the first quenching process of the cam, and having a function of assuring to obtain cryptocrystal martensite, residual austenite and partial of granule carbide on the surface for satisfying performance requirements of rigidity, wearing resistance property, contact fatigue degree and the like of the cam surface in the second quenching process of the cam;simultaneously, the cam heart can obtain lath martensite and fine homogeneous ferrite, and the mechanical property of the cam heart can be improved; according to the invention, design requirements of heat rigidity, wearing resistance property, fatigue strength, mechanical property of the cam heart and deflection can all be satisfied, therefore, the manufactured cams can be extensively used in large-scale heavy-duty mechanical equipment.

The present invention relates to a high-strength, highly wear-resistant, and highly contact-fatigue-resistant steel rail and a production method thereof, and belongs to the field of black steel manufacturing technology. The present invention provides a high-strength and highly fatigue-resistant steel rail, comprising the following chemical components by weight percentage: C: 0.76%˜0.86%; Si: 0.6%˜1%; Mn: 0.7%˜1.5%, Cr: 0.1%˜0.5%, and 0.8%≦Mn %+Cr %≦1.6%; V: 0.05%˜0.3%, Ni: 0.1%˜0.35%, and 0.15%≦V %+Ni %≦0.4%; Mo: ≦0.03%; P: ≦0.02%; S: ≦0.015%; Fe and inevitable impurities: the remaining content, wherein, the metallurgical structure of the steel rail is fine pearlite+A, where, A is proeutectoid ferrite or proeutectoid cementite, and A≦2%. The tensile strength of the obtained steel rail is 1,260 MPa˜1,420 MPa.

The invention provides a steel rail with a surface decarburized layer smaller than 0.3mm and a manufacturing method of the steel rail. The steel rail comprises the following chemical components in percentage by weight: 0.60-0.66% of C, 0.10-0.30% of Si, 0.8-1.2% of Mn, 0.2-0.5% of Cr, less than or equal to 0.020% of P, less than or equal to 0.015% of S, less than or equal to 0.0002% of hydrogen, less than or equal to 0.0020% of oxygen and the balance of Fe and unavoidable impurities. The manufacturing method comprises the steps of smelting and continuously casting; refining, and carrying out vacuum treatment by using VD for longer than 25min, wherein the content of hydrogen is lower than 2.0PPm; and carrying out blank casting treatment, namely carrying out hot delivery and hot charging, wherein the blank casting temperature is higher than 760 DEG C, a heating zone in a heating furnace is at a weak-oxidative atmosphere, the furnace temperature at the heating zone is 1250-1320 DEG C, the air coefficient at the heating zone is 1.0-1.20, a soaking zone is at a reducing atmosphere, the furnace temperature at the soaking zone is 1150-1250 DEG C, and the air coefficient at the soaking zone is 0.80-1.00. The surface decarburized layer of the steel rail is smaller than 0.3mm, so that the polishing quantity of an upper rail of a high-speed rail can be reduced; and the structure of the surface layer of the steel rail is refined, so that the hardness of the surface layer can be favorably improved, the surface contact fatigue injury of the steel rail can be reduced, and the service life of the steel rail can be prolonged.