【School】 bearing weak development process and heat treatment technology --- Power By China's weak home 【Network】.

<br> <BR> <BR> heat Development <BR> <BR> (1) Clean the formation of heat <BR> <BR> heat production of wastewater, waste gas, waste salt, dust, noise and electromagnetic radiation will Dengjun .pollution to the environment. .Solve the heat problem of environmental pollution, the implementation of clean heat (or green heat treatment) is a technology developed in the direction of heat treatment. .In order to reduce SO2, CO, CO2, emissions of dust and cinders, has basically put an end to the use of coal as fuel, the use of heavy oil less and less in favor of the majority of light oil, natural gas is still the best fuel. .<BR> <BR> Burner waste heat utilization has reached a high degree of structural optimization and the burner air - fuel ratio, combustion strict control to ensure reasonable under the premise of the NOX and CO decreased to a minimum; use of gas permeability .carbon, and vacuum carbonitriding heat treatment technology alternatives to reduce the salt treatment with CN-waste salt and toxic contamination of water sources; using water-soluble synthetic oil instead of part of the quenching oil quenching, the use of biodegradable vegetable oil instead of part of mineral oil to .reduce oil pollution. .<BR> <BR> (2) precision heat treatment <BR> <BR> precision heat treatment has two meanings: one is based on requirements of parts, materials, structure size, the use of physical metallurgy knowledge and advanced computer simulation and testing .technology, optimization of process parameters to achieve the required performance or to maximize the potential of the material; the other hand, fully guarantee the stability of optimization process to achieve product quality and dispersion of small (or zero), and heat distortion is zero. .<BR> <BR> (3) energy-saving heat <BR> <BR> scientific production and energy management is the most efficient use of energy has the potential factors, the establishment of specialized treatment plant to ensure full capacity, full capacity is scientific equipment .management options. .Energy structure in the heat treatment, the preferred choice of primary energy; full use of waste heat, waste heat; with low energy consumption, short cycle process instead of a long cycle, energy-consuming process and so on. .<BR> <BR> 4) Heat a small non-oxidation atmosphere <BR> <BR> protected by the use of alternative heating the atmosphere heated to a precise control of oxidation potential of carbon, nitrogen potential of the controlled atmosphere heating, heat treatment to improve the performance of parts, heat treatment .defects such as removal, crack greatly reduced, leaving the finishing heat treatment reduced, improving the utilization of materials and machining efficiency. .Vacuum plus hot quenching, vacuum or low pressure carburizing, nitriding, and seepage Nitrocarburizing boron can improve the quality and reduce distortion, increased life expectancy. .<BR> <BR> Effect of heat treatment technology <BR> <BR> (1) expanded the scope of application <BR> <BR> GCr15 steel GCr15 general quenching of steel rings M 12mm wall thickness less effective, but the quenching BL .When the nitrate cooling capacity, the use of a stirring, string action, water and other measures, the effective ring thickness can be extended to 28mm or so. .<BR> <BR> (2) hardness, stability, good uniformity <BR> <BR> the BL is a slow process of change, the general GCr15 steel to be 4h, GCr18Mo steel to be 5h, ring in the nitrate in the long isothermal .Ministry of the surface of the heart changes in almost the same time, so the hardness and stability, good uniformity, the general BL GCr15 steel after quenching hardness 59 ~ 61HRC, uniformity ≤ 1HRC, unlike the quenching thickness slightly larger ring will appear low hardness, .soft spots, and poor uniformity. .<BR> <BR> (3) to reduce quenching, grinding cracks <BR> <BR> in the railway, rolling mill bearing production, due to large ring size and weight, oil quenching M tissue brittleness, for the quenched .often taken to obtain high hardness, strong cooling measures, resulting in quenching cracks; and BL quenching, due to the BL is much better organized than the M tissue toughness, while the surface of up to -400 ~-500MPa compressive stress, which greatly reduces the quenching .crack orientation; in the surface grinding stress partly offset by a grinding stress, and the overall stress level down, greatly reducing the grinding cracks. .<BR> <BR> (4) bearing service life <BR> <BR> withstand large impact loads for the railway, rolling mill bearings, hardened by the M main failure mode when used as follows: when the inner sleeve assembly cracking, the process of using .in the outer wall by the impact of lost blocks, inner ring fragmentation, while bearing the austempering good impact toughness, surface stress, both sets of cracks within the assembly, or the use of the process out of the block wall jacket, inner sleeve fragmentation tendency .greatly reduced, and the edge of the roller can reduce stress concentration. .Therefore, the isothermal quenching, after quenching than the average life span of M and increased reliability. .<BR>.