Carbide precipitation type rare earth carburizing steel

Abstract

The invention relates to carbide precipitation type rare earth carburizing steel, which is chromium-manganese-silicon-molybdenum rare earth alloy steel. The carbide precipitation type rare earth carburizing steel is used for carburization by a gas carburizing method comprising the following steps of: washing a chromium-manganese-silicon-molybdenum rare earth alloy steel test bar with kerosene, hoisting the washed test bar in a carburizing furnace, adding dropwise a carburizing agent isopropanol and a diluent methanol, dispersing and precipitating ultrafine granular alloy carbides with the mean diameter of 200nm from a carburized layer at the same time of internally diffusing carbon atoms from the surface under the conditions of the temperature of 920+/-5 DEG C, the carbon potential Cp of 1.25+/-0.05 percent and the heat preservation time of 420+/-10min to make 1.6mm deep the carburized layer and 2 to 3 percent the carbon content of the surface layer, reducing the temperature to 840 to 850 DEG C, preserving the heat for 30min, performing impregnation and quenching by using 5 percent PAG aqueous solution and performing tempering at the low temperature of 180+/-5 DEG C. The carburized layer of the chromium-manganese-silicon-molybdenum rare earth alloy has the hardness of HV0.11057 improved by 20 percent compared with that in the prior art, and the abrasive resistance improved by 60 percent, so that the hardness, strength and abrasive resistance of the surface of a work piece are greatly improved.

Description

technical field [0001] The invention relates to a carbide precipitation type rare earth carburizing steel, belonging to the technical field of rare earth alloy steel and carburizing methods. Background technique [0002] Carburizing heat treatment is a chemical heat treatment widely used in the machinery manufacturing industry. Its purpose is to obtain high surface hardness, strength and wear resistance of the workpiece. The carbon content of the surface of the conventional carburizing layer of ordinary carburizing steel is 0.8%~ 1.0%, the microstructure of the carburized layer after quenching and low-temperature tempering treatment is: carbides are distributed on the matrix composed of tempered martensite and retained austenite. The quantity, shape and distribution of carbides play a crucial role in the hardness, strength and wear resistance of the workpiece surface. , it is very easy to appear reticular carbide or coarse horn-like carbide, which will lead to a decrease in...

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Problems solved by technology

The quantity, shape and distribution of carbides play a crucial role in the hardness, strength and wear resistance of the workpiece surface. , it is very easy to appear reticular carbide or coarse horn-like carbide, which will lead to a decrease in the mechanical properties of the workpiece. How to further improve the quality and service life of the workpiece carburized, and obtain superior carburized layer structure and mechanical properties, has always been the work of material heat treatment. research topic

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