Metallographic detection sample preparation method after carbonitriding of high-carbon chromium bearing steel, as well as product

Abstract

The invention discloses a metallographic detection sample preparation method after the carbonitriding of high-carbon chromium bearing steel. The sample preparation method comprises the following steps: tempering for 2-3 hours at high temperature, cooling to room temperature, then cutting, inserting, grinding and polishing a bearing to obtain parts, putting the part in a 5%-6% picric acid alcoholic solution for etching for one minute, cleanly washing the parts and blow-drying to obtain samples. When the samples, prepared by adopting the method, are used for metallographic observation, the depth of carbo-nitride compound particles on the surface of the bearing can be more easily judged, and the detection accuracy can be improved. The invention further discloses samples prepared by adopting the method, the acicular martensite structures and retained austenite structures on the surfaces of the samples are decomposed into troostite structures after being prepared by adopting the method, so that the carbo-nitride compound particles can be more easily differentiated.

Description

technical field [0001] The invention relates to the technical field of bearing surface chemical heat treatment, in particular to a sample preparation method and sample for metallographic detection after carbonitriding heat treatment of high-carbon chromium bearing steel. Background technique [0002] The metallographic carbonitriding heat treatment of the bearing surface can increase the carbon and nitrogen compounds on the surface of the bearing steel part, increase the content of carbon and nitrogen on the surface of the steel part, make the workpiece not easy to deform, and prolong the service life. [0003] The traditional carbonitriding process such as the Chinese patent authorization announcement number is: "Medium-deep carburizing or carbonitriding heat treatment process for bearing or clutch parts" disclosed in the document CN102154652B, which adopts a controlled atmosphere roller type The continuous production line of mesh belt furnace carries out carburizing or car...

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Problems solved by technology

However, when the samples treated by the above-mentioned carbonitriding process are observed under a metallographic microscope, the size of the carbonitride particles on the surface is difficult to distinguish from the size of the carbide particles in the material matrix, see figure 1 As shown; due to the coarse martensite structure on the surface of the part and more retained austenite, the morphology of carbonitride particles and carbide particles in the part matrix is ​​not easy to distinguish under the metallographic microscope, which is likely to cause misjudgment during detection As a result, batches of bearings are scrapped due to insufficient carbonitriding depth, resulting in a lot of cost waste and material waste

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