Vickers hardness is the standard test method for the hardness of ion nitriding layer. The surface hardness is generally measured by 9.8n-98n Vickers hardness tester. When the depth of nitriding layer is less than 0.3 mm, the test force of Vickers hardness shall not exceed 49 n; when the depth of nitriding layer is greater than or equal to 0.3 mm, the test force of Vickers hardness is generally 49 n-98 n. When it is necessary to test the hardness of the compound layer, it should be measured with a micro Vickers hardness tester with a test force of 0.49 N ~ 1.96 n.
It is better to directly sample the parts for hardness inspection. If the parts are too large in volume or the nitriding surface is not allowed to play hardness, the samples of the same furnace can be used instead. However, it must be noted whether the samples are consistent with the temperature of the parts, otherwise the test results of the test block can not reflect the quality of the ion nitriding heat treatment of the parts.
The number of sampling inspection can be determined according to the importance of parts, charging capacity and furnace temperature uniformity. The more important the parts are, the more the charging quantity is, and the worse the uniformity of furnace temperature is, the more the sampling inspection quantity should be.
In order to control and guarantee the heat treatment quality of products, it is possible to comprehensively measure the chemical composition of metal materials, metallographic structure, hardness gradient, penetration depth and macro hardness after heat treatment, and to issue test reports according to the corresponding national standards, industrial standards and foreign standards.
On 2018-08-08 11:45:46
