Determination method for austenitic grain size of pearlite type wire rod

Abstract

The invention discloses a determination method for an austenitic grain size of a pearlite type wire rod. The determination method comprises the following steps: (1) cutting off a small block from the pearlite type wire rod to be used as a test sample; polishing and mechanically burnishing, and then carrying out electrolytic polishing; (2) taking one face of the test sample as an observation region, and carrying out face scanning on the test sample through an EBSD (Electron Backscatter Diffraction) system to obtain an orientation imaging picture; and (3) setting a deflection angle difference of 25 degrees, and counting up the grain size through orientation analysis software of the EBSD system to obtain an average grain size diameter, and obtaining the austenitic grain size of the test sample according to an average grain size diameter comparison table 1. According to the method disclosed by the invention, an accurate quantization effect can be obtained according to parameters of a standard sample preparation process, the repeatability of the result is good and the success rate is high; and the method can clearly present tissue uniformity of the wire rod, also can be matched with a traditional austenitic grain size index and is easy to understand.

Description

technical field [0001] The invention relates to a method for analyzing iron and steel materials, in particular to a method for measuring the austenite grain size of pearlite-like wire rods. Background technique [0002] Austenite grain size has an important influence on the plasticity and toughness of steel materials. According to general requirements, the requirements for high-quality carbon structural steel, alloy structural steel, spring steel, carburized bearing steel and high-speed steel are above grade 5. Some high-end steel grades even reach grade 7 or above. [0003] The national standard GB6394-86 "Determination of Average Metal Grain Size" stipulates that carburizing method, oxidation method, network ferrite method, network pearlite method, network cementite method and grain boundary corrosion method can be used etc. to evaluate the austenite grain size of the material, but in the test and production practice, it is found that the grain size displayed by the oxida...

AI Technical Summary

Problems solved by technology

Oxidation method and hardening method are the most widely used detection methods of austenite grain size at present, both of which need to heat the sample, which can easily cause the growth of austenite grain size, and it is difficult to reflect the austenite grain size. The true austenite grain size of

Images