Metallographic etched process for displaying G Cr15 original austenite grain border

Abstract

A metallographic corrosion method for displaying a GCr15 original austenitic grain boundary comprises adding picric acid 5g into distilled water100ml and mixing continuously, then adding sodium dodecyl benzene sulfonate 5ml 50% and mixing, finally adding ferric chloride 2g, and using after placing for 24 hours. A sample is grinded roughly, grinded finely, polished, cleared, dried, immersed into caustic erodent for 2-5 minutes according to normal method under a quenching tempering condition until etched surface is changed into silver grey, cleaned up through flowing water, cleaned with alcohol 95%, and dried. If the sample is over-corroded, polishing paste W0.5-1.0 or metallographic polishing egent0.5-1.0 is added on silk polishing cloth, the sample is polished slightly with hands, then cleaned with alcohol 95%, and dried. According to practical condition, grain granularity measurement can adopt methods of picture contrast, grid, intercept, quantitative metallography, and the like, to assess according to relevant standards.

Description

technical field [0001] The invention belongs to the technical field of heat treatment, in particular to a metallographic corrosion method for displaying GCr15 original austenite grain boundaries. Background technique [0002] The austenite grain refinement of steel can effectively improve the strength of steel. The finer the grain, the greater the resistance of the expansion of plastic deformation under the action of the external force by the grain boundary, which is conducive to improving the strength of the steel. As the grain boundary increases, the energy consumed by the crack crossing the grain boundary increases, which slows down the crack propagation speed. At the same time, the size of the austenite grain directly affects the morphology, substructure and toughness of the martensite. The austenite grains are refined, and its toughness is correspondingly improved. [0003] Over the years, heat treatment workers and researchers at home and abroad have done a lot of wo...

AI Technical Summary

Problems solved by technology

[0003] Over the years, heat treatment workers and researchers at home and abroad have done a lot of work on the influence of the original austenite grain size of GCr15 bearing steel on the strength, toughness and fatigue life of the steel, and have also achieved a lot of research results. What kind of metallographic corrosion method to display the original austenite grain boundary of GCr15 bearing steel has not been studied enough, some corrosion methods cannot clearly display the grain boundary, some methods are too cumbersome and time-consuming, and some require heating to display , and sometimes the results are not ideal

Therefore, it brings inconvenience and difficulty to refine the original austenite grain of GCr15 bearing steel