THE EFFECT OF THE METHOD AND PARAMETERS OF THE HEAT TREATMENT ON ABRASIVE WEAR RESISTANCE OF 38GSA STEEL

摘要

This paper presents the structure and the results of abrasive wear resistance testing for 38GSA steel in an as-delivered condition (after heat refining) and after volume hardening. Based on the tests conducted by both light and scanning microscopy methods, it was demonstrated that, due to the performed technological operations, this steel differed significantly in terms of structure compared to the as-delivered condition, which affected its performance characteristics. In an as-delivered condition, 38GSA (38MnSi4) steel is characterised by a finegrained ferrite-pearlite structure with martensite areas arranged in bands, which significantly differs from the structure typical of the state of equilibrium. After volume hardening, the steel in question is characterised by a homogeneous fine-stripped martensite structure with clearly visible former austenite grain boundaries. The obtained results of structural testing on 38GSA steel were related to the actual abrasive wear resistance indices obtained by the "rotating bowl" method using various abrasive soil mass types. Tests conducted in the following soils, i.e. light (loamy sand), medium (light loam) and heavy (common loam), including hardness measurements, showed a close relationship between the results obtained for abrasive wear resistance and the phase structure resulting from the heat treatment state of the tested material. The obtained results of the tests on 38GSA steel were compared to those for low-alloyed martensitic abrasive wear resistant steels Hardox 500 and Brinar 500.