Research results of solid particle erosion resistance of 20GL steel with boriding

Abstract

The paper presents the results of experimental studies of solid particle erosion resistance of 20GL structural steel samples with two different variants of surface modification based on the boriding process. Characteristics of modified layers such as depth, composition, microhardness were determined. Tests were carried out according to ASTM G76-13 standard at air-abrasive flow rate of 170 m/s, flow attack angles of 30º and 90°, sample surface temperature of 25ºC. It was found that both considered options of surface modification at an angle of attack of 90 ° flow do not worsen the abrasion resistance of 20GL steel samples, and at flow attack angle of 30 ° increase not less than 8 times. A change in the wear pattern of boriding samples with an increase in the angle of attack from 30° to 90° is noted. As after the boriding process surface embrittlement was observed, the angle of maximum wear for 20GL steel with boriding became equal to 90° in contrast to steel without treatment, where the maximum level of wear is observed at 30°. Thus, the change of fracture type from plastic to brittle was revealed, which should be taken into account in full-scale operation of the treated parts. The obtained results indicate that the process of boriding of pump parts made of 20GL steel will increase their solid particle erosion resistance and extend their overhaul period.