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.

Studies of the Solid Particle Erosion Resistance of 30 L Steel with Different Types of Surface Modification

“…In comparison with earlier studies of solid particle erosion resistance for 20 GL steel with boriding [102], this work revealed a significant increase in the wear intensity for 30 L steel samples with boriding. This may be due to an increased percentage (%) of carbon C: 30 L steel (0.27-0.35) and 20 GL steel (0.15-0.25) [101] and/or a decrease in the percentage (%) of manganese Mn: 30 L steel (0.4-0.9) and 20 GL steel (1.2-1.6) [101].…”

“…The research results demonstrated that boriding processes worsen the solid particle erosion resistance of 30 L steel at flow angles of 30 and 90 degrees due to embrittlement of the surface. In turn, the previously obtained data [102] on the multiple increase in solid particle erosion resistance of 20 GL steel with boriding indicate a significant influence of the chemical composition of steel, in particular the percentage of carbon and manganese, on the strength characteristics of the surface after boriding.…”

“…The specimens were borated in a melt based on sodium tetraborate, sodium fluoride, and sodium chloride salts in a STC 35/50 shaft furnace (Lab-Term, Novosibirsk, Russia) with external heating [102]. Two processes were carried out, which included the following steps:…”

Studies of Boriding Using Possibility to Increase the Corrosion Resistance of Cast Steel 20GL

“…The results in [35] indicate that the boriding process of hydraulic machine parts made of steel 20GL will improve their solid particle erosion resistance and extend their overhaul period.…”

“…Previously, a team of authors conducted research on the solid particle erosion resistance of borided 20GL steel samples [35]. The chemical composition of steel 20GL is given in Table 1.…”