The effect of sulfurization on the grinding wheel cutting ability in the internal cylindrical grinding of nickel superalloys

Abstract

One possible way of preventing excessive growth of smearings/loads on the grinding wheel active surface is the introduction of compounds such as sulfur, graphite, or wax into the grinding wheel volume which exerts an active influence on adhesion during the process of impregnation. Limiting the formation of smearings/loads on the grinding wheel active surface is of crucial importance to achieve effective grinding of hard-to-cut materials (such as nickel superalloys) which are characterized by considerable ductility and a strong chemical affinity to abrasive grains, among other things. This article presents the results of experimental tests performed on plunge grinding and the influence of sulfur impregnation of grinding wheels on the smearing/load intensity on the grinding wheel active surface during the process of internal cylindrical plunge grinding of openings made from Inconel® alloy 600 and Incoloy® alloy 800HT®. Bearing steel 100Cr6 was included in the tests as a reference material. Grinding wheels were impregnated with a new method of gravitational sulfurization combined with centrifuging. The experiments carried out show that the adhesive properties of sulfur allowed for considerable limitation of smearing/loading of the grinding wheel active surface with machined material. This mainly concerned limiting the formation of the largest and most technologically undesirable smearings/loads of the intergranular spaces. The presence of sulfur in the grinding wheel volume had a minor influence on the intensity of smearings/loads in the microareas of the active abrasive grains’ apexes. The tests also showed an increase of 32%–49% in the value of parameter Sa in the surfaces ground with grinding wheels impregnated with sulfur for all the examined materials.