Mechanical Properties Of Quench-Hardened, Martempered And Tempered Astm A 128 Grade B-4 Steel

Abstract

This investigation is conducted to assess the influence of some heat treatment procedures on the structure and mechanical properties of cast ASTM A grade B-4 steel to which formation of grain boundary carbides have been a major problem. Some cast ASTM A grade B-4 steel samples were quench-hardened, martempered and tempered. The as-cast and heat-treated samples were thereafter tested for tensile strength, yield strength, impact strength, ductility and hardness. Some of the samples were also prepared for metallographic examination and their microstructures were studied. It was observed that in all cases, the microstructures were mainly austenite matrix with or without carbides at the grain boundaries and in the austenitic grains depending on the heattreatment adopted. The measured mechanical properties varied and were greatly dependent on the presence or absence of carbides either at the grain boundaries or at both the grain boundaries and in the grains of austenite matrix. Two of the heat treatment procedures were found to be appropriate as post-casting processes suitable for ASTM A 128 grade B-4 steel components designed to function under a condition in which impact strength and hardness are simultaneously required.

The Repair of Defects in High-Manganese Steel Castings by Welding Technology

“…Austenitized parts have better mechanical properties than non-quenched as-casted ones. [4,[7][8][14][15].…”

Workhardening behaviour and microstructural analysis of failed austenitic manganese steel crusher jaws

“…The dark greyish constituents are large carbides, which are at the grain boundaries and in the grain. These large carbides at the grain boundaries and in the grain caused the early fractures 34,35 . The microstructure of as-cast sample revealed large carbide along the austenite grain boundaries ( Figure 12) but heat treated sample that was rapidly quenched in water bath without agitation revealed precipitation of carbide along the austenite grain boundaries ( Figure 13).…”