Examination of Heat Treatment on the Microstructure and Wear of Tool Steels

Abstract

The microstructure of the investigated X153CrMoV12 grade tool steel in delivered condition consisted of spheroidal matrix and primary carbides. The primary carbides were not dissolved under austenitisation time on either 1030°C or 1070°C. The microstructure and abrasion resistance of the steel changed due to quenching from different austenitisation temperatures. After conventional quenching from the higher austenitising temperature, there is more residual austenite in the steel than at quenching from the lower austenitisation temperature, which decreased the wear resistance. As a result of quenching from 1070°C followed by a multiple tempering process around 500 to 540°C, the retained austenite content is reduced and finely dispersed carbides are precipitated in the matrix, resulting in a higher matrix hardness and an increased wear resistance. After cryogenic treatment, the residual austenite content decreases compared to the conventional process, which leads to an increase in hardness and wear resistance.

The Influence of Austenitizing Temperature Level on Microstructure Development in Chromium Ledeburitic Tool Steel

“…The steel in this state contains non-uniformly distributed, irregularly shaped eutectic carbides, almost uniformly distributed quasi-globular secondary carbides and uniformly distributed eutectoid carbides. Carbides are distributed in ferritic matrix [3,5,8]. From the point of view of chemistry three types of carbide particles were determined by EDS measurements, further denoted as K1, K2 and K3.…”

“…Hence, these steels are suitable for variety industrial operations such as cutting, forming [3], plastics moulds, measuring instruments, gauges and many others. [5]. Mechanical properties of tool steels are determined by their phase composition, microstructure, matrix and type, quantity, size and distribution of the carbides.…”

The Possibilities of the Retained Austenite Reduction on Tool Steels

“…2 shows the hardness of martensite as a function of carbon content. It is well known, that the reduction of hardness at more than 85 carbon content is due to the presence of retained austenite [9].…”