The Effect of Sub-Critical Heat Treatment on Hardness, Retained Austenite and Abrasive Wear Resistance of Hypoeutectic 16 mass% Cr-2 mass% Mo Cast Iron with Varying Vanadium Content

Abstract

To increase the matrix hardness without complete hardening, a sub-critical heat treatment was performed by holding the as-cast iron below the pearlite transformation temperature (A 1 ), and exposed to a hypoeutectic 16 mass% Cr-2 mass% Mo cast iron with a 03 mass% vanadium (V). The temperatures were held between 723 K and 923 K with 50 K intervals for 14.443.2 ks and then cooled via air from a fan. In the as-cast state, the hardness of the cast iron increased progressively and the volume fraction of retained austenite (V£) decreased gradually as the V content of specimen rose. With the sub-critical heat treatment, the hardness increased initially and then decreased with an increase in holding temperature. Conversely, the V£ was reduced greatly when the holding temperature was elevated above 823 K. The maximum hardness in the sub-critical heat treatment (H STmax ) was obtained in the temperature range of 823873 K, while the V£ values were approximately 2030%. The largest H STmax value of 830 HV30 was obtained in the specimen with 3 mass% V. The abrasive wear resistance was evaluated by a Suga abrasion wear tester using the specimens heat-treated at selected conditions. The wear resistance increased as the V content increased with the highest wear resistance obtained in the specimens with H STmax .

Effect of Subcritical Treatment (Tempering) on Hardness and Wear of High Chromium White Cast Iron

“…These treatments (destabilization) have been reported in many research papers. However, the research on sub-critical heat treatment is quite limited [10].…”

“…In the reference [10] the relationships between the subcritical heat treatment hardness, the volume fraction of retained austenite (V), and abrasive wear resistance of hypoeutectic 16% Cr-2% Mo cast irons with 0-3%V were investigated. It is found that the subcritical heat treatment can improve the hardness and wear resistance.…”

Improving Grinding Ball Lifespan and Efficiency Through Hardenability Modelling and Optimization

“…[1][2][3]. High-chromium white cast irons are ferrous alloys containing 11-30% Cr and 1.8-3.6% C along with other alloying elements such as molybdenum and nickel [4,5]. The high chromium content in these cast irons provides them with excellent wear resistance, as chromium carbides are formed in the microstructure of the material.…”

“…The formation of secondary carbides depends on a number of factors, including the chemical composition, the temperature and duration of the heat treatment, and the cooling rate after heat treatment. The morphology and characteristics of the carbides can also vary depending on these factors [5,[6][7][8][9][10][11][12]. These carbides can have different crystal structures, sizes, and distributions within the matrix, and can affect properties such as hardness, wear resistance, and toughness [11,13,14].…”