Solidification and abrasion wear of white cast irons alloyed with 20% carbide forming elements

• Published in: Wear 2001-10, Vol.250 (1-12), p.502-510
• Main Authors: Matsubara, Yasuhiro, Sasaguri, Nobuya, Shimizu, Kazumichi, Yu, Sung and Kon
• Format: Article
• Language: English
• Subjects: Abrasion wear; Heat-treatments; Solidification; White cast iron
• ISSN: 0043-1648; 1873-2577
• DOI: 10.1016/S0043-1648(01)00599-3

Three different white cast irons with compositions of Fe–3%C–10%Cr–5%Mo–5%W (alloy no. 1), Fe–3%C–10%V–5%Mo–5%W (alloy no. 2) and Fe–3.5%C–17%Cr–3%V (alloy no. 3) were prepared in order to study their solidification and abrasion wear behaviors. Melts were super-heated to 1873K in a high frequency induction furnace, and poured at 1823K into Y-block pepset molds. The solidification sequence of these alloys was investigated. The solidification structures of the specimens were found to consist of austenite dendrite (γ); (γ+M7C3) eutectic and (γ+M6C) eutectic in the alloy no. 1; proeutectic MC; austenite dendrite (γ); (γ+MC) eutectic and (γ+M2C) eutectic in the alloy no. 2, and proeutectic M7C3 and (γ+M7C3) eutectic in the alloy no. 3, respectively. A scratching type abrasion test was carried out in the states of as-cast (AS), homogenized (AH), air-hardened (AHF) and tempered (AHFT) using the abrasive paper with 120mesh SiC and 10N application load. In all the specimens, the abrasion wear loss was found to decrease in the order of AH, AS, AHFT and AHF states. Abrasion wear loss was lowest in the specimen no. 2 and highest in the specimen no. 1 except for the as-cast and homogenized states in which the specimen no. 3 showed the highest abrasion wear loss. The lowest abrasion wear loss of the specimen no. 2 could be attributed to the fact that it contained proeutectic MC carbide, eutectic MC and M2C carbides having extremely high hardness. The matrix of each specimen was fully pearlitic in the as-cast state but it was transformed by heat-treatments to martensite, tempered martensite and austenite. From these results, it becomes clear that MC carbide is a significant phase to improve the abrasion wear resistance of white cast iron.