Influence of.austempering process on.microstructures and.mechanical properties of.V-containing alloyed ductile iron
Jun-jun Cui 1,2 �� Li-qing .Chen1
1 State Key Laboratory of Rolling and Automation ,Northeastern University , Shenyang 110819 , Liaoning , China 2 College of Mechanical and Vehicle Engineering , Shenyang Institute of Technology , Fushun 113122 , Liaoning , China
Influence of.austempering process on.microstructures and.mechanical properties of.V-containing alloyed ductile iron
Jun-jun Cui 1,2 �� Li-qing .Chen1
1 State Key Laboratory of Rolling and Automation ,Northeastern University , Shenyang 110819 , Liaoning , China 2 College of Mechanical and Vehicle Engineering , Shenyang Institute of Technology , Fushun 113122 , Liaoning , China
ժҪ The in.uence of austempering time and vanadium addition on microstructure and mechanical properties of the alloyed ductile iron has been investigated. The 0.30.wt% V-containing and V-free alloyed ductile irons were .rstly austenitized at 850.��C for 1.h and then austempered in a salt bath at 300.��C for 2, 3 and 4.h, respectively. For the 0.3.wt% V-containing alloyed ductile iron, the transformation product (ausferrite) was .ner, and a small amount of martensite and a large amount of stable austenite were obtained after austempering for 2.h, while higher hardness and compressive strength of 62.8 HRC and 3000.MPa were achieved. For the V-free alloyed ductile iron, lower hardness and compressive strength were measured to be 56.8 HRC and 2320.MPa. As the austempering time increases, the amount of stable austenite decreases in the V-containing ductile iron, typically for the start of the second stage formation (retained austenite (�� r).���� + carbide). Based on this, it is assumed that the optimal processing window (OPW) was narrowed due to the addition of 0.30.wt% V as compared to the V-free ductile iron. When the hardness of 0.30.wt% V-alloyed ductile iron was higher than 59 HRC, the highest wear resist-ance was obtained. The mechanical cutting plays a dominant role in abrasive wear process.
Abstract��The in.uence of austempering time and vanadium addition on microstructure and mechanical properties of the alloyed ductile iron has been investigated. The 0.30.wt% V-containing and V-free alloyed ductile irons were .rstly austenitized at 850.��C for 1.h and then austempered in a salt bath at 300.��C for 2, 3 and 4.h, respectively. For the 0.3.wt% V-containing alloyed ductile iron, the transformation product (ausferrite) was .ner, and a small amount of martensite and a large amount of stable austenite were obtained after austempering for 2.h, while higher hardness and compressive strength of 62.8 HRC and 3000.MPa were achieved. For the V-free alloyed ductile iron, lower hardness and compressive strength were measured to be 56.8 HRC and 2320.MPa. As the austempering time increases, the amount of stable austenite decreases in the V-containing ductile iron, typically for the start of the second stage formation (retained austenite (�� r).���� + carbide). Based on this, it is assumed that the optimal processing window (OPW) was narrowed due to the addition of 0.30.wt% V as compared to the V-free ductile iron. When the hardness of 0.30.wt% V-alloyed ductile iron was higher than 59 HRC, the highest wear resist-ance was obtained. The mechanical cutting plays a dominant role in abrasive wear process.