J.Rassizadehghani
,
H.Najafi
,
M.Emamy
,
G.Eslami-Saeen
材料科学技术（英文）
The influence of microalloying additions on the mechanical properties of a low-carbon cast steel containing combinations of V, Nb, and Ti in the as-cast condition was evaluated. Tensile and hardness test results indicated that good combinations of strength and ductility could be achieved by V and Nb additions. While the yield strength and UTS (ultimate tensile strength) increased up to the range of 378–435 MPa and 579–596 MPa, respectively in the microalloyed heats, their total elongation ranged from 18% to 23%. The presence of Ti, however, led to some reduction in the strength. Microstructural studies including scanning electron microscopy (SEM) and optical microscopy revealed that coarse TiN particles were responsible for this behavior. The Charpy impact values of all compositions indicated that microalloying additions significantly decreased the impact energy and led to the dominance of cleavage facets on the fracture surfaces. It seems that the increase in the hardness of coarse ferrite grains due to the precipitation hardening is the main reason for brittle fracture.
关键词:
Cast steel
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Shengjie YAO
,
Shengjie YAO
,
Xianghua LIU
,
Guodong WANG
金属学报(英文版)
doi:10.1016/S1006-7191(08)60064-2
Ultrafine austenite grains (UFAGs) with size of 1-5 μm were prepared through repetitive treatment, four times, of rapid heating and quenching, and the growth behaviors of these UFAGs during both the reheating and cooling stages were investigated. The results indicated that UFAGs without pinning particles appeared with significant coarsening when the reheating temperature reached 1000℃. Although coarsening still occurred in the cooling stage, the growth was obscured during the isothermal holding process at temperatures between 900 ℃ and Ar3
关键词:
Ultrafine austenite grain
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