A new plastic deformation process for gray cast iron named cylinder covered compression （CCC） was developed. By CCC process, gray cast iron （GCI） specimens, which are embedded in steel cylinders, were hot compress...A new plastic deformation process for gray cast iron named cylinder covered compression （CCC） was developed. By CCC process, gray cast iron （GCI） specimens, which are embedded in steel cylinders, were hot compressed up to 80% reduction in height without the cracking problem. It was clearly observed that the uniform distribution of directional graphite flakes appeared after more than 45 % reduction hot compression. The strength, ductility, and microhardness of GCI after 80% reduction deformation were significantly enhanced： the tensile strength varied from 117 MPa to 249 MPa, while the total elongation varied from 0 to 5.2%, and the microhardness varied from 153 HV to 217 HV. It was shown that the tensile fracture surface presented ductility characters after more than 45% reduction hot deformation.展开更多
The hot deformation characteristics of ductile iron are studied in the temperature range of 973 to 1273K and strain rate range of 0.001 to 1 s-1 by using hot compression tests.Processing maps for hot working are devel...The hot deformation characteristics of ductile iron are studied in the temperature range of 973 to 1273K and strain rate range of 0.001 to 1 s-1 by using hot compression tests.Processing maps for hot working are developed on the basis of the variations of efficiency of power dissipation with temperature and strain rate.The results reveal that the flow stress of ductile iron is sensitive to strain rate.In the processing map under strain of 0.7,a domain is centered at 1273 K and 1 s-1,and the maximum efficiency is more than 36%.According to the maps,the zone with the temperature range of 1173 to 1273 K and strain rate range of 0.1 to 1 s-1 may be considered as the optimum region for hot working.展开更多
基金Item Sponsored by National Natural Science Foundation of China (50271060 ,50371074) Natural Science Foundation of Hebei Province of China (503291)
文摘A new plastic deformation process for gray cast iron named cylinder covered compression （CCC） was developed. By CCC process, gray cast iron （GCI） specimens, which are embedded in steel cylinders, were hot compressed up to 80% reduction in height without the cracking problem. It was clearly observed that the uniform distribution of directional graphite flakes appeared after more than 45 % reduction hot compression. The strength, ductility, and microhardness of GCI after 80% reduction deformation were significantly enhanced： the tensile strength varied from 117 MPa to 249 MPa, while the total elongation varied from 0 to 5.2%, and the microhardness varied from 153 HV to 217 HV. It was shown that the tensile fracture surface presented ductility characters after more than 45% reduction hot deformation.
基金Item Sponsored by National Natural Science Foundation of China and Baosteel(50271061,50371074)
文摘The hot deformation characteristics of ductile iron are studied in the temperature range of 973 to 1273K and strain rate range of 0.001 to 1 s-1 by using hot compression tests.Processing maps for hot working are developed on the basis of the variations of efficiency of power dissipation with temperature and strain rate.The results reveal that the flow stress of ductile iron is sensitive to strain rate.In the processing map under strain of 0.7,a domain is centered at 1273 K and 1 s-1,and the maximum efficiency is more than 36%.According to the maps,the zone with the temperature range of 1173 to 1273 K and strain rate range of 0.1 to 1 s-1 may be considered as the optimum region for hot working.
