Both the production process and the chemical composition of Sx were studied, and the serialization of low carbon ductile iron was also discussed. It was indicated that Sx modifier was sensitive to the carbon equivalen...Both the production process and the chemical composition of Sx were studied, and the serialization of low carbon ductile iron was also discussed. It was indicated that Sx modifier was sensitive to the carbon equivalent (CE) of molten iron and to some alloying elements too. When the CE of molten iron and the contents of alloying elements were changed, the content of Sx must be revised with the change correspondingly. Low carbon ductile iron can be stably changed into the one that non-carbon acicular ferrite and retained austenite (about 25%-28%) by quasi-casting bainitic process of using Sx-2 modifier treated Si-Mn-Cr-Cu-alloyed low carbon molten iron. The austenitic low carbon as-cast ductile iron could be obtained by the Ni-Si-Cr 35 5 2 percent alloys molten iron with less than 2% carbon treated by type Sx-3 modifier. The high-toughness ferritic low carbon as-cast ductile iron which contained more than 85 % ferrite in matrix could be got after the molten iron treated by type Sx-4 modifier, and it’s elongation was more than 10 %.展开更多
The objective of this study is to define agricultural water resources security and its connotation and extension. The definitions of water security, water resources security, and water environment security were summar...The objective of this study is to define agricultural water resources security and its connotation and extension. The definitions of water security, water resources security, and water environment security were summarized, and their relationship was differentiated and analyzed. Based on these, the elements of the conception of agricultural water resources security were hashed and the conception was defined. Agricultural water resources security is the provision of water resource that ensures protection of agriculture against threat, hazards, destruction, and loss. Moreover, the connotation and extension of agricultural water resources security were ascertained. In detail, the connotation of the definition has natural attributes, socioeconomic attributes, and cultural attributes. The extensions of agricultural water resources security include both broad and narrow ones, as well as, food security, agroenvironmental security, agroeconomic security, rural society security, etc. The definition will serve as the frame of reference for developing the researches, limiting the frame of the theory, and founding a appraising system for agricultural water resources security.展开更多
基金The paper is support by Foundation Key Project of Yunnan:Study on inoculated theory and reliability of low carbon ductileiron, NO. 1999E0004Z
文摘Both the production process and the chemical composition of Sx were studied, and the serialization of low carbon ductile iron was also discussed. It was indicated that Sx modifier was sensitive to the carbon equivalent (CE) of molten iron and to some alloying elements too. When the CE of molten iron and the contents of alloying elements were changed, the content of Sx must be revised with the change correspondingly. Low carbon ductile iron can be stably changed into the one that non-carbon acicular ferrite and retained austenite (about 25%-28%) by quasi-casting bainitic process of using Sx-2 modifier treated Si-Mn-Cr-Cu-alloyed low carbon molten iron. The austenitic low carbon as-cast ductile iron could be obtained by the Ni-Si-Cr 35 5 2 percent alloys molten iron with less than 2% carbon treated by type Sx-3 modifier. The high-toughness ferritic low carbon as-cast ductile iron which contained more than 85 % ferrite in matrix could be got after the molten iron treated by type Sx-4 modifier, and it’s elongation was more than 10 %.
文摘The objective of this study is to define agricultural water resources security and its connotation and extension. The definitions of water security, water resources security, and water environment security were summarized, and their relationship was differentiated and analyzed. Based on these, the elements of the conception of agricultural water resources security were hashed and the conception was defined. Agricultural water resources security is the provision of water resource that ensures protection of agriculture against threat, hazards, destruction, and loss. Moreover, the connotation and extension of agricultural water resources security were ascertained. In detail, the connotation of the definition has natural attributes, socioeconomic attributes, and cultural attributes. The extensions of agricultural water resources security include both broad and narrow ones, as well as, food security, agroenvironmental security, agroeconomic security, rural society security, etc. The definition will serve as the frame of reference for developing the researches, limiting the frame of the theory, and founding a appraising system for agricultural water resources security.
