The structure and properties of high chromium white cast iron in different treatment states were studied. Using X ray diffraction method, observing their metallograph and measuring their microhardness, the phases inv...The structure and properties of high chromium white cast iron in different treatment states were studied. Using X ray diffraction method, observing their metallograph and measuring their microhardness, the phases involved in the iron were determined. The notch toughness, macrohardness and the fractograph of the samples are compared and their performance was determined, which mainly depends on the matrix structure. Relatively good comprehensive properties can be obtained in the tempering state. Improvements have been made on the commonly used tempering standard. Tempering for a short period at low temperature can improve the materials′ service performance obviously.展开更多
The effect of manganese on the as-cast structure and hardening behavior of high chromium white cast iron subjected to sub-critical treatment was studied.The results indicate that the fraction of retained austenite and...The effect of manganese on the as-cast structure and hardening behavior of high chromium white cast iron subjected to sub-critical treatment was studied.The results indicate that the fraction of retained austenite and the manganese distribution in as-cast alloys are controlled by manganese content.The manganese distribution in as-cast alloys is not homogeneous.The manganese content in carbide is higher than that in matrix.Whether the secondary hardening occurs or not and the peak hardness of secondary hardening is controlled by manganese content in retained austenite in as-cast structure.Higher manganese content can cause more retained austenite.The secondary hardening occurs in sub-critical treating process if the fraction of retained austenite is high.展开更多
The valence electron structure of alloying austenite of 3C-15Cr high chromium white cast iron with different Mn contents from 1% to 6% is analyzed by BLD method and EET. Results show that the addition of Mn has major ...The valence electron structure of alloying austenite of 3C-15Cr high chromium white cast iron with different Mn contents from 1% to 6% is analyzed by BLD method and EET. Results show that the addition of Mn has major influence on the valence electron structure of the alloying austenite, especially on that of Fe-C, Fe-C-Cr and Fe-C-Cr-Mn unit cells of it. The effect becomes weak when Mn content is over 4%. Based on the effect of n~, F~~, the weighting of each unit cell and the degree of undercooling on phase transition of the aus- tenite, we can calculate the retained austenite content of as-cast structure of the high chromium white cast iron. The calculation results coincide well with those of the experiment. The phase transition characters of the austenite in high chromium white cast iron can be forecasted through valence electron structure analysis of alloying austenite by BLD method and EET on the basis of Fe-C-Cr equilibrium phase diagram.展开更多
The effect of austempering temperature on the microstructure and properties of a high chromium white cast iron was investigated with the Rietveld refinement method. The result shows that the upper bainite exists in th...The effect of austempering temperature on the microstructure and properties of a high chromium white cast iron was investigated with the Rietveld refinement method. The result shows that the upper bainite exists in the sampie austempered at 623 K and the martensite, lower bainite, M7C3, and retained austenite exist in the samples austempered at 563 K and 593 K. The relative content of the retained austenite increases with increasing the austemper- ing temperature from 563 K to 623 K. The higher hardness, impact toughness and impact abrasive wear resistance can be obtained for the specimen austempered at 593 K.展开更多
文摘The structure and properties of high chromium white cast iron in different treatment states were studied. Using X ray diffraction method, observing their metallograph and measuring their microhardness, the phases involved in the iron were determined. The notch toughness, macrohardness and the fractograph of the samples are compared and their performance was determined, which mainly depends on the matrix structure. Relatively good comprehensive properties can be obtained in the tempering state. Improvements have been made on the commonly used tempering standard. Tempering for a short period at low temperature can improve the materials′ service performance obviously.
文摘The effect of manganese on the as-cast structure and hardening behavior of high chromium white cast iron subjected to sub-critical treatment was studied.The results indicate that the fraction of retained austenite and the manganese distribution in as-cast alloys are controlled by manganese content.The manganese distribution in as-cast alloys is not homogeneous.The manganese content in carbide is higher than that in matrix.Whether the secondary hardening occurs or not and the peak hardness of secondary hardening is controlled by manganese content in retained austenite in as-cast structure.Higher manganese content can cause more retained austenite.The secondary hardening occurs in sub-critical treating process if the fraction of retained austenite is high.
文摘The valence electron structure of alloying austenite of 3C-15Cr high chromium white cast iron with different Mn contents from 1% to 6% is analyzed by BLD method and EET. Results show that the addition of Mn has major influence on the valence electron structure of the alloying austenite, especially on that of Fe-C, Fe-C-Cr and Fe-C-Cr-Mn unit cells of it. The effect becomes weak when Mn content is over 4%. Based on the effect of n~, F~~, the weighting of each unit cell and the degree of undercooling on phase transition of the aus- tenite, we can calculate the retained austenite content of as-cast structure of the high chromium white cast iron. The calculation results coincide well with those of the experiment. The phase transition characters of the austenite in high chromium white cast iron can be forecasted through valence electron structure analysis of alloying austenite by BLD method and EET on the basis of Fe-C-Cr equilibrium phase diagram.
基金Item Sponsored by Key Project on Natural Science for the Education Department of Anhui Province (2006KJ080A)
文摘The effect of austempering temperature on the microstructure and properties of a high chromium white cast iron was investigated with the Rietveld refinement method. The result shows that the upper bainite exists in the sampie austempered at 623 K and the martensite, lower bainite, M7C3, and retained austenite exist in the samples austempered at 563 K and 593 K. The relative content of the retained austenite increases with increasing the austemper- ing temperature from 563 K to 623 K. The higher hardness, impact toughness and impact abrasive wear resistance can be obtained for the specimen austempered at 593 K.
