|
Boron gray cast iron as a kind of gray cast iron , widely used in the automotive industry , mechanical industry, construction industry and other sectors . For the purpose of this paper, in order to improve the performance indicators of boron gray cast iron and boron-containing pig iron the boron additive casting into boron gray cast iron, and select the utilization of different proportions SiSr , SiFe its composite Inoculation obtained specimens tested under different conditions . On this basis , research the boron gray cast iron , graphite, eutectic , and boron carbide structure and quantitative metallographic analysis test ; different incubation conditions on the mechanical properties of boron gray cast iron and metallurgical quality indicators . The results show that the : with the SISR gave birth dose increases , the tensile strength of boron-containing gray cast iron , hardness incrementally . Quality of SiSr percentage from 0 to 0.12% of the tensile strength reached a peak , σ_b = 325MPa , and then with the quality of SiSr percentage increased from 0.18% to 0.36% , and gradually decreased to 305MPa . Percentage from 0 to 0.18% when SiSr quality hardness value increased from 231HBS to 273HBS . Hardness peak when the the SISR quality percentage of 0.18% , HB = 273. The Subsequently SISR mass percentage increased from 0.18% to 0.36% , the hardness value from 273HBS to 253HBS . Control standard , we can see that the the graphite distribution by the E-type into a type A distribution of eutectic is refined , boron carbide massive , uniformly distributed in the pearlite , the pearlite volume percentage of more than 95 % . Quantitative image analysis of test data form accurately reflect the characteristics of the boron gray cast iron microstructure . Graphite aspect ratio SiFe inoculation after a 0.12 % SISR 0.48 % to 3.79 ; carbide content in the matrix structure up to reach 4.58% , carbide aspect ratio of 2.06 , the performance index excellent . With the quality of SiSr percentage from 0 to 0.12% , maturity value varies between 0.96 to 1.11 , while the quality coefficient values ??vary within the range of 0.82 to 1.10 . When the percentage of the composite inoculant SiSr quality 0.12% , the maturity of the boron gray cast iron RG = 1.13 , quality factor Qi = 1.10 , excellent metallurgical quality indicators have reached the . To sum up , the experimental using a SiSr SIFE composite inoculant gave birth to good effect . Ratio of 0.12% SiSr 0.48% SiFe , the resulting microstructure and mechanical properties of boron gray cast iron optimal .
|