Research On The Effects Of Modified Superfine SiC Powders On Microstructure And Properties Of Low-temperature High-toughness Nodular Cast Iron

Nowadays nodular cast iron is a kind of widely used metal structure material, due to the good mechanical properties and good maching performance nodular cast iron has been widely welcomed in such aspects as industrial machinery. In as a result of the working environment of nodular cast iron is more for low temperature condition on wind power materials, therefore, the nodular cast iron is needed to maintain the strength and has good low temperature impact toughness at the same time. In addition, in the respect such as shipping, the relatively of nodular cast iron is also large which needs good corrosion resistance. As the high melting point, high modulus and many properties such as oxidation resistance, the modified superfine SiC powders have been used in the field of casting alloy strength.Two sets of samples are mainly discussed in this paper: one group of the samples is five batch furnace without any additives of the casting block. Another group is added five different modification of superfine SiC powders of the casting block under the same conditions. Take experiment on the five kinds of blocks with or without powders. Metallographic observation, grade of nodulizing and content test, tensile test, brinell hardness test, elastic modulus, low temperature impact test and immersion corrosion test have been taken in this paper. And the effect of different modified superfine SiC powders on microstructure and mechanical properties of nodular cast iron have been further discussedThe results show that: After adding different modification of superfine SiC powders, the ferrite content of nodular cast iron matrix organization has increased, the grain get refinement and the distribution of graphite ball have been uniformed, roundness and small, the amount of graphite balls getting more and the spheroidization rate is getting better. Multiple performance is better than the sample that without the modified superfine SiC powders: Most obvious effect of the increase of tensile strength is sample B, increased by 4.5%; Elongation increased the most obvious is sample D, increased by 19.8%. Elastic modulus increase the most obvious is sample A, increased by 9.2%. The change of hardness value is not obvious, but the hardness value of sample D reduced by 4.5%. Low temperature impact toughness has improved, among which the effect of sample D increase is most obvious, under the condition of room temperature,-20℃and-40℃, the low temperature impact toughness increased by 2.5%, 10.3% and 2.5% respectively. The ability of acid and alkali corrosion resistant of sample B enhanced obviously. Overall, sample D shows excellent comprehensive performance.