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合理设计工装、浇注系统,采用覆膜砂制型壳,透气性好,浇注高镍奥氏体球铁阀杆螺母,达到精铸效果,生产成本低。熔炼时控制好化学成分,用QRMg7特制球化剂球化处理,75硅铁加锡、加铋孕育有利于提高球化率、塑性。热处理用1040℃以上高温正火,快速冷却可大幅度提高强度、伸长率。
Reasonable design tooling, pouring system, the use of coated sand molding shell, good ventilation, casting high-nickel austenitic ductile iron stem nut, casting effect, low production costs. Smelting control of chemical composition, with a special nodulizer QRMg7 spheroidization, 75 ferrosilicon plus tin, plus bismuth inoculation conducive to improve the rate of nodularity, plasticity. Heat treatment with normal temperature above 1040 ℃, rapid cooling can greatly improve the strength, elongation.