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我厂曲轴系采用铸态含铜球墨铸铁,不进行热处理。为了保证曲轴的机械性能可达到QT60—2—1.5(即σb≥60公斤/毫米~2、δ≥2%、αk≥1.5公斤·米/厘米~2)的要求,除工艺、操作等方面采取一定措施外,对化学成分特别是磷、硫量也应进行较严格的控制。过去在南京汽车厂试制时曾得出如下结论:铸态球铁曲轴化学成分需控制在表1所示的范围内,其中磷量不得超过0.07%,否则冲击韧性便会显著降低(见表2);硫量过高,则易造成球化不良。为得到所规定的化学成分,对原材料——铸造生铁也就提出了低磷(P≤0.07%)、低硫(S≤0.04%)的要求。
I plant crankshaft cast with ductile iron cast iron, without heat treatment. In order to ensure the mechanical properties of the crankshaft can reach QT60-2-1.5 (ie σb ≥ 60 kg / mm 2, δ ≥ 2%, αk ≥ 1.5 kg · m / cm 2) requirements, in addition to process, operation and so on Certain measures, the chemical composition, especially phosphorus, sulfur should also be more stringent control. In the past in the trial of Nanjing Automobile Factory had reached the following conclusions: As cast iron crankshaft chemical composition to be controlled within the range shown in Table 1, in which the amount of phosphorus should not exceed 0.07%, otherwise the impact toughness will be significantly reduced (see Table 2 ); Sulfur is too high, it is easy to cause bad ball. In order to obtain the specified chemical composition, low phosphorus (P≤0.07%) and low sulfur (S≤0.04%) requirements have also been put forward for the raw material cast iron.