1. The results show that the surface blacks are caused by oil incomplete combustion during heating process in oil-furnace which results in aggregated sooting on the surface of steel parts;
结果表明，海绵钳表面产生黑斑是在油炉加热过程中，加热油燃烧不充分所形成的炭黑滴落聚结在钢表面所致；
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2. The results show that the surface blacks are caused by oil incomplete combustion during heating process in oil-furnace which results in aggregated sooting on the surface of steel parts;
