我厂生产的18号步犁,犁铧和犁壁都采用冷硬铸铁,铸件的白口层要求均匀,深1．5~3毫米(开口处应全为白口);不允许有对火、裂纹、砂眼、气眼等铸造缺陷和明显的扭曲变形。几年来,我们在设备极其简陋,没有化验室的条件下,积累了一些经验。目前,成品率可达80%以上。 I plant production on the 18th step plow, ploughshare and plow wall are made of chilled cast iron, white castings require uniform depth of 1.5 to 3 mm (the opening should be all white); do not allow fire, Cracks, trachoma, eye defects such as casting defects and obvious distortion. Over the past few years, we have accumulated some experience in the equipment is extremely simple, without the laboratory. At present, the finished product rate can reach more than 80%.