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一、夹砂缺陷的形成夹砂是一种铸件的表面缺陷,它严重影响铸件的外砚质量,严重时使铸件报废。产生夹砂的原因主要是砂型表面层受热膨胀而拱起,当砂型表面层裂开但未脱落则形成夹砂,当砂型表面局部凸起但尚未裂开则形成鼠尾,当砂型表面层裂开并脱落则形成结疤。湿型(潮模)铸造较容易产生夹砂,现代化的高压造型流水生产线生产铸件时,防止夹砂缺陷已成为一个重要的问题,另外,干型铸造时也会产生夹砂缺陷。下面着重分析湿型铸造时夹砂缺陷的形成夹砂缺陷形成的机理大致如下:
First, the formation of sand-holding defects Sand is a casting surface defects, which seriously affect the quality of foreign Yan Yan casting, casting castings in serious cases scrapped. The main reason for the sand production is that the sand surface layer is heated and domed, and when the sand surface layer is cracked but does not fall off, sand is formed. When the sand surface is partially raised but not cracked, the tail is formed. When the sand surface layer is cracked Open and fall off the formation of scarring. Wet type (tide mode) casting is easier to produce nip, modern high-pressure molding production line to produce castings, to prevent nip defects has become an important issue, in addition, dry casting will also have nip defects. The following focuses on the analysis of the formation of sand-holding flaws during wet-type casting The mechanism of the formation of nodular flaws is roughly as follows: