不锈钢铸造中气孔怎么处理

摘要：<span style="font-family:宋体;font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-family:宋体;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">不锈钢铸造中气孔怎么处理</span></span> </p> <span style="font-family:宋体;font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-size:small;"><span style="font-family:宋体;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">在不锈钢铸造过程中，经常会出现气孔问题，给铸件加工带来许多麻烦，气孔是金属液体在冷却期间和凝固过程中，析出的气体存留在铸锭中形成的气泡缺陷。下面就来分析一下产生气孔的主要原因</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 1</span></span><span style="font-family:宋体;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、涂料的透气性差或者负压不足，充填砂的透气性差，不能及时排出型腔内的气体及残留物，在充型压力下形成气孔。</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 2</span></span><span style="font-family:宋体;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、浇注速度太慢，未能充满浇口杯，暴露直浇道，卷入空气，吸入渣质，形成携裹气孔和渣孔。</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 3</span></span><span style="font-family:宋体;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、泡沫模型气化分解生成大量的气体及残留物不能及时排出铸型，泡沫、涂料层填充干砂的干燥**，在液态合金的高温包围下，裂解出大量的氢气和氧气侵入铸件是形成气孔的主要原因。</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 4</span></span><span style="font-family:宋体;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、由于浇注系统设计不合理，金属液的充型速度大于泡沫气化退让及气体排出速度，造成充型前沿将气化残留物包夹在金属液体中再次气化形成内壁烟黑色的分解气孔。</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 5</span></span><span style="font-family:宋体;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、浇口杯与直浇道以及浇注系统之间的连接处密封不好，尤其是直浇道与浇口杯的连接密封不好，在负压的作用下很容易形成夹砂及气孔，这种现象可以用伯努利方程计算和解释。</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 6</span></span><span style="font-family:宋体;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、型砂的粒度太细，粉尘含量高，透气性差，负压管道内部堵塞造成负压度失真，使型腔周围的负压值远远低于指示负压，气化物不能及时排出涂层而形成气孔或皱皮。</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 7</span></span><span style="font-family:宋体;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、浇注温度低，充型前沿金属液不能使泡沫充分气化，未分解的残余物质来不及浮集到冒口而凝固在铸件中形成气孔。</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 8</span></span><span style="font-family:宋体;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、钢水脱氧**、炉台、炉内、包内除渣不净，**时间过短，浇注过程中挡渣不力，浇注工艺不合理造成渣孔。</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 9</span></span><span style="font-family:宋体;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、内浇道开设位置不合理，充型时形成死角区，由于型腔内气体压力作用，使气化残留物积聚在死角处形成气孔，内浇道截面积过大，使充型速度大于泡沫气化退让速度，吞食泡沫，在合金内部分解气化，而气体无法排出形成气孔。</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 10</span></span><span style="font-family:宋体;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、浇口杯容量太小，金属液形成涡流，侵入空气生成气孔。</span></span> </p> <span style="font-family:宋体;font-size:small;"> </span>