不鏽鋼鑄造中氣孔怎麼處理

摘要：<span style="font-family:宋體;font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";"><span style="font-size:small;">不鏽鋼鑄造中氣孔怎麼處理</span></span> </p> <span style="font-family:宋體;font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-size:small;"><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">在不鏽鋼鑄造過程中，經常會出現氣孔問題，給鑄件加工帶來許多麻煩，氣孔是金屬液體在冷卻期間和凝固過程中，析出的氣體存留在鑄錠中形成的氣泡缺陷。下麵就來分析一下產生氣孔的主要原因</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 1</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">、塗料的透氣性差或者負壓不足，充填砂的透氣性差，不能及時排出型腔內的氣體及殘留物，在充型壓力下形成氣孔。</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 2</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">、澆注速度太慢，未能充滿澆口杯，暴露直澆道，卷入空氣，吸入渣質，形成攜裹氣孔和渣孔。</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 3</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">、泡沫模型氣化分解生成大量的氣體及殘留物不能及時排出鑄型，泡沫、塗料層填充乾砂的乾燥**，在液態合金的高溫包圍下，裂解出大量的氫氣和氧氣侵入鑄件是形成氣孔的主要原因。</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 4</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">、由於澆注係統設計不合理，金屬液的充型速度大於泡沫氣化退讓及氣體排出速度，造成充型前沿將氣化殘留物包夾在金屬液體中再次氣化形成內壁煙黑色的分解氣孔。</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 5</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">、澆口杯與直澆道以及澆注係統之間的連接處密封不好，尤其是直澆道與澆口杯的連接密封不好，在負壓的作用下很容易形成夾砂及氣孔，這種現象可以用伯努利方程計算和解釋。</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 6</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">、型砂的粒度太細，粉塵含量高，透氣性差，負壓管道內部堵塞造成負壓度失真，使型腔周圍的負壓值遠遠低於指示負壓，氣化物不能及時排出塗層而形成氣孔或皺皮。</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 7</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">、澆注溫度低，充型前沿金屬液不能使泡沫充分氣化，未分解的殘餘物質來不及浮集到冒口而凝固在鑄件中形成氣孔。</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 8</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">、鋼水脫氧**、爐台、爐內、包內除渣不淨，**時間過短，澆注過程中擋渣不力，澆注工藝不合理造成渣孔。</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 9</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">、內澆道開設位置不合理，充型時形成死角區，由於型腔內氣體壓力作用，使氣化殘留物積聚在死角處形成氣孔，內澆道截麵積過大，使充型速度大於泡沫氣化退讓速度，吞食泡沫，在合金內部分解氣化，而氣體無法排出形成氣孔。</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 10</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">、澆口杯容量太小，金屬液形成渦流，侵入空氣生成氣孔。</span></span> </p> <span style="font-family:宋體;font-size:small;"> </span>