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:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><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:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">在不鏽鋼鑄造過程中，經(jīng)常會(huì)出現(xiàn)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(chǎn)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:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、塗料的透氣性差或者負(fù)壓不足，充填砂的透氣性差，不能及時(shí)排出型腔內(nèi)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:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、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(zhì)，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:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、泡沫模型氣化分解生成大量的氣體及殘留物不能及時(shí)排出鑄型，泡沫、塗料層填充乾砂的乾燥**，在液態(tài)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:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、由於澆注係統(tǒng)設(shè)計(jì)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(nèi)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:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、澆口杯與直澆道以及澆注係統(tǒng)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(fù)壓的作用下很容易形成夾砂及氣孔，這種現(xiàn)象可以用伯努利方程計(jì)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:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、型砂的粒度太細(xì)，粉塵含量高，透氣性差，負(fù)壓管道內(nèi)部堵塞造成負(fù)壓度失真，使型腔周圍的負(fù)壓值遠(yuǎn)遠(yuǎn)低於指示負(fù)壓，氣化物不能及時(shí)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:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、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(zhì)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:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、鋼水脫氧**、爐臺(tái)、爐內(nèi)、包內(nèi)除渣不淨(jìng)，**時(shí)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:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、內(nèi)澆道開設(shè)位置不合理，充型時(shí)形成死角區(qū)，由於型腔內(nèi)氣體壓力作用，使氣化殘留物積聚在死角處形成氣孔，內(nèi)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(nèi)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:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、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>