飞轮壳体消失模铸造的缺陷分析及防止
发布时间：2020-04-17 10:46
<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; clear: both; color: rgb(51, 51, 51); font-family: mp-quote, -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; text-align: justify; white-space: normal; box-sizing: border-box; line-height: 1.75;"><span style="margin: 0px; padding: 0px; color: rgb(123, 12, 0);"><strong style="margin: 0px; padding: 0px;"><span style="margin: 0px; padding: 0px; box-sizing: border-box;">1 前言</span></strong></span></p><p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; clear: both; color: rgb(51, 51, 51); font-family: mp-quote, -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; text-align: justify; white-space: normal; box-sizing: border-box; line-height: 1.75;"><span style="margin: 0px; padding: 0px; color: rgb(123, 12, 0);"><strong style="margin: 0px; padding: 0px;"><span style="margin: 0px; padding: 0px; box-sizing: border-box;"><br/></span></strong></span></p><p></p><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">经过近半个多世纪大力推广和迅速发展,消失模铸造工艺技术逐步迈入成熟阶段,其产品由简单的铸件发展到可生产形状复杂的铸件,材质种类也越来越多,质量从几十克至几十吨。消失模铸造工艺的特点之一就是集体作业团队协作,一个合格毛坯的诞生都必须经过数道工序和数个工人的默契配合才能实现。所以铸件毛坯缺陷的产生是在整个的工艺流程过程中一步步积累﹑放大﹑延伸﹑ 最终导致铸件毛坯报废。</span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;"><br/></span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">要根本解决铸件毛坯报废,首先要对飞轮壳体铸件变形、夹渣,铁包砂,冷隔缺陷产生的原因进行认真仔细分析,并通过工艺试验逐步改进和优化,使生产工艺和生产流程更合理更科学,并用科学合理的工艺作为执行标准,严格执行,认真控制与监督,才能保证产品的质量稳定及高工艺成品率和产品合格率。</span></section><p></p><p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; clear: both; color: rgb(51, 51, 51); font-family: mp-quote, -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; text-align: justify; white-space: normal; box-sizing: border-box; line-height: 1.75;"><br/></p><p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; clear: both; color: rgb(51, 51, 51); font-family: mp-quote, -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; text-align: justify; white-space: normal; box-sizing: border-box; line-height: 1.75;"><br/></p><p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; clear: both; color: rgb(51, 51, 51); font-family: mp-quote, -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; text-align: justify; white-space: normal; box-sizing: border-box; line-height: 1.75;"><span style="margin: 0px; padding: 0px; color: rgb(123, 12, 0);"><strong style="margin: 0px; padding: 0px;"><span style="margin: 0px; padding: 0px; box-sizing: border-box;">2 变形缺陷及控制</span></strong></span></p><p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; clear: both; color: rgb(51, 51, 51); font-family: mp-quote, -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; text-align: justify; white-space: normal; box-sizing: border-box; line-height: 1.75;"><span style="margin: 0px; padding: 0px; color: rgb(123, 12, 0);"><strong style="margin: 0px; padding: 0px;"><span style="margin: 0px; padding: 0px; box-sizing: border-box;"><br/></span></strong></span></p><p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; clear: both; color: rgb(51, 51, 51); font-family: mp-quote, -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; text-align: justify; white-space: normal; box-sizing: border-box; line-height: 1.75;"><strong style="margin: 0px; padding: 0px;"><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">2.1 原因</span></strong><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;"></span></p><p></p><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">图2.1所示为三种规格的飞轮壳体,其材质为HT250,主要壁厚为6mm。飞轮壳体铸件为薄壁类壳体铸件,内腔较大,铸件结构不连续,在成型﹑干燥﹑组装﹑浸涂和装箱振实过程中易产生变形,在试生产过程中其废品率高达35%左右。铸件变形主要是因为模型在成型﹑干燥﹑组装﹑涂覆和振实装箱等过程操作不妥和控制不严所致。如泡沫模型在出模时的操作控制﹑干燥时的摆放形式和涂料涂敷的操作都要有严格操作工艺和控制措施,振实装箱时型砂在不同方向施加给泡沫模型的力大小不一致而导致。</span></section><p></p><p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; clear: both; color: rgb(51, 51, 51); font-family: mp-quote, -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; text-align: justify; white-space: normal; box-sizing: border-box; line-height: 1.75;"><img class="rich_pages" src="https://mmbiz.qpic.cn/mmbiz_png/TCIDp9rFWaZALOokCfncnJuKhQOAibibxlfSWSTIvKgvC6cSkv1EM6cibibficAd5Be0zROGmxdViahAWTuMQmCDU0kg/640?wx_fmt=png"/><br/></p><p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; clear: both; color: rgb(51, 51, 51); font-family: mp-quote, -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; text-align: justify; white-space: normal; box-sizing: border-box; line-height: 1.75;"><strong style="margin: 0px; padding: 0px;"><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">2.2 控制</span></strong><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;"></span></p><p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; clear: both; color: rgb(51, 51, 51); font-family: mp-quote, -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; text-align: justify; white-space: normal; box-sizing: border-box; line-height: 1.75;"><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">通过分析,认为首先对泡沫模样的预发泡的密度和粒度进行严格的质量控制﹑要求使用高强度低密度的发炮珠粒进行成型;其次对涂料的配制工艺进行改进增加涂料对泡沫模样的抗变形能力和附着力;提高泡沫模样的强度;同时在泡沫模样壳体上口增加支撑筋, 利用支撑筋对泡沫模样的反作用力来平衡浸涂和振实中涂料和型砂对模型的作用力,从而起到防止变形作用。</span></p><p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; clear: both; color: rgb(51, 51, 51); font-family: mp-quote, -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; text-align: justify; white-space: normal; box-sizing: border-box; line-height: 1.75;"><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;"><br/></span></p><p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; clear: both; color: rgb(51, 51, 51); font-family: mp-quote, -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; text-align: justify; white-space: normal; box-sizing: border-box; line-height: 1.75;"><span style="margin: 0px; padding: 0px; color: rgb(123, 12, 0);"><strong style="margin: 0px; padding: 0px;"><span style="margin: 0px; padding: 0px; box-sizing: border-box;">3夹渣缺陷及控制</span></strong></span></p><p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; clear: both; color: rgb(51, 51, 51); font-family: mp-quote, -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; text-align: justify; white-space: normal; box-sizing: border-box; line-height: 1.75;"><span style="margin: 0px; padding: 0px; color: rgb(123, 12, 0);"><strong style="margin: 0px; padding: 0px;"><span style="margin: 0px; padding: 0px; box-sizing: border-box;"><br/></span></strong></span></p><p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; clear: both; color: rgb(51, 51, 51); font-family: mp-quote, -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; text-align: justify; white-space: normal; box-sizing: border-box; line-height: 1.75;"><strong style="margin: 0px; padding: 0px;"><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">3.1 原因</span></strong><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;"></span></p><p></p><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">飞轮壳体铸件初期夹渣缺陷废品率高达45%,产生夹渣缺陷的来源一方面是在浇注铸件时,模型产生大量固相和液相产物,当固相和液相产物不能及时排出,残留</span><span style="margin: 0px; padding: 0px; font-size: 14px;">在铸件内部</span><span style="margin: 0px; padding: 0px; font-size: 14px;">,就会形成消失模特有</span><span style="margin: 0px; padding: 0px; font-size: 14px;">的夹渣缺陷。</span><span style="margin: 0px; padding: 0px; font-size: 14px;">模型密度越大产生的固相和液相产物就越多</span><span style="margin: 0px; padding: 0px; font-size: 14px;">;另一方面,浇注过程中铁水渗入模型的涂料冲刷进入液态金属,铸件凝固后形成夹渣缺陷,两种原因产生的夹</span><span style="margin: 0px; padding: 0px; font-size: 14px;">渣缺陷外观特征都为黑色块状分布。</span><span style="margin: 0px; padding: 0px; font-size: 14px;">图</span><span style="margin: 0px; padding: 0px; font-size: 14px;">3.1为铸件夹渣缺陷,图3.2为</span><span style="margin: 0px; padding: 0px; font-size: 14px;">铸件碳缺陷图。</span></section><p></p><p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; clear: both; color: rgb(51, 51, 51); font-family: mp-quote, -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; white-space: normal; text-align: center;"><img class="rich_pages" src="https://mmbiz.qpic.cn/mmbiz_png/TCIDp9rFWaZALOokCfncnJuKhQOAibibxlZGqsAJSnZ378kicrwTxIMZ7ypz3fmOPiaibEggLXXTicndMr8gf5KdQSVg/640?wx_fmt=png"/></p><p></p><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;"><br/></span></section><section><strong style="margin: 0px; padding: 0px;"><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">3.2 控制</span></strong><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;"></span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">可通过采用低密度高强度的泡沫模样、设置合理浇冒口系统和正确的浇注操作、提高浇注温度、增加涂层和型砂透气性、提高泡沫模样的表面质量以防止涂料渗入泡沫模样等措施来防治夹渣缺陷的产生。然而如果增大负压、提高浇注温度和涂层及砂型的透气性又会引起渗铁、粘砂等其他缺陷,所以须在泡沫模样密度控制和浇冒口系统设计方面突破。</span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;"><br/></span></section><section><strong style="margin: 0px; padding: 0px;"><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">3.2.1 采用低密度高强度泡沫模样</span></strong><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;"></span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">模型密度越小产生的固相和液相产物越少,模型密度的大小是通过预发珠粒的密度来控制。飞轮壳体铸件主要壁厚为6毫米,属薄壁件,因此,预发泡珠粒密度过小势必影响模型的表面的质量,同时,涂料更易渗入泡沫模样中,反而增加夹渣的机率。通过分析,选取24~26g/ L,26~28g/L,28~30g/L等三种珠粒预发密度对模型质量和夹渣缺陷进行对比。对各种密度进行小批量试验,结果发现预发泡密度在26-28g/L 时,其各项技术指标相对较好,通过使用26-28 g/L的预发泡珠粒其箱体的夹渣废品率小于5%。</span></section><section><br/></section><section><strong style="margin: 0px; padding: 0px;"><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">3.2.2 采用合理浇注系统</span></strong><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;"></span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">浇注系统是消失模铸造的关键工艺,经过初步计算确定浇注系统各组元的截面积,然后经工艺试验进行改进和优化处理,使之合理正确。目前多数浇注系统采用EPS 泡沫板材经手工切割粘接而成,加工以及使用当中有相当大的局限性,表现在:</span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;"><br/></span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">(1)采用电阻丝切割,切割面粗糙,且原材料为泡沫板材,主要使用的包装材料,预发泡密度小(18~20g/L),造成成型过程中的珠粒间隙大,易渗入涂料;</span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;"><br/></span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">(2)由板材切割成的浇注系统形状为实心正方体,有棱有角,浇注时铁水冲刷大,高温铁水不能直接进入浇道底部,铁水降温大,在浇注初期反喷现象严重。</span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;"><br/></span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">鉴于以上原因,改进直浇道成型,改用中空圆柱形直浇道, 设计模具,直接通过成型机成型,使浇注系统的制造与泡沫模样的制造有了相同的过程,通过控制预发泡密度来控制表面粗糙度。其次,优化直浇道形状,为保证铁水温度以及减小铁水对涂层的冲刷,在形状上采用圆柱形直浇道。再者,根据消失模铸造原理,在浇注过程中高温铁水要将EPS泡沫气化,此过程势必会造成铁水温度的损失,因此在保证强度的情况下,EPS泡沫使用越少越好,为此将其做成中空。</span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;"><br/></span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">中空圆柱形直浇道具体有以下优点:圆柱形表面积小且成型制造,表面平整光滑,减少铸件形成夹渣的倾向;浇注初期,铁水直接进入浇道底部,铁水温度损耗少,缩短了浇注时间。</span></section><section><br/></section><section><span style="margin: 0px; padding: 0px; color: rgb(123, 12, 0);"><strong style="margin: 0px; padding: 0px;"><span style="margin: 0px; padding: 0px; box-sizing: border-box;">4 铁包砂缺陷分析及控制</span></strong></span></section><section><span style="margin: 0px; padding: 0px; color: rgb(123, 12, 0);"><strong style="margin: 0px; padding: 0px;"><span style="margin: 0px; padding: 0px; box-sizing: border-box;"><br/></span></strong></span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">铸件死角是铸造的一大难题,不论是湿型砂铸造还是消失模铸造,砂子都不易填补该区,消失模铸造中,在造型时砂子不易流入死角区,砂子的紧实度降低,没有足够的型砂支撑涂层,在铁水的高温度、高密度、高流量,极易冲破涂层产生渗铁等缺陷,图4.1为铸件铁包砂缺陷图。</span></section><p></p><p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; clear: both; color: rgb(51, 51, 51); font-family: mp-quote, -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; white-space: normal; text-align: center;"><img class="rich_pages" src="https://mmbiz.qpic.cn/mmbiz_png/TCIDp9rFWaZALOokCfncnJuKhQOAibibxlH9MGFYFOrgCmCSpdM6WnQ6p0pEgPIfibwIQp7d8qiaIBiaKYfPPWQNUvQ/640?wx_fmt=png"/></p><p></p><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">针对此种情况,根据经验调整振动频率,采用三维振实台,振动加速度的范围在1-2g,根据不同铸件调整振实时间和振实频率。振实时间短、振实频率低时,振实效果不理想;振实时间长,振实频率高时,往往会把已经振实的型砂又再次振松。经过试验将振实时间控制在20s,振实频率为45-50Hz,振幅在1~1.5mm范围。</span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;"><br/></span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">埋砂方式为加入底砂然后振实, 先放入泡沫模样,然后分两次进行填砂,第一次填砂的高度和箱体平或略高一些,目的是将各个不易进砂的位置,通过人工辅助埋砂手段加满加实型砂,确保死角处的砂子紧实高。第二次填砂是覆盖砂,覆盖砂要有足够的厚度,从而保证足够的吃砂量。型砂的紧实度高,渗铁的问题基本得到解决,铁包砂的缺陷得到控制。</span></section><section><br/></section><section><br/></section><section><span style="margin: 0px; padding: 0px; color: rgb(123, 12, 0);"><strong style="margin: 0px; padding: 0px;"><span style="margin: 0px; padding: 0px; box-sizing: border-box;">5 冷隔缺陷分析和控制</span></strong></span></section><section><span style="margin: 0px; padding: 0px; color: rgb(123, 12, 0);"><strong style="margin: 0px; padding: 0px;"><span style="margin: 0px; padding: 0px; box-sizing: border-box;"><br/></span></strong></span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">冷隔是飞轮壳体薄壁铸件的又一个主要缺陷。薄壁的壳体铸件在浇注时,铁水流动速度比厚大</span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">铸件慢,流动时间长,温度降低快,在铁水最后到达的地方,因温度消耗热量过大,出现不能完全融合,而形成冷隔。</span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;"><br/></span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">针对此缺陷,采可通过提高铁水的出炉温度和浇注温度以及浇注速度来解决。将铁水的出炉温度提高到1560℃,浇注温度不低于1480℃,同时在浇注过程操作上下功夫制定了快速浇注的操作原则, 使冷隔缺陷的问题达到了解决。</span></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;"><br/></span></section><p></p><p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; clear: both; color: rgb(51, 51, 51); font-family: mp-quote, -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; white-space: normal; text-align: center;"><img class="rich_pages" src="https://mmbiz.qpic.cn/mmbiz_png/TCIDp9rFWaZALOokCfncnJuKhQOAibibxlVjnMlt53cPIuQxYqyd0SbINxWbUzMR9hv3CIHEuBRyM8UFjwiafO0Kg/640?wx_fmt=png"/></p><p></p><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;"><br/></span></section><section><strong style="margin: 0px; padding: 0px;"><span style="margin: 0px; padding: 0px; box-sizing: border-box; color: rgb(123, 12, 0);">6结论</span></strong></section><section><strong style="margin: 0px; padding: 0px;"><span style="margin: 0px; padding: 0px; box-sizing: border-box; color: rgb(123, 12, 0);"><br/></span></strong></section><section><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;">通过大量的生产试验证明,使用支撑筋可以防止泡沫模样变形, 选用预发泡密度为26-28 g/L的泡沫模型以及用成型的中空圆柱形直浇道有效的解决了夹渣缺陷,通过调整振实参数和人工辅助埋砂解决了铁包砂缺陷,提高铁水的出炉温度﹑浇注温度和合理正确的浇注操作使冷隔缺陷问题达到了有效的控制。</span></section><p></p><p><span style="margin: 0px; padding: 0px; font-size: 14px; box-sizing: border-box;"><br/></span></p><p><br/></p>
