[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$fPPsAQQMjCznzmzBB-DiTdxZAZfaOwAyG6PMj1vXkcCI":3},{"answer":4,"createTime":5,"id":6,"options":7,"origin":8,"question":15,"related":16,"source":22,"type":23},[],"2025-03-02 22:26:35",178210653,[],{"count":9,"courseId":10,"courseImg":11,"courseName":12,"workId":13,"workName":14},44,"8f236bb91a90365177bcf3611f01d076","https:\u002F\u002Ftihai-oss-cloud.itihey.com\u002Fimg\u002Fc491bec2e253ec14fa70be83ad1f3e34.jpg","工程实训A","work_40266165","第11章 焊工实训","11.3、焊钳 放在工作台上, 烧坏电焊机",[17,24,29,34,39,44,49,52,57,62],{"answer":18,"createTime":5,"id":19,"options":20,"question":21,"source":22,"type":23},[],178210647,[],"11.27、而焊接 的钢板,或对 、 及 等材料进行焊接时,为防止 、则利用阴极区 的特性,采用反接法","v1",2,{"answer":25,"createTime":5,"id":26,"options":27,"question":28,"source":22,"type":23},[],178210648,[],"11.25、正接法就是 接直流弧焊机的正极, 接负极;反接法则反之",{"answer":30,"createTime":5,"id":31,"options":32,"question":33,"source":22,"type":23},[],178210649,[],"11.24、直流弧焊机的输出端有固定的 和 之分,而电弧在阳极区和阴极区的 不同,因此在焊接时有两种连接方法,即 和",{"answer":35,"createTime":5,"id":36,"options":37,"question":38,"source":22,"type":23},[],178210650,[],"11.12、钎焊是指采用 的材料作为 ,将 和 加热至 钎料熔点,但 母材熔点的温度,利用 使 充满焊件接头间隙,液态钎料 母材表面,并使其与母材 、冷却后结晶形成 的一种焊接方法.焊接时,被焊焊件处于 ,只适当进行了 ,且没有受到 的作用,其过程只是 和 ,形成一个 的连接层",{"answer":40,"createTime":5,"id":41,"options":42,"question":43,"source":22,"type":23},[],178210651,[],"11.40、对焊件厚度小于 的焊缝,可以不开坡口或开I 形坡口;中厚度和大厚度板对接焊,为保证熔透, .V 形坡口 ,但零件焊后 ;双V形坡口可以避免 的一些缺点,同时可 填充材料;U形及双 U形坡口,其焊缝填充金属量 ,焊后变形 ,但坡口 ,一般用于 焊接结构",{"answer":45,"createTime":5,"id":46,"options":47,"question":48,"source":22,"type":23},[],178210652,[],"11.8、焊接方法的种类很多,一般根据焊接时 所处的 ,把焊接分为 、 和 三大类",{"answer":50,"createTime":5,"id":6,"options":51,"question":15,"source":22,"type":23},[],[],{"answer":53,"createTime":5,"id":54,"options":55,"question":56,"source":22,"type":23},[],178210654,[],"11.43、直击法是在焊机开启后,先将焊条末端 ,然后稍 手腕,使焊条轻轻撞击零件,随即 2 mm~4 mm,就能使电弧引燃,开始焊接",{"answer":58,"createTime":5,"id":59,"options":60,"question":61,"source":22,"type":23},[],178210655,[],"11.42、划擦法操作是在焊机电源开启后,将焊条末端对准焊缝,并保持两者的距离在 以内,依靠手腕的 ,使焊条在零件表面 一下,并立即 2 mm~4 mm,电弧引燃,然后开始正常焊接",{"answer":63,"createTime":5,"id":64,"options":65,"question":66,"source":22,"type":23},[],178210656,[],"11.16、焊接方法灵活,可将大型工件 , ,不必像铸件那样受工艺限制.容易加大尺寸、增加肋板和大圆角,加工快,效率高,生产周期短,且质量易于保证"]