??墊(dian)板(ban)(ban)(ban)(ban)(ban)(ban)：鋁(lv)合金在(zai)高溫時(shi)強度很低，液態鋁(lv)的流動(dong)性能(neng)好，在(zai)焊(han)(han)接(jie)時(shi)焊(han)(han)縫金屬容(rong)易產生下塌(ta)(ta)現(xian)象。為了保證焊(han)(han)透而(er)又不(bu)致塌(ta)(ta)陷，焊(han)(han)接(jie)時(shi)常采(cai)用墊(dian)板(ban)(ban)(ban)(ban)(ban)(ban)來托住熔池及附(fu)近(jin)金屬。墊(dian)板(ban)(ban)(ban)(ban)(ban)(ban)可(ke)(ke)采(cai)用石墨板(ban)(ban)(ban)(ban)(ban)(ban)、不(bu)銹鋼(gang)板(ban)(ban)(ban)(ban)(ban)(ban)、碳素(su)鋼(gang)板(ban)(ban)(ban)(ban)(ban)(ban)、銅(tong)板(ban)(ban)(ban)(ban)(ban)(ban)或銅(tong)棒(bang)等(deng)(deng)。墊(dian)板(ban)(ban)(ban)(ban)(ban)(ban)表面(mian)開一個圓(yuan)弧(hu)形槽，電焊(han)(han)工培訓，以保證焊(han)(han)縫反(fan)面(mian)成(cheng)型(xing)(xing)。也可(ke)(ke)以不(bu)加墊(dian)板(ban)(ban)(ban)(ban)(ban)(ban)單(dan)面(mian)焊(han)(han)雙面(mian)成(cheng)型(xing)(xing)，但要求(qiu)焊(han)(han)接(jie)操作熟練(lian)或采(cai)取對電弧(hu)施(shi)焊(han)(han)能(neng)量嚴格(ge)自動(dong)反(fan)饋控(kong)制等(deng)(deng)工藝措施(shi)。

??焊(han)前預(yu)(yu)熱：薄、小(xiao)鋁件一(yi)般(ban)不(bu)用預(yu)(yu)熱，厚度10mm～15mm時可進行焊(han)前預(yu)(yu)熱，根據不(bu)同類型的鋁合(he)金預(yu)(yu)熱溫(wen)度可為100℃～200℃，可用氧一(yi)焰、電爐或噴燈等加熱。預(yu)(yu)熱可使焊(han)件減(jian)小(xiao)變形、減(jian)少氣孔等缺(que)陷。

??

在電(dian)(dian)(dian)(dian)氣焊作(zuo)業過程中，容易造成觸電(dian)(dian)(dian)(dian)火災及電(dian)(dian)(dian)(dian)弧傷害等(deng)事故。因(yin)此每個焊工(gong)應熟悉有關安(an)全防護(hu)知識，電(dian)(dian)(dian)(dian)焊工(gong)短(duan)期培(pei)訓，自覺遵守(shou)安(an)全操作(zuo)規(gui)程，加強勞動保(bao)護(hu)意識，短(duan)期電(dian)(dian)(dian)(dian)焊工(gong)培(pei)訓，確保(bao)作(zuo)業者(zhe)的身體健康。

(1)焊工是特種(zhong)作業人員，應經(jing)過(guo)(guo)專門培(pei)訓，掌(zhang)握電(dian)氣焊安全技術，并(bing)經(jing)過(guo)(guo)考試合格，取得特種(zhong)作業證書后方能(neng)上崗。

(2)焊機一般采用380V或220V電壓，空載電壓也在(zai)60V以上，因此(ci)焊工(gong)首(shou)先(xian)要防止觸電，特別是在(zai)陰(yin)雨、打雷、閃電或潮濕作業環境中。

1)焊工作業(ye)時要穿(chuan)好(hao)膠底(di)鞋，戴(dai)好(hao)防護手(shou)套，正確(que)使(shi)用(yong)防護面罩;不(bu)得光(guang)膀子、穿(chuan)拖鞋或赤腳作業(ye)。

2)更換焊(han)條時(shi)要戴好防(fang)護手套，夏天出汗及(ji)工作服潮濕時(shi)，注(zhu)意不要靠在鋼(gang)材(cai)上避(bi)免觸(chu)電(dian)。

焊條的選擇原則：

①考慮母材的(de)力學(xue)性能(neng)和(he)化學(xue)成分 焊(han)(han)(han)接(jie)低碳鋼(gang)和(he)低合金(jin)結(jie)構鋼(gang)時，應根據焊(han)(han)(han)接(jie)件(jian)的(de)抗拉強(qiang)度(du)選擇相應強(qiang)度(du)等級的(de)焊(han)(han)(han)條，即等強(qiang)度(du)原(yuan)則；焊(han)(han)(han)接(jie)耐熱鋼(gang)、不銹鋼(gang)等材料時，則應選擇與焊(han)(han)(han)接(jie)件(jian)化學(xue)成分相同或相近的(de)焊(han)(han)(han)條，即等成分原(yuan)則。

②考慮結(jie)構的(de)使(shi)用(yong)條件和(he)特(te)點 對(dui)于承受動載(zai)荷(he)或(huo)沖擊載(zai)荷(he)的(de)焊接(jie)(jie)件，或(huo)結(jie)構復雜(za)、大厚度的(de)焊接(jie)(jie)件，為保(bao)證(zheng)焊縫具有較高的(de)塑性(xing)和(he)韌度，應(ying)選(xuan)擇堿性(xing)焊條

③考慮焊(han)條的工藝性 對(dui)于焊(han)前清理困難，且容易產生氣孔的焊(han)接件(jian)，應當選擇酸性焊(han)條。