熔(rong)孔(kong)(kong)的(de)大(da)小(xiao)(xiao)以融合坡口(kou)兩(liang)邊0.5～1mm為(wei)宜(yi)，太大(da)不容易操作，易產生焊瘤，太小(xiao)(xiao)不能保證背(bei)面成形。 施焊過程中(zhong)嚴格控制熔(rong)池的(de)形狀，隨時觀察熔(rong)池、熔(rong)孔(kong)(kong)的(de)變化(hua)及坡口(kou)根部的(de)熔(rong)化(hua)情況。熔(rong)孔(kong)(kong)的(de)大(da)小(xiao)(xiao)決定焊縫(feng)背(bei)面的(de)寬度和余(yu)高，通常熔(rong)孔(kong)(kong)的(de)直徑比間隙大(da)1～2 mm為(wei)好(hao)。

焊(han)(han)(han)(han)接(jie)過程中(zhong)如發現熔(rong)(rong)(rong)孔(kong)(kong)(kong)過大(da)，正規電(dian)(dian)焊(han)(han)(han)(han)工證(zheng)(zheng)全天實(shi)踐，表明熔(rong)(rong)(rong)池溫(wen)度(du)過高，應迅(xun)速滅弧，正規電(dian)(dian)焊(han)(han)(han)(han)工證(zheng)(zheng)全天實(shi)踐，并(bing)適當(dang)延(yan)長熄弧的時(shi)間(jian)，以降低熔(rong)(rong)(rong)池溫(wen)度(du)，然后恢(hui)復正常焊(han)(han)(han)(han)接(jie)，環翠(cui)區電(dian)(dian)焊(han)(han)(han)(han)工證(zheng)(zheng)全天實(shi)踐，若熔(rong)(rong)(rong)孔(kong)(kong)(kong)太小則可減(jian)慢焊(han)(han)(han)(han)接(jie)速度(du)，當(dang)出現合適的熔(rong)(rong)(rong)孔(kong)(kong)(kong)時(shi)方能進行正常焊(han)(han)(han)(han)接(jie)。如果是二保焊(han)(han)(han)(han)連(lian)弧焊(han)(han)(han)(han)打底焊(han)(han)(han)(han)時(shi)，熔(rong)(rong)(rong)孔(kong)(kong)(kong)過大(da)時(shi)可以使(shi)焊(han)(han)(han)(han)向(xiang)遠離(li)熔(rong)(rong)(rong)孔(kong)(kong)(kong)后方擺動(dong)，減(jian)小熔(rong)(rong)(rong)池前沿的溫(wen)度(du)，熔(rong)(rong)(rong)孔(kong)(kong)(kong)過小則反(fan)之。

1.焊(han)(han)條電(dian)弧焊(han)(han)引弧、收弧、焊(han)(han)接操作(zuo)和(he)定位焊(han)(han)的工藝要(yao)領

2.對接(jie)焊(han)親電弧焊(han)所(suo)用設備、工具(ju)。夾具(ju)的安全檢查方法(fa)

3.水平轉動(dong)對接(jie)焊(han)接(jie)變形(xing)的基(ji)本知識

4.對接焊條電(dian)弧焊焊接工(gong)藝參數的選擇。

焊接(jie)成(cheng)形的特(te)點：接(jie)頭(tou)牢固、密封(feng)性好、可化(hua)大為小(xiao)、以小(xiao)拼(pin)大。可實(shi)現異種金屬的連接(jie)；重量(liang)輕、加(jia)工(gong)裝配簡單。

焊接結構不可拆卸。

焊(han)接應(ying)力(li)變形(xing)大，接頭易產生裂紋、夾渣、氣孔等(deng)缺陷。

壓力容器用鋼板

在(zai)規(gui)定的部件焊接前，正規(gui)電(dian)焊工證全天實踐(jian)，施焊單位應查詢是否(fou)具(ju)有評定資(zi)料。如無資(zi)料或已有資(zi)料的適用范圍與該焊接工程不符(fu)時，必須進(jin)行(xing)評定。

評(ping)定工作應(ying)以可靠的鋼(gang)材(cai)焊(han)接性評(ping)價為基礎，在實施正式(shi)的焊(han)接前按(an)本標準(zhun)規定進行。評(ping)定需用的焊(han)接性評(ping)價資料應(ying)由鋼(gang)材(cai)供(gong)貨方提供(gong)或由施工單位收集(ji)。

支持鋼材焊接(jie)性評(ping)價的資料包括，鋼材的技術參數、鋼材焊接(jie)裂(lie)紋敏感性試驗報告、研究報告應力腐蝕試驗報告、公(gong)(gong)開發表的相(xiang)關、公(gong)(gong)開的相(xiang)關焊接(jie)工程總結等。