埋弧焊不銹鋼管焊接參數比焊條電弧焊多一些，包括焊接電流、電弧電壓、焊接速度、焊接材料、焊絲直徑、焊絲偏移量、焊絲干伸長度、焊絲輸送速度等。

①. 焊接電(dian)流

   焊(han)(han)(han)接電(dian)(dian)(dian)(dian)流(liu)的大小直接影響焊(han)(han)(han)接熔(rong)(rong)池(chi)(chi)的深(shen)淺，焊(han)(han)(han)接電(dian)(dian)(dian)(dian)流(liu)大，熱(re)輸入大、電(dian)(dian)(dian)(dian)弧(hu)挺(ting)度(du)(du)大，焊(han)(han)(han)接熔(rong)(rong)池(chi)(chi)深(shen)；反之則淺。當焊(han)(han)(han)接電(dian)(dian)(dian)(dian)流(liu)較(jiao)(jiao)大時，由(you)于(yu)熔(rong)(rong)深(shen)較(jiao)(jiao)深(shen)，而焊(han)(han)(han)縫(feng)(feng)(feng)寬度(du)(du)變化不(bu)大，所(suo)得到(dao)的焊(han)(han)(han)縫(feng)(feng)(feng)成形(xing)系(xi)(xi)數（焊(han)(han)(han)縫(feng)(feng)(feng)的寬度(du)(du)與焊(han)(han)(han)縫(feng)(feng)(feng)有效厚(hou)度(du)(du)的比值稱為焊(han)(han)(han)縫(feng)(feng)(feng)成形(xing)系(xi)(xi)數）較(jiao)(jiao)小。這樣的焊(han)(han)(han)縫(feng)(feng)(feng)，對(dui)(dui)熔(rong)(rong)池(chi)(chi)中氣(qi)體(ti)和夾(jia)(jia)渣物的上浮和溢出十分不(bu)利(li)，易產(chan)生氣(qi)孔、夾(jia)(jia)渣和熱(re)裂紋。所(suo)以(yi)(yi)一(yi)般增加電(dian)(dian)(dian)(dian)流(liu)時，必須(xu)相應的提高電(dian)(dian)(dian)(dian)弧(hu)電(dian)(dian)(dian)(dian)壓，以(yi)(yi)保(bao)證得到(dao)合(he)理的焊(han)(han)(han)縫(feng)(feng)(feng)形(xing)狀，一(yi)般焊(han)(han)(han)縫(feng)(feng)(feng)成形(xing)系(xi)(xi)數控制在1.3～2.0之間，這樣對(dui)(dui)熔(rong)(rong)池(chi)(chi)中的氣(qi)體(ti)溢出以(yi)(yi)及防(fang)止產(chan)生夾(jia)(jia)渣或熱(re)裂紋等缺陷有利(li)。

②. 電(dian)弧(hu)電(dian)壓

   電(dian)弧(hu)(hu)(hu)電(dian)壓(ya)隨著電(dian)弧(hu)(hu)(hu)長度(du)的變(bian)化(hua)(hua)而變(bian)化(hua)(hua)，電(dian)弧(hu)(hu)(hu)拉長了，電(dian)弧(hu)(hu)(hu)電(dian)壓(ya)則升高(gao)，電(dian)弧(hu)(hu)(hu)挺度(du)下(xia)降，母材受熱(re)面增(zeng)加(jia)，所以(yi)焊(han)接熔(rong)(rong)池的深度(du)減小，焊(han)縫(feng)寬度(du)明顯增(zeng)寬。適當的增(zeng)加(jia)電(dian)弧(hu)(hu)(hu)電(dian)壓(ya)，會(hui)提高(gao)焊(han)縫(feng)質量，但應(ying)與增(zeng)加(jia)焊(han)接電(dian)流相配合。單純地增(zeng)加(jia)電(dian)弧(hu)(hu)(hu)電(dian)壓(ya)，會(hui)使熔(rong)(rong)深減小，造成焊(han)件未(wei)焊(han)透。而且焊(han)劑的熔(rong)(rong)化(hua)(hua)量大，增(zeng)加(jia)焊(han)劑的消(xiao)耗量。焊(han)縫(feng)表(biao)面粗糙，脫渣(zha)困難(nan)，嚴(yan)重時，會(hui)造成焊(han)縫(feng)邊(bian)緣(yuan)咬邊(bian)。

③. 焊接速(su)度(du)

   當焊(han)(han)接(jie)電流(liu)和電弧(hu)電壓(ya)不(bu)變時，焊(han)(han)接(jie)速(su)度提高，電弧(hu)給予焊(han)(han)接(jie)熔(rong)池(chi)中單位(wei)長度的熱量勢必減(jian)少(shao)，導致焊(han)(han)縫(feng)熔(rong)深和焊(han)(han)縫(feng)寬度減(jian)小。過分的增加(jia)焊(han)(han)接(jie)速(su)度，會導致焊(han)(han)接(jie)電弧(hu)對工件(jian)(jian)的加(jia)熱不(bu)足，造成焊(han)(han)件(jian)(jian)未(wei)焊(han)(han)透和邊(bian)緣未(wei)熔(rong)合等缺陷。

④. 焊接材料

   a. 壓(ya)力容器常(chang)用(yong)(yong)不銹(xiu)鋼(gang)埋弧(hu)焊(han)焊(han)絲(si)(si)、焊(han)劑見表4-14，常(chang)用(yong)(yong)奧氏(shi)體型耐(nai)熱鋼(gang)埋弧(hu)焊(han)焊(han)劑與(yu)焊(han)絲(si)(si)見表4-15，結構件常(chang)用(yong)(yong)奧氏(shi)體不銹(xiu)鋼(gang)埋弧(hu)焊(han)焊(han)劑與(yu)焊(han)絲(si)(si)見表4-16。

    b.  常用不銹鋼埋弧焊用焊劑烘焙要求(qiu)見表 4-17 。

   c. 焊劑(ji)顆粒(li)度(du)(du)。熔煉焊劑(ji)顆粒(li)度(du)(du)為2.5～0.45mm（4～40目），燒結焊劑(ji)顆粒(li)度(du)(du)為2～0.28mm（10～60目），焊劑(ji)允許重(zhong)復(fu)使(shi)(shi)用，但重(zhong)復(fu)使(shi)(shi)用前須篩出細粉(fen)和渣(zha)殼，并與新焊劑(ji)混勻(yun)后使(shi)(shi)用。

 ⑤. 焊絲直(zhi)徑(jing)

   焊絲直徑加(jia)粗(cu)，電(dian)(dian)弧范圍擴(kuo)大，使熔寬增加(jia)；如果焊接電(dian)(dian)流保持不變，電(dian)(dian)流密度(du)減小(xiao)，電(dian)(dian)弧挺度(du)下降，則熔深將相應地減小(xiao)。

 ⑥. 焊絲偏(pian)移量a

    焊(han)(han)接(jie)環焊(han)(han)縫時(shi)(shi)(shi)(shi)，焊(han)(han)絲(si)(si)不應在最(zui)高點(dian)或最(zui)低點(dian)，而應在下坡焊(han)(han)的位置上，如圖(tu)4-19所示。焊(han)(han)絲(si)(si)偏(pian)(pian)(pian)移(yi)量(liang)直接(jie)影響焊(han)(han)縫成形，見(jian)圖(tu)4-18。焊(han)(han)絲(si)(si)偏(pian)(pian)(pian)移(yi)量(liang)與焊(han)(han)件外徑和焊(han)(han)接(jie)線能(neng)量(liang)有關(guan)。當(dang)焊(han)(han)接(jie)線能(neng)量(liang)大(da)時(shi)(shi)(shi)(shi)，熔池停(ting)留(liu)時(shi)(shi)(shi)(shi)間較(jiao)(jiao)長，所以(yi)焊(han)(han)絲(si)(si)偏(pian)(pian)(pian)移(yi)量(liang)可(ke)選較(jiao)(jiao)大(da)值。當(dang)焊(han)(han)接(jie)線能(neng)量(liang)小(xiao)(xiao)時(shi)(shi)(shi)(shi)，熔池停(ting)留(liu)時(shi)(shi)(shi)(shi)間較(jiao)(jiao)短，所以(yi)焊(han)(han)絲(si)(si)偏(pian)(pian)(pian)移(yi)量(liang)選取較(jiao)(jiao)小(xiao)(xiao)值。當(dang)焊(han)(han)件外徑較(jiao)(jiao)大(da)時(shi)(shi)(shi)(shi)，熔池中的液(ye)態(tai)金屬(shu)外溢(yi)的傾向(xiang)較(jiao)(jiao)小(xiao)(xiao)，此(ci)時(shi)(shi)(shi)(shi)，焊(han)(han)絲(si)(si)偏(pian)(pian)(pian)移(yi)量(liang)可(ke)取較(jiao)(jiao)大(da)值。焊(han)(han)絲(si)(si)直徑小(xiao)(xiao)于3mm時(shi)(shi)(shi)(shi)，焊(han)(han)絲(si)(si)偏(pian)(pian)(pian)移(yi)量(liang)一般不超過5～10mm，焊(han)(han)絲(si)(si)直徑大(da)于3mm時(shi)(shi)(shi)(shi)，焊(han)(han)絲(si)(si)偏(pian)(pian)(pian)移(yi)量(liang)見(jian)表4-18。

 ⑦. 焊絲干伸(shen)長度L

    焊(han)絲前端(duan)到導電(dian)嘴(zui)前端(duan)的(de)距離稱為(wei)焊(han)絲干伸(shen)(shen)長(chang)度(du)(du)(du)，見圖4-20。焊(han)絲干伸(shen)(shen)長(chang)度(du)(du)(du)L增(zeng)(zeng)加，焊(han)絲的(de)預熱溫度(du)(du)(du)增(zeng)(zeng)加，焊(han)絲熔(rong)化速度(du)(du)(du)增(zeng)(zeng)加，增(zeng)(zeng)加焊(han)絲干伸(shen)(shen)長(chang)度(du)(du)(du)可(ke)提高生產效率，但焊(han)絲干伸(shen)(shen)長(chang)度(du)(du)(du)超(chao)過50mm后會(hui)出現成段爆裂現象。所(suo)以焊(han)絲干伸(shen)(shen)長(chang)度(du)(du)(du)一般控制在17～20mm范圍(wei)內。

 ⑧. 電流種(zhong)類和電極極性

    在(zai)一般情(qing)況下，電(dian)(dian)(dian)弧陽極(ji)(ji)區(qu)的(de)(de)(de)(de)(de)(de)溫度(du)(du)較陰極(ji)(ji)區(qu)的(de)(de)(de)(de)(de)(de)溫度(du)(du)高，但在(zai)使(shi)(shi)用高錳(meng)高硅含氟的(de)(de)(de)(de)(de)(de)焊(han)(han)劑進行埋弧焊(han)(han)時(shi)(shi)，電(dian)(dian)(dian)弧空間氣(qi)體(ti)的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)離(li)勢增(zeng)加，這(zhe)樣，氣(qi)體(ti)電(dian)(dian)(dian)離(li)后正離(li)子釋放至陰極(ji)(ji)的(de)(de)(de)(de)(de)(de)能量也增(zeng)加，使(shi)(shi)陰極(ji)(ji)的(de)(de)(de)(de)(de)(de)溫度(du)(du)提(ti)高，并大于陽極(ji)(ji)的(de)(de)(de)(de)(de)(de)溫度(du)(du)。因而在(zai)用含有高電(dian)(dian)(dian)離(li)電(dian)(dian)(dian)位的(de)(de)(de)(de)(de)(de)埋弧焊(han)(han)劑時(shi)(shi)，若焊(han)(han)接(jie)電(dian)(dian)(dian)源為直流(liu)正接(jie)，則焊(han)(han)絲的(de)(de)(de)(de)(de)(de)熔(rong)(rong)化(hua)速度(du)(du)大于焊(han)(han)件的(de)(de)(de)(de)(de)(de)熔(rong)(rong)化(hua)速度(du)(du)，使(shi)(shi)接(jie)頭熔(rong)(rong)深減小，焊(han)(han)縫余高增(zeng)加。反之用直流(liu)反接(jie)便(bian)可(ke)增(zeng)加熔(rong)(rong)深。使(shi)(shi)用交流(liu)焊(han)(han)接(jie)電(dian)(dian)(dian)源時(shi)(shi)，對形狀的(de)(de)(de)(de)(de)(de)影響(xiang)介于直流(liu)正接(jie)、反接(jie)之間。

  上述各項(xiang)(xiang)焊接參(can)數(shu)(shu)的(de)(de)選擇，不能(neng)(neng)單(dan)項(xiang)(xiang)考慮(lv)，要(yao)有(you)機(ji)地匹(pi)配，進行綜合平衡分析，找出(chu)一個主要(yao)焊接參(can)數(shu)(shu)，在(zai)充(chong)分試(shi)驗(yan)后，才(cai)能(neng)(neng)制訂出(chu)最佳(jia)參(can)數(shu)(shu)。最終要(yao)經過焊接接頭的(de)(de)力學性(xing)能(neng)(neng)考核和耐(nai)腐蝕性(xing)能(neng)(neng)試(shi)驗(yan)（即焊接工(gong)藝評定合格(ge)），滿足產品(pin)設計圖樣要(yao)求后，方能(neng)(neng)在(zai)產品(pin)上正式施焊。表4-19、表4-20所列出(chu)的(de)(de)18-8型奧氏體不銹(xiu)鋼焊接參(can)數(shu)(shu)可供參(can)考。