CO2氣體(ti)保(bao)護焊(han)自(zi)問(wen)世(shi)以來，以其具有明弧(hu)、無渣、低(di)成本、高效節(jie)能、抗銹低(di)氫(qing)等特(te)點，在生產中得到越(yue)來越(yue)廣泛的(de)應用(yong)(yong)。但CO2氣體(ti)保(bao)護焊(han)有兩點主要不足：飛(fei)(fei)濺大(da)和成形差。飛(fei)(fei)濺不僅污染工件(jian)，增加勞動強度，降(jiang)低(di)熔敷(fu)率，還(huan)會(hui)堵塞噴嘴，使送絲不暢。特(te)別在一些重要構件(jian)上，清理飛(fei)(fei)濺較為困(kun)難或者不允(yun)許清理時(shi)，其應用(yong)(yong)受到很(hen)大(da)限(xian)制。除此之外(wai)，由飛(fei)(fei)濺等引起的(de)細小顆粒還(huan)會(hui)帶來粉(fen)塵污染，影響職工的(de)身體(ti)健康。

CMT（Cold Metal Transfer，冷金屬過渡(du)）工(gong)藝(yi)(yi)自2004年正式推出以來，一直受到焊(han)(han)(han)接界的(de)廣(guang)泛(fan)關注，此工(gong)藝(yi)(yi)最重要的(de)特(te)(te)點是(shi)利(li)用其極(ji)(ji)穩(wen)定的(de)電弧(hu)、極(ji)(ji)低的(de)熱輸入量來實現無飛濺的(de)焊(han)(han)(han)接過程(cheng)。CMT工(gong)藝(yi)(yi)與CO2氣體保(bao)(bao)護相結合的(de)焊(han)(han)(han)接工(gong)藝(yi)(yi)具(ju)有極(ji)(ji)穩(wen)定電弧(hu)、無飛濺和良好的(de)焊(han)(han)(han)縫成形等優點，解決了(le)普(pu)通CO2氣體保(bao)(bao)護焊(han)(han)(han)飛濺大、成形差的(de)缺點，是(shi)一種節能高效(xiao)環保(bao)(bao)的(de)焊(han)(han)(han)接工(gong)藝(yi)(yi)，具(ju)有重要的(de)應用價(jia)值(zhi)。但CMT因(yin)其“冷”的(de)特(te)(te)點使得焊(han)(han)(han)縫熔(rong)深普(pu)遍較小，特(te)(te)別是(shi)在(zai)汽車中平(ping)行(xing)接頭和搭接接頭較多，熔(rong)深問題制約了(le)其應用和推廣(guang)，因(yin)此尋找一種解決CMT工(gong)藝(yi)(yi)焊(han)(han)(han)接熔(rong)深的(de)方(fang)法十分(fen)重要。活性劑(ji)CMT焊(han)(han)(han)接的(de)研究(jiu)旨(zhi)在(zai)提高焊(han)(han)(han)縫熔(rong)深，改善焊(han)(han)(han)縫成型。

20世紀(ji)60年(nian)代，烏克蘭巴頓焊(han)(han)(han)接(jie)(jie)研(yan)(yan)究(jiu)所(suo)(PWI)研(yan)(yan)究(jiu)了最初的(de)(de)(de)A-TIG（Activating flux TIG welding）焊(han)(han)(han)接(jie)(jie)工藝。20世紀(ji)90年(nian)代，人們對提高焊(han)(han)(han)接(jie)(jie)效率和降低焊(han)(han)(han)接(jie)(jie)成本有(you)了進一(yi)步的(de)(de)(de)需求(qiu)，美國愛迪生焊(han)(han)(han)接(jie)(jie)研(yan)(yan)究(jiu)所(suo)(EWI)、英(ying)國焊(han)(han)(han)接(jie)(jie)研(yan)(yan)究(jiu)所(suo)(TWI)和日本大阪大學焊(han)(han)(han)接(jie)(jie)研(yan)(yan)究(jiu)所(suo)等多家知名焊(han)(han)(han)接(jie)(jie)機構在A-TIG焊(han)(han)(han)活(huo)(huo)性(xing)(xing)劑(ji)(ji)方面開(kai)(kai)展了廣泛研(yan)(yan)究(jiu)，俄羅斯也在2001年(nian)進行了有(you)關(guan)不銹(xiu)鋼焊(han)(han)(han)接(jie)(jie)方面的(de)(de)(de)活(huo)(huo)性(xing)(xing)劑(ji)(ji)的(de)(de)(de)研(yan)(yan)制(zhi)。我國于20世紀(ji)末(mo)開(kai)(kai)始活(huo)(huo)性(xing)(xing)劑(ji)(ji)焊(han)(han)(han)接(jie)(jie)方面的(de)(de)(de)研(yan)(yan)究(jiu)，國內(nei)外焊(han)(han)(han)接(jie)(jie)學者已經將活(huo)(huo)性(xing)(xing)劑(ji)(ji)應(ying)用到TIG焊(han)(han)(han)、電子(zi)束焊(han)(han)(han)、激光焊(han)(han)(han)、釬焊(han)(han)(han)等領(ling)域，取得了一(yi)定成果。開(kai)(kai)展CO2氣體保護的(de)(de)(de)CMT焊(han)(han)(han)接(jie)(jie)研(yan)(yan)究(jiu)，對于實現綠色制(zhi)造、建立節約型和諧社會(hui)具有(you)重要的(de)(de)(de)現實意義。在此試驗(yan)研(yan)(yan)究(jiu)了活(huo)(huo)性(xing)(xing)劑(ji)(ji)CMT焊(han)(han)(han)接(jie)(jie)，并(bing)分析活(huo)(huo)性(xing)(xing)劑(ji)(ji)在活(huo)(huo)性(xing)(xing)劑(ji)(ji)CMT焊(han)(han)(han)中的(de)(de)(de)作用機理(li)。

1試驗

1.1實(shi)驗材料與設備(bei)

試(shi)驗(yan)采用的(de)母材(cai)為低碳鋼Q235B，試(shi)樣尺寸為200 mm×90 mm×10 mm；φ1.2 mm的(de)H08Mn2SiA實心焊(han)絲(si)；CO2保護氣體；基本(ben)活性劑(ji)是CaF2、Al2O3、Y2O3、B2O3、SiO2、MoO3、MgCO3、Fe2O3和Cr2O3共9種，試(shi)驗(yan)時分(fen)(fen)別(bie)以A，B，C，D，E，F，G，H，I表示對應的(de)單(dan)一活性劑(ji)成(cheng)分(fen)(fen)；活性劑(ji)乳(ru)化劑(ji)為酒精。試(shi)驗(yan)設備(bei)(bei)為奧地利(li)福尼斯公司的(de)TPS5000CMT的(de)數(shu)字化脈沖MIG/MAG焊(han)機(ji)，配備(bei)(bei)VR7000送絲(si)機(ji)和RCU5000i遙控(kong)(kong)器，海德盟(meng)Hi800-M系(xi)列數(shu)控(kong)(kong)系(xi)統和焊(han)接(jie)工作(zuo)臺。

1.2試驗規范參(can)數

采用CMT一元(yuan)化焊接工藝，通過正交試驗確定主要影響(xiang)因素，焊接規范參數如表1所示。

表1焊(han)接(jie)工藝(yi)參數

1.3試驗方(fang)法

采用對(dui)比實驗(yan)法，通過比較單組分活(huo)(huo)性劑焊(han)(han)接試(shi)驗(yan)與(yu)無活(huo)(huo)性劑試(shi)驗(yan)結果，確定(ding)各活(huo)(huo)性劑的(de)影(ying)響次序，分析活(huo)(huo)性劑對(dui)CMT焊(han)(han)的(de)作用機理(li)。每組實驗(yan)重復進行一次，所得焊(han)(han)縫(feng)結果取平均值。

試驗前(qian)先將(jiang)試樣除銹(xiu)，用(yong)角磨(mo)(mo)(mo)機打磨(mo)(mo)(mo)，再用(yong)酒精或(huo)丙酮擦拭，去除油污及其(qi)他雜質。然(ran)后(hou)稱取(qu)一定量的(de)活(huo)(huo)(huo)性(xing)劑，用(yong)乳化劑酒精進行(xing)充(chong)分(fen)乳化，調配攪拌成(cheng)糊狀。用(yong)扁(bian)平毛刷將(jiang)活(huo)(huo)(huo)性(xing)劑涂于(yu)工件待(dai)焊位置寬(kuan)20 mm的(de)區域，活(huo)(huo)(huo)性(xing)劑涂覆厚度以(yi)覆蓋(gai)金(jin)屬表面光澤為宜。最后(hou)在如表1所示(shi)的(de)同一焊接(jie)(jie)參數(shu)下進行(xing)焊接(jie)(jie)試驗。觀察焊接(jie)(jie)現象，用(yong)RCU5000i外加存儲卡記錄焊接(jie)(jie)過程參數(shu)變化；焊后(hou)觀察焊縫(feng)的(de)宏觀成(cheng)形(xing)，并(bing)記錄結果；將(jiang)試驗所得焊縫(feng)沿(yan)距尾(wei)部30mm的(de)距離進行(xing)切割，然(ran)后(hou)打磨(mo)(mo)(mo)、拋光、腐蝕和觀察金(jin)相，記錄焊縫(feng)的(de)熔(rong)深、熔(rong)寬(kuan)等(deng)焊縫(feng)參數(shu)，計算焊縫(feng)的(de)熔(rong)深比等(deng)。

2試驗(yan)結(jie)果和分析

2.1試驗結(jie)果

單一(yi)(yi)(yi)活(huo)性劑(ji)焊縫參(can)數(shu)及無(wu)活(huo)性劑(ji)時焊縫參(can)數(shu)如表2所示，表2單一(yi)(yi)(yi)活(huo)性劑(ji)焊縫參(can)數(shu)，圖1是單一(yi)(yi)(yi)活(huo)性劑(ji)熔深與無(wu)活(huo)性劑(ji)時熔深比直方圖。

圖(tu)2是無活(huo)性(xing)劑時(shi)焊縫的(de)宏觀成形，圖(tu)3為試驗中幾組典型(xing)活(huo)性(xing)劑的(de)金相截面。

2.2活(huo)性劑對焊(han)縫成(cheng)形(xing)的影(ying)響

由表2和(he)圖1可知，普通CMT焊(han)(han)(han)接時，焊(han)(han)(han)縫熔(rong)深(shen)(shen)(shen)(shen)為2.05 mm；涂(tu)活性劑(ji)后(hou)，A、B、D、E和(he)I焊(han)(han)(han)縫熔(rong)深(shen)(shen)(shen)(shen)明顯(xian)高于(yu)不涂(tu)活性劑(ji)的(de)焊(han)(han)(han)縫熔(rong)深(shen)(shen)(shen)(shen)。其(qi)中活性劑(ji)B、D、E對焊(han)(han)(han)縫熔(rong)深(shen)(shen)(shen)(shen)增(zeng)(zeng)加(jia)的(de)程(cheng)度(du)較為明顯(xian)，相比(bi)普通CMT焊(han)(han)(han)縫熔(rong)深(shen)(shen)(shen)(shen)，其(qi)焊(han)(han)(han)縫熔(rong)深(shen)(shen)(shen)(shen)比(bi)增(zeng)(zeng)加(jia)了20%以(yi)上(shang)，說明活性化劑(ji)D、E、B對熔(rong)深(shen)(shen)(shen)(shen)的(de)增(zeng)(zeng)加(jia)有較大的(de)促進作(zuo)用。活性劑(ji)A和(he)I雖(sui)然對熔(rong)深(shen)(shen)(shen)(shen)的(de)影響不如活性化焊(han)(han)(han)劑(ji)D、E、B明顯(xian)，但(dan)其(qi)熔(rong)深(shen)(shen)(shen)(shen)值(zhi)也大于(yu)普通CMT焊(han)(han)(han)，熔(rong)深(shen)(shen)(shen)(shen)增(zeng)(zeng)加(jia)比(bi)達到了10%以(yi)上(shang)。相比(bi)之下，使用C和(he)G兩種活性劑(ji)的(de)焊(han)(han)(han)縫熔(rong)深(shen)(shen)(shen)(shen)只增(zeng)(zeng)加(jia)約5%，F和(he)H不影響熔(rong)深(shen)(shen)(shen)(shen)。

圖2是(shi)普(pu)通CMT焊(han)的焊(han)縫(feng)(feng)(feng)成形，其焊(han)縫(feng)(feng)(feng)為(wei)淺V形，焊(han)縫(feng)(feng)(feng)熔深寬而淺；圖3是(shi)涂(tu)活性劑(ji)A、B、D、E和I的焊(han)縫(feng)(feng)(feng)成形。可以看出，涂(tu)覆活性劑(ji)后，焊(han)縫(feng)(feng)(feng)熔深都有(you)不同(tong)程度(du)的增加，熔寬和余高(gao)都有(you)不同(tong)程度(du)變化(hua)。

從圖2和圖3還可以看出(chu)，添加活性(xing)劑后會使焊縫(feng)表(biao)面形(xing)(xing)(xing)狀有(you)所(suo)改變，其中活性(xing)劑D、E對焊縫(feng)表(biao)面成(cheng)形(xing)(xing)(xing)影響較大，焊縫(feng)表(biao)面比不使用活性(xing)劑時粗糙，熔(rong)渣也有(you)增多，焊縫(feng)呈深V形(xing)(xing)(xing)。

圖4為(wei)焊接(jie)(jie)過程中電(dian)(dian)(dian)流的(de)(de)記錄。從(cong)圖4a可以(yi)看出，焊接(jie)(jie)過程中各單一(yi)活性劑(ji)焊接(jie)(jie)電(dian)(dian)(dian)流曲線基本相似，從(cong)圖4b可以(yi)看出，大(da)部分(fen)活性劑(ji)焊接(jie)(jie)過程的(de)(de)平均(jun)電(dian)(dian)(dian)流與(yu)無(wu)活性劑(ji)時相差不大(da)，SiO2和MgCO3的(de)(de)電(dian)(dian)(dian)流平均(jun)值相比無(wu)活性劑(ji)時有較為(wei)明顯的(de)(de)變化，其中前者(zhe)增(zeng)加，后者(zhe)減小。無(wu)活性劑(ji)時的(de)(de)平均(jun)電(dian)(dian)(dian)流達到(dao)211.5 A，而涂SiO2可以(yi)達到(dao)215 A。

圖(tu)5為(wei)(wei)焊(han)接過(guo)程中電(dian)壓(ya)(ya)的(de)(de)(de)記錄(lu)。從(cong)圖(tu)5a可以看(kan)出，焊(han)接過(guo)程中各活(huo)性(xing)(xing)劑變化曲線(xian)基本趨勢相似，但都有不同程度的(de)(de)(de)波(bo)動。從(cong)圖(tu)5b可以清楚地看(kan)出，各組活(huo)性(xing)(xing)劑焊(han)接過(guo)程的(de)(de)(de)平均(jun)電(dian)流、電(dian)壓(ya)(ya)和無活(huo)性(xing)(xing)劑時的(de)(de)(de)差(cha)別不一樣，其(qi)中涂(tu)覆B2O3和SiO2時的(de)(de)(de)電(dian)壓(ya)(ya)增加(jia)(jia)較為(wei)(wei)明顯，平均(jun)電(dian)壓(ya)(ya)增加(jia)(jia)能達到(dao)0.7 V以上(shang)，涂(tu)MgCO3則無變化，其(qi)余的(de)(de)(de)活(huo)性(xing)(xing)劑電(dian)壓(ya)(ya)都有一定程度的(de)(de)(de)增加(jia)(jia)。

3討論

活(huo)(huo)性(xing)(xing)(xing)劑(ji)(ji)(ji)CMT焊(han)(han)接主要(yao)是通過加(jia)(jia)入活(huo)(huo)性(xing)(xing)(xing)劑(ji)(ji)(ji)改變了(le)(le)焊(han)(han)接電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)弧(hu)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)弧(hu)是由(you)兩個(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極和它們之(zhi)間的(de)(de)氣體空(kong)間組成，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)弧(hu)中的(de)(de)帶電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)粒子(zi)主要(yao)依靠兩電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極間的(de)(de)氣體電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)離(li)和電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極發射(she)(she)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)兩個(ge)物(wu)(wu)理過程(cheng)所(suo)(suo)產(chan)生。在活(huo)(huo)性(xing)(xing)(xing)劑(ji)(ji)(ji)焊(han)(han)接電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)弧(hu)中，活(huo)(huo)性(xing)(xing)(xing)劑(ji)(ji)(ji)對電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)離(li)和電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極發射(she)(she)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)都有(you)影響(xiang)。活(huo)(huo)性(xing)(xing)(xing)劑(ji)(ji)(ji)的(de)(de)加(jia)(jia)入使電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)弧(hu)氣氛的(de)(de)實(shi)效電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)離(li)度明顯(xian)提高，所(suo)(suo)以活(huo)(huo)性(xing)(xing)(xing)劑(ji)(ji)(ji)CMT氣體保(bao)護焊(han)(han)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)弧(hu)比普通CMT氣體保(bao)護焊(han)(han)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)弧(hu)穩定。加(jia)(jia)入活(huo)(huo)性(xing)(xing)(xing)劑(ji)(ji)(ji)（大(da)部分(fen)為金屬氧化物(wu)(wu)）后(hou)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極表面逸出(chu)功(gong)降低，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極發射(she)(she)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)的(de)(de)能(neng)力增強(qiang)，增強(qiang)了(le)(le)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)弧(hu)導電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)能(neng)力，焊(han)(han)接電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)有(you)增加(jia)(jia)的(de)(de)趨勢。

從(cong)試驗結果(guo)(guo)可以(yi)看出，采用活(huo)性(xing)(xing)劑(ji)(ji)CMT焊(han)(han)(han)(han)接(jie)(jie)時，焊(han)(han)(han)(han)接(jie)(jie)電(dian)弧穩(wen)定，A、B、D、E和I五(wu)種活(huo)性(xing)(xing)劑(ji)(ji)的(de)(de)焊(han)(han)(han)(han)縫熔(rong)深增加(jia)(jia)較為明顯(xian)(xian)，在相(xiang)同(tong)的(de)(de)焊(han)(han)(han)(han)接(jie)(jie)工藝規(gui)范下，活(huo)性(xing)(xing)劑(ji)(ji)CMT焊(han)(han)(han)(han)接(jie)(jie)與普(pu)通CMT焊(han)(han)(han)(han)接(jie)(jie)所得到的(de)(de)焊(han)(han)(han)(han)縫熔(rong)深、熔(rong)寬(kuan)和余高等(deng)(deng)都有明顯(xian)(xian)差異。活(huo)性(xing)(xing)劑(ji)(ji)CMT焊(han)(han)(han)(han)接(jie)(jie)在同(tong)等(deng)(deng)規(gui)范下熔(rong)深明顯(xian)(xian)增加(jia)(jia)，同(tong)時熔(rong)寬(kuan)、余高和表面成形也有所變化。同(tong)時由于活(huo)性(xing)(xing)劑(ji)(ji)的(de)(de)加(jia)(jia)入，焊(han)(han)(han)(han)接(jie)(jie)電(dian)弧氣(qi)氛以(yi)及(ji)熔(rong)池流動等(deng)(deng)會受到多方作用，各種效(xiao)果(guo)(guo)并(bing)存，試驗結果(guo)(guo)會表現為占優勢一方的(de)(de)因素(su)。

（1）活(huo)性劑(ji)使(shi)電(dian)弧壓縮，焊(han)縫熔深(shen)增(zeng)加。

電弧收縮(suo)(suo)理(li)論認為(wei)，表面(mian)涂覆活(huo)性(xing)劑(ji)后，因為(wei)活(huo)性(xing)劑(ji)涂層(ceng)本身導電性(xing)不(bu)強，加(jia)之(zhi)活(huo)性(xing)劑(ji)的熔沸(fei)點都比純金(jin)屬(shu)(shu)的高，所以熔池表面(mian)產(chan)生的金(jin)屬(shu)(shu)蒸氣相應減少(shao)(shao)，在(zai)(zai)金(jin)屬(shu)(shu)蒸氣減少(shao)(shao)的情況下，只在(zai)(zai)電弧中心(xin)溫度較高的區域有(you)金(jin)屬(shu)(shu)蒸發，形成陽極(ji)斑(ban)點，即涂層(ceng)的存在(zai)(zai)減小了陽極(ji)斑(ban)點區，從而使電弧收縮(suo)(suo)，電弧壓力(li)增大(da)。

查物質(zhi)屬性可(ke)知，B和Si元(yuan)素的電阻率非常(chang)大，因此這(zhe)兩(liang)種(zhong)(zhong)物質(zhi)導致電弧(hu)收縮的作用效果最為(wei)明顯，熔(rong)深(shen)增加也最為(wei)明顯。由圖5可(ke)知，試驗中(zhong)B2O3和SiO2兩(liang)種(zhong)(zhong)活(huo)性劑在相同焊接規范下(xia)，焊接過程中(zhong)的電壓變化(hua)最大，焊接結果熔(rong)深(shen)增加最為(wei)明顯。很(hen)顯然，在各種(zhong)(zhong)活(huo)性劑中(zhong)，這(zhe)兩(liang)種(zhong)(zhong)活(huo)性劑有相同的特(te)性，同時(shi)這(zhe)種(zhong)(zhong)特(te)性對焊縫熔(rong)深(shen)的增加至(zhi)關重要。

（2）熔池金(jin)屬對流(liu)變化，焊縫(feng)熔深增加。

理(li)論認(ren)為，表(biao)面(mian)(mian)活(huo)性(xing)元(yuan)素引(yin)起熔(rong)(rong)池(chi)(chi)表(biao)面(mian)(mian)張(zhang)力變化，對(dui)(dui)(dui)(dui)熔(rong)(rong)池(chi)(chi)的(de)(de)(de)(de)對(dui)(dui)(dui)(dui)流產生著很(hen)大的(de)(de)(de)(de)影響，同時(shi)熔(rong)(rong)池(chi)(chi)對(dui)(dui)(dui)(dui)流的(de)(de)(de)(de)方向對(dui)(dui)(dui)(dui)熔(rong)(rong)合(he)區(qu)幾何形狀的(de)(de)(de)(de)影響很(hen)大。不(bu)含表(biao)面(mian)(mian)活(huo)性(xing)元(yuan)素的(de)(de)(de)(de)普通CMT焊(han)，表(biao)面(mian)(mian)張(zhang)力隨(sui)溫(wen)度的(de)(de)(de)(de)升高(gao)而減(jian)小(xiao)，因此(ci)從表(biao)面(mian)(mian)看熔(rong)(rong)池(chi)(chi)對(dui)(dui)(dui)(dui)流方向從中心到四周，熱(re)(re)量(liang)較為分散，熔(rong)(rong)深較淺；對(dui)(dui)(dui)(dui)于(yu)活(huo)性(xing)劑CMT焊(han)，活(huo)性(xing)元(yuan)素的(de)(de)(de)(de)存在，使熔(rong)(rong)池(chi)(chi)表(biao)面(mian)(mian)張(zhang)力隨(sui)溫(wen)度升高(gao)而增大，即(ji)熔(rong)(rong)池(chi)(chi)對(dui)(dui)(dui)(dui)流方向從四周到中心，使得(de)熔(rong)(rong)池(chi)(chi)中心區(qu)的(de)(de)(de)(de)熔(rong)(rong)化金(jin)屬具有較高(gao)的(de)(de)(de)(de)溫(wen)度，同時(shi)較多(duo)的(de)(de)(de)(de)熱(re)(re)量(liang)被(bei)液流直接帶向熔(rong)(rong)池(chi)(chi)底部(bu)，使熔(rong)(rong)深增加(jia)，同時(shi)有使熔(rong)(rong)寬減(jian)小(xiao)的(de)(de)(de)(de)趨(qu)勢(shi)。

4結論

（1）CMT焊接采用活性劑后，焊縫熔深(shen)有較(jiao)大程度的增加(jia)，增加(jia)比例在20%以上(shang)。

（2）活(huo)(huo)性(xing)(xing)劑(ji)CMT焊接中，活(huo)(huo)性(xing)(xing)劑(ji)對電(dian)弧氣體電(dian)離和電(dian)極發(fa)射電(dian)子兩個物(wu)理過程都產生重要影響(xiang)，活(huo)(huo)性(xing)(xing)物(wu)質(zhi)的加入(ru)使得電(dian)離電(dian)壓降(jiang)低，電(dian)弧穩定(ding)。

（3）活性劑CMT焊(han)接熔(rong)深增(zeng)加是電(dian)(dian)弧壓(ya)縮和表(biao)面張力共同(tong)作用的結果。其中B2O3和SiO2使焊(han)縫熔(rong)深增(zeng)加明顯(xian)，與B和Si兩元素具有較(jiao)大的電(dian)(dian)阻(zu)率有關(guan)。

（4）活性劑(ji)成分不同，焊(han)縫熔深增加程度也不同。

從目(mu)前試驗(yan)來看，單一(yi)活(huo)性(xing)劑對CMT焊接(jie)有較大的(de)影響(xiang)，研究(jiu)多(duo)組分(fen)活(huo)性(xing)劑CMT焊接(jie)以及進(jin)行(xing)配方設計等(deng)工作仍有待進(jin)一(yi)步探索(suo)(suo)，同時研究(jiu)活(huo)性(xing)劑在不同氣體保(bao)護下的(de)CMT焊接(jie)，對活(huo)性(xing)劑CMT焊接(jie)機理的(de)進(jin)一(yi)步探索(suo)(suo)具有十分(fen)重(zhong)要的(de)研究(jiu)價值。