點焊工件只在有限的接觸面上即所謂“點”上被焊接起來，并形成扁球形的熔核。點焊又分為單點焊和多點焊，多點焊時使用兩對以上的電極，在同一工序內形成多個熔核。點焊方法通常又分為雙面點焊和單面點焊兩大類。雙面點焊時，通常采用搭接接頭和折邊接頭兩種形式（圖6-11).接頭可以由兩個或兩個以上等厚度或不等厚度的工件組成。在設計點焊結構時，必須考慮電極的可達性，即電極必須能方便地抵達構件的焊接部位。同時還應考慮邊距、搭接量、點距、裝配間隔和焊點強度等因素。

  由于不銹鋼的電阻率高、導熱性差，因此與低碳鋼相比，可采用較小的焊接電流和較短的焊接時間。不銹鋼有較高的高溫強度，必須采用較高的電極壓力，以防止產生縮孔、裂紋等缺陷。不銹鋼的熱敏感性強，通常采用較短的焊接時間、強有力的內部和外部水冷卻，并且要準確地控制加熱時間和焊接電流，以防熱影響區晶粒長大和出現晶間腐蝕現象。點焊不銹鋼的電極推薦用硬度較高的電極合金，滿足高電極壓力的需要。

  馬(ma)氏體不(bu)(bu)銹鋼由(you)于有淬火傾向，點(dian)焊(han)時(shi)要(yao)求采用(yong)較長(chang)焊(han)接時(shi)間。為(wei)消除淬硬組織，最好采用(yong)焊(han)后回火的雙(shuang)脈沖(chong)點(dian)焊(han)。點(dian)焊(han)時(shi)一般(ban)不(bu)(bu)采用(yong)電極(ji)的外部(bu)水冷卻，以免(mian)因淬火而產(chan)生裂(lie)紋。

  單(dan)(dan)面(mian)(mian)(mian)點(dian)(dian)(dian)(dian)焊(han)(han)時(shi)，電(dian)(dian)極(ji)由工(gong)(gong)件的(de)同(tong)一(yi)側向焊(han)(han)接處饋電(dian)(dian)。典型的(de)單(dan)(dan)面(mian)(mian)(mian)點(dian)(dian)(dian)(dian)焊(han)(han)方式如圖6-12所示。圖中：（a)單(dan)(dan)面(mian)(mian)(mian)單(dan)(dan)點(dian)(dian)(dian)(dian)點(dian)(dian)(dian)(dian)焊(han)(han)，不形(xing)成(cheng)焊(han)(han)點(dian)(dian)(dian)(dian)的(de)電(dian)(dian)極(ji)采(cai)用大直(zhi)徑和(he)大接觸面(mian)(mian)(mian)以減小電(dian)(dian)流(liu)密度。（b)無分(fen)流(liu)的(de)單(dan)(dan)面(mian)(mian)(mian)雙點(dian)(dian)(dian)(dian)點(dian)(dian)(dian)(dian)焊(han)(han)，此時(shi)焊(han)(han)接電(dian)(dian)流(liu)全部流(liu)經(jing)焊(han)(han)接區。（c)有分(fen)流(liu)的(de)單(dan)(dan)面(mian)(mian)(mian)雙點(dian)(dian)(dian)(dian)點(dian)(dian)(dian)(dian)焊(han)(han)，流(liu)經(jing)上(shang)面(mian)(mian)(mian)工(gong)(gong)件的(de)電(dian)(dian)流(liu)不經(jing)過焊(han)(han)接區，形(xing)成(cheng)分(fen)流(liu)。為了給(gei)焊(han)(han)接電(dian)(dian)流(liu)提(ti)供低電(dian)(dian)阻的(de)通(tong)路。在工(gong)(gong)件下面(mian)(mian)(mian)墊有銅(tong)(tong)墊板。（d)當兩焊(han)(han)點(dian)(dian)(dian)(dian)的(de)間距很大，如在進行骨架構件和(he)復板的(de)焊(han)(han)接時(shi)，為了避免不適(shi)當的(de)加熱引起翹曲和(he)減小兩電(dian)(dian)極(ji)間電(dian)(dian)阻，采(cai)用了特(te)殊的(de)銅(tong)(tong)橋A,與電(dian)(dian)極(ji)同(tong)時(shi)壓緊在工(gong)(gong)件上(shang)。