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(bu)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(shi)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(shi)體(ti)不(bu)銹(xiu)鋼由于有(you)淬火傾(qing)向，點(dian)焊(han)(han)(han)時要求(qiu)采用較(jiao)長(chang)焊(han)(han)(han)接時間。為消除淬硬組織，最好采用焊(han)(han)(han)后(hou)回(hui)火的(de)雙脈沖點(dian)焊(han)(han)(han)。點(dian)焊(han)(han)(han)時一般不(bu)采用電極(ji)的(de)外部水冷卻，以免因(yin)淬火而產生裂紋(wen)。

  單面(mian)(mian)點(dian)(dian)(dian)焊時，電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)由工(gong)件(jian)的(de)同(tong)一側向(xiang)焊接(jie)(jie)處饋電(dian)(dian)(dian)(dian)(dian)(dian)。典型的(de)單面(mian)(mian)點(dian)(dian)(dian)焊方式(shi)如圖6-12所示。圖中：（a)單面(mian)(mian)單點(dian)(dian)(dian)點(dian)(dian)(dian)焊，不(bu)形(xing)成焊點(dian)(dian)(dian)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)采(cai)用大直徑和大接(jie)(jie)觸面(mian)(mian)以減小電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)密度。（b)無(wu)分(fen)流(liu)(liu)的(de)單面(mian)(mian)雙點(dian)(dian)(dian)點(dian)(dian)(dian)焊，此時焊接(jie)(jie)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)全部流(liu)(liu)經焊接(jie)(jie)區。（c)有分(fen)流(liu)(liu)的(de)單面(mian)(mian)雙點(dian)(dian)(dian)點(dian)(dian)(dian)焊，流(liu)(liu)經上面(mian)(mian)工(gong)件(jian)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)不(bu)經過(guo)焊接(jie)(jie)區，形(xing)成分(fen)流(liu)(liu)。為(wei)(wei)了給(gei)焊接(jie)(jie)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)提供(gong)低電(dian)(dian)(dian)(dian)(dian)(dian)阻的(de)通路(lu)。在(zai)工(gong)件(jian)下面(mian)(mian)墊有銅(tong)墊板。（d)當兩焊點(dian)(dian)(dian)的(de)間(jian)距很大，如在(zai)進行骨架(jia)構件(jian)和復板的(de)焊接(jie)(jie)時，為(wei)(wei)了避免不(bu)適當的(de)加熱引起翹曲和減小兩電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)間(jian)電(dian)(dian)(dian)(dian)(dian)(dian)阻，采(cai)用了特殊的(de)銅(tong)橋(qiao)A,與電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)同(tong)時壓緊在(zai)工(gong)件(jian)上。