Preheatingna nufin wani tsari da ke dumama welding gabaɗaya ko a wuraren walda kafin walda. Musamman mai kyau abu don walda high ƙarfi matakin, hardening hali na karfe, thermal conductivity, kauri ya fi girma weldments, da kuma lokacin da yanayi zafin jiki ne ma low, waldi yankin sau da yawa bukatar butt don dumi sama kafin waldi.

Manufar preheating shine don rage saurin sanyaya na haɗin gwiwar welded da preheating zafin jiki. Ana iya gani daga tebur, dumi-dumi na iya rage yawan kwantar da hankali, amma bai tasiri lokacin da za a zauna a cikin babban zafin jiki ba, wanda yake da kyawawa. Don haka lokacin walda karfe tare da yanayin taurin, don rage yawan sanyaya yana rage ƙarfin ƙarfin babban matakan tsari, shine don dumama, maimakon ƙara shigar da kuzari.