Kwa mapaipi amtundu wautali wa gasi, kugwiritsa ntchito chitsulo chapaipi yapamwamba ndiyo njira yayikulu yopulumutsira ndalama.Mchitidwe wamapaipi aku Canada watsimikizira kuti: poyerekeza ndi X60, kukhazikitsidwa kwa makulidwe a khoma la X70 kumatha kuchepetsedwa 14%; Poyerekeza ndi X70, kukhazikitsidwa kwa makulidwe a khoma la X80 kumatha kuchepetsedwa ndi 12.5%.Kuwotcherera ndi imodzi mwamaulalo ofunikira pakupanga zitoliro zachitsulo ndi kupanga mapaipi, chifukwa cha kusinthasintha kwa kutentha kwapang'onopang'ono, kutentha komwe kumakhudzidwa ndi kutentha (HAZ) ndi gawo lofooka la payipi.Kuzizira ndiye gawo lalikulu lodziwira momwe bungwe la HAZ likugwirira ntchito, limakhudzana ndi kutentha kwa kutentha, makulidwe a workpiece ndi mawonekedwe ozungulira.Choncho, kupanga ndondomeko kuwotcherera wololera, kulamulira kuwotcherera kuzirala liwiro akhoza kupeza bwino bungwe ntchito ya HAZ, kupewa HAZ ming'alu, kuonetsetsa chitetezo ntchito payipi.

Ndi kuchuluka kwa kuzirala, microstructure ya X80 pipeline zitsulo HAZ imapatsidwa patsogolo ndi polygonal ferrite, kupereka patsogolo ndi B kapena njere ya lath martensite, kuuma kumawonjezeka.Pamene chowotcherera chotenthetsera chiri chachikulu kwambiri kapena kutentha kwa preheating kumakhala kokwera kwambiri ndipo liwiro lozizira ndilotsika kuposa 2℃/ s, X80 pipeline zitsulo HAZ bungwe amapatsidwa patsogolo kapena B polygon ferrite njere, koma chifukwa cha kukhalapo kwa pearlite ndi MA chilumba gulu chipika kugawa, kumabweretsa coarse kristalo zimakhudza ntchito osauka.Pamene kuwotcherera kutentha kuli kochepa kwambiri kapena kutentha kwa preheating kumakhala kotsika kwambiri ndipo liwiro lozizira ndilokulirapo kuposa 30.℃/ s, X80 pipeline steel HAZ bungwe limapatsidwa patsogolo ndi BF kapena lamellar martensite, zomwe zimapangitsa kuchepa kwa magwiridwe antchito a kristalo.Kupanga kuwotcherera koyenera, kuwongolera kuziziritsa mkati mwa 2 ~ 30℃/ s, X80 pipeline zitsulo HAZ bungwe amapatsidwa patsogolo B, MA pachilumba gulu anamwazikana, coarse njere zone ali kuuma koyenera ndi kukhudza kwambiri ntchito.