No ka pipeline kinoea kūlohelohe lōʻihi, me ka hoʻohana ʻana i ke kila pipeline kiʻekiʻe ke ala nui e mālama ai i nā kumukūʻai.Ua hōʻike ʻia ka hana ʻoihana pipeline o Canada: ke hoʻohālikelike ʻia me ka X60, hiki ke hoʻemi ʻia ka mānoanoa o ka pā paipu X70 i ka 14%; Ke hoʻohālikelike ʻia me X70, hiki ke hoʻemi ʻia ka mānoanoa o ka pā paipu X80 e 12.5%.ʻO ka welding kekahi o nā loulou nui i ka hana ʻana i ka paipu kila a me ke kūkulu ʻana i ka pipeline, ma muli o ka pōʻai wela o ka welding, ʻo ka welding wela i hoʻopili ʻia (HAZ) he wahi nāwaliwali o ka pipeline.ʻO ka helu hoʻoluʻu ka mea nui e hoʻoholo ai i ka hana o ka hui HAZ, pili ia i ka hoʻokomo wela welding, ka mānoanoa o ka mea hana a me ke kūlana radiation a puni.No laila, e hana ana i ke kaʻina hana kuʻikuʻi kūpono, hiki ke loaʻa ka hoʻonohonoho hoʻonohonoho maikaʻi ʻana o ka HAZ, e pale aku i nā māwae HAZ, i mea e hōʻoia ai i ka hana palekana o ka pipeline.

Me ka piʻi ʻana o ka hoʻoluʻu ʻana, hāʻawi ʻia ka microstructure o X80 pipeline steel HAZ me ka polygonal ferrite, e hāʻawi i ka mea nui me ka B a i ʻole ka palaoa o ka lath martensite, e piʻi ka paʻakikī.Ke kiʻekiʻe loa ka hoʻokomo wela o ka welding a i ʻole ke kiʻekiʻe o ka wela preheating a ʻoi aku ka haʻahaʻa o ka māmā ma mua o 2℃/ s, X80 pipeline kila HAZ hui ua haawi mua ia me a B polygon ferrite hua, akā, ma muli o ka noho ana o ka pearlite a me ka moku moku moku mahele mahele, e alakai ana i ka coarse kristal hopena hana poorer.Ke liʻiliʻi loa ka hoʻokomo wela a i ʻole ka haʻahaʻa haʻahaʻa o ka wela preheating a ʻoi aku ka wikiwiki ma mua o 30.℃/ s, X80 pipeline steel hui HAZ ua hāʻawi mua ʻia me BF a i ʻole lamellar martensite, e hopena i ka emi ʻana o ka hopena o ka hopena aniani.Ke hana nei i ke kaʻina hana hoʻoheheʻe kūpono, kaohi ʻana i ka helu hoʻoluʻu i loko o ka pā o 2 ~ 30℃/ s, X80 pipeline steel hui HAZ ua haawi mua ia i ka B, ma ka moku mokupuni i hoopuehuia, o ka coarse grain zone he paakiki kupono a me ka maikai o ka hana.