Rau cov raj xa hluav taws xob ntev ntev, siv cov kav dej qib siab steel yog txoj hauv kev tseem ceeb kom txuag tau cov nqi.Canada txoj kev lag luam kev lag luam tau ua pov thawj tias: piv nrog X60, kev txais yuav X70 cov kav dej phab ntsa tuab tuaj yeem txo tau 14%; Piv nrog X70, kev txais yuav X80 pipeline phab ntsa tuab tuaj yeem txo qis dua 12.5%.Vuam yog ib qho ntawm cov kev sib txuas tseem ceeb hauv kev tsim cov yeeb nkab steel thiab kev tsim cov kav dej, vim qhov tsis sib xws ntawm vuam thermal voj voog, qhov vuam kub cuam tshuam cheeb tsam (HAZ) yog qhov tsis muaj zog ntawm cov kav dej.Txias tus nqi yog lub ntsiab parameter los txiav txim HAZ lub koom haum kev ua tau zoo, nws muaj feem xyuam rau cov vuam cua sov input, lub thickness ntawm workpiece thiab ib puag ncig hluav taws xob mob.Yog li ntawd, ua cov txheej txheem vuam tsim nyog, kev tswj vuam cua txias ceev tuaj yeem tau txais kev ua haujlwm zoo ntawm HAZ, tsis txhob HAZ tawg, thiaj li ua kom muaj kev nyab xeeb ntawm cov kav dej.

Nrog rau qhov nce ntawm qhov txias txias, microstructure ntawm X80 pipeline steel HAZ yog qhov tseem ceeb rau nrog polygonal ferrite, muab qhov tseem ceeb nrog B lossis grain ntawm lath martensite, hardness yuav nce.Thaum lub vuam kub input yog loj dhau los yog preheating kub siab dhau lawm thiab qhov txias ceev yog qis dua 2.℃/ s, X80 pipeline steel HAZ lub koom haum muab qhov tseem ceeb rau nrog los yog B polygon ferrite nplej, tab sis vim muaj pearlite thiab MA kob pawg thaiv kev faib tawm, ua rau cov ntxhib siv lead ua cuam tshuam kev ua haujlwm tsis zoo.Thaum lub vuam cua sov input tsawg dhau los yog preheating kub tsawg dhau thiab qhov txias ceev yog ntau tshaj 30℃/ s, X80 pipeline steel HAZ lub koom haum muab qhov tseem ceeb nrog BF lossis lamellar martensite, uas ua rau txo qis ntawm cov ntxhib siv lead ua cuam tshuam kev ua haujlwm.Ua cov txheej txheem vuam tsim nyog, tswj cov cua txias hauv qhov ntsuas ntawm 2 ~ 30℃/ s, X80 pipeline steel HAZ lub koom haum yog muab qhov tseem ceeb rau B, MA pawg pawg neeg tawg rog, thaj tsam coarse grain tau zoo hardness thiab zoo heev cuam tshuam kev ua tau zoo.