Preheating thiab post-weld heat treatment (PWHT) yog cov kauj ruam tseem ceeb hauv cov txheej txheem vuam uas cuam tshuam rau qhov zoo, kev ua tau zoo, thiab kev nyab xeeb ntawm cov pob qij txha. Los ntawm kev nkag siab txog cov txheej txheem tseem ceeb no, cov welders tuaj yeem ua kom zoo dua cov qauv kev ncaj ncees thiab cov khoom siv ntawm cov khoom siv welded.
Qhov tseem ceeb ntawm Preheating
Preheating muaj cua sov lub hauv paus hlau ua ntej vuam pib. Nws qhov tseem ceeb tuaj yeem raug ntaus nqi rau cov hauv qab no:
Ua kom txias txias
Preheating slows cov txheej txheem txias tom qab vuam, tso cai rau lub diffusion thiab khiav ntawm hydrogen los ntawm cov hlau weld, yog li tiv thaiv hydrogen-induced cracking. Nws kuj txo qhov hardness ntawm weld thiab tshav kub-cuam tshuam cheeb tsam, txhim khu kev tiv thaiv tawg.
Txo kev ntxhov siab
Preheating minimizes kub gradients ntawm welded Cheebtsam, txo welding stresses thiab tej zaum yuav tawg.
Txo kev txwv nyob rau hauv welded lug
Kev ua kom zoo preheating txo qis kev tswj hwm hauv welds, txo qhov tshwm sim ntawm cov kab nrib pleb thiab txhim kho kev sib koom ua ke zoo.
Qhov tseem ceeb ntawm kev kho cua sov tom qab Weld (PWHT)
PWHT cuam tshuam nrog kev sib koom ua ke welded rau tswj cua sov thiab txias tom qab vuam. Nws cov txiaj ntsig suav nrog:
Kev tshem tawm hydrogen
PWHT ntawm qhov kub thiab txias yuav pab tshem tawm cov hydrogen los ntawm qhov chaw vuam thiab qhov kub thiab txias, tiv thaiv kev tawg ntawm cov hlau tsis tshua muaj hlau.
Kev ntxhov siab
Vuam-vim kev ntxhov siab tuaj yeem cuam tshuam lub peev xwm thauj khoom ntawm cov pob qij txha. PWHT, xws li kub-kub tempering, txo cov kev ntxhov siab thiab txhim kho kev sib koom ua ke tiv thaiv deformation thiab tsis ua haujlwm.
Txhim kho weld khoom
Qee cov hlau alloys tuaj yeem pom cov qauv tsis zoo tom qab vuam, cuam tshuam tsis zoo rau cov khoom siv kho tshuab. PWHT txhim kho cov weld lub microstructure, txhim kho cov khoom xws li plasticity thiab toughness.
