Open AccessResearch on Microstructure and Properties in Welded Joint of 700 MPa grade Low Carbon Micro-alloy steel
Author(s) -
Zemao Gu
Publication year - 2021
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1846/1/012051
Subject(s) - bainite , materials science , microstructure , metallurgy , pearlite , welding , ferrite (magnet) , indentation hardness , high strength low alloy steel , alloy steel , alloy , heat affected zone , toughness , composite material , austenite
High-strength residual heat treatment steel bar was tested with welding thermal simulation in Gleeble 3500. Effect of heat input on the microstructure, impact toughness and microhardness of weld heat-affected zone (HAZ)was studied. The results show that with the increase of t 8/5 , microstructure of coarse grain heat-affected zone (CGHAZ)transforms into granular bainite and pearlite in stead of ferrite, feather-like upper bainite and strip-like lower bainite, HAZ impact value increases firstly then decreases and reaches maximum at t 8/5 = 100s and the hardness decreases. And when t 8/5 increased to 60s there were only ferrite and pearlite in the microstructure of CGHAZ. The impact energy of high-strength residual heat treatment steel bar would be at the range of a good level for physical production with the range of t 8/5 from 20s to 300s.