Coarsening of Particles in Coarse Grain Heat-Affected Zone for Ti Microalloyed Steels

2011 ◽  
Vol 704-705 ◽  
pp. 690-694
Author(s):  
Ying Qiao Zhang ◽  
Han Qian Zhang ◽  
Zhi Yong Li
Keyword(s):  
Base Metal ◽  
Heat Affected Zone ◽  
Thermal Cycle ◽  
Microalloyed Steel ◽  
Microalloyed Steels ◽  
Coarse Grain ◽  
Transmission Electron ◽  
Coarsening Behavior ◽  
Welding Thermal Cycle ◽  
Isothermal Growth

The coarsening behavior of Ti (CxN1-x) particles in CGHAZ for Ti-microalloyed steel has been studied after different welding thermal cycles corresponding to heat inputs 30, 60, 100kJ/cm using Gleeble-3800 thermo/mechanical simulator and transmission electron microscopy. Cuboid TiN and a lot of ellipsoidal or elongated particles VC, M3C and M23C6 are observed in the base metal. After welding thermal cycle with peak temperature of 1350°C, irregular particles existed in base metal have also been dissolved even at the lowest heat input of 30kJ/cm. TiN Particles coarsening are observed in CGHAZ with the increase of heat inputs that is just related to dissolution and reprecipitation of particles and irrelevant to isothermal growth of particles. Keywords: microalloyed steel; coarse grain heat-affected zone; TiN particles

Effect of Heat Input on HAZ Properties and Microstructure of SMA490BW Corrosion Resistance Steel

2011 ◽  
Vol 337 ◽  
pp. 517-521
Author(s):  
Yuan Nie ◽  
Li Jun Wang ◽  
Chuan Ping Ma ◽  
Yong Hui Zhu ◽  
Da Li ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Impact Energy ◽  
Heat Affected Zone ◽  
Heat Input ◽  
Thermal Cycle ◽  
Coarse Grain ◽  
Welding Thermal Cycle ◽  
Gleeble 3500 ◽  
The Impact ◽  
Small Content

Welding thermal cycle of SMA490BW corrosion resistance steel with different heat inputs were simulated by using Gleeble-3500 thermo-mechanical simulator to investigate the microstructure and impact toughness of the heat-affected zone (HAZ). The results shows that the microstructure of the coarse-grain heat affected zone(CGHAZ) is mainly composed of lath bainites and the surpass critical coarse-grain heat affected zone(SCCGHAZ) consists mainly of granular bainites with a small content of ferrites. The grain size increased with the heat input increasing, Besides, the impact energy of the surpass critical coarse-grain heat affected zone(SCCGHAZ) is higher than that of the coarse-grain heat affected zone(CGHAZ), when the heat input energy is 15kJ/cm after twice thermal cycle, the impact energy is highest.

scholarly journals Effect of Initial Microstructure on the Toughness of Coarse-Grained Heat-Affected Zone in a Microalloyed Steel

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4760
Author(s):  
Minghao Shi ◽  
Man Di ◽  
Jian Zhang ◽  
Rangasayee Kannan ◽  
Jing Li ◽  
...  
Keyword(s):  
Grain Size ◽  
Base Metal ◽  
Thermal Cycle ◽  
Microalloyed Steel ◽  
Charpy Impact ◽  
Coarse Grained ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Prior Austenite Grain Size ◽  
Prior Austenite Grain

Toughness of the coarse-grained-heat-affected-zone (CGHAZ) strongly depends on the prior austenite grain size. The prior austenite grain size is affected not only by chemical composition, thermal cycle, and dissolution of second-phase particles, but also by the initial microstructure. The effect of base metal microstructure (ferrite/pearlite obtained by air cooling and martensite obtained by water-quenching) on Charpy impact toughness of the CGHAZ has been investigated for different heat inputs for high-heat input welding of a microalloyed steel. A welding thermal cycle with a heat input of 100 kJ/cm and 400 kJ/cm were simulated on the MMS-300 system. Despite a similar microstructure in the CGHAZ of both the base metals, the average Charpy impact energy for the air-cooled base metal was found to be higher than the water-quenched base metal. Through thermo-kinetic simulations, it was found that a higher enrichment of Mn/C at the ferrite/austenite transformation interface of the CGHAZ of water-quenched base metal resulted in stabilizing austenite at a lower A1 temperature, which resulted in a coarser austenite grain size and eventually lowering the toughness of the CGHAZ.

The Effect of the Welding Thermal Cycle on Heat Affected Zone Hardening for 500MPa Grade Screw Thread Steel

2011 ◽  
Vol 189-193 ◽  
pp. 3530-3533
Author(s):  
Jun Fei Fang ◽  
Lei Yang ◽  
Xiao Min Yuan ◽  
Yi Zhu He
Keyword(s):  
Heat Affected Zone ◽  
Heat Input ◽  
Thermal Cycle ◽  
Intrinsic Factor ◽  
Avrami Equation ◽  
Screw Thread ◽  
Martensite Content ◽  
Welding Thermal Cycle ◽  
Hardness Ratio ◽  
Relative Hardness

The hardening behavior of the welding heat affected zone (HAZ) with different heat input for 500MPa grade screw thread steel is investigated in this paper. The single welding thermal cycle was applied to the test steel by a Gleeble-3500 thermal simulator. With the definition of hardness ratio, relative hardness factor and partial hardness zone, the HAZ Max hardness, hardness distribution and hardness mechanism of steel were analyzed. The results show that the HAZ hardness is always higher than the base steel hardness. The hardness ratio is increasing with the heat input decreased. The distribution of relative hardness factor of HAZ can be expressed by the Avrami equation which can describe the distribution of HAZ hardness. The width of partial hardness zone increases rapidly with the heat input increased. But at a certain degree of heat input, the width of partial hardness decreases slightly. The microstructure generated by heat input is the intrinsic factor of the HAZ hardness variation. The HAZ hardness enhances as the martensite content increases. On the contrary the HAZ hardness reduces as the ferrite content enhance on condition the heat input increase or the observed area is far away from the HAZ.

Sign in / Sign up

Export Citation Format

Share Document