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.

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 Study on Hydrogen Diffusion and Sulfide Stress Cracking Behaviors of Simulated Heat-Affected Zone of A516-65 Grade Pressure Vessel Carbon Steel

2020 ◽  
Vol 58 (9) ◽  
pp. 599-609
Author(s):  
Dong Min Cho ◽  
Jin-seong Park ◽  
Jin Woo Lee ◽  
Sung Jin Kim
Keyword(s):  
Heat Affected Zone ◽  
Heat Input ◽  
Thermal Cycle ◽  
Hydrogen Diffusion ◽  
Tensile Load ◽  
Localized Corrosion ◽  
Coarse Grained ◽  
Stress Cracking ◽  
Sulfide Stress ◽  
Sulfide Stress Cracking

Hydrogen diffusion and sulfide stress cracking of simulated heat-affected zone (HAZ) of A516- 65 grade steel were examined using an electrochemical permeation technique, glycerin volumetric method, and constant loading method. HAZ samples were fabricated using a metal thermal cycle simulator with a welding heat input of 20, 35, and 50 kJ/cm. The fractions of bainite and martensite-austenite (M-A) constituent in coarse-grained HAZ (CGHAZ) and intercritical HAZ (ICHAZ) obtained by a simulated thermal cycle with a low heat input (20 kJ/cm) were higher than those with a higher heat input. These fractions contributed to the increase in the reversible hydrogen trap density (N<sub>[H]rev</sub>) and reversibly trapped hydrogen concentrations (C<sub>rev</sub>). Although CGHAZ had higher N<sub>[H]rev</sub> and C<sub>rev</sub> meaning that it is more likely to be vulnerable to brittle failure by hydrogen, actual fracture by sulfide stress cracking (SSC) occurred in ICHAZ composed of a mixture of soft ferrite/pearlite, and hard bainite and M-A. The hydrogen diffusion/trapping parameters, which were obtained from the electrochemical permeation or glycerin method, cannot be directly indicative of the resistance to SSC of the steel in a H<sub>2</sub>S environment. The susceptibility to SSC was more influenced by the level of M-A-localization and localized corrosion attack, acting as a stress intensifier under a tensile load.

Effect of Welding Heat Cycle Peak Temperature and Heat Input on HAZ Grain Size of SMA490BW Corrosion Resistance Steel

2012 ◽  
Vol 602-604 ◽  
pp. 415-420 ◽  
Author(s):  
Ming Yue Zhang ◽  
Yuan Nie ◽  
Qing Ying Wang ◽  
Hui Chen
Keyword(s):  
Grain Size ◽  
Corrosion Resistance ◽  
Heat Affected Zone ◽  
Thermal Cycle ◽  
Great Influence ◽  
Peak Temperature ◽  
Line Energy ◽  
Heat Cycle ◽  
Welding Thermal Cycle ◽  
Gleeble 3500

Welding thermal cycle of SMA490BW corrosion resistance steel with different heat inputs were simulated by using Gleeble-3500 thermo-mechanical simulator to investigate the grain size of the heat affected zone (HAZ). Results show that welding heat cycle peak temperature has great influence on the grain size with the same other conditions, the higher peak temperature is the bigger grain size is; in different welding thermal cycling conditions, line energy affects grain size differently; specimens which experienced two thermal cycle have smaller grain size than which experienced just one thermal cycle.

Investigation on the Weldability of a Zr-Ti Microalloyed Pipeline Steel X120

2012 ◽  
Vol 538-541 ◽  
pp. 1478-1483 ◽  
Author(s):  
Yu Qun Yin ◽  
Hong Hong Wang ◽  
Yong Kuan Yao ◽  
Li Li ◽  
Xuan Wei Lei ◽  
...  
Keyword(s):  
Impact Toughness ◽  
Heat Affected Zone ◽  
Heat Input ◽  
Room Temperature ◽  
Pipeline Steel ◽  
Coarse Grained ◽  
Fine Grained ◽  
Cycle Simulation ◽  
Welding Thermal Cycle ◽  
Temperature Impact

Welding thermal cycle simulation with the heat input of 12~25 kJ/cm and practical welding were undertaken to investigate the weldability of a Zr-Ti microalloyed pipeline steel X120. The microstructure in the simulated coarse-grained heat-affected zone was predominantly bainite. The Vickers hardness and room temperature impact toughness of simulated coarse-grained heat-affected zone is 276~297 (HV10) and 208~225 J, respectively. These results indicated that the X120 steel had good weldability. Practical plate welding with the heat input of 21 kJ/cm also showed that the Zr-Ti microalloyed pipeline steel X120 had high yeild strength (895 MPa) and low temperature (-30°C) impact toughness (183 J, 204 J and 208 J in the fusion line, coarse-grained heat-affected zone and fine-grained heat-affected zone, respectively).

Microstructure and Properties of HAZ in Low-Carbon Bainite E550 Steel during Double-Pass Welding Thermal Cycle

2018 ◽  
Vol 913 ◽  
pp. 317-323 ◽  
Author(s):  
Yun Zong ◽  
Chun Ming Liu
Keyword(s):  
Impact Toughness ◽  
Heat Affected Zone ◽  
Thermal Cycle ◽  
Coarse Grained ◽  
Granular Bainite ◽  
Low Carbon ◽  
Microstructure And Properties ◽  
Welding Thermal Cycle ◽  
Low Carbon Bainite ◽  
The Impact

Investigations on the microstructure and properties of the Coarse-Grained Heat-Affected Zone (CGHAZ) and intercritical reheated Coarse-Grained Heat-Affected Zone (ICCGHAZ) of a low-carbon bainite E550 steel were carried out using thermal simulation technology in this paper.Double-pass welding thermal cycle were performed on Gleeble-3800 thermal simulator, tempering heat treatment of the critical coarse crystal zone carried out in a box resistance furnace, low impact energies at -40 °C and Vickers hardness determined, and the microstructure were observed. The experimental results show that the microstructure of CGHAZ (Tp1 is 1320 °C) was dominated by coarse granular bainite and Lath bainite Ferrite, the impact toughness of CGHAZ was poor. The toughness of the CGHAZ was improved after second welding heat cycle except intercritical two-phase heating. When the peak temperature of the second thermal cycle(Tp2) was 650 °C, martensite-austenite (M-A) constituent of original CGHAZ wasdecomposed and refined, impact toughness and hardness were all higher than that of CGHAZ; When Tp2 is 750 °C, there was a ” necklace” distribution of massive M-A constituent in this ICCGHAZ, the impact energy at -40 °C prominently decreased and Hardness went up; When Tp2 was in the temperature range of 850 °C ~1100 °C, the microstructure was mainly finer granular bainite, the toughness of CGHAZ could be effectively improved; When Tp2 was over 1100 °C, M-A constituents become coarse, the toughness declined slightly . The changing of hardness was the opposite of toughness but the hardness fluctuation was comparatively small. After tempering at different temperature (520 °C~640 °C) , the grain boundary "necklace" structure of ICCGHAZ was still obvious, some of the M-A constituent were decomposed, the hardness decreased, the lowest hardness was obtained in 610 °C.

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