Effect of heat input on microstructure and toughness of coarse grain heat affected zone in Nb microalloyed HSLA steels

2009 ◽  
Vol 16 (5) ◽  
pp. 73-80 ◽  
Author(s):  
Ying-qiao Zhang ◽  
Han-qian Zhang ◽  
Jin-fu Li ◽  
Wei-ming Liu
Keyword(s):  
Heat Affected Zone ◽  
Heat Input ◽  
Coarse Grain ◽  
Hsla Steels

scholarly journals Numerical and Experimental Investigation of the Heat Input Effect on the Mechanical Properties and Microstructure of Dissimilar Weld Joints of 690-MPa QT and TMCP Steel

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 355 ◽  
Author(s):  
Francois Njock Bayock ◽  
Paul Kah ◽  
Pavel Layus ◽  
Victor Karkhin
Keyword(s):  
Heat Affected Zone ◽  
Heat Input ◽  
Lath Martensite ◽  
High Strength ◽  
Primary Recrystallization ◽  
Coarse Grain ◽  
Dissimilar Weld ◽  
Thermal Fields ◽  
Relative Value ◽  
Experimental Comparisons

The study evaluates numerically and experimentally the effect of welding heat input parameters on the microstructure and hardness of the heat-affected zone (HAZ) of quenched and tempered (QT) and thermo-mechanically controlled process (TMCP) 690-MPa high-strength steel. Numerical analyses and experimental comparisons were applied using three heat input values (10, 14, and 17 kJ/cm) in order to predict the thermal fields during welding. Experimental analysis was carried out of the microstructure and microhardness behavior in different HAZ areas. The numerical values indicate that the maximum respective values of temperature measured in QT steel and TMCP steel were about 1300 and 1200 °C for a heat input of 10 kJ/cm, 1400 and 1300 °C for a heat input of 14 kJ/cm, and 1600 and 1450 °C for a heat input of 17 kJ/cm. The cooling times resulted, for a heat input of 10 kJ/cm, in numerical t8/5 (14.5 s) and experimental (18.84 s) increases in hardness in the coarse-grain heat-affected zone (CGHAZ) of the QT steel (317 HV0.1), due to the formation of bainite and lath martensite structures with grain growth. Decreased hardness in the CGHAZ of TMCP steel (240 HV0.1) was caused by primary recrystallization of the microstructure and the formation of more equilibrium products of austenite decomposition. Increasing the heat input (14 to 17 kJ/cm) led to numerical t8/5 (29 s) and experimental (36 s) decreases in hardness in the CGHAZ of QT steel (270 HV0.1) due to the full austenite (thermal weld cycle), and maintained the relative value of TMCP steel (235 HV0.1).

Effect of Heat Input on M-A Constituent and Toughness of Coarse Grain Heat-Affected Zone in an X100 Pipeline Steel

2019 ◽  
Vol 28 (3) ◽  
pp. 1810-1821 ◽  
Author(s):  
Xiao-Nan Wang ◽  
Yan-Jun Zhao ◽  
Peng-Fei Guo ◽  
Xiao-Nan Qi ◽  
Hong-Shuang Di ◽  
...  
Keyword(s):  
Heat Affected Zone ◽  
Heat Input ◽  
Pipeline Steel ◽  
Coarse Grain ◽  
X100 Pipeline Steel

Mechanical Properties of the Heat Affected Zone of an X100 Grade Pipeline Steel

2013 ◽  
Vol 773-774 ◽  
pp. 795-802 ◽  
Author(s):  
Gui Ying Qiao ◽  
Ming Zheng ◽  
Yu Gu ◽  
Xiu Lin Han ◽  
Xu Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Heat Affected Zone ◽  
Heat Input ◽  
Pipeline Steel ◽  
Thermal Simulation ◽  
Peak Temperature ◽  
Coarse Grain ◽  
Fine Grained ◽  
Gleeble 3500

The microstructure and mechanical properties of an X100 grade pipeline steel were investigated by the thermal simulation tests performed on a Gleeble-3500 thermal simulator. The results show that the steel has excellent weldability. Even if the weld heat input gets 40 kJ mm-1, the low impact toughness energy in welding coarse grain heat affected zone (CGHAZ) is still higher than 200 J. Yet, an embrittlement zone emerges in inter-critical HAZ (ICHAZ) at the peak temperature of 750 °C, and the lowest strength appears in fine grained HAZ (FGHAZ) at the peak temperature of 950 °C. Moreover, the strength and toughness decrease with the increase of heat input.

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.

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