scholarly journals Combined effects of welding heat input and peak temperature on precipitation and mechanical properties of the HAZ for modified austenitic medium manganese steels

2021 ◽  
Author(s):  
Wenjin Sun ◽  
Miao Li ◽  
Chengning Li ◽  
wenbin hu ◽  
Xinjie Di
Keyword(s):  
Mechanical Properties ◽  
Heat Input ◽  
Peak Temperature ◽  
Combined Effects ◽  
Welding Heat Input ◽  
Manganese Steels

scholarly journals Microstructural Characteristics and Mechanical Properties of Friction Stir Spot Welded 2A12-T4 Aluminum Alloy

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Huijie Liu ◽  
Yunqiang Zhao ◽  
Xingye Su ◽  
Lilong Yu ◽  
Juncai Hou
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Fracture Mode ◽  
Heat Input ◽  
Tensile Shear ◽  
Microstructural Characteristics ◽  
Friction Stir ◽  
Welding Heat Input ◽  
Mixed Fracture ◽  
Spot Welded

2A12-T4 aluminum alloy was friction stir spot welded, and the microstructural characteristics and mechanical properties of the joints were investigated. A softened microstructural region existed in the joint, and it consisted of stir zone (SZ), thermal mechanically affected zone (TMAZ), and heat affected zone (HAZ). The minimum hardness was located in TMAZ, and the average hardness value in SZ can be improved by appropriately increasing welding heat input. The area of complete bonding region at the interface increased with increasing welding heat input because more interface metals were mixed. In a certain range of FSSW parameters, the tensile shear failure load of the joint increased with increasing rotation speed, but it decreased with increasing plunge rate or decreasing shoulder plunging depth. Two kinds of failure modes, that is, shear fracture mode and tensile-shear mixed fracture mode, can be observed in the tensile shear tests, and the joint that failed in the tensile-shear mixed fracture mode possessed a high carrying capability.

Thermal Simulation Study of 900MPa Grade High-Strength Low Alloy Steel in Welding Procedures

2011 ◽  
Vol 704-705 ◽  
pp. 1128-1132
Author(s):  
Di Xin Yang ◽  
Yuan Fang Sun
Keyword(s):  
Alloy Steel ◽  
Heat Input ◽  
High Strength ◽  
Weld Bead ◽  
Peak Temperature ◽  
Welding Parameters ◽  
Chemical Compositions ◽  
Low Alloy Steel ◽  
Hydraulic Support ◽  
Welding Heat Input

Hydraulic support is an important part of fully mechanized equipments. The constructional steels of hydraulic support with international advanced level mainly adopt the high-strength welding structural steel with its tensile strength of more than 700~1000MPa.This paper analyzes the chemical compositions features of S890 high-strength low alloy steel for 900MPa grade.The Influence of welding parameters,peak temperature and on the microstructures and mechanical properties of welding HAZ of S890 high-strength low alloy steel were investigated by thermo-simulated tests, The influence of welding heat input on the mechanical behaviors of the welded joint was also investigated. The results show that the microstructures of S890 steel change from tempered martensite to bainite and a little ferrite , pearlitic when welding heat input changes from low to high, and accompany the austenite grains coarsening ,so the impact toughness and hardness of welding HAZ at lower peak temperatures and shorter are higher than that at higher peak temperature and long . Welding HAZ produced by the second weld bead will overlap partially with the HAZ produced by the first weld bead. In this area, primitive microstructure tempers again or partial re-phase transformations and re-cools,but the area involved in the overlap is limited,so the influence on the properties of S890 steel is not obvious. In covered arc welding,the influence on the welded join strength of S890 steel is not distinct when heat input change in a certain scope, but the plasticity of the welded join falls off steeply as heat input increases. Keywords: S890 steel; high-strength low alloy steel; weld performance; hydraulic supports

scholarly journals Optimizing the Mechanical Properties in the Repair Zone of 5Cr5MoV by Controlling Welding Heat Input

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 981 ◽  
Author(s):  
Yan Liang ◽  
Yaohui Liu ◽  
Yulai Song ◽  
Wei Cui
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Tensile Properties ◽  
Heat Input ◽  
Cold Working ◽  
Shielded Metal Arc Welding ◽  
Die Steel ◽  
Microhardness Distribution ◽  
Welding Heat Input ◽  
Metal Arc Welding

The influence of welding heat input on the microstructure and mechanical properties of 5Cr5MoV die steel was studied in order to improve the mechanical properties of the cold working die and extend its service life. Shielded metal arc welding (SMAW) method was used with different heat inputs in the range from 4.2 to 6.61 kJ/cm to repair the 5Cr5MoV die steel. Microhardness and tensile properties were performed to evaluate the repaired quality of the cold working die steel. The microhardness of the weld repaired zone gradually decreased from the weld to the tempering zone. The highest microhardness in the weld repaired zone was 863 HV, and finally, it decreased to about 300 HV. With the increase of heat input, the tensile strength of the weld and the heat affected zone increased; nevertheless, the tensile strength of the tempering zone increased first and then decreased. As a result, 6.6 kJ/cm is the best value of heat input judged from the microhardness distribution and the tensile properties.

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.

scholarly journals Significant Influence of Welding Heat Input on the Microstructural Characteristics and Mechanical Properties of the Simulated CGHAZ in High Nitrogen V-Alloyed Steel

2020 ◽  
Vol 39 (1) ◽  
pp. 33-44
Author(s):  
Jing Zhang ◽  
Wenbin Xin ◽  
Guoping Luo ◽  
Ruifen Wang ◽  
Qingyong Meng
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Heat Input ◽  
Prior Austenite ◽  
Alloyed Steel ◽  
Coarse Grained ◽  
High Nitrogen ◽  
Microstructural Characteristics ◽  
Welding Heat Input ◽  
The Impact

AbstractThe microstructural characteristics and mechanical properties of the simulated coarse grained heat affected zone (CGHAZ) in high N V-alloyed steel have been conducted under different welding heat input, characterized by the cooling time taken from 800°C to 500°C (t8/5). The experimental results show that the microstructure is dominantly composed of lath bainite (LB) and granular bainite (GB) at t8/5 30 s– 90 s. The content of LB decreases with t8/5 increasing, and that of GB increases. When t8/5 further increases to 120 s and 180 s, the microstructure mainly consists of intragranular polygonal ferrite (IPF) and acicular ferrite (IAF). The higher t8/5 leads to the increased content of intragranular ferrite (IGF). Meanwhile, the prior austenite grain size (PAGS) progressively increases from 56 ± 6.0 μm to 148 ± 9.9 μm as t8/5 increases from 30 s to 180 s. Besides, EBSD analysis indicates that the fraction of high angle grain boundaries (HAGBs) is 0.570, 0.427 and 0.624, respectively, corresponding to t8/5 30, 90 and 180 s. Moreover, the impact toughness decreases as t8/5 increases from 30 s to 90 s caused by the increased PAGS and GB content, and then sharply increases with t8/5 exceeding 90 s due to the increased formation of IGF, especially IAF. Furthermore, the high nitrogen content accelerates V(C,N) precipitation, which not only inhibits the coarsening of prior austenite grains, but promotes the formation of IGF, resulting in the increased number of HAGBs and raising impact toughness.

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