Improving the microstructures and mechanical properties with nano-Al2O3 treated wire in underwater submerged arc welding

2022 ◽  
Vol 74 ◽  
pp. 40-51
Author(s):  
Maofu Zhang ◽  
Yanfei Han ◽  
Chuanbao Jia ◽  
Zhengang Zheng ◽  
Haixin Li ◽  
...  
2012 ◽  
Vol 562-564 ◽  
pp. 573-577
Author(s):  
Xiao Dong Hu ◽  
Yong Zhang ◽  
Jian Tao Lv ◽  
Sen Zhang

The butt weld of Q345R with the thickness of 40mm has been manufactured with the submerged-arc welding (SAW). The mechanical properties of the weld seam have been tested and the metallurgical structures have been analyzed. Conclusions have been obtained as follows: the metallurgical structure of multi-layer butt weld is much more complicated than the monolayer ones; only the last weld layer has the obvious zones of weld zone, heat-affected zone (HAZ) and fusion area; the weld zone and the fusion area will be heat treated with the next layers weld finished; the mechanical property of the multi-layer butt weld is much better than the monolayer weld determined by the corresponding organization.


Author(s):  
Le Mei ◽  
Junbao Zhang ◽  
Yifeng Huang ◽  
Yan Yu ◽  
Yong Jiang ◽  
...  

Up to now, two kinds of filler metal with or without nickel element for submerged arc welding have been largely used in the reactor pressure vessel (RPV) manufacturing. In order to study the effect of nickel element on weld metal properties of SA-508 Gr.3 Cl.1, submerged arc welding material with nickel (AWS classification F8P4-EGN-F2N, F2 for short) and welding material without nickel (F8P4-EA3N-A3N, A3 for short) were used; and conventional mechanical properties, low-cycle fatigue test, and proton irradiation analysis of the two weld metals were studied. Results show that the mechanical properties of the two different weld metals are similar, except that the Charpy V-notch impact property of the weld metal with nickel is better than that without nickel; the micro-structures of F2 and A3 weld metals are both composed of ferrite base and granular bainite, but the columnar grain size of F2 weld metal is smaller relatively, which results in better impact property. In addition, the irradiated A3 weld metal has fewer dislocation loops than the irradiated F2 weld metal after the same proton irradiation dose; the irradiated weld metals both have higher micro-Vickers hardness than before.


2014 ◽  
Vol 783-786 ◽  
pp. 859-866 ◽  
Author(s):  
Dong Sheng Liu ◽  
Chong Xiang Yue ◽  
Huan De Chen ◽  
Bing Gui Cheng

Key parameters for thermomechanical control process (TMCP) and integrated welding operations have been determined to industrialize extra high strength micro-alloyed low carbon SiMnCrMoNiCu steel plates for bridge applications. Confocal Scanning Microscope was used to make In-situ observation on austenite grain growth during reheating. A Gleeble 3800 thermomechanical simulator was employed to investigate transformation behavior of the TMCP conditioned austenite. Integrated industrial rolling trial was conducted to correlate the laboratory observations and commercial production of the plates. Microstructure factors affecting the toughness of the steel were analyzed. Submerged-Arc Welding (SMAW) trails were conducted and the structures and mechanical properties of the weld joints characterized. The representative plate with thickness of 60 mm consisted of acicular ferrite (AF) + refined polygonal ferrite (PF) + granular bainite (GB) across the entire thickness section exhibit yield strength (YS) greater than 560 MPa in transverse direction and excellent Charpy V Notch (CVN) impact toughness greater than 100 J at-40 °C in the parent metal and the weld joints. These provide useful integrated database for producing advanced high strength steel plates via TMCP. Keywords: Thermo-Mechanical Control Process;Weathering Steel Plate for Bridge; Submerged-Arc Welding without Preheating


2012 ◽  
Vol 472-475 ◽  
pp. 2731-2735
Author(s):  
Xiao Dong Hu ◽  
Qing Kun He ◽  
Jian Tao Lv ◽  
Yong Zhang

The butt weld sample with the material of 15CrMoR has been manufactured with the bonding methods of manual electric arc welding (SMAW) and submerged-arc welding (SAW). The relationship between the microstructure and the mechanical properties has been analyzed in this paper, and the conclusions have been obtained as followed: only the last weld layer has the obvious zones of weld zone, heat-affected zone (HAZ) and fusion area for the multi-layer butt weld, the weld zone and the fusion area will be heat-treated by the next layer welding; the hardness along central intersection shows a W-shaped distribution, and the zone with normalizing organization has the lowest hardness and the surface layer has the highest hardness; the mechanical properties of the multi-layer butt weld are much better than the monolayer weld’s.


2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Prachya Peasura

The pressure vessel steel is used in boilers and pressure vessel structure applications. This research studied the effects of submerged arc welding (SAW) process parameters on the mechanical properties of this steel. The weld sample originated from ASTM A283 grade A sheet of 6.00-millimeter thickness. The welding sample was treated using SAW with the variation of three process factors. For the first factor, welding currents of 260, 270, and 280 amperes were investigated. The second factor assessed the travel speed, which was tested at both 10 and 11 millimeters/second. The third factor examined the voltage parameter, which was varied between 28 and 33 volts. Each welding condition was conducted randomly, and each condition was tested a total of three times, using full factorial design. The resulting materials were examined using tensile strength and hardness tests and were observed with optical microscopy (OM) and scanning electron microscopy (SEM). The results showed that the welding current, voltage, and travel speed significantly affected the tensile strength and hardness (P value < 0.05). The optimum SAW parameters were 270 amperes, 33 volts, and 10 millimeters/second travel speed. High density and fine pearlite were discovered and resulted in increased material tensile strength and hardness.


2014 ◽  
Vol 936 ◽  
pp. 1780-1785
Author(s):  
Peng Xian Zhang ◽  
Peng Zhao ◽  
Yan Quan Cui

Aim at the issue that the bending crack is easy to generate inside dissimilar welded joint of low alloy steel and stainless steel, a new process of submerged arc welding filled with Ni wire is put forward. The influence mechanism of filling quantity of Ni wire to the joint of microstructure evolutions and mechanical properties is mainly explored based on the contrast test of non-filling Ni wire and three different filling speeds of Ni wire. The experiment results indicate that, the filling process of Ni wire supplies austenite forming element, and alters heat allocation process of molten pool. The filling quantity of Ni wire is the quantitative parameter, it is used to control the transition width between low alloy steel and weld metal, also to adjust the peak temperature and holding time at elevated temperature of molten pool. When the value of the filling quantity of Ni wire is determined, the problem of bending crack in the fusion zone of low alloy steel can be solved, and also the overheat damage can be eliminated. At the same time, the grains of weld metal and heat affected zone are refined. And on this basis the plasticity, toughness and microhardness of welded joint can be guaranteed.


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