Effect of welding speed, pulse frequency, and pulse width on the weld shape and temperature distribution in dissimilar laser welding of stainless steel 308 and brass alloy

2021 ◽  
Vol 33 (2) ◽  
pp. 022009
Author(s):  
Haijuan Ding ◽  
Jiaxing Ma ◽  
Chengtao Zhao ◽  
Debiao Zhao
2010 ◽  
Vol 168-170 ◽  
pp. 2293-2298
Author(s):  
Shu Ying Liu ◽  
Xiao Jiao Zhang ◽  
Guang Bao Liu ◽  
Lei Zhang ◽  
Kui Fei Zhao ◽  
...  

It has been carried out the test and research to the stainless steel plate laser welding welded seam, by two-dimensional, three-dimensional appearance observation and tensile methods. Its result is: The YAG laser welding, is welding speed, frequency, pulse width and so on technological parameter influences to be big. In the power limit, raising the power or reducing welding speed; or increasing the frequency, or increasing the pulse width in critical value range, it be possible to increasing joints strength, however, when the pulse width surpasses critical value range its joints strength instead fall. In this study, the parameter that the appearance and the quality are all good of welded seam for welds speed 60mm/min, frequency 10Hz, pulse width 3ms, defocusing amount -1mm, the tensile strength of joints may reach 390MPa. The joints that the performance is good, its keyhole's microscopic appearance is also more complete good, but the joints that the macroscopic appearance is good, it has fine mechanical properties certain by no means. The three-dimensional observation of keyhole appearance is relatively feasible to be appraisal laser welding welded seam newest method,it is worthy discussing and carrying out.


Author(s):  
Angshuman Chattopadhyay ◽  
Gopinath Muvvala ◽  
Vikranth Racherla ◽  
Ashish Kumar Nath

Joining of dissimilar metals and alloys has been envisioned since a long time with specific high end applications in various fields. One such combination is austenitic stainless steel grade SS304 and commercial grade titanium, which is very difficult to join under conventional fusion process due to extensive cracking and failure caused by mismatch in structural and thermal properties as well as formation of the extremely brittle and hard intermetallic compounds. One of the methods proposed in literature to control the formation of intermetallics is by fast cooling fusion process like laser beam welding. The present study has been done on laser welding of titanium and stainless steel AISI 304 to understand the interaction of these materials during laser welding at different laser power and welding speed which could yield different cooling rates. Two types of cracks were observed in the weld joint, namely longitudinal cracks and transverse cracks with respect to the weld direction. Longitudinal cracks could be completely eliminated at faster welding speeds, but transverse cracks were found little influenced by the welding speed. The thermal history, i.e. melt pool lifetime and cooling rate of the molten pool during laser welding was monitored and a relation between thermo-cycle with occurrence of cracks was established. It is inferred that the longitudinal cracks are mainly due to the formation of various brittle intermetallic phases of Fe and Ti, which could be minimized by providing relatively less melt pool lifetime at high welding speeds. The reason of the transverse cracks could be the generation of longitudinal stress in weld joint due to the large difference in the thermal expansion coefficient of steel and titanium. In order to mitigate the longitudinal stress laser welding was carried out with a novel experimental arrangement which ensured different cooling rates of these two metals during laser welding. With this the tendency of transverse cracks also could be minimized significantly.


2013 ◽  
Vol 815 ◽  
pp. 778-781
Author(s):  
Xiao Hong Wu

Used YAG pulse laser to weld 304 stainless steel nuts, studied about the parameters such as peak power, pulse width, defocus distance impacting on the performance of the joints welded by laser. The studies showed that the tensile strength and torque of the nuts increased as the peak power and the pulse width increased.Burn through in welding easy occur when laser pulse energy is too big, pulse width is too wide or defocus distance is too low.


Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3178 ◽  
Author(s):  
Wenbin Wang ◽  
Li Xiong ◽  
Dan Wang ◽  
Qin Ma ◽  
Yan Hu ◽  
...  

A new test method named “Trapezoidal hot” cracking test was developed to evaluate solidification cracking susceptibility of stainless steel during laser welding. The new test method was used to obtain the solidification cracking directly, and the solidification cracking susceptibility could be evaluated by the solidification cracking rate, defined as the ratio of the solidification cracking length to the weld bead length under certain conditions. The results show that with the increase in the solidification cracking rate, the solidification cracking susceptibility of SUS310 stainless steel was much higher than that of SUS316 and SUS304 stainless steels during laser welding (at a welding speed of 1.0 m/min) because a fully austenite structure appeared in the weld joint of the former steel, while the others were ferrite and austenitic mixed structures during solidification. Besides, with an increase in welding speed from 1.0 to 2.0 m/min during laser welding, the solidification cracking susceptibility of SUS310 stainless steel decreased slightly; however, there was a tendency towards an increase in the solidification cracking susceptibility of SUS304 stainless steel due to the decrease in the amount of ferrite under a higher cooling rate.


2006 ◽  
Vol 505-507 ◽  
pp. 205-210
Author(s):  
Wen T. Chien ◽  
S.W. Chang

A predictive model is presented for the prediction of shear strength in laser welding AISI304 stainless steel. Welding experiments conducted using a pulsed Nd:YAG laser machine while the laser welding parameters and their levels have been arranged according to design of experiments of Taguchi method. The tensile tests are performed after welding and the measurements of tensile strength are further calculated for shear strength. The data can be analyzed using the principles of Taguchi method for determining the optimal laser welding parameters and for investigating the most significant laser welding parameter on shear strength. Furthermore, the results are treated as the training and recalling patterns for constructing a predictive model using back-propagation neuron network to predict shear strength for the range of laser welding operation tested. It is indicated that welding speed is the most significant affecting parameters on shear strength. In addition, an increase in welding speed causes a decrease in shear strength is found. An average error 5.75%for shear strength can be found by comparing the experimental results obtained from conducting verification tests with the predicting values obtained from the established predictive model. It shows that the predictive model is capable of good predicting behavior of laser welding AISI304 stainless steel.


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