Analysis of transient thermo-fluidic behavior of melt pool during spot laser welding of 304 stainless-steel

2018 ◽  
Vol 256 ◽  
pp. 109-120 ◽  
Author(s):  
Ambuj Shah ◽  
Arvind Kumar ◽  
J. Ramkumar
Keyword(s):  
Stainless Steel ◽  
Laser Welding ◽  
304 Stainless Steel ◽  
Melt Pool

A Study on Laser Welding of Titanium and Stainless Steel

2018 ◽  
Author(s):  
Angshuman Chattopadhyay ◽  
Gopinath Muvvala ◽  
Vikranth Racherla ◽  
Ashish Kumar Nath
Keyword(s):  
Stainless Steel ◽  
Laser Welding ◽  
Weld Joint ◽  
Welding Speed ◽  
Fusion Process ◽  
Longitudinal Stress ◽  
Transverse Cracks ◽  
Cooling Rates ◽  
Melt Pool ◽  
Longitudinal Cracks

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.

Study on Laser Welding of Phone Nuts

2013 ◽  
Vol 815 ◽  
pp. 778-781
Author(s):  
Xiao Hong Wu
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Laser Pulse ◽  
Laser Welding ◽  
Pulse Energy ◽  
Pulse Width ◽  
Peak Power ◽  
Laser Pulse Energy ◽  
304 Stainless Steel ◽  
Power Pulse

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.

Microstructure Analysis of Fiber Laser Welding between E36 and 304 Stainless Steel

2015 ◽  
Vol 52 (4) ◽  
pp. 041403
Author(s):  
刘东宇 Liu Dongyu ◽  
李东 Li Dong ◽  
李凯斌 Li Kaibin ◽  
陈倩倩 Chen Qianqian
Keyword(s):  
Stainless Steel ◽  
Laser Welding ◽  
Fiber Laser ◽  
Microstructure Analysis ◽  
304 Stainless Steel ◽  
Fiber Laser Welding

Underwater local dry cavity laser welding of 304 stainless steel

2018 ◽  
Vol 260 ◽  
pp. 146-155 ◽  
Author(s):  
Ning Guo ◽  
Yunlong Fu ◽  
Xiao Xing ◽  
Yangkun Liu ◽  
Sixiang Zhao ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Laser Welding ◽  
304 Stainless Steel ◽  
Cavity Laser

scholarly journals Analysis of Melt-Pool Behaviors during Selective Laser Melting of AISI 304 Stainless-Steel Composites

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 876 ◽  
Author(s):  
Abolhasani ◽  
Seyedkashi ◽  
Kang ◽  
Kim ◽  
Woo ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Temperature Gradient ◽  
Eutectic Mixture ◽  
304 Stainless Steel ◽  
Reinforcement Particle ◽  
Laser Melting ◽  
Aisi 304 Stainless Steel ◽  
Aisi 304 ◽  
Reinforcing Particles ◽  
Melt Pool

The melt-pool behaviors during selective laser melting (SLM) of Al2O3-reinforced and a eutectic mixture of Al2O3-ZrO2-reinforced AISI 304 stainless-steel composites were numerically analyzed and experimentally validated. The thermal analysis results show that the geometry of the melt pool is significantly dependent on reinforcing particles, owing to the variations in the melting point and the thermal conductivity of the powder mixture. With the use of a eutectic mixture of Al2O3-ZrO2 instead of an Al2O3 reinforcing particle, the maximum temperature of the melt pool was increased. Meanwhile, a negligible corresponding relationship was observed between the cooling rate of both reinforcements. Therefore, it was identified that the liquid lifetime of the melt pool has the effect on the melting behavior, rather than the cooling rate, and the liquid lifetime increases with the eutectic ratio of Al2O3-ZrO2 reinforcement. The temperature gradient at the top surface reduces with the use of an Al2O3-ZrO2 reinforcement particle due to the wider melt pool. Inversely, the temperature gradient in the thickness direction increases with the use of an Al2O3-ZrO2 reinforcement particle. The results of melt-pool behaviors will provide a deep understanding of the effect of reinforcing particles on the dimensional accuracies and properties of fabricated AISI 304 stainless-steel composites.

Investigations on the Microstructure and the Fracture Surface of Pulsed Nd: YAG Laser Welding of AISI 304 Stainless Steel

2012 ◽  
Vol 445 ◽  
pp. 418-423
Author(s):  
Seyed Ali Asghar Akbari Mousavi ◽  
A. Garehdaghi
Keyword(s):  
Stainless Steel ◽  
Laser Welding ◽  
Cooling Rate ◽  
304 Stainless Steel ◽  
Chemical Compositions ◽  
Operational Parameters ◽  
Δ Ferrite ◽  
Higher Power ◽  
304 Austenitic Stainless Steel ◽  
Pulsed Nd:Yag Laser Welding

The paper presents pulsed Nd:YAG laser welding of the 304 stainless steels. The welding tests were carried out with various operational parameters. The effects of laser welding variables on the geometry, microstructure and solidification of the weld are considered. The austenitic or ferritic solidification is produced in the 304 austenitic stainless steel depended upon the cooling rate and its chemical compositions. The possiblity of austenitic solidification compared with the ferritic solidification decreases with the chromium to nickel equivalent ratio and that increases with cooling rates. Moreover, more δ ferrite is obtained if the cooling rate is increased or the higher power laser is used. The surface of fracture samples was considered and the reason for failure was investigated. The study shows that the fracture is in ductile type.

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