scholarly journals Effect of Disk Laser Beam Offset on the Microstructure and Mechanical Properties of Copper—AISI 304 Stainless Steel Dissimilar Metals Joints

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1294 ◽  
Author(s):  
Miroslav Sahul ◽  
Ema Tomčíková ◽  
Martin Sahul ◽  
Matej Pašák ◽  
Barbora Ludrovcová ◽  
...  

Deoxidized oxygen free copper C12200, 1 mm in thickness, was welded to 1-mm thick AISI 304 stainless steel with disk laser. The butt-welded joints were produced with different welding parameters. Full factorial design of experiment (DoE) approach consisting of three factors and two levels was utilized. Laser powers used for welding were 1.3 and 1.9 kW and welding speeds of 20 and 30 mm/s. Two beam offsets were tested, namely, 100 μm toward copper side and 200 μm toward AISI 304 steel. It was found that beam offset possesses the largest influence on the welded joints’ tensile strength. Tensile strengths attained values more than 3.7 times higher in comparison to the AISI 304 steel beam offset. When lower laser power was used, the higher tensile strength was attained for copper sheet offset. Higher microhardness was observed when laser beam was offset to AISI 304 steel side. The average microhardness of the weld metal was higher than that of the weaker base material, copper sheet. Energy dispersive X-ray spectroscopy (EDS) analysis confirmed the heterogeneity in elemental composition across the welded joint interface, being lower when laser beam was offset to AISI 304 steel side. On the other hand, the copper content dropped to the average composition of weld metal at the distance of about 140 μm from copper-weld metal interface.

2011 ◽  
Vol 117-119 ◽  
pp. 402-408
Author(s):  
Shazarel Shamsudin ◽  
Phoon Chee Yoon

Product with low cost, lightweight and enhanced mechanical properties were the main reasons welding dissimilar materials thrived by most of the industries. The laser welding technique which has high-energy density beam was found suitable of carrying this task. This paper attempts to investigate welding of AISI 304 stainless steel to AISI 1008 steel through Nd:YAG pulse laser method. The main objective of this study was to find out the weldability of these materials and investigate the mechanical properties of the welded butt joints. Peak power, pulse duration and weld speed combinations were carefully selected with the aims of producing weld with a good tensile strength, minimum heat affected zone (HAZ) and acceptable welding profile. Response surface methodology (RSM) approach was adopted as statistical design technique for tensile strength optimization. Statistical based mathematical model was developed to describe effects of each process parameters on the weld tensile strength and for response prediction within the parameter ranges. The microstructure of the weld and heat affected zones were observed via optical microscope. The results indicate the developed model can predict the response within ±9% of error from the actual values.


2013 ◽  
Vol 228 ◽  
pp. S306-S311 ◽  
Author(s):  
J. Alphonsa ◽  
B.A. Padsala ◽  
B.J. Chauhan ◽  
G. Jhala ◽  
P.A. Rayjada ◽  
...  

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1569
Author(s):  
Asif Ur Rehman ◽  
Muhammad Arif Mahmood ◽  
Fatih Pitir ◽  
Metin Uymaz Salamci ◽  
Andrei C. Popescu ◽  
...  

For laser-melting deposition (LMD), a computational fluid dynamics (CFD) model was developed using the volume of fluid and discrete element modeling techniques. A method was developed to track the flow behavior, flow pattern, and driving forces of liquid flow. The developed model was compared with experimental results in the case of AISI 304 stainless steel single-track depositions on AISI 304 stainless steel substrate. A close correlation was found between experiments and modeling, with a deviation of 1–3%. It was found that the LMD involves the simultaneous addition of powder particles that absorb a significant amount of laser energy to transform their phase from solid to liquid, resulting in conduction-mode melt flow. The bubbles within the melt pool float at a specific velocity and escape from the melt pool throughout the deposition process. The pores are generated if the solid front hits the bubble before escaping the melt pool. Based on the simulations, it was discovered that the deposited layer’s counters took the longest time to solidify compared to the overall deposition. The bubbles strived to leave through the contours in an excess quantity, but became stuck during solidification, resulting in a large degree of porosity near the contours. The stream traces showed that the melt flow adopted a clockwise vortex in front of the laser beam and an anti-clockwise vortex behind the laser beam. The difference in the surface tension between the two ends of the melt pool induces “thermocapillary or Benard–Marangoni convection” force, which is insignificant compared to the selective laser melting process. After layer deposition, the melt region, mushy zone, and solidified region were identified. When the laser beam irradiates the substrate and powder particles are added simultaneously, the melt adopts a backwards flow due to the recoil pressure and thermocapillary or Benard–Marangoni convection effect, resulting in a negative mass flow rate. This study provides an in-depth understanding of melt pool dynamics and flow pattern in the case of LMD additive manufacturing technique.


Author(s):  
J. A. Korbonski ◽  
L. E. Murr

Comparison of recovery rates in materials deformed by a unidimensional and two dimensional strains at strain rates in excess of 104 sec.−1 was performed on AISI 304 Stainless Steel. A number of unidirectionally strained foil samples were deformed by shock waves at graduated pressure levels as described by Murr and Grace. The two dimensionally strained foil samples were obtained from radially expanded cylinders by a constant shock pressure pulse and graduated strain as described by Foitz, et al.


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