Meeting weld quality criteria when laser welding Ni-based alloy 718

2012 ◽  
Author(s):  
Ali Khan ◽  
Paul Hilton ◽  
Jon Blackburn ◽  
Chris Allen
Keyword(s):  
Laser Welding ◽  
Quality Criteria ◽  
Alloy 718 ◽  
Weld Quality

Visual Evaluation of Cast Dental Alloys Welds Discontinuities in the Field of Fixed Prosthodontics

2011 ◽  
Vol 383-390 ◽  
pp. 4058-4064
Author(s):  
Sorin Porojan ◽  
Liliana Sandu ◽  
Florin Topală
Keyword(s):  
Laser Welding ◽  
Base Metal ◽  
Visual Inspection ◽  
Incomplete Fusion ◽  
Weld Quality ◽  
Dental Alloys ◽  
Visual Evaluation ◽  
Fixed Prosthodontics ◽  
Microplasma Welding

It is essential for a weld to satisfy the requirements of certain standards in the field where it is applied. The aim of the study was to highlight the discontinuities which can appear in the joints achieved by laser and microplasma welding of base metal dental alloys used in fixed prosthodontics. All types of discontinuities which are visible from visual inspection were searched: inclusions, inadequate joint penetration, incomplete fusion, undercuts, overlaps, underfills. Recognizing the defects and discontinuities and their delimitation was essential in determining the weld quality. The obtained results were satisfactory for the purpose both for microplasma and laser welding. Using these methods, welds without defects, which meet minimum acceptable standards for each case, could be obtained.

Quality Assessment and Metallurgical Examination of Laser Welded Sheets

2009 ◽  
Vol 83-86 ◽  
pp. 611-615
Author(s):  
Numan Abu-Dheir ◽  
Bekir Sami Yilbas
Keyword(s):  
Laser Welding ◽  
Laser Power ◽  
Laser Scanning ◽  
Scanning Speed ◽  
Careful Examination ◽  
Welding Parameters ◽  
Weld Quality ◽  
Laser Weld ◽  
Power Intensity ◽  
Segregation Profile

Laser welding of steel 316L sheets is considered and the effects of laser welding parameters on the laser weld quality and metallurgical changes in the weld section are presented. The laser weld quality is assessed through careful examination of weld geometrical features, and the resulting weld microstructure. Metallurgical changes in the weld sites are examined using optical, and electron scanning microscope (SEM). Two levels of heat inputs are used-1500W and 2000W; and two scanning speeds of 2cm/s and 4cm/s are used to laser weld 316L sheets. It is found that at the high laser power intensities, evaporation takes place in the irradiated region and as the laser power intensity increases further, a cavity is formed at the top surface of the welding cross section. A similar situation is also observed as the laser scanning speed reduces. The low diffusivity of the alloying elements at high temperatures preserves the segregation profile. The scattered partitioning of the cells and dendrite boundaries are observed due to the presence of Cr and Mo.

Effect of water depth on weld quality and welding process in underwater fiber laser welding

2017 ◽  
Vol 115 ◽  
pp. 112-120 ◽  
Author(s):  
Ning Guo ◽  
Xiao Xing ◽  
Hongyun Zhao ◽  
Caiwang Tan ◽  
Jicai Feng ◽  
...  
Keyword(s):  
Laser Welding ◽  
Fiber Laser ◽  
Water Depth ◽  
Welding Process ◽  
Weld Quality ◽  
Fiber Laser Welding ◽  
Effect Of Water

Effect of shielding conditions of local dry cavity on weld quality in underwater Nd:YAG laser welding

2006 ◽  
Vol 174 (1-3) ◽  
pp. 34-41 ◽  
Author(s):  
Xudong Zhang ◽  
Eiji Ashida ◽  
Susumu Shono ◽  
Fukuhisa Matsuda
Keyword(s):  
Laser Welding ◽  
Nd:Yag Laser ◽  
Weld Quality

Auto-Control of Defocus Distance during Filling Laser Welding of Ti-Alloy with Wire

2011 ◽  
Vol 287-290 ◽  
pp. 2456-2459 ◽  
Author(s):  
Xin Song Chen ◽  
Wei Yao ◽  
Ai Qin Duan
Keyword(s):  
Control System ◽  
Laser Welding ◽  
Real Time ◽  
Welding Process ◽  
Numerical Control ◽  
Ti Alloy ◽  
Numerical Control System ◽  
Weld Quality ◽  
The Stability

The defocus distance is one of the most important factors during filling laser welding with wire. Keeping defocus distances stability is the pre-condition to acquire the stable weld quality. In this paper, a QUANTA laser camera was used to measure the defocus distance, and it is compensated in real time through the numerical control system. The results reveal that the fixed defocus distances can be acquired using this system. And the experiments by using auto-controlling method of the defocus distance show that the stability of welding process can be improved greatly and the good weld quality can be easy to be obtained.

Post-Weld Quality Inspection for CO2 Laser Tailored Blank Welding with Vision Sensor

2010 ◽  
Vol 97-101 ◽  
pp. 4337-4341 ◽  
Author(s):  
Yuan Yuan Zou ◽  
Ming Yang Zhao ◽  
Lian Zhu Liu
Keyword(s):  
Laser Welding ◽  
Weld Seam ◽  
Quality Inspection ◽  
Weld Quality ◽  
Image Processing Algorithm ◽  
Visual Sensor ◽  
Tailored Blank ◽  
Time Required ◽  
Visual Testing ◽  
Geometrical Defects

The traditional method for post-weld quality inspection is visual testing by people. Major limitations of this method are the subjectivity of judgments and time required to perform the inspection. With the increasing use of laser welding in the automotive industry, the manufacturers are struggling with the challenge to automate the quality inspection process. This paper discussed the automatic post-weld quality inspection technology by computer vision sensing for mono-thickness tailored blanks of CO2 laser welding. A visual sensor was developed for acquiring the original image of the weld seam. The sensor consists of a PC based vision camera and a stripe-type laser diode. An image processing algorithm was presented to detect the geometrical defects of the weld seam. Some experiments are carried out and some applications are given.

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