In-process monitoring and feedback control for stable production of full-penetration weld in continuous wave fibre laser welding

Distortion is one type of defect in the weld, which is troublesome for some reasons, especially in thin plate welding. Distortion was found in fibre laser welding processing for 0.7mm thickness Ti6Al4V plate. The purpose of this paper is to understand and evaluate the effect of distortion on stress level by FEA and tensile test. A group of 0.7mm Ti6Al4V plates welded using continuous wave fibre laser. FEA models were established for fibre laser welded Ti6Al4V in abaqus 6.7.

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Remote Fibre Laser Welding of Advanced High Strength Martensitic Steel

Metals ◽

10.3390/met10040533 ◽

2020 ◽

Vol 10 (4) ◽

pp. 533 ◽

Cited By ~ 3

Author(s):

Urban Prijanovič ◽

Marica Prijanovič Tonkovič ◽

Uroš Trdan ◽

Matej Pleterski ◽

Matija Jezeršek ◽

...

Keyword(s):

Laser Welding ◽

Continuous Wave ◽

Martensitic Steel ◽

High Strength ◽

Fibre Laser ◽

Optimal Parameters ◽

Lap Joint ◽

Tensile Shear ◽

Allotriomorphic Ferrite ◽

Clamping System

The study presents the results of remote robotic laser welding of advanced high strength Docol® 1200 M martensitic steel. One mm thick samples were welded in a lap joint configuration using a special clamping system. Welding was done using a continuous-wave (CW) fibre laser with a constant welding power of 300 W and constant focus diameter Ø 1.8 mm. Welding was done using 12 different welding speeds in the range from 0.15 to 1 m/min, whereas the inclination angle was kept constant at 0°. The influence of various welding speeds and linear heat inputs during welding on microstructural changes were examined by the occurrence of acicular and allotriomorphic ferrite or martensite. Results revealed big influence of the clamping system on the accumulation of the laser beam energy, heat sink and consequently weld size and geometry, as well as its microstructure and joint strength. Tensile-shear strength, microstructure and hardness results confirmed laser power of 300 W and 0.6 m/min welding speed as the optimal parameters, at which a martensitic structure was obtained in the weld. The width of the heat affected zone (HAZ) in this case is 1100 μm.

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Weld Geometry Investigation on Dissimilar Boron Steel Laser Welded for TWB Application

International Journal of Automotive and Mechanical Engineering ◽

10.15282/ijame.16.4.2019.12.0546 ◽

2019 ◽

Vol 16 (4) ◽

pp. 7364-7374

Author(s):

M. N. M. Salleh ◽

M. Ishak ◽

M. H. Aiman ◽

M. M. Quazi ◽

A. M. Hanafi

Keyword(s):

Tensile Strength ◽

Laser Welding ◽

Low Power ◽

Peak Power ◽

Continuous Wave ◽

Fibre Laser ◽

Boron Steel ◽

Welding Parameters ◽

Transition Line ◽

Power Laser

The pulse wave (PW) mode is an excellent replacement for continuous wave (CW) mode f laser welding in the tailor-welded blank (TWB) application for the automotive ndustry. Due to its ability to produce higher peak power in low power laser pulse mode, he weld penetration and high weld quality can be achieved similarly to the utilization of very high power laser of CW mode. This present work was carried out to investigate the ffect of pulse laser welding parameters of a dissimilar thickness of boron steel for the TWB application. Low power fibre laser with 200 W average power was chosen in this xperimental work. Response surface method (RSM) was used for the design of xperiment (DOE) by applying Box-behnken design (BBD) since there were three rocess factors involved. The process factors are peak power (PP), welding speed (WS) nd focal position (FP) and tensile strength is the response for the weld joint. The metallurgical analysis was conducted at the cross section of sample possessing highest nd lowest tensile strength. Boron steel was successfully welded by using low power fibre aser with PW mode in butt joint configuration. It was found that the highest tensile trength possessed fracture located at the base metal, which is convincing the strength of he joint. For microstructure, finer grain produced at the centre of the fusion zone (FZ) ompared to the FZ near the transition line which produced coarser and medium grain. Finer grain size in FZ contributes to the higher microhardness value and tensile strength f the joint compared to the BM region.

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