scholarly journals Pulsed Nd: YAG Laser Parameters Effect on Welding Uncoated Advance High Strength Steel (AHSS) for Automotive

2021 ◽  
Vol 84 (1) ◽  
pp. 91-100
Author(s):  
Muhammad Naqiuddin Mat Salleh ◽  
Mahadzir Ishak ◽  
Kazuhiko Yamasaki ◽  
Moinuddin Mohammed Quazi ◽  
Aiman Mohd Halil
Keyword(s):  
Penetration Depth ◽  
Weld Pool ◽  
Welding Speed ◽  
High Strength Steel ◽  
Focal Length ◽  
High Strength ◽  
Boron Steel ◽  
Deep Penetration ◽  
Bead Width ◽  
Yag Laser

Pulse wave (PW) welding technique has become more adequate process to produce a deep penetration welding with smaller fusion zone and heat affected zone for automotive steel joint. A 1.6 mm thickness of N22CB boron steel from advance high strength steel (AHSS) type was welded by using PW mode from a low power Nd: YAG laser. The process parameters studied in this paper are pulsed energy, Ep, focal length, F, and welding speed, S. Bead-on-plate (BOP) welding was used in this experiment. The effect of parameters on the weld pool geometry was studied. Higher pulsed energy gives high weld penetration and higher weld width, contributing to the bigger weld pool size. Positive defocus position of focal length produces weld geometry with high penetration depth and smaller bead width compared to negative defocus position. Lower welding speed could produce deep penetration depth as the high heat input produced.

scholarly journals Welding Process Optimization of WELDOX960 High Strength Steel

2018 ◽  
Vol 207 ◽  
pp. 04005
Author(s):  
Min Hu
Keyword(s):  
Penetration Depth ◽  
Process Optimization ◽  
Process Parameters ◽  
Welding Speed ◽  
High Strength Steel ◽  
Welding Process ◽  
Welding Current ◽  
High Strength ◽  
Influence Of Process Parameters ◽  
Steel Analysis

This paper studies WELDOX960 high strength steel, analysis of the welding ability of WELDOX960 high strength steel. Analyze the weld ability of WELDOX960 high-strength steel materials, and study the influence of process parameters such as welding current, welding voltage, and welding speed on penetration depth and weld width in the automated welding process. Through this test, the welding process is optimized to ensure the weld quality. The results show that WELDOX960 high-strength steel adopts multi-layer and multi-pass welding to form better welds.

EXPERIMENTAL EVALUATION OF CO2 LASER CUTTING QUALITY OF UHSS USING OXYGEN AS AN ASSISTED GAS

2016 ◽  
Vol 78 (7) ◽  
Author(s):  
Abdul Fattah Mohamad Tahir ◽  
Ahmad Razelan Rashid
Keyword(s):  
Co2 Laser ◽  
High Strength Steel ◽  
Laser Power ◽  
Laser Cutting ◽  
Cutting Speed ◽  
High Strength ◽  
Gas Pressure ◽  
Kerf Width ◽  
Boron Steel ◽  
Major Factors

Development of new material known as Ultra High Strength Steel (UHSS) able to improve the vehicle mass thus reflecting better fuel consumption. Transformation into high strength steel has been a significant drawback in trimming the UHSS into its final shape thus laser cutting process appeared to be the solution. This study emphasizes the relationship between Carbon Dioxide (CO2) laser cutting input parameters on 22MnB5 boron steel focusing on the kerf width formation and Heat Affected Zone (HAZ). Experimental research with variation of laser power, cutting speed and assisted gas pressure were executed to evaluate the responses. Metrological and metallographic evaluation of the responses were made on the outputs that are the kerf width formation and HAZ.  Positive correlation for power and negative interaction for cutting speed were found as the major factors on formation of the kerf. For the HAZ formation, thicker HAZ were formed as bigger laser power were applied to the material. Cutting speed and gas pressure does not greatly influence the HAZ formation for 22MnB5 boron steel.

scholarly journals Characterization of Temperature Fields in Laser Beam Welded Hollow-Cylindrical Cold Crack Samples from High Strength Steel 100Cr6

2021 ◽  
Author(s):  
Eric Wasilewski ◽  
Nikolay Doynov ◽  
Ralf Ossenbrink ◽  
Vesselin Michailov
Keyword(s):  
Laser Beam ◽  
High Strength Steel ◽  
Unit Length ◽  
Laser Beam Welding ◽  
High Strength ◽  
Temperature Fields ◽  
Deep Penetration ◽  
Heating Rates ◽  
Hydrogen Distribution ◽  
Cooling Rates

Abstract This work presents a comparative study of thermal conditions that occur during laser beam welding of high strength steel 100Cr6 that often leads to a loss of technological strength and may conditionally produce cold cracks. The results from both experiments and thermal-metallurgical FE-simulations indicate that the type of heat coupling changes significantly when welding with different process parameters, e.g., in the transition between conduction and deep penetration welding. Further, the simulations show that as a result of the high welding speeds and reduced energy per unit length, extremely high heating rates of up to 2x104 K s-1 (set A) resp. 4x105 K s-1 (set B) occur in the material. Both welds thus concern a range of values for which conventional Time-Temperature-Austenitization (TTA) diagrams are not currently defined, so that the material models can only be calibrated using general assumptions. This noted change in energy per unit length and welding speeds causes significantly steep temperature gradients with a slope of approximately 5x103 K mm-1 and strong drops in the heating and cooling rates, particularly in the heat affected zone near the weld metal. This means that even short distances along the length present a staggering difference in relation to the temperature peaks. The temperature cycles also show very different cooling rates for the respective parameter sets, although in both cases they are well below a cooling time t8/5 of one second, so that the phase transformation always leads to the formation of martensite. The results from this study are intended to be used for further detailed experimental and numerical investigation of microstructure, hydrogen distribution, and stress-strain development at different restrain conditions.

Microstructure and Mechanical Properties of Aluminum Alloy/High Strength Steel Double Beam Laser Deep Penetration Welded Joint

2019 ◽  
Vol 944 ◽  
pp. 448-457
Author(s):  
Hong Xi Chen ◽  
Li Cui ◽  
Dong Qi Lu ◽  
Yao Qing Chang ◽  
Xu Xia ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
High Strength Steel ◽  
High Strength ◽  
Deep Penetration ◽  
Mechanical Resistance ◽  
Lap Joint ◽  
Beam Laser ◽  
Double Beam ◽  
Laser Deep Penetration Welding ◽  
Deep Penetration Welding

A new dual beam laser deep penetration welding technology for lap joint of 1.5 mm thick aluminum alloy and high strength steel was explored in this paper, and the effects of three different beam energy ratios (RS=0.25,0.33,0.5) on weld formation, interface microstructure and mechanical properties were studied. The result shows that under certain conditions of other parameters, double beam laser deep penetration welding process can be applied to lap joint of aluminum alloy / high strength steel with good weld shape when RS=0.25,0.33,0.5. As RS increases from 0.25 to 0.5, the penetration of the weld reduces from 575 μm to 424.2μm, the thickness of intermetallic compound (IMC) layer at the interface between aluminum alloy and weld metal reduces from 3.4 μm to 2.5 μm, the average microhardness of the IMC layer decreases from 771.1 HV to 571.9 HV, the mechanical resistance of the joint raises from 95.7N/mm to 115.2N/mm. When RS=0.5, double beam laser deep penetration welding of aluminum alloy / high-strength steel joints has the highest mechanical resistance of joints, because of the relatively good plastic ductility of the joint.

Hot Forming Analysis of Car Door Bar for Ultra High Strength Steel

2010 ◽  
Vol 160-162 ◽  
pp. 836-841
Author(s):  
Yun Kai Gao ◽  
Da Wei Gao ◽  
You Zhi Deng ◽  
Wei Cao
Keyword(s):  
High Strength Steel ◽  
Thickness Distribution ◽  
High Strength ◽  
Simulation Method ◽  
Hot Forming ◽  
Forming Limit ◽  
Boron Steel ◽  
Shell Elements ◽  
Forming Simulation ◽  
Ultra High Strength Steel

Ultra high strength steel plays an important role of light weighting in automotive industry. The hot forming simulation of car door bar is processed with 22MnB5 ultra high strength boron steel. FEM is built with the 12 nodes shell elements and MAT 106 is selected in LS-DYNA. The hot forming processes include two heat transfers. One is the process from the oven to the tools after the blank is heated. The other is the process after the blank contacts the tools. The hot forming simulation results are obtained by LS-DYNA. The results show that the thickness distribution, the forming limit and the maximum effective plastic strain and other performances attain to standards. It is proved that the hot forming simulation method is correct.

Residual Stress Analysis and Weld Bead Shape Study in Laser Welding of High Strength Steel

2013 ◽  
Author(s):  
Wei Liu ◽  
Fanrong Kong ◽  
Radovan Kovacevic
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Laser Welding ◽  
Welding Speed ◽  
High Strength Steel ◽  
Laser Power ◽  
Measurement Data ◽  
Welding Process ◽  
High Strength ◽  
Weld Bead

The X-ray diffraction (XRD) technique is employed to measure residual stress induced by the laser welding of 6.7 mm thick ASTM A514 high strength steel plates. The distribution of residual stress in the weld bead is investigated. The results indicate that the fusion zone (FZ) has the maximum tensile stress, the transition from tensile to compressive stress tends to appear in the heat affected zone (HAZ), and the initial stress far from the weld center are not influenced by the welding process. Based on the measurement data, the influence of the laser power and the welding speed on residual stress is obtained. The magnitude of residual stress near the weld bead increases with an increase in laser power or a decrease in welding speed. The welds with incomplete penetration have a considerably lower magnitude of residual stress in FZ than ones with full penetration. Post-weld heat treatment is utilized to relieve residual stress in the weld bead. Although residual stress is not completely relieved after the heat treatment, a dramatically reduced magnitude and much more uniform distribution are achieved. In addition, the effects of the laser power, the welding speed, the laser spot diameter, and the gap between two plates on the weld shape are also studied.

scholarly journals A Feasibility Study Comparing Two Commercial TIG Welding Machines for Deep Penetration

2019 ◽  
Vol 269 ◽  
pp. 01004
Author(s):  
Richard French ◽  
Hector Merin-Reyes ◽  
Will Yeadon
Keyword(s):  
Weld Pool ◽  
Feasibility Study ◽  
Tig Welding ◽  
Deep Penetration ◽  
Bead Width ◽  
The University ◽  
Deep Penetration Welding ◽  
Lower Production ◽  
Welding Technique

Developing a deep penetration TIG welding technique to produce welds of equal quality to the industrial standard practise of laser-based welding techniques has the potential to lower production complexity and cost. Higher currents levels are required to increase penetration depth in conventional TIG welding but this results in excessive weld bead width amongst other detrimental effects. However, through K-TIG and A-TIG techniques these detrimental effects can be circumnavigated. Prior experimental work on weld pool dynamics in conventional TIG welding in higher current regions has been sparse as TIG welding enhanced through novel techniques provides the best quality welds. This paper is an early feasibility study for novel deep penetration welding techniques motivated by observations made during research done at The University of Sheffield where unexpected activity in the weld pool was identified during TIG welding with a VBC IE500DHC between 300A – 1000A. This current range is labelled the ‘Red Region’. Understanding the fluid dynamics of the molten metal in the weld pool at the ‘ Red Region' current level will help in the creation of novel techniques for deep penetration TIG welding. Addressing this, this paper compares the quality of welds produced between 100A and 200A on 316 Stainless Steel by two industrially leading welding machines; the Miller Dynasty 350 and the VBCie 500DHC.

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