scholarly journals Modeling, Simulation and Experimental Studies of Distortions, Residual Stresses and Hydrogen Diffusion During Laser Welding of As-Rolled Steels

10.5772/34478 ◽  
2012 ◽  
Author(s):  
T. Bhme ◽  
C. Dornscheidt ◽  
T. Pretorius ◽  
J. Scharlack ◽  
F. Spelleke
Keyword(s):  
Residual Stresses ◽  
Laser Welding ◽  
Hydrogen Diffusion ◽  
Experimental Studies ◽  
Modeling Simulation

scholarly journals Predicting How Crack Tip Residual Stresses Influence Brittle Fracture

2002 ◽  
Author(s):  
Saeid Hadidimoud ◽  
Ali Mirzaee-Sisan ◽  
Chris E. Truman ◽  
David J. Smith
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Experimental Studies ◽  
Crack Tip ◽  
Distribution Model ◽  
Relative Importance ◽  
Local Approach ◽  
Weibull Parameters ◽  
Experimental Scatter ◽  
Crack Tip Blunting

A probability distribution model, based on the local approach to fracture, has been developed and used for estimating cleavage fracture following prior loading (or warm pre-stressing) in two ferritic steels. Although there are many experimental studies it is not clear from these studies whether the generation of local residual stress and/or crack tip blunting as a result of prior loading contribute to the enhancement in toughness. We first identify the Weibull parameters required to match the experimental scatter in lower shelf toughness of the candidate steels. Second we use these parameters in finite element simulations of prior loading on the upper shelf followed by unloading and cooling to lower shelf temperatures to determine the probability of failure. The predictions are consistent with experimental scatter in toughness following WPS and provide a means of determining the relative importance of the crack tip residual stresses and crack tip blunting. We demonstrate that for our steels the crack tip residual stress is the pivotal feature in improving the fracture toughness following WPS. The paper finally discusses these results in the context of the non-uniqueness and the sensitivity of the Weibull parameters.

Numerical and Experimental Studies of Residual Stresses in Multipass Welding of High Strength Shipbuilding Steel

2015 ◽  
Vol 59 (3) ◽  
pp. 133-144 ◽  
Author(s):  
Guangming Fu ◽  
Tetyana Gurova ◽  
Marcelo I. Lourenco ◽  
Segen F. Estefen
Keyword(s):  
Residual Stresses ◽  
Experimental Studies ◽  
High Strength ◽  
Shipbuilding Steel ◽  
Multipass Welding

Hybrid-laser welding-induced distortions and residual stresses analysis of large-scale stiffener panel

2022 ◽  
Vol 245 ◽  
pp. 110411
Author(s):  
M. Hashemzadeh ◽  
Y. Garbatov ◽  
C. Guedes Soares
Keyword(s):  
Residual Stresses ◽  
Laser Welding ◽  
Large Scale

scholarly journals Influence of Beam Speed on Residual Stresses in the Vicinity of Laser Welds

2014 ◽  
Vol 996 ◽  
pp. 463-468
Author(s):  
Nikolaj Ganev ◽  
Kamil Kolařík ◽  
Zdenek Pala ◽  
Stanislav Němeček ◽  
Jiří Čapek
Keyword(s):  
Residual Stresses ◽  
Laser Beam ◽  
Laser Welding ◽  
Grain Sizes ◽  
Laser Welds ◽  
Contribution Mapping ◽  
Compressive Residual Stresses

One of the drawbacks of the laser welding is distortion of the welded bodies that is closely linked with the generation and redistribution of residual stresses in the vicinity of the weld. In this contribution, mapping of surface macroscopic residual stresses and grain sizes was performed for several welds created with the laser beam with various speeds. Larger distortions are exhibited by samples manufactured with higher laser beam speed, which also exhibit substantial compressive residual stresses perpendicularly to the welds axis.

scholarly journals Selected Properties of the Surface Layer of C45 Steel Parts Subjected to Laser Cutting and Ball Burnishing

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3429 ◽  
Author(s):  
Agnieszka Skoczylas ◽  
Kazimierz Zaleski
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Laser Cutting ◽  
Experimental Studies ◽  
Hardened Layer ◽  
Ball Burnishing ◽  
Absolute Value ◽  
The Impact ◽  
Compressive Residual Stresses

In this article, we report the results of experimental studies on the impact of ball burnishing parameters on the roughness, microstructure and microhardness of the surface layer of laser-cut C45 steel parts. We also analysed the distribution of residual stresses generated in the surface layer of these parts. Laser-cut parts often require finishing to improve the quality of their surface. The tests performed in this study were aimed at assessing whether ball burnishing could be used as a finishing operation for parts of this type. Ball burnishing tests were performed on an FV-580a vertical machining centre using a mechanically controlled burnishing tool. The following parameters were varied during the ball burnishing tests: burnishing force Fn, path interval fw and the diameter of the burnishing ball dn. Ball burnishing of laser-cut C45 steel parts reduced the surface roughness parameters Sa and Sz by up to 60% in relation to the values obtained after laser cutting. Finish machining also led to the reorganization of the geometric structure of the surface, resulting in an increase in the absolute value of skewness Ssk. This was accompanied by an increment in microhardness (maximum microhardness increment was ΔHV = 95 HV0.05, and the thickness of the hardened layer was gh = 40 µm) and formation of compressive residual stresses in the surface layer.

Finite Element Modeling of Hard Roller Burnishing: An Analysis on the Effects of Process Parameters Upon Surface Finish and Residual Stresses

2007 ◽  
Vol 129 (4) ◽  
pp. 705-716 ◽  
Author(s):  
Partchapol Sartkulvanich ◽  
Taylan Altan ◽  
Francisco Jasso ◽  
Ciro Rodriguez
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Process Parameters ◽  
Surface Finish ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Cost Effective ◽  
Machined Surface ◽  
Fem Model ◽  
Roller Burnishing

Hard roller burnishing is a cost-effective finishing and surface enhancement process where a ceramic ball rolls on the machined surface to flatten the roughness peaks. The ball is supported and lubricated by hydrostatic fluid in a special tool holder. The process not only improves surface finish but also imposes favorable compressive residual stresses in functional surfaces, which can lead to long fatigue life. Most research in the past focused on experimental studies. There is still a special need for a reliable finite element method (FEM) model that provides a fundamental understanding of the process mechanics. In this study, two-dimensional (2D) and three-dimensional FEM models for hard roller burnishing were established. The developed 2D FEM model was used to study the effects of process parameters (i.e., burnishing pressure, feed rate) on surface finish and residual stresses. The simulation results were evaluated and compared to the experimental data. Results show that the established FEM model could predict the residual stresses and provided useful information for the effect of process parameters. Both FEM and experiments show that burnishing pressure is the most influence, where high burnishing pressure produces less roughness and more compressive residual stress at the surface.

Effect of phase transformations on residual stresses in laser welding 09G2 steel

2003 ◽  
Vol 17 (8) ◽  
pp. 645-649 ◽  
Author(s):  
V A Karkhin ◽  
V A Lopota ◽  
N O Pavlova
Keyword(s):  
Residual Stresses ◽  
Laser Welding ◽  
Phase Transformations
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