scholarly journals Simulation of Multipass Welding With Simultaneous Computation of Material Properties

2000 ◽  
Vol 123 (1) ◽  
pp. 106-111 ◽  
Author(s):  
Lars Bo¨rjesson ◽  
Lars-Erik Lindgren
Keyword(s):  
Residual Stresses ◽  
Microstructure Evolution ◽  
Material Properties ◽  
Base Material ◽  
Steel Plates ◽  
Filler Material ◽  
Temperature History ◽  
Temperature Dependent ◽  
Butt Welding ◽  
Thick Steel

Multipass butt welding of two 0.2 m thick steel plates has been investigated. The objective is to calculate residual stresses and compare them with measured residual stresses. The material properties depend on temperature and temperature history. This dependency is accounted for by computing the microstructure evolution and using this information for computing material properties. This is done by assigning temperature dependent material properties to each phase and applying mixture rules to predict macro material properties. Two different materials have been used for the microstructure calculation, one for the base material and one for the filler material.

Numerical Analysis of the Effect of Phase Transformation on Residual Stresses in an Autogenous Beam Edge Weld

2013 ◽  
Vol 768-769 ◽  
pp. 652-659
Author(s):  
Martina M. Joosten
Keyword(s):  
Thermal Analysis ◽  
Numerical Analysis ◽  
Heat Source ◽  
Residual Stresses ◽  
Phase Transformations ◽  
Material Properties ◽  
Base Material ◽  
Temperature Dependent ◽  
Thin Beam ◽  
Beam Edge

This paper presents the numerical analysis of phase proportions and residual stresses in an autogenous beam edge weld. The thin beam was welded running a heat source along its longer edge using a TIG process. There is no addition of any material so the focus of modelling the process could be concentrated on the thermal analysis and the phase transformations. Temperature dependent material properties and a continuous cooling transformation (CCT) diagram of the base material were provided. The simulations took into account metallurgical effects and used a Goldak-type heat source. Simulations with and without phase transformations were carried out, in order to analyse the effect on the predicted residual stress.

Evolution of Temperature Distribution and Microstructure in Multipass Welded AISI 321 Stainless Steel Plates With Different Thicknesses

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Soheil Nakhodchi ◽  
Ali Shokuhfar ◽  
Saleh Akbari Iraj ◽  
Brian G. Thomas
Keyword(s):  
Stainless Steel ◽  
Temperature Distribution ◽  
Residual Stresses ◽  
Arc Welding ◽  
Welding Process ◽  
Steel Plates ◽  
Temperature History ◽  
Transient Temperature ◽  
Multipass Welding ◽  
Aisi 321

Prediction of temperature distribution, microstructure, and residual stresses generated during the welding process is crucial for the design and assessment of welded structures. In the multipass welding process of parts with different thicknesses, temperature distribution, microstructure, and residual stresses vary during each weld pass and from one part to another. This complicates the welding process and its analysis. In this paper, the evolution of temperature distribution and the microstructure generated during the multipass welding of AISI 321 stainless steel plates were studied numerically and experimentally. Experimental work involved designing and manufacturing benchmark specimens, performing the welding, measuring the transient temperature history, and finally observing and evaluating the microstructure. Benchmark specimens were made of corrosion-resistant AISI 321 stainless steel plates with different thicknesses of 6 mm and 10 mm. The welding process consisted of three welding passes of two shielded metal arc welding (SMAW) process and one gas tungsten arc welding (GTAW) process. Finite element (FE) models were developed using the DFLUX subroutine to model the moving heat source and two different approaches for thermal boundary conditions were evaluated using FILM subroutines. The DFLUX and FILM subroutines are presented for educational purposes, as well as a procedure for their verification.

Numerical Modelling of Residual Stress and Distortion in Welded Thin Steel Plates

2008 ◽  
Author(s):  
M. Tsunori ◽  
C. M. Davies ◽  
D. Dye ◽  
K. M. Nikbin
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Welding Process ◽  
Steel Plates ◽  
Thin Plates ◽  
Welding Distortion ◽  
Butt Welding ◽  
Thin Steel ◽  
Out Of Plane ◽  
Plate Size

Current trends in ship design are to reduce panel thickness in order to minimise the vessels weight and hence maximise speed. These panels are manufactured through butt welding thin steel plates with the addition of fillet welded stiffeners. Excessive distortions are exhibited in these thin plates due to the welding process, resulting in major rectification or re-manufacturing costs. The aim of this study is to develop a tool to predict welding residual stresses and distortions in order to understand their governing factors, and thus enabling the optimum fabrication processes to be realized to minimise welding distortion. Finite element simulations are performed of the butt and fillet welding process in 4 mm thick plates of ferritic DH-36 steel and the residual stresses and distortions are predicted. Thermal and residual stress profiles are verified against experimental measurements. The effects of plate and stiffener dimensions are examined numerically. In addition, a sensitivity analysis has been carried out to quantify the effects of restraint on a small butt welded plate. It is concluded that final distortion may be severely reduced, in the plate size considered, if only an out-of-plane constraint is imposed on the plate’s surfaces. Further welding experiments are required to validate these findings.

scholarly journals Disk Laser Welding of Armor Steel/ Spawanie Laserem Dyskowym Stali Pancernej

2014 ◽  
Vol 59 (4) ◽  
pp. 1641-1646 ◽  
Author(s):  
D. Janicki
Keyword(s):  
Laser Welding ◽  
Focal Point ◽  
Base Material ◽  
Steel Plates ◽  
Welding Parameters ◽  
Maximum Output ◽  
Butt Welding ◽  
Disk Laser ◽  
Armor Steel ◽  
Charpy Absorbed Energy

Abstract The paper describes the application of an Yb:YAG disk laser with a maximum output of 3.3 kW for the butt welding of armor steel plates ARMOX 500T 3.6 mm thick. The influence of laser welding parameters such as laser power beam, welding speed, focal point position on weld quality and mechanical properties of joints was studied. A proper selection of disk laser welding parameters provides non-porous and cracks free fully-penetrated welds with the aspect ratio up to 6.4. There was approx. 40% reduction in the hardness of heat affected zone (HAZ) in comparison to hardness of the base material (BM). The hardness values at the weld metal and the BM were similar. The joints exhibited about 15% lower ultimate tensile strength when compared with that of the BM. Charpy absorbed energy of the joints was approx. 30% lower than that of the BM.

scholarly journals Butt welding of thin sheets of S960MC steel

2021 ◽  
Vol 93 (2) ◽  
pp. 5-12
Author(s):  
Miloš Mičian ◽  
Martin Frátrik ◽  
Libor Trško ◽  
Marek Gucwa ◽  
Jerzy Winczek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Heat Affected Zone ◽  
Base Material ◽  
Mag Welding ◽  
Filler Material ◽  
Thin Sheets ◽  
Butt Welding ◽  
Strength Limit ◽  
Strength Tests

The paper presents the application of MAG welding to TMCP steels (thermo-mechanically controlled processed) grade S960MC and 3 mm thick. In the analyzed joints, the research focused on their mechanical properties and changes in the heat-affected zone (HAZ) that occur in this type of steels. The hardness and tensile strength tests carried out showed a significant decrease in the properties of the joint compared to the declared values of the base material and the filler material used in the tests. In the case of hardness, it was a decrease of 34% in HAZ and by 15-21% in relation to the strength limit. Changes in HAZ properties of a joint correlate with changes in its structure.

Prediction of Residual Stresses and Distortions in Welded Structures

1993 ◽  
Vol 115 (1) ◽  
pp. 52-57 ◽  
Author(s):  
B. L. Josefson
Keyword(s):  
Residual Stresses ◽  
Spot Welding ◽  
Thermal Design ◽  
Welding Residual Stress ◽  
Temperature History ◽  
Residual Stress Field ◽  
Butt Welding ◽  
Box Beams ◽  
Design Loads ◽  
Good Agreement

A good knowledge of the welding residual stress field and the corresponding distortion is needed when the interaction between manufacturing stresses and future (mechanical and/or thermal) design loads is studied, for example, with respect to possible crack initiation and growth in the HAZ, and also with respect to buckling. It is proposed here that a qualitatively good estimate of the welding residual stresses can be obtained by using FEM without following the temperature history during welding and cooling in detail. The procedure proposed is applied to two different problems: multi-pass butt welding of pipes, and spot welding of box beams. For the case of multi-pass butt welding of pipes, experimental results are available and a good agreement with these results is observed.

scholarly journals Evaluation of residual stresses in a tube-to-plate welded joint

2019 ◽  
Vol 300 ◽  
pp. 19005 ◽  
Author(s):  
Andrea Chiocca ◽  
Francesco Frendo ◽  
Leonardo Bertini
Keyword(s):  
Residual Stresses ◽  
Numerical Simulations ◽  
Thermal Cycle ◽  
Transient Analysis ◽  
Welded Joint ◽  
Base Material ◽  
Welding Process ◽  
Deep Understanding ◽  
Experimental Tests ◽  
Temperature Dependent

A deep understanding of the manufacturing process is needed in order to achieve safety and quality requirements for parts and components; to this regard, residual stresses play an important role in welded structures. Residual stresses are mainly caused by the extremely severe thermal cycle to which the welded metal and base material are subjected to during welding process and their knowledge leads to a better static and fatigue assessment of welded joints. This work deals with the study of residual stresses for a tube to plate T-joint, made of S355JR carbon steel. The work was carried out by both numerical simulations and experimental tests. The numerical simulations were performed by Ansys FE code through a structural-thermal full transient analysis to evaluate stress, strain and temperature in each node at each step of the simulation. The “birth and death” method was employed, together with temperature-dependent material properties.A2Danda3D simulation were performed, in order to evaluate possible differences due to the welding process. Numerical results were compared to some preliminary measurements obtained through an incremental cut made on the plate.

scholarly journals Determination of the Temperature-Dependent Thermal Material Properties in the Cooling Process of Steel Plates

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Dimitri Rothermel ◽  
Thomas Schuster ◽  
Roland Schorr ◽  
Martin Peglow
Keyword(s):  
Heat Conduction ◽  
Material Properties ◽  
Nonlinear Partial Differential Equation ◽  
Steel Plates ◽  
Temperature Evolution ◽  
Cooling Process ◽  
Temperature Dependent ◽  
Material Parameters ◽  
Thermophysical Characterization

Accelerated cooling (ACC) is a key technology in producing thermomechanically controlled processed (TMCP) steel plates. In a TMCP process, hot plates are subjected to a strong cooling resulting in a complex microstructure leading to increased strength and fracture toughness. The microstructure, residual stresses, and flatness deformations are strongly affected by the temperature evolution during the cooling process. Therefore, the full control (quantification) of the temperature evolution is essential regarding plate design and processing. It can only be achieved by a thermophysical characterization of the material and the cooling system. In this paper, the focus is on the thermophysical characterization of the material properties which govern the heat conduction behavior inside of the plates. Mathematically, this work considers a specific inverse heat conduction problem (IHCP) utilizing inner temperature measurements. The temperature evolution of a heated steel plate passing through the cooling device is modeled by a 1D nonlinear partial differential equation with temperature-dependent material parameters which describe the characteristics of the underlying material. Usually, the material parameters considered in IHCPs are often defined as functions of the space and/or time variables only. Since the measured data (the effect) and the unknown material properties (the cause) depend on temperature, the cause-to-effect relationship cannot be decoupled. Hence, the parameter-to-solution operator can only be defined implicitly. By proposing a parametrization approach via piecewise interpolation, this problem can be resolved. Lastly, using simulated measurement data, the presentation of the numerical procedure shows the ability to identify the material parameters (up to some canonical ambiguity) without any a priori information.

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