Reduction in welding induced residual stresses and distortions of butt welded plates subjected to heat treatments

2016 ◽  
pp. 481-488
Author(s):  
M Hashemzadeh ◽  
Y Garbatov ◽  
C Soares
Keyword(s):  
Residual Stresses ◽  
Heat Treatments

Influence of Heat Treatment on Characteristic Behavior of Co-Based Alloy Hardfacing Coatings Deposited by Plasma Transferred Arc Welding

2011 ◽  
Vol 462-463 ◽  
pp. 593-598 ◽  
Author(s):  
Hong Xia Deng ◽  
Hui Ji Shi ◽  
Seiji Tsuruoka ◽  
Hui Chen Yu ◽  
Bin Zhong
Keyword(s):  
Residual Stresses ◽  
Vickers Hardness ◽  
Arc Welding ◽  
Steel Substrate ◽  
Heat Treatments ◽  
Material System ◽  
Coating Surface ◽  
Plasma Transferred Arc ◽  
Transferred Arc ◽  
Plasma Transferred Arc Welding

The Plasma transferred arc welding (PTAW) is widely used for hardfacing components exposed to severe conditions. Without post welding heat treatments, large tensile residual stresses remain in the hardfacing coating, which is detrimental. In this paper, a set of post welding heat treatments was evaluated for the heat-resistant steel substrate – Co-based alloy hardfacing coating system. Microstructural and mechanical properties, including the chemical phases of coating surface, the microstructure of coating surface, the Vickers hardness and the residual welding stress, were investigated before and after the heat treatments. Results revealed that during the heat treatments, some elements reprecipitated and the secondary carbide Cr23C6 was formed. After the treatments, a more regular structure and a higher Vickers hardness were obtained. Moreover, the tensile residual stresses in the coating decreased significantly. Therefore, it can be inferred that the post welding heat treatments employed in this paper were proper for this material system.

scholarly journals Microstructure and Residual Stress Evolution of Laser Powder Bed Fused Inconel 718 under Heat Treatments

2020 ◽  
Author(s):  
Giulio Marchese ◽  
Eleonora Atzeni ◽  
Alessandro Salmi ◽  
Sara Biamino
Keyword(s):  
Residual Stresses ◽  
Inconel 718 ◽  
Heat Treatments ◽  
Powder Bed Fusion ◽  
Stress Evolution ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Melt Pool ◽  
Sintering Mechanisms ◽  
Dendritic Structures

AbstractThe current work aimed to study the influence of various heat treatments on the microstructure, hardness, and residual stresses of Inconel 718 processed by laser powder bed fusion process. The reduction in residual stresses is crucial to avoid the deformation of the component during its removal from the building platform. Among the different heat treatments, 800 °C kept almost unaltered the original microstructure, reducing the residual stresses. Heat treatments at 900, 980, and 1065 °C gradually triggered the melt pool and dendritic structures dissolution, drastically reducing the residual stresses. Heat treatments at 900 and 980 °C involved the formation of δ phases, whereas 1065 °C generated carbides. These heat treatments were also performed on components with narrow internal channels revealing that heat treatments up to 900 °C did not trigger sintering mechanisms allowing to remove the powder from the inner channels.

scholarly journals A Review of Heat Treatments on Improving the Quality and Residual Stresses of the Ti–6Al–4V Parts Produced by Additive Manufacturing

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1006 ◽  
Author(s):  
Óscar Teixeira ◽  
Francisco J. G. Silva ◽  
Luís P. Ferreira ◽  
Eleonora Atzeni
Keyword(s):  
Fatigue Life ◽  
Additive Manufacturing ◽  
Residual Stresses ◽  
Electron Beam Melting ◽  
Heat Treatments ◽  
High Melting Point ◽  
High Corrosion Resistance ◽  
Beam Source ◽  
Powder Bed ◽  
Metallic Parts

Additive manufacturing (AM) can be seen as a disruptive process that builds complex components layer upon layer. Two of its distinct technologies are Selective Laser Melting (SLM) and Electron Beam Melting (EBM), which are powder bed fusion processes that create metallic parts with the aid of a beam source. One of the most studied and manufactured superalloys in metal AM is the Ti–6Al–4V, which can be applied in the aerospace field due to its low density and high melting point, and in the biomedical area owing to its high corrosion resistance and excellent biocompatibility when in contact with tissues or bones of the human body. The research novelty of this work is the aggregation of all kinds of data from the last 20 years of investigation about Ti–6Al–4V parts manufactured via SLM and EBM, namely information related to residual stresses (RS), as well as the influence played by different heat treatments in reducing porosity and increasing mechanical properties. Throughout the report, it can be seen that the expected microstructure of the Ti–6Al–4V alloy is different in both manufacturing processes, mainly due to the distinct cooling rates. However, heat treatments can modify the microstructure, reduce RS, and increase the ductility, fatigue life, and hardness of the components. Furthermore, distinct post-treatments can induce compressive RS on the part’s surface, consequently enhancing the fatigue life.

Residual Stresses, Distortion, and Heat Treatment

2015 ◽  
pp. 487-497
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Residual Stresses ◽  
Heat Treatments ◽  
Stress Evaluation ◽  
Prediction Techniques ◽  
Deformation Gradients

Temperature and deformation gradients developed in the course of manufacturing can have undesired effects on the microstructures along their path; the two most common being residual stress and distortion. This chapter discusses these manufacturing-related problems and how they can be minimized by heat treatments. It also provides information on residual stress evaluation and prediction techniques.

Mathematical Modeling on the Residual Stresses in Coatings Due to Heat Treatments

2020 ◽  
Vol 978 ◽  
pp. 514-521
Author(s):  
M.K. Srinath ◽  
M.S. Ganesha Prasad
Keyword(s):  
Residual Stresses ◽  
Coefficient Of Thermal Expansion ◽  
Thermal Strain ◽  
Heat Treatments ◽  
Air Cooling ◽  
Elastic Plastic ◽  
Strain Components ◽  
Cooling Phase ◽  
The Difference ◽  
Plasticity Coefficient

Coatings are implemented on engineering metals and alloys to augment the surface properties such as hardness as well as resistance to wear and corrosion. Heat treatments of coated metals/alloys are performed to aid in the progress of the bonding of the coatings to the substrate. During the air cooling process, the difference in the compositions of the coating and the substrate materials causes them to cool at different rates, which leads to straining in them. The paper presents the research on the mathematical investigation to evaluate the residual stresses in coatings caused due to heat treatments and subsequent air cooling. The mathematical modelling is executed to formulate the equations to represent the residual stresses retained in the coatings due to the heat treatments and subsequent air cooling. Air cooling undergoes two stages namely the initial quenching phase and the final cooling phase. During the quenching phase, the strain was expressed by considering the elastic, plastic and thermal strain components. Poisson’s ratio, deviatoric stress differential of the modulus of plasticity, coefficient of thermal expansion and change in temperature are used to express the elastic, plastic and thermal strain components. During the final cooling phase, the strain was expressed by considering only the elastic and thermal stain components, as the plastic staining the coating material generally does not occur during the final cooling phase and occurs only during the initial quenching phase. From the strain components, the residual stresses for the coatings in the x, y and z axis were formulated. Thus, the total residual stress is the sum total of stresses caused during the initial quenching phase and the final cooling phase.

Residual Stresses in Laser Beam Welded Butt Joints of the Airframe Aluminium Alloy AA6056

2006 ◽  
Vol 524-525 ◽  
pp. 413-418 ◽  
Author(s):  
Peter Staron ◽  
W.V. Vaidya ◽  
Mustafa Koçak ◽  
Jens Homeyer ◽  
J. Hackius
Keyword(s):  
Residual Stresses ◽  
Laser Beam ◽  
Sheet Thickness ◽  
High Energy ◽  
Heat Treatments ◽  
Stress Profile ◽  
X Ray Diffraction ◽  
Butt Joints ◽  
Residual Stress Profile ◽  
Weld Heat

Residual stresses in CO2 laser beam welded AA6056 Al-sheets of 3.2 and 6.0 mm thicknesses were studied using neutron and high-energy X-ray diffraction. The influence of the temper T4 and T6 before welding, the effect of sheet thickness in T6 temper, and the effectiveness of post-weld heat treatments T6 and T78 for the reduction of residual stresses in the sheets welded initially in the T4 temper were examined. It was found that tensile longitudinal stresses were significantly higher when welded in T6 than in T4. With the increase in the sheet thickness from 3.2 to 6.0 mm, the residual stress profile was affected more than the stress level when welded in T6. For 3.2 mm sheet, the post-weld heat treatments T6 and T78 did not lead to a significant reduction in residual stresses when welded in T4.

Normalizing, Annealing, and Spheroidizing Treatments; Ferrite/Pearlite and Spherical Carbides

2015 ◽  
pp. 277-291
Keyword(s):  
Mechanical Properties ◽  
Residual Stresses ◽  
Ferrite Matrix ◽  
Heat Treatments ◽  
Carbon Steels ◽  
Medium Carbon ◽  
Grain Structures ◽  
Medium Carbon Steels ◽  
Normalizing Annealing ◽  
Strength And Toughness

This chapter describes heat treatments that produce uniform grain structures, reduce residual stresses, and improve ductility and machinability. It also discusses spheroidizing treatments that improve strength and toughness by promoting dispersions of spherical carbides in a ferrite matrix. The chapter concludes with a brief discussion on the mechanical properties of ferrite/pearlite microstructures in medium-carbon steels.

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