Heat Treatment Of Welded Joints Research Articles

Computer simulation of diffusion in multiphase systems

A general model to treat multicomponent diffusion in multiphase dispersions is presented. The model is based on multicomponent diffusion data and basic thermodynamic data and contains no adjustable parameters. No restriction is placed on the number of components or phases that take part in the calculations, as long as the necessary thermodynamic and kinetic data are available. The new model is implemented into the DICTRA software, which makes use of THERMO-CALC to handle the thermodynamics. The model is applied to carburization of Ni alloys and heat treatment of welded joints between dissimilar materials. In both cases, the diffusion is accompanied by carbide formation or dissolution. A good agreement between experiments and calculations is found, despite the fact that no adjustable parameters are needed.

Electron beam welding and zone heat treatment of welded joints in titanium alloys and high‐strength steels

Electron beam welding and zone heat treatment of welded joints in titanium alloys and high‐strength steels

Structure and properties of welded joints from various titanium alloys

Metallographic, x-ray diffraction, x-ray microspectral and hardness testing techniques have been used to examine the changes in the structure, phase composition, microhardness and the distribution of alloying elements in the parent metal and in the heat affected zone and in the seams of welded joints formed from various titanium alloys (VT6-OT4, VT6-VT20, VT23-OT4, VT23-VT6, VT23-VT19 and VT23-VT32) in the post welded condition. Recommendations have been made concerning the heat treatment of welded joints in the alloys examined. 4 refs., 3 figs., 1 tab.

Local heat treatment of welded joints in large spherical tanks

Local heat treatment of welded joints in large spherical tanks

The heat treatment of welded joints in the flash welding of high strength casing pipes

The heat treatment of welded joints in the flash welding of high strength casing pipes

Heat treatment of welded joints of alloy 36NKhTYu

1. In the heat-affected zones adjacent to a welding seam obtained by argon-arc or electron-beam welding of alloy 36NKhTYu, intermittent decomposition does not occur during aging; this has a deleterious effect on the strength properties and the endurance in cyclic loading of specimens. 2. To eliminate structural inhomogeneity and to improve the strength properties and the endurance of welded joints of alloy 36NKhTYu, it is indispensable, after welding, to carry out a second quenching at 930–1100°C.

A review of the metallurgy of heat treatment of welded joints

This paper deals with the metallurgical changes which occur during heat treatment of welded joints. Stress relieving heat treatment in the temperature range below A 1, the normalizing heat treatment and the heat treatment in the intercritical range A 1–A 3, are all considered. The thermal regime of welding is described. The practice of intercover of the weldment before applying PWHT to ambient temperature is described. It is stressed that the aim of stress-relieving heat treatment is not only to relax internal stresses but also to improve the microstructure and impact properties of HAZ and weld metal, to improve dimensional stability and increase resistance against stress corrosion. Examples are given of the effect of annealing in the intercritical range A 1–A 3 on the improvement in toughness of electroslag welded joints. Changes in dislocation distribution and density, precipitation processes and grain sizes during PWHT are described.

Fracture toughness of 80mm thick electroslag welded joints with COD approach application

The paper deals with searching for criteria for the mechanical properties estimation of thick walled electroslag welded joints with an aim to find out whether the COD approach would be reliable for the differentiation of brittle fracture resistance. Three types of C-Mn steels modified by titanium, vanadium and molybdenum respectively with yield point of about 40 kp/mm 2, applied usually for pressure vessels and bridge constructions were used in the experimental work. The welded joints were tested in as-welded, stress relieved, and normalized and tempered conditions respectively. It was stated that the COD approach distinguishes quite well the above mentioned variants of the heat treatment of welded joints and base materials apart from the necessity of some precision of testing procedure and evaluation of test results. The adventage not under discussion of COD approach in comparison to classic methods lies in the interpretation of brittle fracture resistance by the parameter of the defect size particularly for the conditions where no valid K IC values are obtained.