Heat-affected zone

About: Heat-affected zone is a research topic. Over the lifetime, 18787 publications have been published within this topic receiving 231744 citations.

Hybrid welding with arc and laser beam

Abstract: This paper deals with a combination of two different welding processes, i.e. the synergic action of two different heat sources for fusion welding. The major part of the paper is focused on the combined action of a welding arc and a laser beam. The main advantage of the use of both heat sources is more efficient use of the energy supplied. With certain parameters, the quantity of molten material increases by 100% compared with the sum of the individual quantities of molten material in the individual processes. The paper further presents several practical applications of the combined welding process. Eventually, development of arc augmented laser welding may progress in two directions; the first being the synergic effect of a laser beam and plasma welding arc and the second the combination of tandem laser welding and consumable electrode welding. This paper presents two such cases schematically.

Prediction of Residual Stresses in Welded T- and I-Joints Using Inherent Strains

Abstract: In order to develop a predicting method of residual stresses in fillet welded T- and I-joints, a concept of inherent strain, being regarded as a source of the residual stresses, was introduced. With the proposed method, the residual stress of an interested weldment may be predicted by performing an elastic analysis, in which the inherent strain is replaced to equivalent distributed loads. The inherent strain distributions in various welded T- and I-joints were investigated by numerical simulations. The results showed that the inherent strains distributing in flange side and in web side of the several joints are almost the same. The inherent strains vary not only with the average temperature rise due to welding, but with the geometric ratio of the joints. Being simplified by a trapezoid curve, the inherent strain distribution in a fillet weld was expressed by formulas, in which heat input, material properties, and geometric dimensions were taken into account. Welding residual stresses in T- and I-joints, predicted by the proposed method employing the derived formulas, were compared with those obtained by thermal elasto-plastic analysis, and good agreement was recognized. The validity of the proposed method was also confirmed by experiments.

More creep resistant turbine rotor, and procedures for repair welding of low alloy ferrous turbine components

Abstract: A more creep resistant turbine rotor and novel methods for repairing worn surfaces of Cr-Mo-V steam turbine components are disclosed. These methods include specified alloy compositions and welding procedures that minimize weld stresses and cracking. These alloys exhibit improved creep and fatigue properties and are preferably deposited using a gas tungsten arc welding procedure. Bead sequencing, cooling side plates and the use of run-off tabs are also disclosed for minimizing welding defects in turbine rotors and discs.

Stress corrosion cracking susceptibility of friction stir welded AA7075–AA6056 dissimilar joint

Abstract: Two aluminium alloys, AA7075 and AA6056, were friction stir welded, with the AA7075 alloy placed on the advancing side of the welding tool. Microstructural observations revealed the development of a recrystallised fine-grained weld nugget, with two different grain sizes, resulting from the two different base materials. Slow strain rate tensile (SSRT) tests in air have shown that the weld nugget is marginally overmatched in the weldment, and the fracture occurred in the relatively weaker thermo-mechanically affected zone/heat affected zone (TMAZ/HAZ) of the AA6056 alloy. SSRT tests in 3.5% NaCl solution at a nominal strain rate of 10−6 s−1 have shown that this dissimilar weldment is not susceptible to stress corrosion cracking (SCC) under these test conditions. Also in this case fracture was observed in the TMAZ/HAZ of the AA6056 alloy, with a behaviour very similar to that observed in the tests in air. However, at a still lower nominal strain rate, 10−7 s−1, the TMAZ/HAZ region of AA7075 alloy was found to be susceptible to SCC, exhibiting intergranular fracture. As a whole it is concluded that though the weld nugget is resistant to SCC, the TMAZ/HAZ region of AA7075 in the weldment is prone to SCC in 3.5% chloride solutions at nominal strain rate levels in the order of 10−7 s−1.