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Butt welding

About: Butt welding is a research topic. Over the lifetime, 7153 publications have been published within this topic receiving 44467 citations.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the influence of inhomogeneous Hydrogen Removal Heat Treatment (HRHT) procedures on the residual stresses in multi-pass welds of S 1100 QL was investigated.
Abstract: Most of the research on Hydrogen Assisted Cold Cracking (HACC) in high strength steel welds conducted over the last several decades has focused on single-pass welds, especially considering materials with yield strengths about 700 MPa. The guidelines for avoiding cracking that have been developed from such work are therefore useful only where a root pass is the critical event. The well-known guideline is using preheating temperature. Such guideline is very limited when applied to multi-pass welds. In order to support this need, this paper presents the influence of inhomogeneous Hydrogen Removal Heat Treatment (HRHT) procedures, i.e. sole preheating, controlled interpass temperature and combined preheating and controlled interpass temperature, on the residual stresses in multi-pass welds of S 1100 QL. Thereafter, these results are used to identify HACC problems in S 1100 QL and are not reported here. The results were achieved by decent thermal and structural finite element simulations of a five-layer welded 12 mm thick plate at a realistic restraint provided by respective Instrumented Restraint Cracking (IRC) test. The simulations show that the inhomogeneous heat treatment procedures significantly increase the residual stresses as compared to welding without any heat treatment. In contrast to more general anticipations, an increasing controlled interpass temperature does not necessarily lead to a stress reduction, but can even increase the stresses dependent on the location in the multi-pass welds. Maximum residual stresses generally appear in the upper third part of the weld and are not located beneath the top surface where is a typical location used to detect residual stresses in real welded components. If the restraint intensity given to the welded component is not proper, such heat treatment procedures with various temperatures seem to be useful to reduce residual stresses in multi-pass welds.

21 citations

Patent
06 Nov 1996
TL;DR: In this paper, a high energy laser and sheet clamping mechanism is used to clamp each sheet blank in place between an associated electromagnet and ferromagnetic clamping shoes, with the proximal edge portions of the sheets abutting.
Abstract: An apparatus is disclosed for positioning, clamping and welding together proximal edge portions of two sheet blanks. The apparatus incorporates a high energy laser and sheet clamping mechanism used to clamp each sheet blank in place between an associated electromagnet and ferromagnetic clamping shoes. The shoes are positioned above a corresponding electromagnet and are vertically movable theretowards on the activation of the electromagnet. In use, the sheets are held in place with the respective sheet blanks sandwiched between the associated electromagnets and shoes with the proximal edge portions of the sheets abutting. The high energy laser is movably provided in the apparatus to move an emitted laser beam along a predetermined path over the abutting proximal edge portions to perform welding operations.

21 citations

Patent
30 Sep 2008
TL;DR: In this paper, a welding method for making a weld via laser-arc hybrid welding is described. But the welding method also includes using a fiber laser source in the laser arc hybrid welding.
Abstract: A welding method is disclosed. The welding method includes making a weld via laser-arc hybrid welding. The welding method also includes using a fiber laser source in the laser-arc hybrid welding.

21 citations

Journal ArticleDOI
W Sudnik, D Radaj1, W Erofeew
TL;DR: In this article, a model of laser beam weld shape formation which comprises butt and overlap joints with a small gap between the parts to be joined is considered, and the model is based on the equations of energy transport and of equilibrium at the free surfaces for balancing vapour pressure, capillary pressure and a correction term.
Abstract: A model of laser beam weld shape formation which comprises butt and overlap joints with a small gap between the parts to be joined is considered. It is the goal of the simulation to predict the effect of technological parameters on the reinforcement or concavity of the weld or weld root and on the area of the load-carrying cross section which controls the strength of the joint. The model is based on the equations of energy transport and of equilibrium at the free surfaces for balancing vapour pressure, capillary pressure and a correction term. The correction term allows balancing the metal volume taking into account thermal expansion and shrinkage during welding and the gap width between the parts to be joined. Verification of the simulation results for gap widths in the range 0-0.2 mm shows that the model corresponds sufficiently well to the experimental data when considering laser beam weld formation in butt and overlap joints of 1.5-6.0 mm sheet thickness. The model explains the weld concavity occurring with gaps in butt and overlap joints, the increase in penetration depth for butt welds with gaps and the widening of the molten zone near the gap in overlap joints.

21 citations

Journal ArticleDOI
TL;DR: In this paper, a detailed failure analysis conducted on high density polyethylene which acts as the liner of composite compresses natural gas cylinder was observed after about 2000 cycles of hydrostatic pressure testing at 250 bars.
Abstract: This article discusses a detailed failure analysis conducted on high density polyethylene which acts as the liner of composite compresses natural gas cylinder. Leakage from the cylinder was observed after about 2000 cycles of hydrostatic pressure testing at 250 bars. Visual inspection revealed that the leakage occurred from the circumferential fusion joint between the cylinder and dome section. The cylinder and dome sections were produced from different techniques and joined together by using a heated tool butt welding process conducted by a local manufacturer. The joined components work as an integral part. The investigation was carried out using various techniques including mechanical, thermal and metallurgical examination. Fractography of the failed joint surface showed stepwise marks typical of a fatigue failure. Mechanical testing results showed that the strength of dome section was significantly lower than that of the cylinder section. Moreover, both the tensile and fatigue strength of joint was also almost half that of the cylinder. The fracture surface of the broken welded joint showed brittle failure. The melting points of both the cylinder and the dome sections were found almost same by differential scanning calorimeter but large difference was found between the melt point indexes of both sections. The results suggested that the failure was actually a stress cracking via a process of slow crack growth, which occurred due to use of a dome material having inferior properties and very high melt flow index. These properties inhibited proper fusion and resulted in a poor weld joint. Consequently, the weld joint of lower strength eventually failed in macroscopically brittle manner upon cyclic loading.

21 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202328
2022122
2021112
2020219
2019290
2018349