Influence Of Welding Conditions Research Articles

Influence of welding conditions and flux composition on chemistry of welds using recycled steel slag in submerged arc welding

The slag generated by steel-making plant has been employed to manufacture flux essential for submerged arc welding process. The developed flux has been used for depositing beads on plates, and the weld metal chemistry has been evaluated. The effect of welding conditions and flux composition on element transfer behavior has been investigated. The experiments were carried out as dictated by the design matrix generated using CCRD in response surface methodology. The data generated during experimentation was used to develop mathematical models. The developed models were tested for their adequacy through the ANOVA technique in design expert software. It is interesting to note that the recycled slag provided the chemistry of weld metal which is accepted as per ASME specifications. The rise in welding current increases the amount of carbon in weld metal from 0.11 to 0.14 wt.%, whereas it decreases with increasing travel speed. Manganese content decreases (1.28 wt.% to 0.795 wt.%) with increasing welding current (250 A to 650 A). The increase in welding speed from 4.44 mm/s to 8.88 mm/s results in an increment in manganese content from 0.87 wt.% to 1.21 wt.%. Since increasing travel speed decreases heat input per unit length of the weld, evaporation of manganese is suppressed. Therefore, the highest manganese content was achieved at a lower current (250 A) and higher speed (8.88 mm/s). Smooth beads with evenly distributed ripples free from surface defects like undercuts, porosity, pockmarks, etc., were achieved.

Analysis of the Effects of Welding Conditions on the Formation of the Structure of Welded Joints of Low-Carbon Low-Alloy Steels

To obtain reliable joints in the conditions of open construction is complicated or impossible to use stationary machines and apparatuses, so requirements to welding processes are of special interest. The most interest concerning the support of strength and reliability of welded joint is specific processes developed after the crystallization of weld at weld zone. The value of the zone of thermal influence depends on the welding conditions and properties of metal that is welded. That is why the research on the influence of welding conditions on the formation of the structure of welded zone and thermal influence zone is actual.

Investigation on the effect of power and velocity of laser beam welding on the butt weld joint on TRIP steel

In this study, the characterization of laser weld joint on transformation-induced plasticity (TRIP) steel sheets coupled with Nd:YAG laser welding was investigated, and the influence of welding conditions like angle of weld, power of laser, and welding speed on the strength of the joint was measured. The microstructure, tensile behavior, and microhardness of TRIP laser-welded sheets were examined in detail. The power was maintained constant, i.e., 1800 W, and by relatively varying the velocity from 25 to 30 mm/s, the strength of the joint increased drastically to 11%. In contrast, by varying the power, the effect of velocity was reduced; however, the point performance was enormously stable. Finally, the microhardness behavior of the heat-affected zone and fusion zone was investigated and discussed.

Resistance spot weld bonding of steel sheets

The use of innovative resistance welding methods with bonding for joining construction materials opens new possibilities in expanding ranges of combined materials in various industrial sectors. The article presents the results of experiments of resistance spot welding-adhesive bonding, using the weld-through technique. The influence of welding conditions (technological parameters of welding) and adhesive bonding conditions (method of surface preparation, size and thickness of the overlap during bonding) on the process of creating hybrid connections is presented. The tests combined DC01 steel sheets without protective coverings and DP 600 with Z140 zinc protective coating and designed for applications in the automotive industry one-component epoxy adhesive was used.

Dissimilar friction stir welding of immiscible titanium and magnesium

Dissimilar friction stir welding of an immiscible metal combination, titanium and magnesium, was performed. Aluminum thin foil was inserted between the titanium and magnesium in order to simultaneously react with these two immiscible materials. The welding parameters including aluminum foil thickness, probe offset and welding speed were optimized to fabricate a sound titanium/magnesium joint. The influence of welding conditions on the reaction layer formation, aluminum distribution and tensile strength of the obtained joints was systematically examined. With an increase in the aluminum foil thickness, the size and amount of the welding defects generated inside the magnesium stir zone increased due to the poor material flow. The optimal joint showed the highest tensile strength of ∼150 MPa, which is ∼88% of the tensile strength of pure magnesium, and fractured at the magnesium heat affected zone, which is attributed to the formation of properly thin intermetallic compound layer at the weld interface and the inhibition of brittle intermetallic compounds formation inside the magnesium stir zone.

Influence of welding conditions on crack opening displacements in welded CT specimens

To investigate the effect of weld induced residual stresses on the crack performance, standard compact tension specimens were cut into two pieces, then joined to form welded specimens under various welding conditions. The crack opening displacement was measured by digital image correlation technique. It is found that specimens welded in the opposite direction show smaller crack opening displacement than those welded in the same direction. The crack opening displacement decreased as the distance from the crack tip to the center of weld line was increased from 8 mm to 30 mm. The crack opening displacement of the specimens with 30-minute time interval was lower than that of the specimens without interval, regardless of welding directions.

Microstructure and Mechanical Properties of Laser Welded Dual Phase and Mild Steel Joints for Automotive Applications

Recently, the laser welding technology of carbon steel is being widely used compared with arc welding technology for its better welding characteristics. In the present study, the influence of welding conditions of both laser beam welding (LBW) and gas metal arc welding (GMAW) as a comparative study on the weld joint microstructures, hardness distribution and fatigue properties crosses the butt-welded joints of dual phase (DP) steel and mild steel are investigated. The results show that LBW produced narrow welds with complete penetration while GMAW produces wide fusion and heat affected zones. The microstructure of the fusion zone of laser welded DP steels contains mainly bainite, martensite, and a few amount of acicular ferrite phases. Hardness values of the heat-affected zone (HAZ) for dual-phase (DP) steels showing lower values for both LBW and GMAW processes due to the tempering action of the martensite phase. A narrow softening region was clearly observed in the HAZ welded for LBW compared with GMAW. In general, the fatigue life of the welded joints is improved by using laser welding technique.

Friction stir welding of aluminium casting alloys

The results of testing friction stir welding quality in relation to EN AC-43200 (AK9) and EN AC-45000 (AK64) aluminium casting alloys are presented. The test joints were made with the use of a welding machine constructed on the basis of numerically controlled milling machines. The assessment of the joint quality was made based on visual inspection, mechanical testing, weldment structure analysis and hardness tests. The purpose of the investigation was to discover the possibility of friction stir welding of casting alloys and the influence of welding conditions on joint properties and structure. The test results show good weldability of aluminium casting alloys by the FSW method. Sound welds can be obtained in a relatively wide range of welding parameters while the weld strength is satisfactory. In order to obtain the highest quality joints, the workpieces must be pressed onto the other, while the welding process cannot run with excessively high speed. The best mechanical properties of the joints were achieved when the friction process was conducted at a rotational speed of the mixing tool of 900 rpm.

Influence of welding conditions on resistance flash welds

The contribution gives an insight into resistance flash welding with emphasis on process dynamics. For the experiments ribbed mild steel concrete reinforcement bars were used with a range of welding parameters used in a normal welding praxis. The welded bars were tested for tensile strength and the results were used to develop a regression model. The model was designed to predict weld piece strength according to input welding parameters. The input welding parameters were: welding force, welding current and welding time.

Influence of Welding Conditions on Residual Stresses of Multi-Pass Tube Sheet Welds

Residual stresses and residual plastic strains of the welded structures are the products of nonlinear behaviors during welding. The residual stresses will cause errors during the assembly of the structure and injure the beauty of appearance of the structure. Based on an elastic-plastic-model, finite element numerical simulation of a representative tube sheet penetration assembly with loop welding line joined by multi-pass welding is carried out and the influence of welding conditions on residual stresses of the tube sheet welds is studied in this paper. Nonlinear three dimensional transient temperature fields and real-time dynamic stresses field are analyzed by FEM. The heat source is modeled as a moving heat flux following a double ellipsoid distribution and the temperature-dependent properties of materials are considered. The method of birth and death of element in finite element analysis is applied to simulate the gradual growth of weld pass metal. It is shown that welding sequence, size of groove welding and weld toes dressing will obviously change the magnitude of the residual stresses of tube sheet welds.

Development of friction stir welding of high strength steel sheet

For friction stir welding (FSW) of advanced high strength steel (AHSS) sheets with tensile strength grades between 590 and 1180 N mm−2, the appropriate welding condition range and the influence of welding conditions on microstructures and mechanical properties of the welds were investigated. The appropriate welding conditions to avoid defects such as the incomplete consolidation at the bottom of the weld were obtained for the steel sheets up to 1180 N mm−2 grade. The higher tool rotation speed evidently resulted in the larger volume fraction of martensite and higher hardness in the stir zone (SZ), attributed to an increase in the peak temperature of its thermal cycle. The tensile strength of the weld joint was as high as that of the base metal for the steels up to 980 N mm−2 grade, but slightly lower than that of the base metal for the steel of 1180 N mm−2 grade due to the heat affected zone (HAZ) softening.

Prediction of Hot Cracks of T-Joints in Full-Penetration Welding Process

In this study, the influence of welding conditions on the formation of a pear-shaped bead crack is examined through experiments on full-penetration welding of T-joints. These problems are analyzed using the finite element method (FEM). The formation and growth of a pear-shaped bead crack in T-joints welded by full-penetration, high-current pulsed MAG (Metal Active Gas) welding is simulated using temperature-dependent interface elements, which are introduced in the thermal-elastic-plastic FEM analysis. The experimental results show that a pear-shaped bead crack does not occur when the heat input is greater than 2 500 J/mm, or when the penetration bead is formed. However, according to commonly accepted knowledge, both large heat input and a large penetration bead (deep penetration relative to the penetration width) lead to hot crack formation. To understand these experimental results, FEM simulations are conducted and the influences of heat input and the size of the penetration bead are investigated.

The Influence of Welding Conditions on Mechanical Properties and Microstructural Change of TIG Welded Joint in Extruded Plate AZ31B Mg Alloy

This present work investigated the influence of welding conditions, such as welding current, diameter of welding wire on the microstructural change, and mechanical properties of TIG welded joint in extruded AZ31B Mg plate. It was found that a good and sound welded joint was achieved in all welding conditions. The grain size decreased with increasing welding current and decreasing diameter of welding wire. In addition, the second phases were homogeneously distributed in the grain and grain boundary as the welding current and the diameter of the welding wire were decreased. β discontinuous precipitates were observed in the welded joint; this microstructure has not been reported by previous researches investigating AZ31B Mg alloy. The hardness value was affected by the existence state of the second phase and the hardness of the welded joint region was lower than the other regions in welded AZ31B Mg alloy. The strength of the welded joint region was influenced by the grain size and had more than 90 %, compared to that of ASTM standard specification.

Hydrogen attack on simulated weld heat affected zone of 3Cr–1Mo–0.25V steel

Hydrogen attack and the associated change in mechanical properties in a 3Cr–1Mo–0.25V steel subjected to a simulated welding thermal treatment were investigated to show the influence of welding conditions on the heat affected zone. The maximum peak temperature reached in the simulated welding process affected the microstructure, which in turn is related to the occurrence of different quantities of methane bubbles.

Influence of welding conditions and residual stresses on strength of Al<SUB>2</SUB>O<SUB>3</SUB>/Ti diffusion welds

Influence of welding conditions and residual stresses on strength of Al<SUB>2</SUB>O<SUB>3</SUB>/Ti diffusion welds

Determination of fracture mechanics properties of welded joints and comparison with the failure behaviour of wide plates

Fracture behaviour of different welded joints of 15 MnNi 6 3 and 20 MnMoNi 5 5 steel is studied by testing Charpy-V impact, fracture mechanics specimens as well as wide plate specimens of different sizes. The influence of welding conditions and stress relief heat treatment on the failure behaviour of the heat affected zones is examined. Fracture mechanics test data are used in order to predict failure loads of the wide plates by the R6-procedure and by FE-calculations.

高窒素ステンレス鋼被覆アーク溶接金属のブローホール防止

The report is composed of a study of the influence of four factors, oxygen, hydrogen, ferrite content and welding conditions, on the blowholes in the weld metal, using covered arc-welding electrodes for the pitting corrosion resistant austenitic stainless steel with high nitrogen concentration (25Cr-13Ni-1Mo-0.35 N). Compositions of gas in the blowholes of weld metal were also checked.The experimental results were as follows;1) As the amount of hydrogen in weld metal increases, so does the number of blowholes in a circumstances where oxygen content are high (0.06%). The number of blowholes decreases when oxygen content are lower and the influence of hydrogen for blowholes also decreases. The number of blowholes is very few at 0.04% oxygen and 5 ppm hydrogen.2) The number of blowholes much fluctuates by welding conditions when both oxygen content (0.06%) and hydrogen content (8 ppm) are high. When oxygen content (0.04%) and hydrogen content (5 ppm) are both lower, the number of blowholes in weld metal decreases and blowhole is almost exempted from the influence of welding conditions.3) The number of blowholes does not change until ferrite content exceeds 5% but it begins to increase when ferrite content exceeds 50%.4) Hydrogen and nitrogen gas were found in the blowholes of weld metal with oxygen content 0.06% and hydrogen content at 8 ppm.5) It can be concluded that prevention of blowhole in stainless steel weld metal with high nitrogen concentration (0.29-0.34%) could be achieved by lowering oxygen content less than 0.04% and hydrogen content at 5 ppm.