Welding Of Parts Research Articles

Spot Welding Error Analysis in Making Rear Brake Arm in Spot Welding Part at PT. XYZ

As a manufacturing company engaged in the manufacture of automotive parts, it produces components for motorized vehicles, especially for two wheels, with the production of spare parts in the form of arm rear brakes. In the manufacture of these spare parts, it is really necessary to pay attention to all the needs, such as materials which, in other words, really have an influence on the strength of the material. Included in the process that goes through spot welding, it needs to be considered in the stages of the process to be optimal because, if not, it will cause failure of a product so that defective products are obtained at this welding point. Improvement of the production process of this product can be done by identifying control factors and arrangements using the 5 why analysis, fishbone, and pareto methods until the production process is stable and the results obtained are good and according to the expected standards until the needs of all parties are met.

Enhancing the bending strength of PEEK biomedical material welding parts using continuous drive friction welding with progressively increased welding area method

Enhancing the bending strength of PEEK biomedical material welding parts using continuous drive friction welding with progressively increased welding area method

Cyclic performance study of Q460D steel and ER55-G welds after high temperature

Coupon test specimens with the gauge length part of Q460D high-strength steel or ER55-G weld respectively were heated up to high temperature of 900 °C and then cooled in water. Uniaxial tensile tests were conducted on those cooled specimens. The engineering stress-engineering strain curves were obtained. Meanwhile, twelve smooth round bar specimens made of Q460D high-strength steel and ER55-G welds were heated up to high temperature of 900 °C and then cooled naturally or cooled in water. Cyclic loading tests with two different loading protocols, namely constant amplitude and variable amplitude, were conducted on these specimens at different strain levels. The engineering stress-engineering strain curves of each specimen were obtained, enabling to compare and analyze the differences of the results in cyclic mechanical properties of each specimen in terms of damage morphology, hysteresis performance, and ductility characteristics. The test results show that the different cooling methods after the high temperature of 900 °C have a significant impact on the ultimate strength and elongation of Q460D high-strength steel and ER55-G welds. The ultimate strength of the specimens after water cooling was significantly higher than that of the specimens after natural cooling, while the elongation result was opposite. It was obvious from the test results that water cooling and natural cooling after high temperature led to a decrease in ductility and energy absorption capacity of the base metal and welds to various degrees, while their energy dissipation capacity was significantly improved at low strain level.

Towards an in-process ultrasonic phased array inspection method for narrow-gap welds

The marriage of welding and Non-Destructive Testing (NDT) processes at the point of manufacture has enabled the detection and correction of defects during the welding process. This has demonstrated clear financial and production benefits by reducing weld rework and ensuring schedule certainty, however this is yet to be demonstrated for use with narrow-groove welding practises. Narrow-groove welds are notoriously difficult to inspect using traditional Phased Array Ultrasonic Testing (PAUT) techniques due to large thicknesses and the vertical nature of Lack-of-Sidewall Fusion (LOSWF) defects. This is further complicated by the presence of partially-filled weld geometries during in-process inspection, which cause geometric reflections which can mask or falsely indicate the presence of a defect. A solution to this is proposed in this work, by adapting a dual-tandem phased array imaging system for the imaging of LOSWF defects in a partial weld geometry. This considers a two array system utilising a phased array probe on each weld side, coupled with an advanced dual-aperture Full Matrix Capture (FMC) acquisition technique. Advanced multi-mode image processing algorithms such as the Total Focusing Method (TFM) and Phase Coherence Imaging (PCI), with adaptive delay law calculation, have shown high sensitivity to LOSWF defects in a mock partial weld geometry. Additionally, an adaptive Probe Centre Spacing (PCS) technique is defined for in-process inspection based on amplitude and phase coherence sensitivity in partial weld geometries, with the effects of partial weld reflections analysed and discussed. These results have demonstrated the effectiveness of a dual-tandem phased array approach to imagine LOSWF defects during the in-process inspection of narrow-gap welds.

Сварка деталей из полимерных композиционных материалов на основе термопластов. Часть 4. Методы испытаний и контроля качества сварки деталей из термопластов

This article is a continuation of a series of articles on welding parts made of polymer composite materials based on thermoplastics. In the fourth article in the series, the most common methods of quality control and test of welded joints of products made of polymer composite materials based on thermoplastic binders are considered. Typical defects of welded joints of plastics have been determined. The technologies of destructive and non-destructive inspection of welded joints of plastic products are considered.

Comparative Investigation of the Tensile Strength of Steel Bars With and Without Couplers

Connection in reinforced concrete is unavoidable due to limited length of steel. As known the maximum length of steel 12 metres and used for beams, columns, plates, foundations, etc. Sometimes several buildings use long spans between column to column for architecture causes longer steel needs. If spans are more than 12 metres the steels should be connected by welding, coupler drates, and other parts of connection. Coupler drates one of the most popular connection and it is easy to make connection between steels in the reinforcement concrete. This research aims to determine the behaviour of steels when they were tensioned at testing machine either full steel bar and connected steel bar by coupler drates. The testing was conducted at the materials laboratory the references for testing are Indonesian standards for testing materials like SNI - 2052 - 2017, SNI - 8389 - 2017 and SNI - 07 - 0408 - 1989. The type of steel bars for testing are drate steels of diameters 25 mm and 32 mm and the type of test is tensioning test. The results of testing for normal steel bar of D- 25 mm is 619.3 MPa and D-32 mm is 636 MPa respectively and steel bar with coupler drates for D- 25 mm is 428 MPa and D-32 mm is 522.5 MPa respectively. It means tension strength of D-25 mm coupler drates decreases 30.88 % and tension strength of D-32 mm decreases 17.84 % as compared with steel bars.

Сварка деталей из полимерных композиционных материалов на основе термопластов. Часть 3. Методы сварки деталей из полимерных композиционных материалов на основе термопластов с преобразованием различных видов энергии

This article is a continuation of a series of articles on welding parts made of polymer composite materials based on thermoplastics. The welding methods of plastics based on thermoplastics with the transformation of various types of energy into thermal one and their classification are considered. The features of the friction welding, ultrasonic welding, high-frequency welding and radiation welding technologies are given. The main parameters of the technological modes of the considered welding methods, the fields of their use, advantages and disadvantages are determined.

Numerical Study of Laser Welding of 270 μm Thick Silicon–Steel Sheets for Electrical Motors

In this study, the shape of laser welding parts required to develop a welding automation system was analyzed to improve the production process of thin-plate silicon–steel. During laser welding, a welding defect occurs in the welding area, resulting in beads. This can be measured and analyzed through computational fluid dynamics. When welding thin plates with a laser, precise parameter settings are required to reduce bead height and side effects to improve weld quality. Twelve simulation cases with different laser powers and scan speeds were carried out to compare bead heights. We discussed ways to improve the productivity of electrical steel sheets by applying data collected through simulations of a laser welding automation system.

A Study of Annealing Effects on the Joints of a Rotary Friction Welds of AISI 1030 Steel

This study is concerned with the post-heat treatment of rotational friction welds. AISI 1030 carbon steel parts are welded by rotational friction welding (RFW). The welding process parameters include friction pressure (P1), friction time (T1); Forging pressure (P2), forging time (T2). During the friction phase, the rotational speed is 1450 rpm; after that, the welding parts is stopped immediately and pressed together. The weld samples will be annealed at 650 °C for 4 hours. The change in the properties of the material of a RFW weld joint such as hardness, tensile strength, bending strength as well as grain size when undergone a heat treatment process was investigated. The obtained results show that the annealing process strongly changes the mechanical properties through altering the microstructure of the weld. Particularly, the weld hardness and tensile strength decrease significantly while the bending strength and elongation increase as a result of the increase in grain size and uniformity of the phase distribution. The annealed weld has a hardness reduction of nearly 20% and a tensile strength reduction of about 24% compared to the original weld. The elongation in the tensile test increases from 1.1% for weld specimens to 2.54% for post-heat-treated welds. In the bending test, the maximum load before the appearance of cracks on the specimen increased by about 42% when comparing the post-heat and original weld specimens.

Creep behaviour and microstructure evolution in Super 304H–P92 heterogeneous welds

ABSTRACT The paper deals with results of long-term stress rupture tests on “cross-weld“ specimens made of Super 304 H – P92 heterogeneous welds. Stress rupture tests were carried out at temperatures of 625°C and 650°C up to 20,000 hours to rupture. Creep rupture strength and WSF values of Super 304 H – P92 welds for 10,000 hours at both 625°C and 650°C were calculated. The preferential location of failure was the intercritical part of the heat affected zone in P92 steel. Hardness of both base materials did not show significant changes during creep exposure at both 625°C and 650°C. However, gradual hardening of the weld metal occurred. Metallographic studies were performed in individual parts of heterogeneous welds. A special attention was paid to precipitation reactions in both base materials and heat affected zones. A residual content of vanadium in Super 304 H steel affected precipitation processes. Vanadium partly substituted niobium in the modified Z-phase ((V,Nb)CrN).

Optimization of Bead Geometry during Tungsten Inert Gas Welding Using Grey Relational and Finite Element Analysis.

Mild steel welded products are widely used for their excellent ductility. Tungsten inert gas (TIG) welding is a high-quality, pollution-free welding process suitable for a base part thickness greater than 3 mm. Fabricating mild steel products with an optimized welding process, material properties, and parameters is important to achieve better weld quality and minimum stresses/distortion. This study uses the finite element method to analyze the temperature and thermal stress fields during TIG welding for optimum bead geometry. The bead geometry was optimized using grey relational analysis by considering the flow rate, welding current, and gap distance. The welding current was the most influential factor affecting the performance measures, followed by the gas flow rate. The effect of welding parameters, such as welding voltage, efficiency, and speed on the temperature field and thermal stress were also numerically investigated. The maximum temperature and thermal stress induced in the weld part were 2083.63 °C and 424 MPa, respectively, for the given heat flux of 0.62 × 106 W/m2. Results showed that the temperature increases with the voltage and efficiency of the weld joint but decreases with an increase in welding speed.

Characterization of galvanized steel-low alloy steel arc stud welded joint

This paper investigates the possibility of successfully welding a Low Alloy Steel (LAS) stud to Galvanized Steel (GS) plate.Arc Stud Welding (ASW) was performed on joining LAS studs to GS plates. Welding parameters were selected based on weld trails. The first tests of the welded joints were based on visual inspection for welding defects such as lack of fusion and undercut welding defects. The good quality should be free of these defects and have full weld reinforcement. Other weld qualifications included torque strength test, microhardness test, and microstructure examination.The LAS studs have been successfully welded to a galvanized steel plate using the arc stud welding process. Higher welding current with adjusted welding time (800 A, 0.3 s) gave full weld reinforcement, the best joint appearance, and strength. Martensite phase was detected in the weld area and heat affected zone (HAZ), affecting the joint mechanical properties. Hardness property varied across the welded joint, and maximum hardness was recorded at the HAZ at the stud side. Hardness increased with the increasing welding current. At 800 A, welding current hardness was 10% higher than at 400 and 600 A. Torque strength was affected by weld reinforcement, and 800 A gave the best weld reinforcement that produced the highest torque strength.The main research limitation is the difficulty of welding LAS studs and GS plates. In conventional welding methods, such as gas metal arc welding, it is hard to get full weld penetration due to the geometry restrictions of the joint, which results in partial weld penetration between the studs and the plates. Furthermore, the issue of zinc evaporation during welding can be reduced by the advantage of the very high welding speed (in milliseconds) of ASW that overcomes the problem of continuous welding that usually results in the formation of harmful porosities and poor weldability.In this research, galvanized steel plates were successfully welded to LAS studs using the ASW process. The welding parameters for this dissimilar welding joint were carefully selected. Microstructure changing due to the welding process was investigated. The joint mechanical properties were evaluated.

Creep Resistance and Microstructure Evolution in HR3C-P92 Heterogeneous Welds

The paper deals with results of long-term stress rupture tests on „cross-weld“ specimens made of HR3C–P92 heterogeneous welds. Stress rupture tests were carried out in air at temperatures of 625 and 650 °C up to ca 20 000 h to rupture. Creep rupture strength values of HR3C–P92 welds for 104 h at both 625 and 650 °C were calculated. The preferential location of failure was the intercritical part of the heat affected zone in P92 steel. Local changes of hardness during creep exposure were evaluated by hardness profiles across the welds. Metallographic studies were performed in individual parts of heterogeneous welds. A special attention was paid to precipitation reactions in both base materials and heat affected zones.

Non-destructive Inspection System Development for Secondary Battery Welding Part

In this paper, we develop a non-destructive inspection system for secondary battery welding. In a secondary battery, when the insulation or separator of each electrode is damaged by an impact from the outside depending on the degree of welding, an internal short circuit occurs during charging and fires even if it does not ignite at that time. To detect this, a non-destructive AOI (Automatic Optical Inspection) system is developed that compares the inspection target with the reference image to determine whether there is a proper indentation in the welding part. The system consists of a precision alignment stage on the lower part and imaging equipment that performs AOI, a non-destructive inspection on the upper part. And the appropriate exposure, i.e., the aperture setting of the used camera, was confirmed through the experiment according to the position of the pole .

용접부 샌드 블라스팅 표면처리에 따른 부식 영향 연구

Recently, consumer complaints on car corrosion have been steadily increasing. The main cause of corrosion is calcium chloride, which is commonly used in winter, and the lower parts of the car, such as suspension, are more affected by it. Corrosion affects the parts durability by weakening them and threatening the passenger safety if exposed to continuous loads. Therefore, herein, a method of improving corrosion performance was studied by applying the surface treatment to the welding part of the steel plate used in the manufacture of cross members among automobile suspension parts. Specimens were manufactured through brushing and the sand blasting surface treatment, and cross-cut adhesion tests and repeated corrosion tests were conducted. The test results showed that the cause of the electrodeposition coating and corrosion defects was the oxide layer formed from oxidation after welding, and the sand blasting surface treatment was very effective in removing the oxide layer.

Hydrogen damage in a power boiler: A study of damage selectivity and conditions

We report two evaporator tube failures that took place in the same boiler owing to hydrogen damage within an interval of approximately one year. Notably, hydrogen damage occurred selectively on recently repaired tubes. In contrast, some of the original tubes that had been operating for 18 years or longer remained intact under the same environment. Comprehensive metallurgical investigation and chemical analysis revealed that the older tubes slowly developed a thin film of evaporation residue on their inner surface, which had a protective effect and suppressed the progress of corrosion. Hydrogen damage is more likely to proceed in the electric resistance welding (ERW) part than in the other parts. Kinetic consideration proved the rapid (within 18 hours) progression of hydrogen damage in evaporator tubes. Moreover, it confirmed that the hydrogen damage could be stemmed by instantaneous shutdown without improving the water quality immediately. The cleaning test suggested that tubes that already suffered hydrogen damage may be further damaged during acid cleaning. These results can help identify the cause of hydrogen damage in evaporator tubes due to poor water quality and determine the area of tube renewal/repair.

Weldability of Nickel/Aluminum Dissimilar Materials Laser Welding Part II: Microstructure Development, Solidification Behavior and Mechanical Properties of Polycrystalline Aluminum Alloy

The weldability and fabricability of nonheat treatable Aluminum-Magnesium alloy 5083H116 in shipbuilding industry by attractive laser welding are progressively assessed in this paper. The response of crack-resistant microstructure development, phase transformation and mechanical properties to energy input is very sensitive and distinguishable during laser welding process. Supersaturation of α-Al solid solution is prominently released by granular Al3Mg2 β phase during rapid solidification. Keyhole weld profile leads to parabolic-shaped distributions of alloying components and nonequilibrium β phase. Heat flow and solute elements are thermometallurgically accumulated in neck region, where maximum β phase and alloying element cluster are located. Asymmetrically, amount of Magnesium-rich β phase in the left portion of weld is the largest, dispersive β phase nearby weld center softening region is the lowest, where mechanical properties are worst, and diffusion-limited β phase in the right side is intermediate. There is significant discrepancy between left side, right side and center part of weld in solute redistribution and β/α eutectic phase transformation, which substantially contribute to obvious tensile properties fluctuation. Nucleation and growth of a few β phase particles in the dimple heterogeneously weaken weld integrity and are detrimental to weld strength and ductility. Weld specimens ductilely fracture in the center part, and plastically experience much deformation. Fracture surface morphologies show plenty of large and deep dimples after intense plastic deformation. Loss of strengthening elements and hydrogen-related porosity are attributed to evaporation-dependent weld pool instability. Additionally, the eutectic-driven microstructure analysis results are in consonance with mechanical behavior. The internal temperature development, molten pool duration, solid/liquid interface location, heat dissipation and weld quality should be appositely balanced by processing variables rearrangement.

Diffusion-limited Nonequilibrium Phase Transformation of Nickel/Aluminum Dissimilar Materials during Laser Welding Part I: Precipitation-strengthened Polycrystalline Nickel-based Superalloy

Polycrystalline heterogeneities of grain growth, phase transformation and tensile properties are discussed by metallography, spectroscopy and fractography when choosing laser welding with butt-joint configuration to satisfactorily minimize effect of inappropriate weld pool shape on microstructure and mechanical properties of γʹʹ precipitation hardable nickel-based superalloy in aerospace industry. There is parabolic relationship between weld penetration and diffusion-limited nucleation, growth and coarseness of secondary dendrite arm spacing alongside fusion boundary through nonequilibrium solidification process, which is dendritically susceptible to grain growth variation and metallurgical discontinuities. The amount, size, morphology and distribution of nonequilibrium intermetallic phase near the dendrite boundaries are kinetically and thermodynamically rely on weld pool shape whose crystal structure is incoherent with γ solid solution austenite phase and increases preference for crack initiation and propagation of brittle intergranular and ductile dimple fracture failures to enormously contribute to losses of strength and ductility. Unsymmetrical keyhole weld is thermometallurgically inconvenient for amelioration of microstructure and mechanical properties on either side, and adversely mitigates resistance to hypereutectic-aided dendrite embrittlement. Beneficial grain refinement and suppression of detrimental nonequilibrium intermetallic phase at the same time are challenging. This problem is an integral part of inhomogeneous microstructure and mechanical properties. The finer grain size occurs, the larger grain boundary area is available for Laves/γ eutectic-type reaction and vice versa. Contributions of coarse grain kinetics and metallurgical reaction thermodynamics to weld disintegration and fracture failure mechanism of tensile properties are explained by microstructure characterization of multicomponent and multiphase weld. Finally, it is imperative to dendritically balance these important factors to minimize inevitable interface solidification products and anomalous substructure growth, and reasonably advance superior mechanical properties of reliable weld.

Weldability of Nickel/Aluminum Dissimilar Materials Laser Welding Part I: Microstructure Development, Solidification Behavior and Mechanical Properties of Polycrystalline Nickel-based Superalloy

Weldability-related issues, including asymmetrical weld pool shape, γ phase multicomponent microstructure development, solidification behavior and mechanical properties, of γʹʹ precipitation-strengthened polycrystalline nickel-based superalloy are experimentally analyzed during keyhole laser welding repair. The crucial relationship between them provides weldability improvement opportunities and defect-free high quality weld for feasible aerospace materials laser processing. Attractive neck transition region of weld is more vulnerable to coarser dendrite than bottom part in the vicinity of fusion boundary, and this location is also liable to abundant Laves/γ eutectic phase formation because of heat and solute accumulation. The dominant chemical inhomogeneity brings about microstructure anomalies and irregular morphology to deteriorate hot cracking resistance. Because of thermometallurgical factors of selective alloying partition in the molten pool, partition-resistant Cr is chemically accumulated in dendrite core, while partition-susceptible Ti, Al, Mo and Nb are enriched in high-supersaturation interdendrite region, which consequently result in serious segregation and extensive Nb-rich intermetallic phase formation across solidification interface. Dendrite refinement and aggressive Laves/γ eutectic phase formation suppression are not simultaneously satisfied by low heat input under nonequilibrium solidification conditions. Therefore, mechanical properties are only partially improved by diffusion-limited microstructure refinement as result of phase instability. In other words, reductions of tensile strength and ductility are attributed to brittle Laves/γ eutectic phase formation during terminal stage of solidification. The severity of eutectic reaction thermodynamically depends on nail-shaped keyhole profile, solidification conditions and solute redistribution ahead of solid/liquid interface. Additionally, viable control of weld metallurgical and mechanical properties progressively encourages optimal combination of laser power and welding speed to interdendritically minimize disadvantages of eutectic phase formation by a variety of welding conditions optimization.

Effect of welding current on properties of activated gas tungsten arc super duplex stainless steel welds

Abstract A comparative evaluation of the influence of welding current on Tungsten Inert Gas (TIG) welding and Activated Tungsten Inert Gas (ATIG) welding on the depth of penetration and microstructure properties was performed. Various super duplex stainless steel (SDSS) beads on plate weld joints were studied. Visual observation showed that lower welding current resulted in partial weld penetration in the case of both TIG and ATIG weldments. Weld joints obtained by the ATIG process have a higher depth of penetration and depth/width ratios than weld joints obtained in the conventional TIG process at comparatively lower welding currents. Further, microstructural characterizations were performed using optical microscopy. The weld zone microstructure consists of grain boundary austenite (GBA), widmanstätten austenite (WA) and intragranular austenite (IGA). Ferrite percentage in bulk material and each weldment was measured using ferrite scope. The TIG-welded heat affected zone (HAZ) joints showed higher ferrite content than activated flux TIG-welded HAZ joints for various welding current conditions. Ferrite content measured in the weld-zone, HAZ and base material was within the ranges of the standard values. The TIG weld zone showed higher hardness than that of the ATIG weld zone.