As the springback of sheet metal during unloading may cause deviation from a desired shape, accurately predicting is essential for design stamping operations. Finite-element models have not been successful in springback; hence there need analytical to make such predictions. In this study, model based on differential strains after relief maximum bending stress derived six different deformation patterns order predict analytically. The each pattern estimated by residual between outer and inner...

Abstract The primary purpose of this investigation was to study welding residual stress relaxation by repeated loading. A coupling finite element analysis model for prediction the and mechanical after external loads presented. accuracy verified through experiments. Also, it is found that weldment relaxed loads, greatest amount obtained early loads. As repetition count increased, became smaller than in stage.

The primary purpose of this investigation was to study the characteristics armor steel weldment combat vehicles by using GMAW narrow gap welding (NGW). results showed that mechanical properties and residual stress distribution NGW were improved, compared with conventional X-groove weldment. Additionally, ballistic tests according MIL-HDBK-1941 carried out verify ability result process qualified for vehicle.

Weld pores redistribution, the effectiveness of using tungsten inert gas (TIG) dressing to remove weld pores, and changes in mechanical properties due TIG Ti-3Al-2.5V weldments were studied. Moreover, cracks investigated. The results show that less than 300 μm size are redistributed or removed via remelting dressing. Regardless temperature condition, welding showed ductility, there was a loss 7% tensile strength weldments. Additionally, it considered porosity redistribution by fluid flow...

Ti-alloys have high specific strength and are widely used for the filed of space aeronautics plant. However, it is difficult to process Ti-Alloys due its yield cannot raise machining speed because has a possibility catching fire while processing. In order reduce number processes Ti-alloys, researches related Additive Manufacturing(AM) been actively carried out at moment. As initial stage AM market started use raw material powder metal, currently being developed based on welding.In this...

GMAW and GTAW processes have been used for welding of equipment mounting pads during decades. For improving the mobility survivability KWV(Korean Wheeled Vehicle), various types are required numbers were increased. In this research, productivity process, new technology stud was studied. study, mechanical properties weldment investigated to compare with those weldment. Also, research durability carried out proved its fatigue strength under condition KWV's 32,000 km load profile.

Wire arc additive manufacturing (WAAM) is being considered as a technology to replace the conventional process of titanium alloys. However, coarse β grains, which can extend through several deposited materials, result in strong textures and anisotropy. As solution, we study plastic deformation effects ultrasonic needle peening (UNP) on microstructure. UNP treated materials deform plastically dislocation density increases. Fine α+α' grains with low aspect ratio are observed specimens. WAAM...

A quantitative failure criterion was developed for aluminium (Al) tubes. The is based on the critical damage value as calculated from Cockroft and Latham ductile can be used to determine forming limit during warm hydroforming or a crash. As-extruded, fully annealed, T6-tempered Al 6061 tubes were tested evaluate effect of heat treatment conditions temperature. To assess formability tubes, uniaxial tensile tests hydraulic bulge performed in temperature range 25—300°C. measured flow strength...

Tandem GMAW is one of the high performance welding process and used in many industries to increase productivity. An evaluation presented mechanical properties microstructural characteristics conventional Single welds 30mm thickness 490MPa grade steel by comparison method. Welding sequence bead with hight was kept, avoiding effect shape sequence. Tension, bending, hardness Charpy impact test results met requirement specification showed similar distribution GMAW. Volume fraction ferrite phase...

Double layered tube is assembled with an inner and outer tube, similar in material or not, contacting closely deforming simultaneously when subjected to external force. For the manufacturing of double hydroforming assembly technology has several advantages. Therefore this study, characteristics was investigated. The free bulge test performed produce formability diagrams tubes at various forming pressure feeding amounts. hexagonal shape also estimate dimensional accuracies through corner...

Hydroformability and fracture criteria of FE analysis based on ductile were investigated in warm hydroforming A16061 tube. To evaluate the hydroformability, uni-axial tensile test bulge performed at room temperature <TEX>$200^{\circ}C$</TEX>. The measured flow stresses used as input parameters for analysis. damage values calculated by maximum radius free bulged tubes. Damage compared hexagonal shaped hydroformed parts. As a result, formability critical value extruded tube is lower than that...

Hydroformed parts have higher dimensional accuracy, structural strength, and repeatability. Particularly in the automotive industry, manufacturing of with complex shapes from tubular materials sometimes requires one or more pre-forming operations such as bending before hydroforming process. The pre-bending process is an important for successful case where perimeter blank nearly same that final product. bendability a tube depends on parameters radius, welding methods, mechanical properties...

Strain hardening behavior during hydroforming has been experimentally investigated. The variation of flow stress was used as an index strain respective processes and the estimated from correlationship between effective strain. local hardness after hydroformig also predicted by By using inter-relationships hardness-flow stress-effective at variable pre-strains, successfully analyzed. comparison with measured confirmed that methodology in this study feasible can be quantitatively estimated.