Tensile Shear Test Results Research Articles

Hot metal pressing joining of carbon fiber reinforced plastic to AZ31 Mg alloy and the effect of the oxide surface layer on joint strength

In this study, a new material joining process called hot metal pressing (HMP) was developed. The feasibility, nature and mechanisms of this process were investigated for joining carbon fiber reinforced plastic (CFRP) and an AZ31 Mg alloy. Two sets of joint specimens were prepared, one set with as-received Mg sheets, and the other with Mg alloy sheets that had been annealed for different duration times. It was observed that an oxide layer, introduced on the surface of the Mg alloy by the annealing, had a significant influence on the bonding strength of the joints. Tensile shear test results showed that a high strength joint of approximately 5.1kN could be achieved. Bubble formation and the decomposition of the CFRP near the joint interface was observed on the joints with the as-received Mg alloy sheets, but was not observed on the joints that had oxide layers on the Mg alloy sheets after annealing. Moreover, the oxide layer grew into the CFRP near the joint interface for joints with the annealed Mg alloy sheets, indicating the possibility of mechanical anchoring effects which greatly enhanced the joining strength.

Joint properties and microstructure of diffusion-bonded grade 2 titanium to AISI 430 ferritic stainless steel using pure Ni interlayer

Diffusion welding/bonding has been successfully used to joint dissimilar metals widely. In this study, pure Ti and AISI 430 ferritic stainless steel plates were joined through diffusion welding using a Ni interlayer at various temperatures (800, 825, 850 and 875 °C), holding times (15, 30, 60 and 120 min) and under a constant pressure (3 MPa) under argon shielding media. The welded joints were subjected to tensile-shear tests and hardness tests in order to determine their interfacial strength. In addition, microstructural properties of the joined interface were examined using optical and scanning electron microscope (SEM). The tensile-shear test results showed that the fractures occurred mostly in the interface of the Ni-ferritic stainless steel web at lower temperatures. It was seen from the hardness results that the highest hardness value was obtained for the titanium side and the hardness values increased with increasing welding temperature and holding time. SEM/EDS examinations showed that the diffused atoms and diffusion distance increased depending on the increasing temperature and holding time.

Weldability window and the effect of interface morphology on the properties of Al/Cu/Al laminated composites fabricated by explosive welding

Abstract Explosive welding is one of the joining techniques which employs high energies derived from explosives to join materials with similar and dissimilar properties. In this paper, the weldability criteria which should be met to achieve good welds were calculated for aluminum–copper joints. Different morphologies for welding interface (straight, wavy and melted layer) were obtained with changing welding parameters. Results on the microstructure, micro-hardness and tensile-shear tests were reported. Tensile-shear test results indicate that shear bond strength increases with increasing explosive ratio. However, shear bond strength decreases when the explosive ratio exceeds R = 2.2 due to the formation of brittle intermetallics at the interface. This knowledge may be utilized for establishment of a relation between microstructure and properties in the process of manufacturing.

RETRACTED ARTICLE: An investigation on mechanical and metallurgical properties of 2024-T3 aluminum alloy spot friction welds

In this study, the spot friction welding of 2024-T3 aluminum alloy with 1.6 mm in thickness has been investigated. The effects of the tool rotational speed (630, 1000, and 1600 rpm), shoulder penetration depth (0.3 and 0.7 mm), and pin geometry (cylindrical and triangular shape) have been discussed on the metallurgical and mechanical properties. Results indicated that the pin geometry has a considerable effect on the shape of the stir zone. The results of tensile shear tests showed that the tensile shear load increased with increasing rotational speed in the shoulder penetration depth of 0.3 mm, while high shoulder penetration depth had a bilateral effect on the tensile shear load. In addition, the results showed that the tensile shear load of welds made with the triangular pin at a low rotational speed, and a low shoulder penetration depth was more than of welds made with the cylindrical one, which was attributed to a finer grain size generated in the stir zone. Observation of the failed specimens indicated two types of failure modes under tensile shear loading conditions including the fractures that occurred in the vicinity of keyhole (shear fracture) and the fractures that occurred in shoulder indentation (tensile shear-mixed fracture mode). The microhardness tests with both pins showed that the minimum hardness was measured in the heat-affected zone.

Effects of Process Parameters on Tensile Shear Strength of Friction Stir Spot Welded Aluminium Alloy (EN AW 5005)

Abstract Aluminium and its alloys have been used in automotive technology since the first model of the car. The need for aluminium material is getting increased for weight reduction, improved fuel economy and vehicle performance. The amount of the aluminium used in a car is mainly related with joining processes of aluminium alloy. This can be achieved by developing the welding techniques for aluminium alloys. The purpose of this study was to determine the effects of friction stir spot welding parameters on tensile shear strength of friction stir spot welded lap joint EN AW 5005 Aluminium alloy. The variable parameters were tool rotation (rpm), dwell time (s) and the tool pin height (mm). Tensile shear test results indicated that the weld performance was significantly affected by the tool rotation, dwell time and the tool pin height. The results of the study indicates that there are optimum process parameters which give the highest tensile shear strength.

Mechanical property and joining characteristics of laser direct joining of CFRP to polyethylene terephthalate

This study was performed to investigate the joining possibility and characteristics of the dissimilar joint between carbon fiber reinforced plastics (CFRP) and amorphous polyethylene terephthalate (PET) plastic using a continuous wave (cw) diode laser with a line-shaped beam. Tensile shear test results demonstrated that strong lap joints with a maximum load of 3200 N could be produced under some proper conditions, and base amorphous PET plastic sheet was elongated without fracture. It was confirmed from SEM observation that the dissimilar lap joint was tightly bonded near the joint interface between two materials, and simultaneously integrated by the interdiffusion and mixing process at the joint interface of two materials through rapid melting, solidification and cooling during laser joining. Through high speed video camera observation, the joining phenomena generating in the laser irradiated part during laser joining of CFRP to PET was obviously identified. Consequently, it was revealed that strong dissimilar lap joint of CFRP to engineering plastic could be possible by a direct laser irradiation without adhesive bonds or mechanical fasteners.

Applicability of adhesive–embossing hybrid joining process to glass-fiber-reinforced plastic and metallic thin sheets

Adhesive–embossing hybrid joining process was applied to A2017P and three types of glass-fiber-reinforced plastic (GFRP) thin sheets. Optical microscopy shows that a sound A2017P–thermosetting GFRP hybrid joint without crack/delamination in the composite or adhesive failure can be produced by optimizing adhesive thickness, embossing stroke and embossing temperature. The results of tensile shear test indicate that the optimally hybrid-bonded A2017P–GFRP joint exhibits improved load carrying capability, slip displacement and better energy absorbing characteristics than the adhesively bonded joint when subjected to tensile loading. This investigation shows that the adhesive–embossing hybrid joining process is a competitive alternative joining method for the fabrication of ultra lightweight thermosetting GFRP-metal hybrid structures and has great potential for wider applications, which is attributed to its benefits in terms of joining properties, operation simplicity, weight-cost effectiveness and recyclability.

Laser direct joining of carbon fiber reinforced plastic to aluminum alloy

Laser direct joining of carbon fiber reinforced plastic (CFRP) to aluminum alloy was performed using a high quality continuous wave diode laser with a line-shaped beam. The tensile shear test results demonstrated that a strong lap joint with about 3000 N could be produced between CFRP (of 3 mm thickness and 20 mm width) and aluminum alloy (of 2 mm thickness and 30 mm width). The joints fractured along the joint interface or in the melted zone of CFRP. It was observed from the cross sections of the joints that many bubbles of submillimeter size were irregularly formed in the wide and shallow melted zone of the CFRP. Moreover, melted polyamide plastic was tightly bonded on atomic or molecular sized level through nanometer thick aluminum oxide film (κ-Al2O3) existing on aluminum alloy surface, suggesting high possibility of chemical or physical bonding between CFRP and metal. Consequently, it was confirmed that a strong lap joint of CFRP to aluminum alloy could be produced by direct irradiation of a laser beam.

Cu-Sn 삽입금속을 이용한 DP강의 아크 브레이징 접합부의 미세조직과 인장특성

The following results were obtained, microstructures and tensile properties in arc brazed joints of DP(dual phase) steel using Cu-5.3wt%Sn insert metal was investigated as function of brazing current. 1) The Fusion Zone was composed of <TEX>${\alpha}Fe+{\gamma}Cu$</TEX> and Cu23Sn2. The reason for the formation of these solid solutions. Despite, Fe & Cu were impossible to solid solution at room temperature. It's melting & reaction to something of insert metal & Base Metal (DP Steel) by Arc. Brazing Process has faster cooling rate then Cast Process, Supersaturated solid solution at room temperature. 2) The increase Hardness of Fusion Zone was directly proportional to the rise of welding current. Because, <TEX>${\alpha}Fe+{\gamma}Cu$</TEX> phase (higher hardness than the Cu23Sn2.(104.1Hv < 271.9Hv)) Volume fraction was Growth, due to increasing the amount of base metal melting by High current. 3) The results of tensile shear test by Brazing, All specimens happen to fracture in Fusion Zone. On the other hand, when Brazing Current increasing tend to rise tensile load. but it was very small, about 26-30% of the base metal. 4) The result of fracture analysis, The crack initiate at Triple Point for meet to Upper B.M/Under B.M/Fusion Zone. This Crack propagated to Fusion zone. So ruptured by tensile strength. The Reason to in the fusion zone fracture, Fusion zone by Brazing of hardness (strength) was very lower then the base metal (DP steel). In addition the Fusion Zone's thickness in triple point was thin than the base metal's thickness in triple point.

Influence of Pin Profile on Quality of Friction Stir Lap Welds in Carbon Fiber Reinforced Polypropylene Composite

In recent years, interest on friction stir welding has grown more since such a joining technique allows welding of light weight alloys like aluminum and its alloys which are difficult to weld or even unweldable with the traditional fusion welding processes. This process can also be one of the joining processes considered for welding polymer matrix composites such as polypropylene composites which find a number of applications in different industries. This paper presents the effect of tool pin profile on surface appearance and tensile shear strength of friction stir lap welds in carbon fiber reinforced poly- propylene composites with 4 mm thickness. Four high speed steel tools with different pinprofiles of threaded cylindrical, threaded cylindrical-conical, simple cylindrical-conical and threaded conical were employed for this study. Using these tools, lap welds were made under similar conditions of tool rotational speed, welding speed and tilt angle. Specimens were prepared for tensile shear testing. The tensile shear test results showed that the threaded cylindrical-conical tool produced a weld with better surface appearance and higher tensile shear strength.

Dissimilar Metal Joining of Steel to Aluminum Using the Arc Heat Source

Car manufactures have been asked to avoid the unnecessary waste of energy and reduce pollution. Replacing steel with lightweight materials on car bodies is considered as one method to reduce the vehicle weight to achieve these requirements. Therefore, in this study, we selected a modified metal inert gas welding-brazing process to join aluminum to zinc coated steel on the lap geometry. The main purpose of this research was to reveal the relationship between weldability and various process parameters such as Zn coated thickness, kind of coated treatment type, filler wire type and welding condition. Metallurgical observations and mechanical testes were carried out to evaluate the weld quality. Based on these results, we could find that the weldability of dissimilar materials were depend on sufficient and regular wetting by heat input and gap condition. The tensile-shear test results, all the fracture occurred in the HAZ of aluminum and the strength was up to 70% of base metal of aluminum. However zinc coated thickness in the range of 10㎛ to 30㎛ was no related with welded strength. Also we could find that silicon content of filler wire is very important to minimize the thickness of intermetallic compound layer. Silicon might be disturbed to the growth intermetallic compounds.

순티타늄판의 Nd:YAG 레이저 용접성에 관한 연구(IV) - 겹치기 용접 및 실물 열교환기로의 적용 -

With large specific strength and outstanding corrosion resistance and erosion resistance in sea water, titanium and titanium alloy are widely used in heat exchanger production. In particular, pure titanium demonstrates outstanding molding performance and may be considered optimal for production of heat exchanger. Since titanium is very vulnerable to oxidation and embrittlement during welding, processes with less heat input are widely used, and laser welding is widely applied by considering production performance and shield etc in atmosphere. So far, 1st report and 2nd report compared and analyzed embrittlement degrees by bead colors of weldment through oxygen and nitrogen quantitative analysis and hardness measurement, and evaluated welding performance and mechanical properties of butt welding. This study evaluated field applicability of lap welding to heat exchange plate of LPG re-liquefaction device for ships through tensile stress test, hardness test and internal pressure test etc after deducing optimal weding condition and applying to actual heat exchange plate. In bead overlap area, the experiment produced sound welds with no porosity or defect by increasing and decreasing laser power, and tensile-shear test results indicated virtually the same tension and yield strength as base metal. As a result of measuring hardness at lateral cross section and bead overlap zone of actual heat exchanger welds, hardness difference within 20Hv was produced at base metal, HAZ and weldment, and as a result of pneumatic and hydraulic pressure test, no leakage occurred.

Weldability and mechanical properties of dissimilar aluminum–copper lap joints made by friction stir welding

Lap joints of 1060 aluminum alloy and commercially pure copper was produced by friction stir welding and the effect of welding speed on interface morphology, microstructure, and joint strength was investigated. The experimental results revealed that in the aluminum close to the Al/Cu interface, a dark area was formed. In this area the intermetallic compounds of Al 4 Cu 9 and Al 2 Cu, and some microcracks were detected. The frequency of such microcracks decreased with increasing welding speed. On the other hand, at higher welding speeds of 118 and 190 mm/min, the cavity defects were formed inside the joints as a result of insufficient heat input. The results of tensile shear test revealed that the maximum tensile shear strength of joint was obtained at welding speed of 95 mm/min. At this welding speed, no cavity defects, and few microcracks were observed in the weld.

Comparison of mechanical properties and microstructure of weld nugget between weld-bonded and spot-welded dual-phase steel

Weld bonding, which is a combination of resistance spot welding and adhesive bonding, is finding application in vehicle structures that involve advanced high-strength steels. The strength of weld-bonded specimens is attributed to the strength of the weld nugget and adhesive strength. The existence of an insulating epoxy adhesive layer causes a rise in contact resistance and current density during the welding stage, and thus enhances the heat input. The aim of the present study is to explore the mechanical properties and microstructure of the weld nugget in weld-bonded dual-phase steel by means of comparison with a spot-welded nugget. Tensile-shear tests, weld lobe determination, microstructural characterization, and microhardness tests of weld-bonded and spot-welded specimens were conducted. The results of tensile-shear tests show that the weld nuggets of weld-bonded specimens have a higher tensile-shear force and energy absorption, and exhibit button-pullout fracture more easily at lower welding current. The weld lobe of weld-bonded dual-phase steel is too narrow. The results of microstructural characterization and microhardness tests indicate that, compared with resistance spot welding specimens, weld-bonded specimens have a larger nugget size at lower current; finer martensite and lower hardness in the heat-affected zone; and slightly more ferrite and lower hardness in the fusion zone. The comparative results are useful for optimizing the processing parameters and improving the weld quality of weld bonding.

Effect of Surface Roughness on the Adhesive Strength of the Heat-Resistant Adhesive RTV88

Heat-resistant adhesive RTV88 is a hyper-elastic material and so far there have been little research on using RTV88 in adhesive joints. In this study, the effect of surface roughness on the adhesive strength of RTV88 was examined. Aluminum adherends were first sandblasted in order to generate rough surfaces, and then tensile–shear tests on Al/RTV88 single lap joints were performed. The shear strength was shown to be influenced by surface roughness. Peel failure was dominant when the surface roughness was at a low level. However, cohesive failure was the major type of failure when the surface roughness was at a high level. Effective area, peel failure area, and cohesive failure area were introduced to explain the effects of surface roughness on the adhesive strength. An empirical relation for the failure force was proposed, based on these parameters. Tensile tests of the RTV88 bonding was performed in order to obtain the necessary data. Finally, the empirical relation for the failure force was verified by tensile–shear test results.

レーザロール溶接法による低炭素鋼と純チタンの接合

Recently, the demands of dissimilar metal joint have been increasing in industry, especially in automobile industry. Therefore, research and development of dissimilar metal joining is accelerated. The Laser Roll Welding has been developed by M. Kutsuna and M. Rathod. Joining of dissimilar metals, such as Fe-Al and Fe-Cu has been studied. And titanium has superior corrosion resistance; it is used for the clad plate for splash zone of bridge pier, the sea-water plant, the condenser of a nuclear power plant and so on. It is well known that fusion welding of steel and titanium is difficult due to the brittle intermetallic compound formation. In the present work, the effect of process parameters on the formation of intermetallic compound at the interlayer was investigated to get a sound joint. The mechanical properties and microstructures of welded joint were also studied. The results of tensile shear test showed that the strength of joint increased with the decrease in interlayer thickness. When the interlayer thickness was less than 25 μm, tensile shear test specimens were failed in base metal of low carbon steel.

The influence of some factors on steel/steel bonding quality on there characteristics of explosive welding joints

Explosive welding is a solid state process in which controlled explosive detonations force two or more metals together at high pressures. The resultant arrangement is joined with a high quality metallurgical bond. The aim of this study was to investigate of strength of explosive welding metals which had same chemical compositions. In this study, it was taken different welding interfaces (straight, wavy and continuous solidified-melted) with changing explosive welding parameters (stand-off distance (s), explosive loading (R) and anvils). Joined metals were investigated in heat treatment and non heat treatment conditions. Microstructures, microhardness, tensile shear strength and bending test results were reported. Effect of anvil on explosive welding process was evaluated in joining/no joining performance. It was shown that bonding interface changed from straight to wavy structure when explosive loading and stand-off distance were increased. On wavy interface, when explosive loading was increased wavy length and amplitude increased. Results of tensile shear and bending tests showed that heat treated specimens have more strength than which of unheat-treated ones. According to tensile shear test results, straight and wavy interfaces had similar strength. Also, bending zone has shown some cracks after the bending test of unheated specimens.

An investigation on the explosive cladding of 316L stainless steel-din-P355GH steel

In this study, 316L stainless steel and DIN-P355GH grade vessel steel were cladded by explosive welding technique. Microstructure, hardness and tensile shear strength, and fracture toughness of the cladded metals were evaluated. The bond interface of the cladded metals shows a wavy morphology. The hardness was increased in the parent and flyer plate near the bond interface while a general decrease was observed in both parent and flyer plate away from welded interface. Tensile shear test results showed that the bonding is acceptable. The impact toughness of the cladded metals at a given test temperature is found significantly higher than that of parent plate alone because of the high impact toughness of 316L austenitic stainless steel layer. Consequently, mechanical properties of the low-carbon steels can be increased by explosive cladding with austenitic stainless steel.

An investigation on the explosive cladding of 316L stainless steel-din-P355GH steel

In this study, 316L stainless steel and DIN-P355GH grade vessel steel were cladded by explosive welding technique. Microstructure, hardness and tensile shear strength, and fracture toughness of the cladded metals were evaluated. The bond interface of the cladded metals shows a wavy morphology. The hardness was increased in the parent and flyer plate near the bond interface while a general decrease was observed in both parent and flyer plate away from welded interface. Tensile shear test results showed that the bonding is acceptable. The impact toughness of the cladded metals at a given test temperature is found significantly higher than that of parent plate alone because of the high impact toughness of 316L austenitic stainless steel layer. Consequently, mechanical properties of the low-carbon steels can be increased by explosive cladding with austenitic stainless steel.

Investigation of explosive welding parameters and their effects on microhardness and shear strength

The aim of this study was to investigate the strength of explosive welded metals with the same chemical compositions. Different welding interfaces (straight, wavy and continuous solidified-melted) were used with changing explosive welding parameters [stand-off distance (s), explosive loading (R) and anvils]. Joined metals were investigated under heat-treated and untreated conditions. Results on the microstructure, microhardness, tensile shear strength and bending tests are reported. According to the experimental results, the effect of the anvil on the explosive welding process was only the joining or not-joining performance. It was shown that the bonding interface changed from a straight to a wavy structure when the explosive loading and stand-off distance were increased. For wavy interfaces, when the explosive loading was increased the wavy length and amplitude increased. Results of tensile shear and bending tests showed that heat-treated specimens have more strength than untreated samples. According to tensile shear test results, straight and wavy interfaces had similar strength. In addition, in bending tests of untreated specimens it was shown that the bending zone had some cracks.