Friction Welding Research Articles

Studying the STA effects on aluminium alloy joints by friction welding

This article examines the properties of joints fabricated by friction welding (FW) using AA6061-T6 and AA7075 as examples of both similar and dissimilar metals. It also looks at how heat treatment after welding affects the metallurgical characteristics of the joint. The heat treatment method under investigation combines solutionizing heat treatment with synthetic ageing (STA). The tensile characteristics, microhardness, and microstructure of the as-welded and STA-treated welded specimens are assessed in the paper using mechanical testing equipment and metallurgical characterization methods. The findings demonstrate that the joint characteristics are enhanced by precipitate nucleation occurring in the joint interface of the FW similar and dissimilar joint under STA treatment. On the other hand, the STA influence on the tensile strength (TS) of joints made with AA7075 was greater than that of similar joints made with AA6061-T6, as well as dissimilar joints made with both AA6061-T6 and AA7075. Additionally, after STA treatment, the similar joints showed a uniform distribution of hardness. However, in the dissimilar joint after STA treatment, the hardness dropped suddenly on the AA6061-T6 side, specifically from the partially deformed zone (PDZ) towards the heat affected zone (HAZ).

Fatigue fracture behavior of a Ti17 joint under various heat treatment specifications prepared by linear friction welding

A comprehensive study to investigate and characterize the fatigue fracture behavior of linear friction welded Ti17 joint and Ti17 joint under various post welding heat treatment (PWHT) specifications is critical to providing a foundation for the life design of a ‘blisk’ manufactured by linear friction welding. This study addressed this issue. High cycle fatigue tests were carried out. EBSD was employed to examine the microstructures in welding center zone (WCZ), thermal mechanical affected zone (TMAZ), heat affected zone (HAZ) and base metal (BM) across the Ti17 friction welded interface. The results show that the as welded Ti17 joint tends to fracture at WCZ &TMAZ during the fatigue service with a life of 45201, where a heterogeneous structure is formed as ‘refined equiaxed β grain - coarse β grain - basket-weave β grain with lamellar α partially dissolved - basket-weave β grain’ corresponding to ‘WCZ - TMAZ - HAZ - BM’. After aging at 550 °C, the Ti17 joint tends to fracture along the boundary between TMAZ and HAZ + BM with a life of 42338, where a heterogeneous structure is formed as ‘α′ colony with coarse ‘α laths’ - basket-weave β grain’ corresponding to ‘WCZ &TMAZ - HAZ & BM’. After aging at 630 °C, Ti17 joint tends to fracture at BM with a life of 75121, where a heterogeneous structure as ‘refined α′ laths with basket-weave characteristics - coarse basket-weave of α′ laths in β grains' corresponding to ‘WCZ &TMAZ -HAZ & BM’ region is formed.

The Impact of the Rotary Friction Welding Pressure on the Mechanical and Microstructural Characteristics of Friction Welds Made of the Alloys TiAl6V4 and 2024 Aluminum

The Impact of the Rotary Friction Welding Pressure on the Mechanical and Microstructural Characteristics of Friction Welds Made of the Alloys TiAl6V4 and 2024 Aluminum

Investigations into the Microstructure and Texture Evolution of Inertia-Friction-Welded Dissimilar Titanium Alloys

The welded joint of a dissimilar titanium alloy was obtained via inertial friction welding technology. The characteristics of the bonding interface and the microstructure of the welded joint were investigated via optical microscopy, scanning electron microscopy and electron backscattered diffraction. The results show that fine, equiaxed grains and interdiffusion bands of the elements Mo and Sn were formed in the weld zone under the high temperature and plastic deformation of the inertial friction welding. The weld zone and thermo-mechanically affected zone formed ⟨1¯21¯0⟩ α texture and ⟨111⟩ β texture, respectively.

Tensile joint strength characterizations for Cr-Ni-Mo steel (AISI 316) during direct drive friction welding process

Tensile joint strength characterizations for Cr-Ni-Mo steel (AISI 316) during direct drive friction welding process

Effects of Ambient Temperature on the Mechanical Properties of Frictionally Welded Components of Polycarbonate and Acrylonitrile Butadiene Styrene Dissimilar Polymer Rods.

Rotary friction welding (RFW) has no electric arc and the energy consumption during welding can be reduced as compared with conventional arc welding since it is a solid-phase welding process. The RFW is a sustainable manufacturing process because it provides low environmental pollution and energy consumption. However, few works focus on the reliability of dissimilar polymer rods fabricated via RFW. The reliability of the frictionally welded components is also related to the ambient temperatures. This work aims to investigate the effects of ambient temperature on the mechanical properties of frictionally welded components of polycarbonate (PC) and acrylonitrile butadiene styrene (ABS) dissimilar polymer rods. It was found that the heat-affected zone width increases with increasing rotational speeds due to peak welding temperature. The Shore A surface hardness of ABS/PC weld joint does not change with the increased rotational speeds. The Shore A surface hardness in the weld joint of RFW of the ABS/PC is about Shore A 70. The bending strength was increased by about 53% when the welded parts were placed at 60-70 °C compared with bending strength at room temperature. The remarkable finding is that the bending fracture position of the weldment occurs on the ABS side. It should be pointed out that the bending strength can be determined by the placed ambient temperature according to the proposed prediction equation. The impact energy was decreased by about 33% when the welded parts were placed at 65-70 °C compared with the impact energy at room temperature. The impact energy (y) can be determined by the placed ambient temperature according to the proposed prediction equation. The peak temperature in the weld interface can be predicted by the rotational speed based on the proposed equation.

Effects of rotational speed on the mechanical properties and performance of AA6061-T6 aluminium alloy in similar rotary friction welding

Similar rotary friction welding with AA6061-T6 rod material was carried out at four variations of rotational speed in order to study the effect of rotational speed on the joint properties. The increase in rotational speed produces higher hardness value in DRZ area, i.e. the lowest microhardness value in the DRZ area was 129 VHN at 380 rpm and increased to 192 VHN at 1700 rpm due to a grain refinement process that increased the hardness as the Hall–Petch equation. Otherwise, in the HAZ and TMAZ area, the microhardness profile has a decreasing trend due to the welding rotation increases. All welded joints have a lower strength than the base metal, about 68% for tensile and 83% for fatigue. The observations on the fracture surface of tensile and fatigue test showed that the fracture’s area occurs in the same region where the lowest microhardness and roughness grain sizes occur.

Effects of material combination for ultrasonic spot welding on microstructure and strength of Al/Al, Al/Cu, and Al/Ni dissimilar joints

The dissimilar joining of Al/Cu and Al/Ni is required to reduce the weight of electronic and electrical devices. Ultrasonic spot welding (USW) is expected to be applied to dissimilar materials because of the low heat input during the joining process. However, to obtain high strength via USW, the relationship among the welding parameters, joining strength, and microstructure for different material combinations must be investigated. In this study, Al/Al, Al/Cu, and Al/Ni are joined via USW by systematically varying the welding parameters; subsequently, their tensile shear load and microstructure are investigated. Results show that the vibration amplitude and welding time impose greater effects on the joint strength than the welding pressure for all material combinations. High-strength joints that fractured at the Al upper plate are obtained by optimizing the welding parameters for each material combination. Al/Ni bonding had a narrower margin of welding time to obtain a higher tensile shear load compared with other material combinations. This is due to the high heating rate and maximum temperature of Al/Ni joints, which cause the excessive deformation of the Al upper plate during prolonged welding. Texture analysis showed that recrystallized grains with GOSS orientation was remained in the high-strength dissimilar joints.

Performance Test of Weld Zone of Rotary Friction Welding of Titanium Alloy Drill Pipe

With the development of complex oil and gas reservoirs, it is difficult for traditional carbon steel to meet the requirements of drill pipe materials in drilling process. Titanium alloy has gradually become a new choice of drill pipe material because of its low density and good corrosion resistance. Titanium alloy has poor weldability and weld zone of titanium alloy drill string is easy to become initial defect and lead to drill pipe failure. Therefore, it is essential to evaluate the performance of titanium alloy drill pipe weld zone. In this paper, the weld zone of titanium alloy rotary friction welding is tested. Metallographic structure, hardness, tension and impact mechanical tests, fracture toughness evaluation and bending fatigue test are carried out. The test results show that the metallographic structure of weld zone changes under the influence of temperature, resulting in different mechanical properties of weld zone from that of pipe body zone. The yield strength and tensile strength in the weld zone are higher than those in the pipe zone, but the fracture toughness is lower than that in the pipe zone. The fatigue life of specimens in weld zone is more than 107 in drilling mud environment. In general, the mechanical properties of weld zone meet drilling requirements.

Multi-scale analyses of phase transformation mechanisms and hardness in linear friction welded Ti17(α + β)/Ti17(β) dissimilar titanium alloy joint

The Ti17(α + β)-Ti17(β) dual alloy-dual property blisk produced using Linear Friction Welding (LFW) is considered as high-performance component in advanced aeroengine. However, up to now, microstructure evolution and relationship between microstructure and micro mechanical properties of LFWed Ti17(α + β)/Ti17(β) dissimilar joint have not been thoroughly revealed. In this work, complex analyses of the phase transformation mechanisms of the joint are conducted, and phase transformations in individual zones are correlated to their microhardness and nanohardness. Results reveal that α dissolution occurs under high temperatures encountered during LFW, which reduces microhardness of the joint to that of Ti17(α + β) and Ti17(β). In Thermo-Mechanically Affected Zone of Ti17(α + β) (TMAZ-(α + β)) side joint, a large number of nanocrystalline α phases form with different orientations. This microstructure strengthens significantly by fine grains which balances partial softening effect of α dissolution, and increases nanohardness of α phase and microhardness of TMAZ-(α + β). Superlattice metastable β phase precipitates from metastable β in Weld Zone (WZ) during quick cooling following welding, because of short-range diffusion migration of solute atoms, especially β stabilizing elements Mo and Cr. The precipitation of the superlattice metastable β phase results in precipitation strengthening, which in turn increases nanohardness of metastable β and microhardness in WZ.

Structure and Protectiveness of Rust Layers Grown on Low-Alloyed Steels Under Cyclic Wet/Dry Corrosion Tests

Carbon steels are widely used in various infrastructures due to their superior mechanical properties in addition to low cost, but the mechanical properties can be deteriorated when steels are corroded. It is well-known that the weathering steels where small amounts of alloying elements such as Cu, Cr, Ni, Si and Mn are included form compact protective rust layers during the long-term exposure to atmospheric environment, resulting in superior corrosion resistance. However, as some of the alloying elements such as P that are effective to improve the atmospheric corrosion resistance of carbon steel cause segregation in the solidification process during welding, the amounts of such alloying elements have been strictly limited. The segregation of additive elements can be suppressed in stir friction welding, so-called FSW, in which metallic materials are joined in a solid state, leading to the assumption that the restrictions on the types and amounts of alloying elements can be reduced when FSW is applied instead of conventional welding. In the present work, the structure and corrosion resistance of rust layers formed on various low-alloyed steels designed for FWS are evaluated. Ingots of various low-alloyed steels including Al and P, both of which have been proved to be effective to improve the atmospheric corrosion resistance of carbon steel, were prepared using a high-frequency vacuum induction furnace. The ingots were hot-rolled at 1273 K into a plate with the thickness of approximately 2 mm and then cut into specimens with the dimension of 20 mm × 30 mm. All specimens were subjected to a laboratory cyclic corrosion test according to SAE J2334 which simulates a severe coastal atmosphere environment. In the SAE J2334 test, the specimens were kept for 6 h in a tightly sealed box where the temperature and relative humidity (R. H.) were controlled at 323 K and 100%, respectively (humid stage). Then the specimens were immersed in an aqueous solution containing 0.5 mass% NaCl, 0.1 mass% CaCl2 and 0.075 mass% NaHCO3 for 15 min. (immersion stage), followed by holding for 17h 45 min. in the sealed box at 333 K and 50%R. H. (dry stage). These three stages were repeated up to 30 cycles. After the cyclic corrosion test, rust layers on the specimens were characterized with X-ray diffraction and elemental distributions in the rust layers were evaluated with energy-dispersive spectroscopy. The corrosion current density was estimated from extrapolating Tafel slopes in polarization curves measured for the specimens subjected to the cyclic corrosion test. In XRD measurements for the specimens after 30 cycles of the cyclic corrosion test, peaks derived from α-FeOOH, β-FeOOH, γ-FeOOH and Fe3O4 were found. The fraction of the components in rust layers grown on the specimens was estimated, providing the fractions: 30-50% of α-FeOOH, 20-40% of β-FeOOH, 4% of γ-FeOOH and 30-50% of Fe3O4. Among the components, the fraction of α-FeOOH which is well-known as protective rust increased with increasing the addition of Al and P in specimen. Furthermore, it was found from EDS analysis on the cross-sections of the specimens that Al and P were distributed in the rust layers formed on the specimens in which Al and/or P were included. This indicates that Al and P can be related to the imcreased fraction of α-FeOOH in rust layers. The corrosion current density decreased with increasing the amounts of Al and P in the specimens, implying that Al and P improved the protectiveness of rust layers, that is, the increased corrosion resistance of low-alloyed steels. Similar trend was found in the corrosion rate estimated by the weight-loss method. These beneficial effects of Al and P are attributed to the increased fraction of protective α-FeOOH in rust layers.

Effect of Tensile Strength on Friction Welding of Tube-to-Tube Plate Processed Samples: A Mechanical and Metallurgical Approach

Effect of Tensile Strength on Friction Welding of Tube-to-Tube Plate Processed Samples: A Mechanical and Metallurgical Approach

Pengaruh Variasi Parameter Waktu Gesek Dan Jarak Penekanan Terhadap Kekuatan Impak Sambungan Hasil Friction Welding Pada Baja AISI 4140

Friction welding is a welding technique that uses heat generated by friction, and this concept works on the surfaces of two materials that are in contact, namely rotating while the other is stationary and applying a compressive force at the same speed to provide heat to melt one metal into another. This study aimed to determine the effect of friction time and pressure distance variations on impact strength in the friction welding process of AISI 4140 steel. A solid cylinder having Ø 20 mm. So, this research will be carried out using the experimental method; it is found that friction welding using 90 seconds and a pressure distance of 4 mm produces an average absorbed impact energy of 31.31 joules and an average impact price of 0.05692 joules/mm2 and for the lowest value, namely at 60 seconds and the pressure distance is 2 mm with the average value of the impact absorbed is 6.44 joules. The average impact price is 0.01168 Joule/mm2. Because the longer the friction time and the pressure distance, the results of the friction welding better.

Pengaruh Variasi Kecepatan Putar Dan Jarak Penekanan Terhadap Kekuatan Impak Pada Sambungan Baja AISI 4140 Dan AISI 4340 Dengan Metode Pengelasan Gesek (Friction Welding)

Welding is one of the means to achieve better economic production and has a role in the construction and metal fields. Friction welding is one of several types of welding methods. The parameters that affect the strength of the joints in friction welding are rotational speed, pressing distance and friction time. Therefore, to produce connection strength in a production, appropriate parameters are needed. This study aims to determine the effect of variations in rotational speed and pressing distance on impact strength in AISI 4140 and AISI 4340 steel joints. mm. In this study, the results obtained were that the higher the rpm rotation and the greater the pressure distance given, the melting area in the welding joint area is wide and evenly distributed which makes the weld joint strong. This is proven, using a rotational speed of 1400 rpm and a pressing distance of 4 mm has the highest impact energy yield value of 138.349 Joules and the highest impact price yield value of 1.7293 Joules/mm2 . Meanwhile, the lowest value of the impact energy yield is 14.266 Joules and the lowest value of the impact price is 0.1783 Joules/mm2 using a rotational speed of 720 rpm and a pressing distance of 2 mm.

Fenomena Las Gesek (Friction Welding) Dengan Variasi Waktu Gesek Pada Material AISI 1040 Dengan Kuningan

Friction welding is one of the metal joining methods, by utilizing the heat generated from the physical contact of two metals in the form of friction that occurs continuously on the two metals to produce a welding joint. This research aims to find out what phenomena occur in the connection between AISI 1040 and Brass. The materials used are AISI 1040 solid cylinder with a diameter of 16 mm and brass solid cylinder with a diameter of 16 mm. This research uses experimental method. The friction time used is 6 minutes, 7 minutes, and 8 minutes with a variation of pressing distance of 3 mm, 4 mm, 5 mm with a rotating speed of 1000 rpm. The free heat process of 200 ℃ was carried out on AISI 1040 before the welding process. From the time variation and pressing distance variation that has been carried out in this study, the results obtained from the two materials do not occur. There are several phenomena seen after the welding process such as the occurrence of plastic deformation in brass and the formation of a brass thermoplastic layer attached to the surface of AISI 1040, in the time variation of 6 minutes and 7 minutes the brass thermoplastic attached to AISI 1040 is small and thin, while in the time variation of 8 minutes the brass thermoplastic layer attached to AISI is quite a lot and thick but no connection has occurred. This friction welding method is likely to connect the AISI 1040 material with brass by increasing the friction time performed.

High-pressure linear friction welding of dissimilar AA5052-H34 and AA6061-T6 joint

Dissimilar linear friction welding (LFW) of AA5052/AA6061 was performed at different applied pressures. A dissimilar joint obtained at a high applied pressure of 200 MPa exhibited a tensile strength equivalent to that of the AA5052 base material, mainly because of the high density of low-angle grain boundaries (LAGB) per unit area at the weld regions. Meanwhile, the joints obtained at low applied pressures of 30 and 100 MPa softened at the weld regions because the LAGB density decreased because of the increased peak welding temperature. Therefore, the joints fractured in the weld regions, and the tensile strength of the joints decreased. Because dissimilar AA5052/AA6061 joints have metallurgical inhomogeneities and strength mismatches, plastic strain constraints near the weld interface of the soft material inevitably occur during tensile testing. Although the Vickers hardness at the weld interface on the AA5052 side had the lowest value, fracture was suppressed owing to the plastic strain constraint. At 100 and 200 MPa, the average grain diameters as a function of Z on the AA5052 side of the dissimilar AA5052/AA6061 joints matched the plot obtained from the similar AA5052 joint. At an applied pressure of 30 MPa, the average grain diameter was much larger than that of similar joints because the dissimilar joints underwent lower strain during LFW compared to similar joints, which resulted in the suppression of grain refinement during continuous dynamic recrystallization (CDRX).

Interfacial microstructure and mechanical properties of rotary inertia friction welded dissimilar 422 martensitic stainless steel to 4140 low alloy steel joints

In this work, dissimilar rotary inertia friction welds between 422 martensitic stainless steel and 4140 martensitic low-alloy steel were made to fabricate prototype heavy-duty diesel engine pistons. The influence of the inertia friction welding process and post weld heat treatment (PWHT) temperature on the interfacial microstructure evolutions and corresponding effects on mechanical properties of the 422/4140 welds were evaluated in detail. Carbon diffused from the 4140 side to the 422 side during PWHT at 650 °C for 1.5 h, causing the formation of a hard carbide-rich layer on the 422 side, and a softer but discontinuous C-depleted layer the 4140 side. PWHT at 700 °C for 1.5 h greatly accelerated C diffusion across the interface relative to 650 °C, resulting in a thicker hard carbide-rich layer and a relatively thick and continuous layer of coarse C-depleted grains (ferrite) on the 4140 side. In addition, the PWHT temperature greatly influenced the tensile properties and fracture behavior of the welds, with the 650 °C PWHT-ed samples failing predominately in a ductile manner in the 4140 heat affected zone during tensile testing. Conversely, the 700 °C PWHT specimens exhibited a strength reduction compared with the 650 °C PWHT specimens because of additional coarsening of the interfacial ferrite layer and softening of the base materials during PWHT, with brittle fracture between the hard and soft layers the predominate failure mechanism. Based on the findings, a reduced PWHT temperature and/or time, minimizing the hardness differential of the base metals, and pre-heating the 422 steel prior to welding are the potential pathways to achieve a more optimal balance between desirable tempering and stress relief of the weld microstructure and undesirable C migration across the weld interface, and to reduce the strength mismatch across the weld.

Evolution of Microstructure in MLX®19 Maraging Steel During Rotary Friction Welding and Finite Element Modeling of the Process

Abstract Inertia friction welding (IFW) is a solid-state welding process for joining engineering materials. In this paper, a 2.5D finite element (FE) model was developed to simulate IFW of MLX®19 maraging steel. The predicted results showed a non-uniform temperature distribution, with a decrease in temperature from the periphery to the center of the weld interface. Higher temperature and lower stress distributions were predicted in the weld zone (WZ) and the adjacent regions in the vicinity of the WZ. The von-Mises effective stress, effective strain, and strain-rate were investigated at different time-steps of the FE simulation. The effective stress was minimum at the weld interface, and the effective strain and strain-rate attained a quasi-steady-state status with the ongoing IFW after a threshold time (∼6.5 s). The simulated results were validated by comparing the predicted flash morphology with an actual IFW weld, and temperature profiles measured at specific locations using embedded thermocouples. The difference between the experimental and the simulated results was ∼4.7%, implying a good convergence of the model. Microstructural characterizations were performed across different regions, and the observed features were found to be in agreement with the expected microstructure based on the simulated thermal profiles, which included almost complete (∼90%) and partial transformation of martensite to austenite in the WZ and thermomechanically affected zone (TMAZ), respectively. Analyses of crystallographic texture showed that the material (i.e., both transformed austenite and martensite) underwent pure shear deformation during IFW.

Fatigue Behavior of Rotary Friction Welding of Acrylonitrile Butadiene Styrene and Polycarbonate Dissimilar Materials.

Understanding the fatigue behaviors of weld joints is significant in engineering practice. Rotary friction welding (RFW) can join the additively manufactured polymer components. Until now, no research has focused on the fatigue behavior of polymer components jointed via RFW. This study investigates the fatigue life of ABS/PC dissimilar components fabricated via RFW and proposes the fatigue mechanism based on the failure structure. This work uses five different cyclic loads and rotational speeds to investigate the fatigue life. The fatigue life of the RFW of ABS/PC dissimilar rods is better compared with the pure ABS and pure PC specimens due to weld and integrity microstructural changes resulting from the combination of ABS and PC materials. The number of cycles until the rupture of RFW of ABS/PC dissimilar components (y) can be determined by the cyclic load (x) according to the prediction equation of y = -838.25x2 - 2035.8x + 67,262. The fatigue life of the RFW of ABS/PC dissimilar components increase with the increased rotational speed. The number of cycles until rupture (y) can be determined by the different rotational speeds (x) according to the prediction equation of y = 315.21x2 + 2710.4x + 32,124.

Fatigue strength improvement of linear friction welded butt joints of low carbon steel by pressurizing after oscillation

Although linear friction welding (LFW) has received significant attention as an effective solid-state welding method, the fatigue properties of LFW joints have not been fully investigated. In this study, the fatigue strength of the steel joints fabricated using LFW was investigated and improved by increasing the pressure after oscillation. Low-carbon steel SM490A was successfully joined using LFW without unbonded areas or apparent softening in the heat-affected zone (HAZ). The microhardness, microstructure, weld toe shape, and fatigue life were assessed to investigate their relationships with the pressure conditions after oscillation. The results indicated that increasing the pressure after oscillation improved the area fraction of martensite (M) and the hardness of the weld interface center. The weld toe radius (ρ) and weld toe angle (α) also increased regardless of the upset control condition. The increasing of the pressure after oscillation from 50 MPa to 300 MPa increased ρ from 0.4 mm to 2.1 mm and the α increased from 92.7° to 103.4° at the weld center, accompanied by a reduced stress concentration factor (Kt) from 3.0 to 1.7. Under the fatigue test conditions of the stress range of 380 MPa, the fatigue life of the LFW as-welded joints was increased by approximately 31 % when the pressure after oscillation was 250 MPa compared to that of 50 MPa and by 87 % when it was 300 MPa compared to that of 250 MPa. Despite the possibility of fracture initiation at the weld toe at the edge of the LFW joints, the fatigue strength demonstrated a substantially longer fatigue life than the S-N design curve FAT90 recommended by the International Institute of Welding.