Friction Welding Machine Research Articles

５０５２／２０１７アルミニウム合金異材摩擦肉盛材の機械的性質

5052 aluminum alloy plate used for substrate and 2017 aluminum alloy bar used for consumable rod, both monolayer and multilayer friction surfacing were done using a numerical controlled full automatic friction welding machine. Effects of the surfacing conditions on structure and mechanical properties of both monolayer and multilayer deposits were investigated. It was clearly observed that the circular pattern appeared on the surface of both monolayer and multilayer deposits by the rotation of consumable rod, and the interval of circularly pattern become narrower with increasing of the rotation of consumable rod. The monolayer deposit has a tendency to incline toward right side (Retreating side) further than center of deposit for the traverse direction of consumable rod. And, the 2nd surfacing of multilayer deposit recognized to incline toward the 1st deposit side. A little of incomplete welds was observed at both sides of monolayer deposit. The incomplete parts of welds 1st deposit in multilayer deposit was disappeared by 2nd surfacing. Microstructures of both monolayer and multilayer deposits were finer than those of the substrate and consumable rod. The surfacing efficiency of 2nd surfacing in multilayer deposit showed higher value than that of the monolayer deposit. Hardness of both deposits showed higher value than that of the substrate and same value of consumable rod. The softened area was recognized at 2.5 mm distance from the weld interface of substrate and consumable rod. The tensile strength of multilayer deposit showed higher value than that of the monolayer deposit, and both deposits showed higher value than that of the substrate.

円管摩擦圧接の摩擦トルクに及ぼす円管内径の影響

The present paper describes the effects of inner diameter on friction torque during friction stage of friction welding with mild carbon steel pipes whose outer diameter is 16 mm. The experimental conditions included inner diameter (i.e., pipe thickness) and friction speed. A conventional friction welding machine was used to join all specimens. The following conclusions are given. (1) When various pipes with different inner diameters were welded under same friction welding conditions, the friction torque curves for each pipe is different in the first phase of the friction stage, particularly in the wear stage. That is, the initial torque and elapsed time for initial torque decreased with increasing inner pipe diameter. (2) The initial torque and elapsed time for initial torque decreased with increasing inner pipe diameter when the joints of solid bars to pipes were welded under the same friction welding conditions. (3) When pipes of the same inner diameter were welded: a) the friction torque in the first phase of the friction stage varied due to sparks flashing from the welded interface, and b) the initial torque and elapsed time for initial torque increased with decreasing friction speed. (4) The result in (3) indicates that the seizure temperature at low relative speeds at the welded interface was lower than that at high relative speed.

443 位相制御摩擦圧接によった6063アルミニウム合金継手の機械的性質(OS 溶接・接合(3))

The mechanical properties of phase controlled friction welded joints of both 6063 aluminum alloys square bar and grooved square bar, which were friction welded by using a numerical controlled brake type friction welding machine, were examined. The phase controlled friction welding was using a servo motor positioning with hydraulic brake system. The burr was not generation from comer, and the burr occurred from the side. The burr of rotational side deviated to reverse side of the rotational direction, and the burr of fixed side inclined towards rotational side. The tensile strength of both square bar joint and center of grooved bar joint showed about 80% that of base metal, but the tensile strength of corner of grooved bar joint showed about 67% that of base metal. The elongation of joints was increased with increasing of friction time, but the elongation of all joints were lower than that of the base metal.

Impact performance of friction welded butt joints between 6061-T6 aluminium alloy and type 304 stainless steel

The tensile strength and energy absorption for dissimilar metal friction welds between 6061-T6 Al alloy and type 304 stainless steel at high rates of loading were determined using the split Hopkinson bar. Cylindrical tensile specimens machined from as welded butt joints of 13 mm in diameter were used in both static and impact tests. Friction welding was conducted using a brake type friction welding machine under two different welding conditions. The effects of welding conditions and loading rate on the joint tensile properties were examined. Results show that the joint tensile properties were greatly affected by the welding parameters, and were slightly enhanced with increased loading rate. Scanning electron microscope observations revealed that the tensile fracture modes in the butt joint specimens varied with loading rate and depend on welding conditions. Microhardness profiles across the weld interface were measured to investigate the extent of the heat affected zone. The slight enhancement of the joint tensile properties with increasing loading rate is primarily attributed to the strain rate dependence of the thermally softened 6061-T6 Al alloy base material.

Observation of Joining Phenomena in Friction Stage and Improving Friction Welding Method

This report describes the observation result of joining phenomena in the friction stage, and an improvement of the conventional friction welding method with similar materials. The materials used were carbon steels and a brake type (direct drive) friction welding machine was used for joining. As the improving friction welding method, relative speed was instantaneously rendered to zero at the end of each friction time. The wear of both surfaces started at periphery portion (outer surface) of the joint and moved to center portion (center axis). Seizure and joining began at center portion and then extended toward periphery portion. The friction torque reached to initial peak torque when the welded interface was joined completely and upsetting of both base metals started. It was determined that friction welded joints with 100% joint efficiency and good bend ductility could be obtained by using only the friction stage up to initial peak torque and without the need for the forging (upsetting) stage. As a conclusion, friction welded joints made without using the forging stage has the same mechanical properties as those welded by the conventional friction welding process including that stage. The friction welding method without forging stage has the advantages of less burn-off (axial shortening) and less burr.

Mechanical Properties of Friction Surfaced 5052 Aluminum Alloy

5052 aluminum alloy used for substrate and consumable rod, was friction surfaced using a numerical controlled full automatic friction welding machine. Effects of the surfacing conditions on some characteristics of deposits were investigated. It was clearly observed that the circularly pattern appeared on the surface of deposit by the rotation of consumable rod. The deposit has a tendency to incline toward the advancing side further than center of deposit for the feed direction of consumable rod. This deviation accompanied the decrease of the rotational speed of consumable rod. The width of deposit increased with increasing friction pressure, and decreasing rotational speed of consumable rod. The thickness of deposit became thinner when the consumable rod was high revolution. The surfacing efficiency decreased with increasing friction pressure and rotational speed of consumable rod, but increased with increasing feed speed. Microstructure of the deposit was finer than that of the substrate and consumable rod. The softened area was recognized at 3 mm distance from the weld interface of substrate. The tensile strength of deposit increased with increasing friction pressure. The maximum tensile strength of deposits showed 88.8% of the base metal of substrate.

異種材摩擦圧接における接合現象と母材降伏強度との関連

The present paper describes the relationship between joining phenomena, i.e. the friction stage and the yield strength of substrates of dissimilar friction welding. The materials used were oxygen free copper (OFC), commercially pure titanium (P-Ti), commercially pure aluminum (A1050) and type 7075 aluminum alloy (A7075). The combinations of P-Ti/OFC, A1050/OFC and A7075/OFC were joined by using a conventional friction welding machine. The same friction welding condition was used for all combinations. Main conclusions are obtained as follows. (1) The friction process, i.e. joining behavior, friction torque curve and welded interface behavior was observed different for each joint. The welded interface of P-Ti/OFC joint sparked, and intensively flew from P-Ti substrate. The upsetting (deformation) occurred at only P-Ti side during the friction stage after initial peak torque. The upsetting also occurred at only A1050 and A7075 substrates for A1050/OFC and A7075/OFC joints, respectively. (2) The temperature of each joint during friction welding process was measured at centerline, half radius (1/2R) and periphery portions. The maximum temperature of P-Ti/OFC joint was much higher than those of both A1050/OFC and A7075/OFC joints. The maximum temperature of A1050/OFC joint was almost same as that of A7075/OFC joint after initial torque. (3) In P-Ti/OFC joint, wear and adhesion of surfaces started at periphery portion (outer surface) of OFC substrate, and they extended toward center portion (center axis). Then, the P-Ti substrate adhered to OFC substrates after the weld faying surface of P-Ti substrate became the wear state. In A1050/OFC joint, the wear and the adhesion started at whole surface of A1050 substrate. In A7075/OFC joint, wear and adhesion started at periphery portion of both A7075 and OFC substrates, and they extended toward center portion. (4) It is considered that the joining behavior, friction torque and welding temperature were affected by the relationship between the loaded friction pressure and the yield strength of substrates.

炭素鋼の位相制御摩擦圧接に関する研究

It is difficult to match joint phases at the particular position of a rotation side a fixed side using a conventional friction welding machine, because the rotating spindle does not control the exact stop position. A development of positioning controlled friction welding meets to be solved such difficulties as stop at the specified position during duration of braking. This positioning control friction welding was achieved by installing servo motor positioning system. A phenomenon of positioning control was examined by the friction welding of carbon steel. The positioning control was satisfactory performed with sufficient accuracy. The undershoot and the overshoot behaviors were observed to the specified position during operation. Heavy metal flow was observed in the vicinity of weld interface in case of positioning control. Characteristic flash was formed by the heavy metal flow during positioning control. The metal flow became heavy with the stopping period increase. The direction of metal flow was circumferential, when positioning control friction welding. The rotative direction of metal flow was changed due to the overshoot or the undershoot behavior. When stopping period was optimized, metal flow became minimized. In this examination, 0.3 s was optimum stopping period. The fracture of tensile test specimens occurred at the base metal, when the position was controlled. However, tensile strength of positioning controlled joints was equal to the strength of base metal. The positioning control did not affect on the tensile strength of welded joints.

アルミニウム合金と炭素鋼の摩擦圧接

Friction welding of dissimilar metals was performed to evaluate the formation of intermetallic compound during welding. In our research, A6061 aluminum alloy and S45C carbon steel were applied to investigate effect of friction welding parameters on the strength of welded joint. A continuous drive vertical friction welding machine was employed. Tensile test results revealed that the maximum tensile strength was achieved at extremely short friction time and high upset pressure, that was friction time 1 s and upset pressure about 250 MPa. The joint strength reached 92% of the tensile strength of A6061 base metal. Tensile strength of friction welding was increasing with increasing upset pressure under friction time 1 s. However, tensile properties were deteriorated with increasing friction time. Prolonged friction time to 3 s was given less joint strength 52% than that of 1 s. It was observed that the amount of intermetallic compound was increasing with increasing friction time at weld interface. Partly formed intermetallic compound on weld interface were recognized at friction time 1 s. However, intermetallic compound layer were severely developed with longer friction time at weld interface. Consequently it was concluded intermetallic compound layer deteriorated the tensile properties of weld joints.

Impact Tensile Properties of Friction Welded Butt Joints between 6061 Aluminum Alloy and Type 304 Stainless Steel

The tensile strength and energy absorption for dissimilar metal friction welds between 6061 Al alloy and Type 304 stainless steel at high rates of loading are determined using the split Hopkinson bar. Cylindrical tensile specimens machined from as-welded butt joints of 13 mm in diameter are used in both static and impact tests. Friction welding is conducted using a brake type friction welding machine under two different welding conditions. The effects of the welding conditions and loading rate on the joint tensile properties are examined. Results show that the joint tensile properties are greatly affected by the welding parameters, and are slightly enhanced with increasing loading rate. Macroscopic observations reveal that the tensile fracture modes in the butt joint specimens vary with loading rate, depending on the welding conditions. Microhardness profiles across the weld interface are measured to investigate the extent of the heat-affected zone (HAZ). The slight enhancement of the joint tensile properties with increasing loading rate is due to the strain-rate dependence of the thermally-softened 6061 Al alloy base material.

515 細粒鋼の摩擦圧接における継手強度

This report describes the joint strength of fine grained steel (FGS) friction welded joints by using the low heat input friction welding method (LHI method) which was developed by authors. The FGS base metals were joined by using the continuous drive friction welding machine with an electromagnetic clutch in order to prevent braking deformation during rotation stop. It was clarified that the friction welded joints with 100% joint efficiency could be obtained by using only the friction stage up to initial torque without the forge (upsetting) stage. That is, the joint tensile strength of the friction welded joints was obtained at the time that the friction torque reached the initial torque. In addition, the joint welded by the LHI method did not cause softening and the grain growth in the heat affected zone. As a conclusion, the LHI method without the forge stage to the FGS base metal welds provides the advantages of less burn-off, less burr, non-softening and less grain growth.

Rotary friction welding of an Fe 3Al based ODS alloy

An Fe 3Al based oxide dispersion strengthened (ODS) alloy is under consideration for possible use as tubes in advanced heat exchangers, and it is necessary to investigate methods of joining the alloy to itself, and to Haynes 230 alloy. Previous experience on iron aluminides has shown them to be weldable by several processes, but it is known that fusion processes invariably lead to a loss of the Y 2O 3 oxide dispersion which is an essential feature of ODS alloys. Therefore, solid state processes offer a potential advantage, and in this work continuous drive rotary friction welding has been investigated as a method to join the Fe 3Al ODS alloy in both the recrystallized and unrecrystallized condition. Trials were also undertaken to join both recrystallised and unrecrystallized material to Haynes 230 alloy. All welds were made in 15-mm diameter material, using a conventional continuous drive rotary friction welding machine. Welds were evaluated initially using tensile tests, and detailed metallographic observations of the grain size, and the nature of the solid state interface between the materials. It was found possible to make high quality welds containing no flaws for a variety of welding conditions. The microstructural condition of the Fe 3Al ODS alloy had no apparent influence on weldability, and no difficulty was encountered in making the dissimilar metal joints. The results obtained are discussed in terms of the microstructures obtained, and are compared with other studies on joining iron aluminides and ODS alloys.

５０５２アルミニウム合金摩擦肉盛材の機械的性質

5052 aluminum alloy used for substrate and consumable rod, was friction surfaced using a numerical controlled full automatic friction welding machine. Effects of the surfacing conditions on some characteristics of deposits were investigated. It was clearly observed that the circularly pattern appeared on the surface of deposit by the rotation of consumable rod. The deposit has a tendency to incline toward the right side further than center of deposit for the feed direction of consumable rod. This deviation accompanied the decrease of the rotational speed of consumable rod. The width of deposit increased with increasing friction pressure, and decreasing rotational speed of consumable rod. The thickness of deposit became thinner when the consumable rod was high revolution. The surfacing efficiency decreased with increasing friction pressure and rotational speed of consumable rod, but increased with increasing feed speed. Microstructure of the deposit was finer than that of the substrate and consumable rod. The softened area was recognized at 3 mm distance from the weld interface of substrate. The tensile strength of deposit increased with increasing friction pressure. The maximum tensile strength of deposits showed 88.8% of the base metal of substrate.

摩擦圧接の接合メカニズムに関する研究 ３ 低入熱摩擦圧接における摩擦時間，摩擦トルクと継手特性の関係

In the previous reports 1 and 2, the authors have clarified the joining mechanism in the first phase of friction stage during friction welding process. The present paper describes the relationship between the friction time, friction torque, and joint properties of friction welding for a low heat input friction welding method. The materials joined were mild steels (same materials), and a brake type friction welding machine was used for joining. In actual experiment, i.e., the low heat input friction welding method (LHI method), the electromagnetic clutch was used in order to exclude braking deformation at rotation stopping. The following are concluded. (1) The joints obtained only in the first stage (up to initial peak torque) had 100% joint efficiency and 90 degrees bend ductility with no crack. It was determined that friction welded joints with 100% joint efficiency and good bend ductility could be obtained by using only the friction stage up to initial peak torque and without the need for the forging (upsetting) stage. (2) The fracture occurred at the substrates (not at the welded interface) in welded joints when friction torque was close to initial peak torque. It was clarified that those joints has less width of heat affected zone and less width of hardening. (3) It was clarified that the friction welded joints without using the forging stage (the friction welded joints by using the LHI method) have same mechanical properties as those welded by the conventional friction welding process including that stage. The LHI method has more advantages, i.e., less burn-off and less burr.

Study of friction welding of polyethylene

The effect of friction welding condition on the friction welding phenomena of high density polyethylene was investigated with a brake type friction welding machine which was built as a trial for polyethylene.The experimental results are as follows;1) The initial torque, steady torque and total loss were increased by increase of friction pressure. These tendencies were the same manner as carbon steel.2) The rate of total length of rotated side and fixed side changed with friction welding condition. These phenomena were different from the those of carbon steel.3) The friction welding condition range of polyethylene for good appearance became narrower than that of carbon steel.4) In the case of polyethylene, the environment in workshop became worse by occurrence of cotton dust, scatter of liquefied polyethylene and bad smell, when friction welding was investigated except pertinent friction welding condition. Therefore, this material required sufficient care, when friction welding condition was selected.

110 Impact Tensile Properties of Friction Welded Butt Joints between 6061 Aluminum Alloy and Type 304 Stainless Steel

The tensile strength and energy absorption of dissimilar metal friction welds between 6061 Al alloy and Type 304 stainless steel at high rates of loading are determined using the split Hopkinson bar. Round tensile specimens machined from as-welded butt joints of 12 mm diameter are used in both static and impact tension tests. Friction welding is conducted using a brake type friction welding machine under two different welding conditions. The effects of welding parameters and loading rate on the tensile properties of friction welded butt joints are investigated. It is demonstrated that the tensile properties are greatly affected by the welding conditions, and are slightly enhanced with increasing loading rate. Macroscopic observations reveal that the tensile fracture mode of friction welded butt joints varies with loading rate, depending on the welding conditions. Microhardness measurements are performed to examine the extent of the heat-affected zone (HAZ) across the weld interface. The slight enhancement in the tensile properties of friction welded butt joints with increasing loading rate is due to the strain rate dependence of the thermally-softened 6061 Al alloy base material.

摩擦圧接における第１位相の摩擦トルクのシミュレーション

The authors have clarified the joining mechanism of the first phase of friction stage during friction welding process for similar materials. The present paper describes the simulated friction torque in the first phase during friction stage for joining of mild steels. The joining model of the wear stage and the seizure stage were constructed from the joining phenomenon that was obtained by experiment. In actual simulation, the real contact area and the thermal stress at welded interface in the wear stage, and the seizure temperature and the relative speed of welded interface in the seizure stage were taken into consideration. The calculations of the friction torque and the temperature of welded interface were carried out under the conditions that were coupled with the friction pressure, the relative speed and the yield strengths of base metals. The following are concluded. (1) The calculated values of friction torque, initial torque and elapsed time for initial torque were in approximate agreement with the experimental values. The calculated values of temperature at welded interface of center portion were higher than that of periphery portion at the time that the friction torque reached to the initial torque. (2) It was clarified that the initial torque value depends on the seizure temperature at welded interface, and the yield strength that correspond to the seizure temperature. (3) Simple calculation for required level to capacities of the friction welding machine can be estimated the initial torque by the seizure temperature.

Stress‐strain characteristics of S15C carbon steel friction‐welded butt joints under impact tensile loading

Stress-strain characteristics of S15C carbon steel friction welded butt joints under impact tensile loading are evaluated using the split Hopkinson bar. Round tensile specimens machined from as-welded butt joints of 13 mm diameter are used in both static and impact tension tests. Friction welding is carried out using a brake type friction welding machine under fixed welding conditions. The effect of strain rate up to e≅700/s on the tensile stress-strain characteristics of both friction welded butt joints and a base material (S15C carbon steel) is studied. It is shown that the flow stress for friction welded butt joints is always higher than that for the base material at low and high rates of strain, but the former are less sensitive to strain rate than the latter. Microhardness measurements are conducted to examine the extent of the heat-affected zone (HAZ) across the weld interface. Metallographic examination reveals that there are zones of different grain structure through the weld region. The increase in the flow stress for friction welded butt joints is attributed to the presence of a locally-hardened region within the HAZ.

６０６１アルミニウム合金の水中摩擦圧接

The some characteristics of the underwater friction welded joints of 6061 aluminum alloy, which were made by using a brake type friction welding machine, were examined with different welding conditions. The highest temperature of the friction welding process on the underwater welding was considerably lower than that of the atmospheric welding, and both friction pressure and friction time did not hardly affected to the temperature on the friction welding process. The total loss of the underwater welded joint became smaller compared with atmospheric welded joint, moreover the width of softening area on the underwater welded joint reduced and the softening ratio also decreased. The maximum joint efficiency of the underwater welded joint could be obtained 86%, it was slightly lager than that of the atmospheric welded joint which was 82%. The elongation of the underwater welded joints were lower than that of the atmospheric welded joint. Both the underwater and atmospheric welded joints fractured in the softened area under the tensile load.

ポリエチレンの摩擦圧接に関する研究

The effect of friction welding condition on the friction welding phenomena of high density polyethylene was investigated with a brake type friction welding machine which was built as a trial for polyethylene.The experimental results are as follows;1) The initial torque, steady torque and total loss were increased by increase of friction pressure. These tendencies were the same manner as carbon steel.2) The rate of total length of rotated side and fixed side changed with friction welding condition. These phenomena were different from the those of carbon steel.3) The friction welding condition range of polyethylene for good appearance became narrower than that of carbon steel.4) In the case of polyethylene, the environment in workshop became worse by occurrence of cotton dust, scatter of liquefied polyethylene and bad smell, when friction welding was investigated except pertinent friction welding condition. Therefore, this material required sufficient care, when friction welding condition was selected.