Type Friction Welding Research Articles

서보모터방식 마찰용접을 이용한 TiAl 합금과 SCM440의 접합에 미치는 용접조건의 영향

Abstract In this study, characteristics of TiAl alloy and SCM440 (Cr-Mo steel) have been investigated with thevarious joining condition by servo motor type friction welder. The experimental factors of friction welder used inthis study are spindle revolution, friction speed, and distance, upset speed and distance, respectively. Servomotor type friction welder could be controlled by the level of oil pressure, and it could be performed by positioncontrol dependence of electrical energy. Mechanical properties and morphology of welded interface were charac-terized by various joining condition. This aroused due to the bond strength dependence on friction heat and sizeof the heat affected zone. Therefore, it is necessary to have enough friction heat and decreased heat affectedzone for good friction welding between dissimilar metals. An optimum bond was obtained between TiAl alloy andSCM440 by controlling friction speed and distance. At the spindle revolution 4,000 rpm, friction speed 120 mm/min, friction distance 15 mm, the bond strength was found to be 312 MPa.(Received February 11, 2016; Revised February 17, 2016; Accepted February 25, 2016)Key words : TiAl alloy, SCM440, Servo-motor type friction welding, Joining factors

The effects of process parameters for joining of AISI 1010-Cu alloys by friction welded

In this study, the effects of process parameters for joining of AISI 1010 low carbon steel and copper alloys by friction welded were investigated. Low carbon steel and commercial copper each of 12 mm diameter was used to fabricate the joints. The friction welding tests were carried out using a direct-drive type friction welding machine which was designed and manufactured for this purpose by us. After friction welding, in order to determine the microstructural changes that occurred, the interface regions of the welded specimens were examined by means of OM, SEM, EDS and X-Ray analysis. Microhardness and tensile tests were conducted to determine the mechanical properties of the welded specimens. The experimental results indicated that AISI 1010 low carbon steel could be joined to copper using the friction welding technique and for achieving a welding with a sufficient strength, the friction time has to be held as short as possible, while the rotational speed, friction and forging pressure has to be as high as possible. Tensile strength values also confirmed this result and at the interface did not occurred intermetallic phases. The maximum tensile strength of 294,67 MPa could be obtained for the joints welded under the welding conditions of rotation speed of 2300 rpm, friction pressure of 40 MPa, forging pressure of 80 MPa, friction time of 6 s and forging time of 3 s.

Interface characterization of friction welded low carbon steel and copper alloys

Abstract In this study, the interface characterization of friction welded AISI 1010 low carbon steel and copper alloys was investigated. The friction welding tests were performed by using a direct drive type friction welding machine. After friction welding, interface regions of the welded specimens were examined by optical microscopy, SEM-EDS, and X-ray analysis to determine the microstructural changes. Microhardness and tensile tests were conducted to determine mechanical properties of the welded specimens. The experimental results indicated that AISI 1010 low carbon steel could be joined to copper using the friction welding technique for achieving a weld with sufficient strength. Tensile strength values also confirmed this result and intermetallic phases did not occur at the interface.

회주철의 마찰용접 특성에 관한 연구 - 입열량 이론식을 중심으로 -

Joining of grey cast iron by fusion welding has much difficulties for its extremely low ductility and low toughness because of the flake form of the graphite. And the brittle microstructure, i.e. ledeburite may be formed during fusion welding by its rapid cooling rates. By these kinds of welding problem, preheat and post heat treatment temperature must be increased to avoid weld crack or welding problems. In order to avoid these fusion welding problem, friction welding of cast iron was carried out for improving joint soundness, establishing friction welding variables. There is no factor for evaluating friction weldability in continuous drive type friction welding. In this point of view,this study proposed the parameters for calculating friction weld heat input. The results obtained are as follows ; 1. There was a close relationship between tensile strength and flash appearance of friction welded joint. 2. Tensile strength was decreased and flash was severely oxidized as increasing frictional heating time. 3. As increased forging pressure P2, flash had a large crack and tensile strength was decreased. 4. As powdered graphite by rotational frictional force induced flat surface and hindered plastic flow of metal ,tensile strength of welded joint was decreased. 5. Heat input for continuous drive type friction welding could be calculated by the factors of P1, P2 and upset distance(δ).

A6061 合金のイナーシャ式摩擦圧接継手の強度に及ぼす入熱，寄りしろ，ばり形状の影響

The effect of heat input on joint strength in the brake type friction welding has become clear, but the effect in the inertia type friction welding is not clear even at present. Then in this report, inertia type friction welding of 6061 aluminum alloy was carried out in order to examine the effect of unit heat input, burn-off length and burr shape on the joint strength. The heat input (mechanical work) was calculated by burn-off speed and welding pressure in the final stage. The joint strength was examined by tensile test. The final stage (welding time) of inertia type friction welding corresponding to the upset stage of brake type friction welding was searched using the relationship between heat input and joint strength. Using the most proper-final stage obtained, the relationships between unit final deformation heat input and joint strength, final burn-off length and joint strength, and burr shape and final deformation heat input were examined. Also the minimum unit final deformation heat input and minimum final burn-off length required for making a sound joint were also examined. The results showed that within this experiment the most proper-final stage (welding time) was 0.1s, and the limit unit final deformation heat input and limit final burn-off length were 19J/s and 0.3mm, respectively.

Effect of rotational speed on the interface properties of friction-welded AISI 304L to 4340 steel

The aim of this study is to investigate experimentally the interface properties in terms of rotational speed in friction-welded AISI 304L to AISI 4340 alloy steel. Friction welding was conducted with five different rotational speeds using a direct-drive type friction welding machine. Friction pressure, forging pressure, friction time and forging time are fixed. The integrity of joints was investigated by scanning electron microscopy, while the mechanical properties assessments included microhardness and tensile tests. The experimental results showed that the thickness of full plastic deformed zone (FPDZ) formed at interface reduce as a result of more mass discarded from the welding interface with increase of the rotational speed. It was also observed that the width of the FPDZ has a important effect on the tensile strength of friction-welded samples and the tensile strength increases with increase of the rotational 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.

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.

929 摩擦圧接における摩擦時間と継手強度との関係

This report describes relationship between friction time in friction stage and joint strength of friction welding joints. The materials used were mild carbon steels, and a brake type friction welding equipment was used for joining. In actual experiment, the electromagnetic clutch was used in order to exclude the braking deformation at rotation stopping. As experimental method, the relative speed was instantaneously rendering to zero at each friction time. The authors have determined that 100% of joint efficiency in tensile test, i. e. all joints fracture at substrate (not at interface), could be achieved without upsetting stage. That is, the tensile strength of the friction welded joints were dominated by friction welding process until the time that the friction torque reached to the initial peak torque. These joints could be bent in 90 degrees-bend tests, and this result was same as that of the joints welded by conventional welding process, i. e. by using upsetting stage. As a conclusion, the friction joints welded by using no upsetting stage have same mechanical properties as those welded by conventional friction welding process including that. The experimental method without upsetting stage has some advantages, e. g. less burn-off and the burr.

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.

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.

摩擦圧接の接合メカニズムに関する研究 １ 摩擦圧接における第１位相の接合現象の観察

Many investigations have been reported for the mechanism of friction welding process of similar materials. However, the mechanism has not been clarified precisely up to now. A series of studies has been carrying out to clarify the joining mechanism of friction welding process. As for the first step, the present paper describes the joining phenomena in the first phase of friction welding process, i.e., friction stage. The materials joined were mild steels (same materials), and a brake type friction welding equipment was used throughout this experiment. Main conclusions are obtained as follows. (1) When the weld faying surfaces of both substrates contacted each other, the friction torque rapidly increased and maintained at the nearly constant. Following this, the friction torque reached to the initial peak torque. (2) The wear of both surfaces started at the periphery portion (outer surface) of joint, and moved to the center portion (center axis). Then, seizure and joining began at the center portion, and they extended toward the periphery portion. (3) The friction torque reached to the initial peak torque when the welded interface was joined completely and upsetting of both substrates started. (4) The joining models at the first phase in wear and the seizure stages were made from the observation results. As a conclusion, the first phase of friction stage was composed of the wear and the seizure stages.

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.

212 ブレーキタイミングが摩擦圧接継手の機械的性質に及ぼす影響(OS 溶接・接合)

Effects of brake timing on the mechanical properties of welded joints of 5052 aluminum alloy, which were made by using a numerical controlled brake type friction welding machine, were investigated. The total loss of welded joint became shorter with decrease of brake timing. The highest tensile strength of welded joint was 240.8 MPa, joint efficiency was 93.2%, at brake timing of 0 second. The tensile strength of welded joints under conditions of brake timing from -0.1 to 0.2 seconds showed almost same value, and they were fractured at the heat affected zone. The highest elongation of welded joint was obtained when braking time 0.2 seconds. The welded joints, exceed the elongation of 14%, were fractured at the soften area. But welded joints, elongation under 5%, were fractured at the weld interface.

衝撃引張荷重下におけるＳ１５Ｃ炭素鋼摩擦圧接継手の応力‐ひずみ特性

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.