Takeshi Sawai

The relationships between tensile strength and deformation heat input in the upset stage or upset bum-off length was examined on the friction welding of copper to various metals. It was found that in Cu/Cu, Cu/S35C, Cu/SNC631, Cu/SUS304 and Cu/Ni joints, a stable tensile strength was obtained when the deformation heat input in the upset stage or the upset bum-off length exceeded a certain value. In Cu/Mo joint, tensile strength was low. In Cu/Ti joint, it was not possible to classify joints into sound and poor by the deformation heat input in the upset stage or the upset bum-off length.

SUS304ステンレス鋼同種摩擦圧接継手の入熱と引張強さおよび疲労強度の関係を検討した。入熱は、摩擦入熱、変形入熱に分類され、摩擦過程、アプセット過程および全過程のそれぞれの入熱とした。その結果、アプセット過程の変形入熱120J/s以上、アプセット寄りしろが1.0mm以上の場合に、圧接界面近傍の熱影響部で破断し、引張強さの大きい継手が得られた。また、良好な継手では、疲労試験中の加工硬化により、疲労強さはSUS304母材よりも大きくなる。そして、疲労試験から求めた疲労限度で継手性能を判断すると、引張試験同様に、あるアプセット過程の変形入熱およびアプセット寄りしろ以上の場合に良好な継手が作成できることが明らかとなった。

Friction welding of SUS304 stainless steel was carried out in order to examine the relationship between joint strength and deformation heat input in the upset stage or upset bum-off length. Joint strength was evaluated by tensile and fatigue testings. It was found that the deformation heat input in the upset stage or the upset bum-off length correlated well with joint strength. That is, when the deformation heat input in the upset stage and upset bum-off length exceed 120 J/s and 1.0 mm respectively, a stable tensile strength was obtained. The tensile strength of sound joints was lower than that of SUS304 base material, because the heat affected zone of joints was softened by the friction heat and the fracture of sound joints occurred in this softened area. Meanwhile, the fatigue strength of sound joints was higher than that of SUS304 base material. This is probably because the material near the weld interface was hardened due to the work hardening. Evaluating the fatigue limit obtained in the fatigue test revealed that when the deformation heat input in the upset stage and the upset bum-off length exceed a certain value, sound joints can be produced as well as good tensile strength.

6061アルミニウム合金を用いて、同種摩擦圧接を行い、各種入熱と引張強さおよび疲労強度の関係について検討した。入熱は、摩擦入熱および変形入熱に分けられ、それらを合計した全入熱の3つの入熱を、摩擦過程およびアプセット過程の両過程で測定した。その結果、アプセット過程の変形入熱が200J/s以上、アプセット寄りしろが4mm以上の場合に、熱影響部で破断する引張強さの安定した継手が得られた。そして、疲労強さは、引張強さに比べて、界面の接合状態や軟化状態に影響されやすく、界面の接合が良好で軟化領域が広い継手では、疲労強さは大きくなることが明らかとなった。

Friction welding of 6061 aluminum alloy was carried out in order to examine the relationship between deformation heat input in the upset stage, upset bum-off length and joint performance. The joint performance was evaluated by tensile testing and fatigue testing. Stabilized tensile strength was obtained when the deformation heat input in the upset stage and the upset bum-off length exceeded 200 J/s and 4 mm, respectively. Weld condition at the weld interface and the width of softened area affected fatigue strength more than tensile strength. That is, when the weld condition at the weld interface is good and the softened area is wide, fatigue strength increases. On the other hand, when the weld condition at the weld interface is good and the softened area is narrow, and when the weld condition at the weld interface is somewhat poor in spite of the wide softened area, fatigue strength decreases. The fatigue limit obtained by the fatigue testing reveals that, when the deformation heat input in the upset stage and the upset bum-off length exceed a certain value, sound joints can be produced.

6061アルミニウム合金管の同種摩擦圧接継手の入熱と継手性能(引張強さ)の関係および入熱と寄りしろの関係について検討した。入熱は、摩擦入熱および変形入熱に分けられ、それらを合計した全入熱の3つの入熱を、摩擦過程、アプセット過程および全過程で測定した。その結果、アプセット過程の変形入熱がもっとも引張強さと密接な関係があることが判明し、アプセット過程の変形入熱が500J/s以上、アプセット寄りしろは、5mm以上で良好な摩擦圧接継手となることが明らかとなった。

ニューラルネットワークを用いて、6061アルミニウム合金同種摩擦圧接継手の最適摩擦圧接条件を模索した。ニューラルネットワークの入力と出力には、圧接条件因子、寄りしろおよび引張強さなどを用い、種々組み合わせて学習を行った。その結果、学習に用いた条件の範囲内では、最適圧接条件の設定が可能であることを示した。

Inertia type friction welding of 6061 aluminum alloy was carried out in order to examine the effect of unit heat input (mechanical work) on the joint strength. The heat input was calculated by burn-off speed and welding pressure in the final stage. The joint strength was examined by tensile tests. The final stage(welding time) in the inertia type friction welding corresponding to the upset stage in the brake type friction welding was searched using the relationship between heat input and joint strength. After that, using the most proper final stage, the relationship between unit final deformation heat input and joint strength, and final burn-off length and joint strength was examined. The minimum final heat input and minimum final burn-off length required for making a sound joint were also examined. The results showed that the most proper-final stage(welding time) was 1.0s and when the limit final stage was 1.0s, the limit unit deformation heat input and limit burn-off length were 60J/s and 10min respectively.

Inertia type friction welding of 6061 aluminum alloy was carried out in order to examine the effect of unit heat input (mechanical work) on the joint strength. The heat input was calculated by burn-off speed and welding pressure in the final stage. The joint strength was examined by tensile tests. The final stage(welding time) in the inertia type friction welding corresponding to the upset stage in the brake type friction welding was searched using the relationship between heat input and joint strength. After that, using the most proper final stage, the relationship between unit final deformation heat input and joint strength, and final burn-off length and joint strength was examined. The minimum final heat input and minimum final burn-off length required for making a sound joint were also examined. The results showed that the most proper-final stage(welding time) was 1.0s and when the limit final stage was 1.0s, the limit unit deformation heat input and limit burn-off length were 60J/s and 10min respectively.

Friction welding of Cu to 1050 aluminum alloy, Cu to S15CK carbon steel, and SUS304 stainless steel to 6061 aluminum alloy were carried out in order to examine the effects of deformation heat input in the upset stage and the upset loss on the joint performance such as tensile strength. As a result, it was made clear that the deformation heat input in the upset stage and the upset loss were not a factor for evaluating the friction weldability, becase of formation of excessive intermetallic compound when the friction time was long.

Friction welding of 5052 Aluminum alloy similar material was carried out in order to examine the effects of deformation heat input and upset loss in the upset stage on the joint performance such as tensile strength. As the results, it was made clear that the deformation heat input in the upset stage was a dominant factor for controlling the friction weldability, increasing the deformation heat input in the upset stage caused an increase in the tensile strength of the weld joints and joints of stable-high tensile strength was obtained with 350J/S or more deformation heat input, and increasing the upset loss caused an increase in the tensile strength of the weld joints and joints of the stable-high tensile strength was obtained with about 7mm.

Friction welding of 5056 aluminum alloy similar material was carried out in order to examine the relationship between the heat input and the joint performance. The joint performance is evaluated by tensile test. The heat input is a heat source for welding solid materials and is classified into six inputs, that is, friction heat input and deformation heat input during friction stage, upset stage and total stage respectively. The most important heat input for evaluating the joint performance among these heat inputs was experimentally investigated through the tensile strength of welded joints because the friction mechanism is much complexed. As the results, the deformation heat input during the upset stage was much related with the joint performance, and the good weld joints were obtained with the deformation heat input over 100 J/s, moreover, it was recognized that the deformation heat input was proportioned to the upset burn-off length, therefore with the upset loss over 2 mm the good weld joints were obtained.

With the prime objective of contriving an effective method of drilling on conventional machine tools with conventional drills, the high feed rate drilling of aluminum alloy A1050, A2017 and A6061 is attempted with titanium nitride coated SKH56 drills under cutting conditions (1500rpm, 1.0mm/rev) harsher than those generally employed. Results obtained of cutting characteristics such as cutting forces, drill wear, heat generated, chip shape hole finish etc were examined in order to determine the critical cutting condition for conventional drills. From results obtained it is found that the high feed drilling of aluminum alloy A1050 is difficult practically. While high feed drilling in A2017 and A6061 alloys is very feasible.

Friction welding of 5056 aluminum alloy similar material was carried out in order to examine the relationship between heat input and joint performance. The joint performance is evaluated by tensile test. The heat input is a heat source for welding solid materials and is classified into six categories, viz. friction heat input and deformation input during friction stage, upset stage and total stage. The most important heat input for evaluating the joint performance among these heat input was experimentally investigated through the tensile strength of welded joints because the friction mechanism is much complex. It was found that the deformation heat input during the upset stage was correlated well with the joint performance, and the sound joints were obtained with the deformation heat input over 100J/s. Moreover, it was recognized that the sound joints could be obtained with upset burn-off length over 2mm.

今まで日本における摩擦圧接は、主に回転運動を利用している。ただし、この方法では回転させられない材料では溶接が不可能である。そこで、回転運動の代りに直線運動を行う振動摩擦圧接を行った。本研究では、実験用振動摩擦圧接機を用いた。その結果、それぞれ摩擦速度が0.12m/sから0.26m/s、振幅が1.1mmから2.28mm および軸負荷が5kgfから30kgfで良好な継手を作製できることを確認した。

Friction welding of stainless steel SUS304(JIS) was carried out in order to examine the effects of mechanical work caused by rotation and axial pressure on the joint performance such as tensile strength. The mechanical work could be classified into two parts of work, that is, friction work and deformation work. During friction welding, the upsetting quantity and the friction torque were measured and recorded, and the deformation work and the friction work as a mechanical work were calculated using these upsetting and torque data. Tensile test was carried out to evaluate the joint performance and the relationship between the joint performance and the mechanical work was examined. The results showed that increasing the friction pressure and decreasing the friction speed caused an increase in the mechanical work and in the area of adhesive friction surface. Furthermore, increasing the mechanical work caused an increase in the tensile strength of the weld joints. But, the friction work, one of the mechanical work, did not directly relate to an increase in the tensile strength, meanwhile the deformation work was a dominant factor for controlling the friction weldability.

低炭素鋼(0.16%C)を用いて摩擦圧接を行い、摩擦圧接中の回転数と摩擦トルクから熱入力を算出し、熱入力と継手性能(引張強さ、曲げ強さ、ねじり強さ、衝撃強さ、圧接部の硬さ分布および金属組織など)との関係について検討した。 その結果、、熱入力が継手性能に与える影響を明らかにした。

摩擦過程での摩擦推力を反転させ、圧接中の圧接母材を引き離し、そのときの摩擦トルクの記録と6061アルミニウム合金の圧接端面の観察を行った。良好な引張強さを有する継手(完全継手)は、摩擦トルクの変動が少ないことから、トルクの変動を十点平均荒さに準じた手法で測定し、トルクの安定した完全継手を得るための指標( 値)を模索し検討した。 その結果、引き離した母材の圧接端面と 値は一定の関係にあることが明らかとした。そして、通常の同種摩擦圧接実験より熱入力を算出した。 値と熱入力との関係を検討し、トルクの変動によってある程度熱入力を予測できることを示した。