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1 Mechanical Properties and Weldability of Turbine Impeller Materials for High Temperature Exhaust Gas Turbocharger IN100 The increase in environmental awareness in recent years has led to increased demands for improved fuel economy and the reduction of air pollution generated by automobiles. In light of this, there are increasing needs for the use of turbochargers, particularly with regard to gasoline engines. In order to achieve reduced fuel consumption, exhaust gas temperatures exceed C and can reach C. This research focuses on turbine impellers, evaluating their mechanical properties at elevated temperatures and their weldability to shaft. It was found that 246-equivalent and IN100-equivalent joints have superior properties as turbine impeller materials with regard to high temperature exhaust gas. 1. 緒言 ( 1 ) CO ( 2 ) Ni 713C 713C 713C IN IN 試験方法第 1 表 SCM435H 第 2 表 HIP HIP MPa 3 h 713C 43

2 第 1 表 wt Table 1 Typical chemical composition of superalloy and shaft ( wt% ) wt Ni Cr Mo Fe C Si Mn P S Ti C < < 0.5 < 0.25 < < < 0.15 < 0.2 < < < < 0.2 < 0.2 < IN < < 0.1 < 0.1 < < SCM435H < < 0.03 < 0.03 wt l Nb Zr B Co W Nb + Ta Ta Hf V C < < IN < < SCM435H h h h h h h IN h h mm 15 mm 第 2 表 Table 2 Superalloy density 247 IN100 3 mm 713C 247 IN C 700 R = 0.01 ( g/cm 3 ) C IN MPa MPa kv 10.5 m 1 m/min ( FE-SEM ) 3. 結果および考察 3. 1 新タービンインペラ候補材の高温強度評価第 1 図第 2 表 713C 247 IN ( MPa g 1 cm 3 ) C IN 第 1 図 Fig. 1 Temperature dependence of tensile strength of round bar specimens 44

3 C 247 IN100 IN C IN IN 第 2 図 247 IN C ( 3 ) IN C 第 3 図 247 IN100 1 IN ( 3 ) IN ( MPa g 1 cm 3 ) C *1 IN * *1 700 *2 815 R = 0.01 第 2 図 800 Fig. 2 xial fatigue properties of specimens cut from T/W and of round bar specimens at 800 ( MPa g 1 cm 3 ) C ( 3 ) 1 Larson-Miller C = 20 第 3 図 246 IN C 713C IN100 第 2 表 IN100 IN IN100 1 IN C 合金鋼シャフトとの接合性評価 Ni l Ti l Ti ( 4 ) l Ti IN ( h ) 第 3 図 850 Fig. 3 Diagram of stress vs. time to rupture of round bar specimens at 850 第 4 図 713C IN100 45

( a ) 713C ( b ) 247 ( c ) 246 ( d ) IN100 1.7 1.7 1.7 1.7 B B B B 2.5 2.3 2.7 2.7 200 µm 200 µm 200 µm 200 µm 第 4 図 713C 247 246 IN100 mm Fig.

3 mm ( 5 ) 第 5 図 713C 247 IN100 HIP ( MPa ) 1 000 800 600 400 200 0 713C 247 246 IN100 第 5 図 713C 247 246 IN100 Fig.

4 ( a ) 713C ( b ) 247 ( c ) 246 ( d ) IN B B B B µm 200 µm 200 µm 200 µm 第 4 図 713C IN100 mm Fig. 4 Microstructures of dissimilar joints between turbine wheels and chromium molybdenum shaft ( unit : mm ) B 1.7 mm 0.5 mm 713C 2.5 mm mm IN mm ( 5 ) 第 5 図 713C 247 IN100 HIP ( MPa ) C IN100 第 5 図 713C IN100 Fig. 5 Tensile strength of dissimilar joints between several turbine impellers and chromium molybdenum steel shafts 246 HIP 713C 752 MPa 734 MPa MPa 512 MPa 713C MPa IN MPa 720 MPa 713C 第 6 図 713C 246 IN 第 6 図 - ( b ) 第 7 図 713C 247 第 7 図 - ( a ) 713C 第 7 46

5 ( a ) 713C ( b ) µm 500 µm ( c ) 246 ( d ) IN µm 500 µm 第 6 図 713C IN100 Fig. 6 Fracture surfaces of dissimilar joints ( a ) ( b ) ( c ) 713C 50 µm 50 µm ( d ) ( e ) ( f ) 247 第 7 図 713C 247 Fig. 7 Fracture surfaces at higher magnification after tensile test 図 - ( b ) - ( c ) 第 7 図 - ( d ) - ( e ) - ( f ) 247 第 7 図 - ( d ) - ( c ) 713C 第 7 図 - ( e ) - ( f ) 47

247 第 8 図 713C 247 713C 50 247 第 6 図第 7 図 247 713C 247

and chromium molybdenum steel joints ( a ) 713C ( b )

6 247 第 8 図 713C C 第 6 図第 7 図 C 247 第 7 図 - ( e ) - ( f ) 247 第 9 図 Hf Hf g ( 6 ) 第 9 図 247 Fig. 9 Hot tear along with fusion line between 247-equivalent and chromium molybdenum steel joints ( a ) 713C ( b ) µm 200 µm 第 8 図 713C 247 Fig. 8 Microstructure of dissimilar joints ruptured by tensile test 48

7 3 247 IN 結言 713C IN IN C IN IN100 参考文献 ( 1 ) utomotive Technology Vol pp ( 2 ) IHI pp ( 3 ) erospace Structural Metals Handbook ( 4 ) W.. Owczararski Process and metallurgical factors in joining superalloys and other high service temperature materials Superalloys Source Book SM ( 1984 ) pp ( 5 ) p. 69 ( 6 ) T. B. Massalski BINRY LLOY PHSE DIGRMS second edition Vol. 2 p

Fig. 1 Sampling positions from the ingot. Table 2 Chemical compositions of base metal (%) Fig. 2 (unit: mm) Shape and size of fatigue test specimen. T

Fig. 1 Sampling positions from the ingot. Table 2 Chemical compositions of base metal (%) Fig. 2 (unit: mm) Shape and size of fatigue test specimen. T Friction welding of ADC 12 aluminum alloy diecastings Kazuyoshi KATO* and Hiroshi TOKISUE* Both squeeze and gravity castings of ADC 12 aluminum alloy were friction-welded, using a brake type welding machine.