¹!!! u i i! KPVSOBM!PG!MFF.NJOH!JOTUJUVUF!PG!UFDIOPMPHZ! WPM/!34-!OP/!2-!KBOVBSZ!3123! z ¾ Ö Š µ æ» u Te-Su Chen, Lee-Der Liu, Ju-Jen Liu, I-Yon Lin d ž Department of Chemical and Materials Engineering, Lee-Ming Institute of Technology»t Ben-Yuan Lin ž Department of Mechanical Engineering, Lee-Ming Institute of Technology î sg hï ½ Õ å ž hï ì x k iõ}iáïì³ u x Ùk ½ m i }i Ùsg x ³ m ½ m e Í x à x Á à iõ}iáïì³ sg ì x õ i i mø Ùk i iõùk}i ke m ÕÙks d x ië i p k ½ m m ÔËkçp Œ iæïm 950 ÕzÙk { Õ k i ï ké ä i x i Ôe ïð ¹ v x Õ }àä eg Æï d ê Ùk i n ÔÍ ï õ mk s d x} Í Ö õ ±û ³ Ô n êù iõùk}i Ìn Á±³e ³ Ô k e k n iõr }iáïì³ Ô ½m! 161
Abstract This article aimed at the induction heat treatment on steel. We designed some heat treatment conditions to discuss the importance of tempering during tensile fracture. We tried to distinguish the tensile characteristics of steels treated by different induction heating treatments. We designed three heat treatment conditions to emphasis the importance of tempering process by compared with the row material. Three heat treatment conditions including the first one, quenching, the second one, quenching and tempering and the last one, normalizing. We induction heated the center position of specimens to 950. At the same time, we inspected heating temperature around the heated position by infrared thermometer to control heating time. We also inspected hardness and fracture type of specimens after tensile test. The result showed that, the tensile strength of the steel shaft could be hardened after quenching because of the martensitic formation and stress distribution. The normalized specimens recovered the ductility and maintain the tensile strength because the lower cooling rate in air. When we quenched and tempered specimens, we obtained better toughness, and the tensile strength could be raised about 20. It could be seen the importance of tempering after quenching. Key Words: steel, tensile strength, induction heating 162
Í ½ m n}ô Á x Æïe i Ô kézù kõ Á u Ù Á iõ à Á u (Martensite) j Á  u } r d Á z km k Á ÔÙk}i k u}i u (Tempered Martensite)k ³ } iõùk}i nk Á ³e±û³ f ³ é iá ÔïŠ ~ { nk xá d³e À ³ [1-2] d ä e Ç Á vá} xá Á u m xá Ôeè ³ { nk xá k Á xá Ôe dšjì š ½ x e õ j}én x ³e u z ³ sg x ³ p x ei k iõ}iáïì ³ [3-4] e¼ gl v[5] 1045 ½m i Ô e m Ô à 950 1095 iõn um 200 500 Á { Ô}i Ý k Ô w Œ m {Á}i Ô }in i Ô HRC55 ï uá Ô çà HRC40 HRC42 êùs d Ìm 900 Õ Œn Ð x} iõá }in m d Á ³e±³ { ³ Án ³ f Ô i dá Á u s}i u u x wn [6] i¾ sg u À i i Çç 240 mm q Âýà 12.5 mm ÇÔà 50 mm iv ~ v Ë u o(hi Tech Corp.) 100 Ô okç MTS o 100 kn (MTS 810) ï ±³ e ³ } d ïâý 12.5 mm q 80 mm Ç 240 mm iv 163
à iõ}iáïì³ sg ì õ i i mø Ùk i iõùk }i kem ÕÙks d x ië} i p Ùk ½ m ½ mø j kezi ½ à 300 MHz m à 12 kw ½ zïâ Æï Š x ³ Ôç 15 mm Âýh i ç 5 mm m ÔËkçp Œ i Ë iæïm 950 Õ Ùki } i Ë i i Í Õzm 200 2 Õ s d Ìm 950 Õ Ò Â Õ ky i ïð» v 1045 s Ì Ô 570 MPa Ç 20 dõ Ô 690 MPa Ç 17 [7] Æ à i Ô ¹ ì ¹ v s Áõ i Ôi 847 MPa Ç ço 12 Ê s ¹ ü n Áõ} i i Ô ïn Ù}à É êù}ies dá i ±³e ³ Ö i Ô à Hi Tech o ï- Ç ¹ uq näl±³ õ i ïà 103986 (N) inäl Á e Ç u n näl ³ i i ïà 77396 (N) inäl Ái q i k ÌmÝ Ù iì É i à ±³ e ³ } d sg u MTS 810 ï ¹n äl±³ ³ ï- Ç d h v ³ } Ì Ì v ±³ } Ì ä Á ÃwØl[8-9] }à Ô Á ³ ~¹ Ú Ôe iš Ô ìš k u Ô à } e Ù{ Á ì ê Ù ½m Ùks d x }à Í Ö õ ±û³ Ô n iõùk}i xn Á ±³e ³ Ô k e k n iõr }iáïì³ pà± ³ e ³ ïq i ÐÁ± ³ ï Ì ïn à q êù ³ ïì q À q à } ± ³ æ Ð ³ Ì ¾ Ð [10-18] 164
È } k Õ» Ô (MPa) i h ï (N) Ç ( ) ï ( ) 1 õ 103986 847 12.6 39 2 ½m Õ i 77396 631 0.2 2 3 ½m Õ ie}i 108791 886 9.8 35 4 ½m Õs d 96480 786 16.6 46 ±³ ³ i q àõ n à ½m Õ i 35 30 25 ) N20 ( k D A15 O L 10 5 0 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 DISPLACEMENT (mm) ±³ ( ) ³ (h ) Ô d 165
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