STRUCTURAL ALLOY STEELS SCM GRADE

MATERIALS
GRADE		 CHEMICAL COMPOSITION %
C Si Mn P S Cr Mo
SCM415 0.13~0.18 0.15~0.35 0.60~0.85 ＜0.030 ＜0.030 0.90~1.20 0.15~0.30
SCM418 0.16~0.21 0.15~0.35 0.60~0.85 ＜0.030 ＜0.030 0.90~1.20 0.15~0.30
SCM420 0.18~0.23 0.15~0.35 0.60~0.85 ＜0.030 ＜0.030 0.90~1.20 0.15~0.30
SCM421 0.17~0.23 0.15~0.35 0.60~0.85 ＜0.030 ＜0.030 0.90~1.20 0.15~0.30
SCM430 0.28~0.33 0.15~0.35 0.60~0.85 ＜0.030 ＜0.030 0.90~1.20 0.15~0.30
SCM432 0.27~0.37 0.15~0.35 0.60~0.85 ＜0.030 ＜0.030 1.00~1.50 0.15~0.30
SCM435 0.33~0.38 0.15~0.35 0.60~0.85 ＜0.030 ＜0.030 0.90~1.20 0.15~0.30
SCM440 0.38~0.43 0.15~0.35 0.60~0.85 ＜0.030 ＜0.030 0.90~1.20 0.15~0.30
SCM445 0.43~0.48 0.15~0.35 0.60~0.85 ＜0.030 ＜0.030 0.90~1.20 0.15~0.30
SCM822 0.20~0.25 0.15~0.35 0.60~0.85 ＜0.030 ＜0.030 0.90~1.20 0.35~0.45

QUENCH-TEMPER HARDNESS (FOR TEST PIECE)

MATERIALS
GRADE		 HEAT TREATMENT ℃
QUENCH TEMPER HARDNESS
SCM415 1st. 850~900Oil quench
2nd. 800~850Oil quench or 925~ 850~900Oil quench		 150~200Air cooled 235~321
SCM418 1st. 850~900Oil quench
2nd. 800~850Oil quench or 925~ 850~900Oil quench 		150~200Air cooled 248~331
SCM420 1st. 850~900Oil quench
2nd. 800~850Oil quench or 925~ 850~900Oil quench 		150~200Air cooled 262~352
SCM421 1st. 850~900Oil quench
2nd. 800~850Oil quench or 925~ 850~900Oil quench		 150~200Air coole 285~375
SCM430 830~880Oil quench 530~630 Rapidly cooled 241~302
SCM432 830~880Oil quench 530~630 Rapidly cooled 255~321
SCM435 830~880Oil quench 530~630 Rapidly cooled 2691~331
SCM440 830~880Oil quench 530~630 Rapidly cooled 285~362
SCM445 830~880Oil quench 530~630 Rapidly cooled 302~363
SCM822 1st. 850~900Oil quench
2nd. 800~850Oil quench or 925~ 850~900Oil quench		 150~200Air cooled 302~415