A.高鋁耐熱鑄鐵 B.球墨鑄鐵 C.高鉻鑄鐵 D.不銹鋼
A.50ppm B.80ppm C.100ppm C.150ppm
A.1/2-1/3 B.1/3-1/4 D.1/5-1/6 C.1/9-1/10