Optional material: steel casting, grade 65-35, class 2 astm a27 or steel investment casting grade 1a type 1c 1020, astm a732 casting classification, mil-std-2175, class 4 grade d; material steel 1015 to 1025 (uns g1050 to g1025) per astm a576 or astm a108; preservative oil per vv-l-800