... 68/143, 70/135,70/140, 75/150, 80/143, 80/156, 92/188, 95/191, 105/191, 100 ... ingredients. Material of barrel raw materialThe finished product processing requirements 38CrMoAlA,SACM645 Nitriding treatment Cr12MoV,Cr12Alloy steel38CrMoAlA, ... temperatureMaterial of screw raw material The finished product processing requirements38CrMoAlA,SACM645,42CrMoNitriding treatment42CrMo,AISI 4140Hard chrome coated ...