... .Material:special alloy steel 2.Good customer service bimetallic conical twin screw barrel for WPC profile production specification:35/76, 45 ... requirements38CrMoAlA,SACM645,42CrMoNitriding treatment42CrMo,AISI 4140Hard chrome coated layer 4Cr5MoSiV1,SKD-61,SKD-11Spraying bimetal alloy layer and nitriding treatment HPM38,SI36 ...