... , the hardness reach HRC59°-61°,which is suitable for processing of 50-60% fiberglass, Bakelite, dynamoelectric injection machine, magnetic particle ... fiberglass , PC,PVC, acryl, transparent plastic. The service lifetime of four or six times longer than the nitrided screw. Grade B ... and other plastics with high corrosion.The service lifetime of four or six times longer than the nitrided screw. Grade ...