M4X18W9 JIS B1188 Phil Pan Split Washer Flat Washer Sems M/S Zinc (Pack Qty 2,000) BC-516003

Screw: Class 4.8 carbon steel. Class 4.8 carbon steel. Split Lockwasher: Split lockwashers shall be made from a carbon steel that conforms to the following chemical composition requirements: Carbon: 0.54 - 0.81%; Silicon: 0.15 - 0.35%; Manganese: 0.30 - 0.90%; Phosphorus: 0.030% max.; Sulfur: 0.030% max Flat Washer: Plain washers shall be made from a carbon steel that conforms to the following chemical composition requirements: Carbon: 0.12% max.; Manganese: 0.50% max.; Phosphorus: 0.040% max.; Sulfur: 0.045% max