Ultra Stainless™ Unslotted Hex Washer Head Self Drilling Screw

Starts with 410 stainless and adds 2% molybdenum (the same ingedient in 316). Salt spray test - 500 hours. Ultra Stainless™ Marutex® screws are tempered and quenched; regular T-410 self drilling screws are case hardened. The additional carbon in Marutex® provides hardness for betting drilling. Surface Hardness Approx. 50 HRC.Core Hardness Approx. 50 HRC. Carbon C 0.25. Silicon Si 0.48. Manganese Mn 0.49. Phosphorus P 0.018. Sulfur S 0.001. Nickel Ni 0.48. Chrome Cr 13.42. Moly Mo 1.96. Copper Cu 0.47