PACIFIC 4130 is a chromium-molybdenum low alloy steel with lower carbon than the more popular 4140. Because of lower carbon content, it has better weldability but lower hardenability (response to hardening). Maximum achievable hardness by furnace hardening is approximately 52 HRC. 4130 can be hardened by either water or oil quenching. PACIFIC 4130 is furnished in either the annealed or normalized condition depending upon mill availability.