PACIFIC 4150FM is a high strength chromium-molybdenum alloy which is readily machined in the heat treated condition. The controlled addition of sulfur gives 4150FM its unique free machining characteristics. Also, in sizes 3-1/4" through 11" diameters, it is calcium treated for additional ease of machining and extended tool life. These sizes are also rough turned oversize to clean up at nominal size. This saves the expense of machining the next larger size, as required with most hot rolled bars. 4150FM is not as weldable as 4142 because of the higher carbon content. However, it is weldable with proper procedures. It can also be induction hardened. Sizes through 6-1/2" diameter are stress relieved after machine straightening.