AISI 4140 Composition, Low alloy steel (4100 Series, Cr-Mo Alloyed, 0.40% C ) C (carbon) 0.38 – 0.43 % Cr (chromium) 0.8 – 1.1 % Fe (iron) 96.8 – 97.8 % Mn (manganese) 0.75 – 1 % Mo (molybdenum) 0.15 – 0.25 % P (phosphorus) 0 – 0.035 % S (sulfur) 0 – 0.04 % … Continue reading AISI 4140 Composition, Low alloy steel (4100 Series, Cr-Mo Alloyed, 0.40% C )