The chemical composition of 4130 is as follows:
Carbon 0.28-0.33%
Manganese 0.70-0.85%
Phosphorus 0.035 max
Sulfur 0.040 max
Chromium 0.80-0.90%
Molybdenum 0.15-0.25%
Silicon 0.15 max 4130 steel has a carbon content of .28-.33%, manganese of 0.70-0.85%, phosphorus at 0.035%. 4130 also contains chromium and molybdenum, which are both used in the quench and temper process to provide 4130 with its strength and toughness. 4130 does not contain sulfur, but 4150 contains 0.15%.
