Specification 1.Chromium molybdenum alloy steel. 2.Slightly higher carbon content than 4130. 3.Greater strength and heat treatment. 4.Good processability and easy polishing. 5.Good toughness and small quenching deformation. Application 1.Connection rods,conveyor pins. 2.Gears,stem assemblies. 3.Pump shafts and tool holders. Chemical composition NAME C Si Mn P S Cr Mo 4140 0.38-0.45 0.17-0.37 0.50-0.80 â?¤0.035 â?¤0.035 0.90-1.20 0.15-0.20 Similar grade GB AISI/ASTM DIN JIS 40CrMo 4140 1.7225 SCM44