Chemical composition:
Chemical Composition
C Si Mn P S Ni Cr Cu
≤
45Mn 0.42 ~ 0.50 0.17 ~ 0.37 0.70 ~ 1.00 0.035 0.035 0.30 0.25 0.25
50Mn 0.48 ~ 0.56 0.17 ~ 0.37 0.70 ~ 1.00 0.035 0.035 0.30 0.25 0.25

Mechanical properties:
Grades blank sample
Size
/ mm heat treatment process of the mechanical properties of the steel hardness delivery status
/ HBS
Normalizing quenching and tempering σb / MPa σs / MPa δ5,,, (%) ψ (%) Ak / J ≤
≥ No heat annealed steel
45Mn 25 850 840 600 620 375 15 40 39 241 217
50Mn 25 830 830 600 645 390 13 40 31 255 217

Characteristics and Uses:
45Mn: carbon quenched and tempered steel, strength, toughness and hardenability than 45 steel high, after quenching obtain better mechanical properties, cutting performance is still good, but poor weldability, cold plastic deformation is low, there is a tendency to temper brittleness, generally in the quenched state, can also be used in the quenched and tempered or normalized condition. Used in the manufacture of parts subject to wear and tear, such as shafts, spindles, crank, spline shafts, connecting rods, axle joints, engaging lever, gear, clutch plates, bolts, nuts and so on.
50Mn: strength, elasticity, hardness are high, more use in the quenched and tempered condition, can also be used in some cases in the normalized condition, poor welding performance. For the manufacture of high wear resistance, high load is applied at the heat treatment of parts such as gear, gear shaft, the friction plate and 80mm below the cross section of the mandrel and the like.