To achieve the hardness specified for your part with induction heat treatment, the right steel grade must be selected. The greatest hardness range directly correlates to the carbon content of the steel being used. To help you develop accurate parts and specify reasonable tolerances for hardness and case depth results, Zion Industries has created the following guidelines for the maximum surface hardness achievable using induction hardening.

Materials Carbon Content Hardness-HRc Comments
  1019 0.15 – 0.2 30 Typically carburized  
  1035 0.32 – 0.38 45 Can reduce by tempering  
  1040 0.37 - 0.44 52 Can reduce by tempering  
  1045 0.45 – 0.50 55+ Can reduce by tempering  
  1050 0.48 – 0.55 58-60 Can reduce by tempering  
  1070 0.65 – 0.75 65 Can reduce by tempering  
  1140 0.37 – 0.44 50 Can reduce by tempering  
  1141 0.37 – 0.45 52 Can reduce by tempering  
  1144 0.40 – 0.48 52-55 Can reduce by tempering  
  1151 0.48 – 0.55 55 Can reduce by tempering  
  4140 0.38 – 0.43 54-59 Can reduce by tempering  
  4145 0.43 – 0.48 55-62 Can reduce by tempering  
  4150 0.48 – 0.53 65 Tendency for cracking  
  4340 0.38 – 0.43 54-59 Very crack prone  
  52100 0.98 – 1.10 62-66 Temper soon after HT  
  8620 0.17 – 0.22 37-42 Typically carburized  
  Ductile Iron Varies Depends Pearlite determines HT  
  Powdered Metal Varies Depends Watch Porosity  
  High Density PM Varies Depends Watch Porosity