Prediction of Steel Hardness in Plastic Deformation Process

The hardness prediction model is established based on the relationship of true stress-strain and engineering stress-strain.When the steel reaches plastic deformation stage,the true stress is regarded as the yield point for the corresponding plastic deformation.And the true strain ∈ is transferred into the relative true yield strain ∈sp to evaluate hardness value in the plastic deformation stage.The Brinell hardness of 45 steel is calculated in a range of different strains and the results obtained show that it is in good agreement with the test results.And it can be used to predict the various hardness values of 45 steel in the plastic deformation process.