Effect of Elastic Modulus Line Selection on the Yield Strength R_p0.2 Measured Value of Steels

The tensile test of Q235B carbon structural steel and DP780 high strength steel at room temperature were carried out, and the effect of elastic modulus line selection on the yield strength R_p0.2 measured value was studied. The results show that the fitting degree between elastic modulus line and stress-strain curve will affected the value of elastic modulus line slope m_E, thus affected the yield strength R_p0.2 measured value. For the Q235B carbon structural steel with obvious yield platform, the accuracy of m_E value had little influence on the R_p0.2 measured value, but for the DP780 high strength steel with continuous yield phenomenon, the accuracy of m_E value directly affected the R_p0.2 measured value.