STRENGTHENING EVALUATION METHOD FOR PRECIPITATION STRENGTHENING TYPE HIGH-STRENGTH STEEL

摘要

PPROBLEM TO BE SOLVED: To provide a strengthening evaluation method for precipitation strengthening type high-strength steel to evaluate the strengthening of precipitation strengthening type high-strength steel, on the basis of a fact seen on the atomic level as to minute carbon-containing deposit. PSOLUTION: This strengthening evaluation method is equipped with a measurement step (STEP 5) for measuring the kind and amount of elements contained in the carbon-containing deposit in steel by a three-dimensional atom-probe field ion microscope, a calculation step (STEP 6) for calculating the rate of deposit causing a p-value to fall within a range from 0.2 to 0.5, based on a measurement result at the measurement step, assuming that the p-value shows the rate of oxygen where oxygen and carbon constituting the deposit are assumed to be (CSB1-p/SB, OSBp/SB) in terms of an atomic ratio, and an evaluation step (STEP 7) for evaluating deposition strengthening on the steel, based on the rate obtained in the calculation step. In the evaluation step, it is determined that prescribed strengthening has been made, when the above rate falls within an appropriate range. PCOPYRIGHT: (C)2006,JPO&NCIPI