The heat treatment process, due to various reasons after quenching mold often need to be re quenching and tempering, such as leakage processing, using re quenching correct deformation, failure mode, hardness, repair re selection process changes, heat treatment operation errors etc.. Re quenching need not to need to add one annealing, normalizing, become the relevant technical personnel need to consider. The past is to add another annealing, normalizing, the reason is: ① repeated quenching grain will increase, and may produce "Na" organization (and view that the multiple quenching grain will refine, toughness increase); ② each quenching will form the micro crystal crack, repeated quenching micro crystal crack formation the macro crack and deformation will increase. Whether or not to re quenching annealing, there is no clear statement theory, the concrete operation stultify oneself "back to the phase change heat coil heating reason" section, though two different processes, process has little difference, but is essentially the same, is repeated quenching. If a practice, not heavy quenching annealing does no harm, but also good. In view of the present market by number of D2 steel cold work die, from the market to buy two pieces of Cr12MoV steel material, Size 120 mm fire a + 500 ℃ tempering 3 h two. Repeat quenching every × 120 mm × 100 mm, the vacuum gas quenching, oil quenching test. Invariant of quenching and tempering process, the sample size is 120mm × 100 mm × 100mm, quenching process: 1020 ℃ for 150 min; tempering process: 180 ℃× 3h. Repeated quenching medium without any annealing, normalizing treatment. Steel material repeat after quenching, gas quenching material appearance plane found no major abnormalities and oil quenching material appearance plane has obvious bulge phenomenon, with heat treatment rules; grain size is second to fifth times, seventh times with the increase of the phenomenon, but not obvious; found no grain size is not a Nessler's organization, crystal crack phenomenon, may be due to test multiple is not enough, not found. According to the above, D2 (Cr12MoV material chemical composition of normal can be repeated 1 to 2 times quenching), without annealing, normalizing, material will not have abnormal.