The Surface Structure And Carburizing Behavior Character Of Pretreated Fe

Carburizing process is a commonly chemical heat treatment in the manufacture industry. The workpieces would have the high surface hardness, high abrasion resistance and high fatigue strength but toughness and plastic in the heart by carburizing process, that reduced the abrasion and extended service life.The process of carburizing general in the temperature of 900-950℃,in order to gain a more thick layer of carburizing (more than 5 mm),the temperature have to increased to 980-1000℃. In require of the thickness, the carburizing process select from 6h to 12h, or longer. But the austenite crystal augment and deformation of workpiece with time prolonged.In order to found the ways to accelerate carburizing process. The Q235 plate treated by decarbonizated, then grain sub-micron layered organizational structure by oxidation-reduction. Carburizing in different temperatures from 750℃to 900℃. The carburized samples inspected by OM,SEM,EDS and microhardness instrument to observation,analysis,research.The simplified model used in computer simulation of carburizing process, and flexibled the simulation state more approached to the experimental resullts by adjusted the parameters. Through experiments and simulation, understand the carburization character of Fe by surface pretreated.The main results of this paper are as follow:(1) After the pretreated of oxidation-reduction, the crystal refinement in the region near to the surface.(2) Through different times of oxidation-reduction pretreatment, the thickness of carburizing layer increased by the frequency of treatment. (3) Carburized in different temperatures, the time from 15min to 2h, the thickness of carburizing layers of pretreated 10%-80% more than untreated.(4) Through computer simulation, obtain the estimated value of parameters in carburizing process that carbon diffusion coefficient of pretreated sample 1.2-3.3 times untreated, the speed factor of carburization of 1.1-1.8 times than without.(5) As the carburizing temperature increased, the effects of acceleration weaken.