Effects Of Nitrogen On Properties Of High Chromium Cast Iron

In the paper industry of rapid growth, disc refiner plates performance has become anincreasing concern. The majority of pulp refiner plate use in high chromium cast ironmaterials, its excellent wear resistance can completely meet the needs of this industry, but itslow toughness cannot adapt to poor paper material environment. Will be damaged due toexcessive impact energy when the raw materials mixed with sand iron and other debris, theplate will be damaged by the high impact energy, which reduces the life of the plate. In thispaper, the nitride chromium added to the high chromium cast iron in the smelting process formodification of the high chromium cast iron, which obtained good results, Which nitrogenwere added to the mass percentage of0.05%,0.07%,0.1%,0.2%,0.4%and the carboncontent from3.3%to2.9%.For significantly improved performance of high chromium cast iron add nitrogen, Theheat treatment system for the1020°C air quenching+510°C tempering and add nitrogen0.07%,the toughness of high chromium cast iron up to6.4J/cm2and hardness to keep in61.5HRC.Add the amount of nitrogen increased, toughness will be reduced, the hardnessincreases. The Factsage software to simulate the phase diagram was informed that thenitrogen to expand the austenite region, The more added to the amount of nitrogen, at roomtemperature to get the more retained austenite. To use Image-Pro Plus software analysis ofthe carbide morphology obtained that nitrogen can reduce carbide size while increasing thecarbide number, add too much nitrogen can make carbide becomes bigger.Tempering temperature will affect the performance of high chromium cast iron, whenthe tempering temperature increases, the toughness of high chromium cast iron increased, thedecrease in hardness. When the tempering temperature up to530°C and add nitrogen to0.07%, the toughness of high chromium cast iron to reach6.6J/cm2and hardness as low as55HRC.Reduce the quenching temperature can improve the toughness of high chromiumcast iron, when the quenching temperature of980°C, nitrogen0.07%, the toughness of highchromium cast iron up to7.2J/cm2hardness remains in60.5HRC. It’s the best performanceof the material。...