A Study On HT250 And 45 Steel Surface Permeated Aluminum Process And Organization

In this paper, the influence of the microstructure on their properties which comes from the aluminizing on the steel and iron surface is studied. We used high power video microscope (HSVM) and field emission scanning electron microscopy (FESEM) to study the relationship between the structure of 45 steel and HT250 and leaching time, hot dipping temperature etc. The microstructure and properties of steel were measured and analyzed by using HSVM, FESEM and HXD-1000C type micro hardness tester.The coating thickness of HT250 becomes thicker with the increase of the hot dip time and temperature, but its change trend gradually becomes slow. The effect of the temperature on the coating is much greater than the time.When using the three auxiliary agents K2ZrF6, CrO3 and ZnCl2, the thickness of the coating is obviously different under the same infiltration condition.By coating agent, the effect of K.2ZrF6 is best and CrO3 is the second and the third is ZnCl2.The grain refinement, strength and toughness of the steel matrix were improved slightly after the Aluminizing treatment of 45 steel. After aluminizing on the surface of the metal, the produces 100～300μ m aluminized layer,which composed of many kinds of intermetallic compounds,such as Al2O3. FeO, FeAl3, Fe2Al5 and so on.This structure is compact and completely covers metal surface,which has good oxidation resistance.The hardness test and electrochemical corrosion test show that the layer of aluminum alloy has good corrosion resistance and excellent wear resistance. The hardness of the alloy is higher and the surface of the alloy layer has better wear resistance after aluminuming. The surface of the alloy layer has a good cathodic protection, and the corrosion resistance of the alloy layer is improved. The petrochemical experiment result shows that the alumetized steel is a kind of cheap and fine material to get great economic benefits.