Effects of Al Content in Pack Powder on Microstructure and Mechanical Properties of Aluminized N80 Oil Casing Steel

Aluminized N80 oil casing steel was packed by different Al content of pack powder.The aluminizing process was introduced.The metallographic,element distribution,phase composition,microhardness of aluminized N80 casing steel were analyzed using optical microscope,SEM,XRD,microhardness equipment in respective.The results show that the aluminizing layer with a thickness from 450 to 650 μm can be obtained on the surface of N80 casing steel after hightemperature vacuum-pack processing by different Al content of pack powder.With the increase of Al content in the pack powder,the thickness of aluminizing layer increase.From the surface to the matrix,the Al content gradiently decreases in the aluminized layer microstructure.The different Al content in the pack powder causes the different phase in the surface of aluminized layer.The Fe3Al phase is obtained with the pack powder of 10% and 20%Al content,but the 35%Al content pack powder get the FeAl phase.The microhardness of aluminized layer with different Al content in the pack powder is higher than that of the microhardness of matrix.Microhardness gradually reduces and tends to constant from the surface to the matrix.