THE EFFECT OF SANDBLASTING TME ON PRODUCING NANOCRYSTALLINE SURFACE OF PO733 STEEL(DIN: 1.8509)

Techniques to produce nano-structured materials are severe plastic deformation (SPD) and surface severe plastic deformation (SSPD). This paper reports our study on severe plastic deformation that applied on samples surfaces with sandblasting by hard particles of silica and then annealing. The samples made of nitriding steel PO733 (DIN: 1.8509).The grain size of the nano-crystalline surface layer was in the range of 20 nm, determined using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis, Mechanical behavior of nano-crystalline surface was investigated using micro hardness test.The result show grain size decreases to nanometer scale(even 15mm), by increase time of sandblasting, but this decreasing is not linear. Thickness of nano-crystalline surface is independent by time of sandblasting and its stable. It was demonstrated that the mechanical behavior of samples surface was markedly improved when its grain size was reduced to nano-scale. The nano-crystalline surface caused by the sandblasting and annealing treatment exhibited considerably higher hardness.

Keywords:

PO733 steel (DIN: 1.8509) , Nano-crystalline surface , Mechanical properties , Sandblasting