Surface characteristics of low carbon steel JISG3101SS400 after sandblasting process by steel grit G25

Abstract EN

This research aims to study the surface characteristics of low carbon steel JISG3101SS400 processed by sandblasting using steel grit G25.

the sandblasting process is conducted at a fixed nozzle pressure of 5 bars and pressure angle of 90o, and varying nozzle-to-surface distances at 15, 25, and 30 cm, and blasting durations of 25, 45, and 120 s.

Surface characterization is firstly carried out by conducting observation on the surface’s morphology by a scanning electron microscope (SEM) and chemical composition by an energy dispersive X-ray Spectroscopy (EDS).

subsequently, visual inspection and measurement on surface roughness and hardness profile identification by rockwell and micro-vickers hardness tests are conducted.

a paint thickness test using ASTMD7091 was undertaken to observe the surface characteristics related to the coating process.

based on the result, the sem analysis found valleys, granules, micro-cracks, and grits embedded on the surface.

the visual inspection shows that the roughness is within the range in ISO8501 with values being Ra18.1 and Ra21.4 μm.

the hardened layer exhibits a maximum hardness value of 332HV and a depth of more than 50 μm by sandblasting parameters of 15 cm distance and 120 s duration.

Both roughness and hardness profiles are confirmed, increasing with closer nozzle-to-surface distance and longer blast duration.

It is concluded that sandblasting using steel grit G25 is effective in improving the mechanical strength and surface hardness of low carbon steel SS400.

these mechanical properties are essential in the paint coating of machinery applications such as pumps, tanks, ships, and pipelines.