Nabil B. Sada
The Journal of Mechanical Science and Technology, vol. 23, no. 8, pp.2277-2284, 2009

Abstract : Round bars of 13.6 mm diameter made from low alloy steel were sprayed by hard-coating Lubrotec 19985 under the following spraying parameters: the rotation speed varied from 500 to 900 rpm, the feeding speed from 0.1 to 1.0 mm/rev, and the nozzle tip distance from 100 to 200 mm; the sprayed bars were then subjected to bending test. Depending on the thickness of the produced coating, the modulus of elasticity and yield bending stress of the coating were calculated by applying the bending deflection formula and an equivalent cross-sectional area technique, respectively. The results obtained indicated that the thickness, hardness, yield bending stress, and modulus of the elasticity of coating were varied with the variation in spraying parameters. The optimum spraying parameter was a rotation speed of 700 r.p.m, a nozzle tip distance of 200 mm, and a feed rate of 0.1 mm/rev. This optimum parameter produced an acceptable thickness of 1.14 mm, a hardness of 148 HV, a bending stress of 404.9 MPa, and a modulus of elasticity of 91.47 GPa. The results obtained can also help determine the modulus of elasticity and yield bending stress of the various coating materials when a coated round bar is subjected to the bending test.

Keyword : Low alloy steel; Spraying process; Lubrotec 19985; Hardness test; Bending test