Effect of Heat Treatment Process on The Microstructure and Mechanical Properties of The Spray Coating Ni-Cr on CT38 Steel

Abstract

The thermal spray has been commonly used in several applications to replace the plating technology due to high adhesion, low cost, and environmental pollution. The thermal coating is usually used to rehibilitate the small disrepair of the crankshaft but the dimension and mechanical properties of such parts are still maintaned. Commonly, the microstructure and mechanical properties are greatly affected by depth of thermal coating, and thermal coating needs to be conducted the heat treatment to homogenize the microstructure between metals of coating and base metals as well as to improve the adhesion, hardness, and wear intensity. In this work, the effects of heat treatment on the microstructure and mechanical properties of the coating layer based on 80Ni-20Cr onto the surface of CT38 steel were conducted. SEM images and EDS analysis were used to determine the distribution of elements before and after heat treatment. In addition, mechanical properties such as Vicker hardness (HV), wear intensity, and adhesion were practically measured. As a result, after heat treatment by annealing under 1100oC during 8h, HV and adhesion were significantly higher than the case of non-heat treatment; meanwhile, wear intensity was found with 3 times lower compared to the unheated sample. The strong bilateral diffusion between Cr from coating layer and C from CT38 steel component to form carbide along with a formation of bond Ni-Fe was thought to be the main cause resulting in the improvement of mechanical properties and was demonstrated in this study.

Effect of Element Addition and Heat Treatment Process on the Properties of High Manganese Steel

“…2). The second way to heat treat samples is quite complicated and called by a new heat treatment process [19], [20]. The specimens were annealed before water quenched.…”

Synthesis of TiN and TiO2 thin films by cathodic cage plasma deposition: a brief review

“…In the beginning, the gas nitriding technique was presented in which nitrogen atoms were introduced into the surface of the material, keeping it at a certain temperature and exposure to permeable air. The most commonly used gases are ammonia, a mixture of ammonia and nitrogen, or a mixture of ammonia with hydrogen [23,24]. Depending on the application and the depth of the desired nitrided layer, the samples are treated for 10-120 h at 510 °C temperature [25].…”