Analysis of subsurface defects occurrence in abrasion resistant Creusabro steel after WEDM including the study of morphology and surface topography

Abstract

Unconventional wire electrical discharge machining technology is an indispensable part of the production of many industrial devices. Material separation takes place at very high local temperatures, and therefore, some undesirable surface and sub-surface defects are formed. Not only the occurrence of defects but also the quality of the machined surface is very important for the end customer, so it is necessary to monitor it carefully. For this reason, a 33-round planned experiment was carried out for the study of the impact of the machine parameters setup on the topography and morphology of the steel Creusabro 4800. (This material has not yet been the subject of any similar publication.) Metallographic preparations of all samples that allowed the study of subsurface defects using light and electron microscopy were produced. In order to investigate changes in the chemical composition of the surface and subsurface layers of the effects of WEDM machining, a complex chemical composition analysis was performed. A significant effect of the machine parameters setup on the occurrence of subsurface defects was demonstrated and the presence of burned cavities could be completely eliminated with machine parameters setup: gap voltage = 60 V, pulse on time = 8 μs, pulse off time = 40 μs, wire speed = 12 m min⁻¹ and discharge current = 25 A.

Keywords:

• Creusabro 4800
• defects
• electrical discharge machining
• machining parameters
• morphology
• topography
• WEDM

Additional information

Funding

This part of the work was carried out with the support of CEITEC Nano Research Infrastructure (ID LM2015041, MEYS CR, 2016–2019), CEITEC Brno University of Technology. This work was supported through the internal grant provided by the Jan Evangelista Purkyně University in Ústínad Labem, called SGS (Student Grant Competition), No. 0004/2015, and partly by the Ministry of Education, Youth and Sport of the Czech Republic, the program NPU1, project No. LO1207.