Analysis of the wire electrical discharge machinability of roots of steam turbine blades

This paper presents method for the unconventional machining of the blades of steam turbines. Blade material as steel X12Cr13 was chosen into the investigation. Blade failures in gas turbine engines often lead to loss of all downstream stages and can have a dramatic effect on the availability of the turbine engines.. Conventional machining of the roots of steam turbine blades causes high temperature and rapid wear of tool which makes machining expensive WEDM is currently regarded among the most popular non-conventional machining. WEDM allows treatment of hard, brittle materials and composite, irrespective of their structure (thin-wall components) and mechanical properties. Submitted work is an analysis of potential impact on the received thickness of heat affected zone by appropriate heat treatment of material prior to WEDM. Such action is intended to eliminate or reduce the initiating impact of any microcracks on the formation of surface defects on the turbine blades roots during operation. The aim of the article is to replace the traditional methods of machining the blades roots by WEDM and thus the elimination of problems such as the need to monitor the tool wear. The presented experimental study was carried out on a modern wire EDM Sodick AQ327L. Investigated were the effects of WEDM of X12Cr13 steel as the Heat Affected Zone, the micro-fractures and surface roughness parameters.