HPT Blade Tip Repair
Within the aerospace industry, it has become much more economical to repair costly engine components than to replace them. Worn HTP blade tips can be repaired for reuse with a specialized welding process. Before the actual welding can begin, the blade must be precisely and uniformly preheated to the correct temperature.
Both preheat and weld processes can be accomplished with integrated Blade Tip Repair Systems manufactured by Induction Atmospheres. These systems provide cost effective induction heating technology to bring the blade tip up to welding temperature (typically 1800°F) in just minutes.
Preheating Procedure
During the preheating procedure, the blade is placed inside a specially designed, kidney-shaped induction heating coil as shown at right. As heat is applied from a 3kW or 5KW power supply, blade temperature is monitored with an optical pyrometer. Once the target temperature has been reached, the welding repair process can be initiated.
System Options
Two types of Blade Tip Repair Systems are available: a Gas Purging System which remove contaminants and impurities by circulating gas through the dovetail during welding; and Atmospheric Glove Box Systems which provide a cost-effective alternative provided the blade tips are already free of contaminants.
Temperature Uniformity
Both systems offer a high degree of temperature uniformity. To evaluate temperature variation across the surface of the blade, IA engineers placed thermocouples on both convex and concave sides, as well as the leading and trailing edges. The test results showed exceptional temperature uniformity with an average temperature delta of only +/- 2 °F during operation.
Complete System Integration
Both systems also offer full integration of their atmospheric, heating and welding components. For example, no heat can be applied to the blade until the preset oxygen level is reached, and the actual welding process cannot be initiated until the blade reaches the target heating temperature. Once the preset system parameters have been reached, an easy-to-use console provides single button control for each stage of the repair process.
The advanced solid state heating technology within these systems provides heat ramp up, hold and ramp down at any rate or level. Both systems are designed with operator comfort in mind and feature adjustable height controls and water cooled hand surfaces.
Both systems are designed to heat treat the blades for stress relief after the actual welding procedure is completed.
