PROCESSES, PRODUCTS AND TECHNOLOGIES DEVELOPED
Vacuum Heat Treatment Furnace Facility
The Gas Turbine Research Establishment (GTRE), Bangalore, has installed a furnace for vacuum heat treatment of forgings in stainless steel, Ti-based alloys and Ni-based superalloys. At present, the facility is being used for heat treatment of Kaveri engine components like shafts, fan-drums, bearing housings and discs, etc.
The furnace consists of hot-zone, vacuum chamber and pumping system, gas quenching (cooling) system, electric supplies with controls, vacuum gages and temperature instruments, pneumatic and a water cooling system. The operating range of the furnace is 200-370(C with a vacuum range of 0.001-0/0001 m bars. The hot-zone of the furnace is shielded by a raDIATion shield-pack. Vacuum chamber is constructed with the help of high temperature and corrosion resistance stainless steel. The chamber contains necessary ports for gas quenching and vacuum pumping systems and entries for power feed.
The bottom head of the vacuum chamber has pneumatically-operated autoclave type closure door to ensure safety during opening and closing. The job for heat treatment is inserted into the vacuum chamber along with the test piece from the bottom. For meeting the test requirements, the job has to conform to the test-specimen standards.
For uniform cooling of job, the gas quenching system circulates inert gas through internal circumferential nozzles in the furnace. The capacity of the gas tank is 750 gallons at 125 psig min. All instruments are cooled with the help of 100 cfm air circulation fan. Motor and starter alarms on the furnace are controlled sequentially by a PROM. A power supply of 150 KVA capacity is required and modular valve pneumatic system is used for supply of air to pneumatically-operated equipment. A water cooling system does the internal cooling of the furnace.
CNC Wirecut EDM Facility
The Gas Turbine Research Establishment, Bangalore, has installed a Wirecut CNC Electric Discharge Manufacturing Facility to manufacture firtree roots of discs (compressor and turbine) of Kaveri engine. The facility consists of machine tool, power supply and dielectric supply units. Till now, variable guide mechanism brackets of HP compressor honeycomb for sealing rings and jet pipe hump petals have been manufactured for Kaveri engine using the facility. Rig cascade blades have also been manufactured with the help of this facility.
The machine tool comprises a main work table (X-Y table), an auxiliary table (U-V table) and a wire drive mechanism. The work piece is mounted and clamped on the main work table. The main table moves along X and Y axes, in steps of 1 micron with the help of servo motors; the U-V axes are parallel to X and Y axes. A travelling wire, continuously fed from wire feed spool travels through the work piece and goes finally to waste wire box. Along its path, the wire is supported under tension between a pair of wire guides on the upper and lower sides of the work piece. Lower wire guide is stationary, whereas U-V table supports the upper guide. As the material removal, i.e., machining proceeds, the work table carrying the work piece is displaced transversely along a pre determined path and stored in the controller in the form of software. The path specifications (path computer program) can be supplied to the controller through a program or directly through the controller keyboard. When X-Y table moves along the predetermined path while U-V table is kept stationary, a straight cut on a predetermined pattern is formed in the work piece by electric discharge in the gap between wire and work piece. For producing taper machining, wire electrode has to be tilted. The path information of X-Y and U-V tables is fed to controller in terms of linear and circular elements through NC program. The power supply unit consists of electric pulse generator, motor driver units for X, Y, U, and V axes, and a controller.
During machining, dielectric supply unit flushes water continuously through nozzles on both sides of the work piece for cooling the machining zone. The dielectric medium provides widening of spark gap across the wire work piece gap minimising short circuit, resulting in high cutting speed as water has good cooling effect on both the wire and work piece. Water flushing is done to achieve a stable machining condition.
High Altitude Test for Kabini Engine
High altitude tests for Kabini engine were carried out at Altitude Test Facility at CIAM, Moscow. Performance tests at high inlet pressure and temperature corresponding to flight at Mach nos. up to 0.9 and altitude up to 11 km were carried out. These tests indicated sound structural integrity and established flat rating concepts. Tests were also conducted successfully for generation of compressor characteristics, surge margins and performance at supercritical air entry conditions. Engine light-up trials at various altitudes and Flight Mach nos. were tried and found satisfactory. Air turbine starter tests at various altitudes were tried successfully. Combustion flame stability tests were conducted for altitudes of 12, 13.5 and l5 km at M=0.3,0.35 and O.4, respectively and were found to be satisfactory. All other systems on the engine, viz., exhaust, fuel, oil, VGCS, and starter were satisfactorily functioning during these altitude tests.
RECENT DRDO DEVELOPMENT
Data Concentrator System
The Data Concentrator (DC) System developed by the Electronics & Radar Development Establishment (LRDE), Bangalore, is a statistical multiplexer and concentrator, which enhances the data communication capability of army radio engineered network (AREN)-the tactical communication network of Indian Army. In addition, it provides data communication integration between army static switched communication network (ASCON) and AREN. It can be used to extend the range of ASCON data ports. It can also be used independent of AREN and ASCON networks to provide data communication facility to a large number of subscribers spread over a geographical area.
The DC System supports 16 asynchronous data subscribers up to 19.2 kbps data rate and provides 4 km range on field cable. It also enables extension of range for 16 data subscribers of ASCON using field cable or radio relay with multiplexing equipment. It has been designed based on ITU-X.3, X.25, X.28, and X.29 recommendations and meets JSS 55555 environmental specifications and MIL-STD 461C EMC.
The DC System has successfully undergone user trials and is likely to be productionised by Bharat Electronics.
IAT EXCELS IN FLOWER SHOW-99
The Institute of Armament Technology (IAT), Pune, bagged 74 prizes at the prestigious 34 Annual Flower and Vegetable Show organised by Poona Women's Council during 18-19 September 1999. IAT won 26 first prizes, 26 second prizes, 15 third prizes, and 7 trophies in the categories of gARDEns, lawns, cut flowers, potted plants, vegetables and fruits.