In a major development in the thermal power sector, Bharat Heavy Electricals Limited (BHEL) is setting up a facility to assess low cycle fatigue effects in rotors required for such power plants. This will help India to soon manufacture its own super alloy steam turbine rotors for efficient coal based thermal power plants.

To increase the efficiency of coal based thermal power plants, the use of nickel based super alloy materials as against chrome based steels is required. The nickel based Alloy 617M has been selected by the Indian Advanced Ultra Super Critical (AUSC) consortium. The alloy is industrially available and the AUSC consortium has already expressed its confidence in the indigenous development of the alloy. However, lack of experimental data on the performance of Alloy 617M rotors hinders its effective usage in the Indian AUSC power plant.

Overcoming this challenge, the Department of Science & Technology under its Clean Energy Research Initiative has supported a project to BHEL (R&D), Hyderabad for the establishment of High Temperature Spin Test Rig (HTSTR).

It will be the first facility in India for experimental validation of the design of AUSC steam turbine rotor relating to creep-fatigue damage (deterioration of metals and alloys subjected to a cyclic thermomechanical load at elevated temperature) and will also be the only one of its kind in India in terms of establishing a real size engineering experimental set-up.

It will subject the turbine rotor segments of weight upto 9000 kilograms to various damage conditions similar to that in the plant operation, like high temperatures upto 800 degree Celsius, high speed upto 3600 revolutions per minute (RPM), followed by long term steady state operation and controlled heating and cooling. The facility will be a significant step towards Atmanirbhar Bharat in this sector. 

The facility will enable the design validation of 800 Megawatts AUSC steam Turbine rotors for certifying the long term performance of Super Alloy Monometallic and Bimetallic welded rotor with a total of 2000 startups (hot+warm+cold) and 100000 hours of total steady state operation.  This is achieved through accelerated testing within 200 cycles and 10000 hours respectively. A unique test protocol for accelerated testing is formulated by the BHEL team with the guidelines of ASME standards. Two rotor segments – Monometallic (Alloy 617M) and Bimetallic welded portions (Alloy 617M and 10 Chrome) of actual steam turbine rotor will be subjected to equivalent operating conditions over its guaranteed timeline by increasing the temperatures and achieving desired thermal gradients within the rotors, during the heating and cooling operations.

This unique test protocol and its visualisation software are registered under the Indian patents and copyrights act.