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I would like to ask if anyone had experienced similar issue. When we turned on the cooling water pump, the center body of the turbine aft support leg is observed to be bulged slightly.
We do understand the material of the aft support leg is stainless steel and is thin (of about 3mm according to GE). Thickness gauging and metallurgy test found that the material of the aft support leg is indeed in healthy state.
We do experience water leak from the edge of the aft support leg in which we thought it is due to material fatigue. However, we are continuously experiencing water leak from the support leg and the cause of the leak always come from the weldment. Hence, we are suspecting that the weldment crack could be due to this slight bulge from the support leg as we only experience this weldment failure during start up (when cooling water pump runs when start up command is initiated), and not even at firing temperature of the gas turbine which removes the possibilities of failure due to material failure (high temperature).
We do understand the material of the aft support leg is stainless steel and is thin (of about 3mm according to GE). Thickness gauging and metallurgy test found that the material of the aft support leg is indeed in healthy state.
We do experience water leak from the edge of the aft support leg in which we thought it is due to material fatigue. However, we are continuously experiencing water leak from the support leg and the cause of the leak always come from the weldment. Hence, we are suspecting that the weldment crack could be due to this slight bulge from the support leg as we only experience this weldment failure during start up (when cooling water pump runs when start up command is initiated), and not even at firing temperature of the gas turbine which removes the possibilities of failure due to material failure (high temperature).