Published on 22 January 2013
A series of friction welding trials at TWI has proved that the process can be used satisfactorily to complete a specific weld in nuclear power station boilers.
In building boilers for Hartlepool and Heysham Nuclear Power stations a system of thermocouple probes was required to fit into selected boiler headers to record local steam temperatures.
TWI was approached by Babcock Power, the boiler manufacturers, to undertake development of the 'mast to closure dome' friction weld and subsequently make the production welds.
The header domes were forged from 316 austenitic stainless steel and were to be friction welded to tubular extensions machined from solid 316 stainless bar.
The successful completion of the welds with acceptable destructive test results demonstrated that friction welding, a solid phase bonding process, had successfully been applied in this most demanding application.
The welding trials showed that sound joints can be achieved by continuous drive friction welding between 63.5mm OD and 36.6mm ID stainless steel tube and that the joints exhibited acceptable bend, tensile and metallurgical properties.
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