PRZOOM - /newswire/ -
Bootle, Merseyside, United Kingdom, 2010/11/23 - A new benchmark in the coupling of re-bars has been set by steel reinforcement specialist Hy-Ten with the UK’s first friction welded coupler.
Fully approved by independent test laboratories, the HT Welded Coupler offers enhanced structural performance, significant site productivity gains with additional material cost savings.
“In the past, to create a coupled joint, both bars have to be threaded – one end receiving a coupler in the factory, the other end being positioned and screwed-in on-site. Our system requires no threading. We friction weld the couplers to the re-bar in the factory so they are simply screwed together on site in one quick and efficient process. You don’t even need a torque wrench.” commented Hy-Ten director Richard Webster.
Hy-Ten has invested a substantial sum in researching, perfecting and setting up the new process. Using a dedicated machine, couplers are rotated at high speed. The re-bar is offered up to the coupler and the friction between the surfaces scours and heats the metal surfaces to fusing point.
Extensive trials by the Certification Authority for Reinforcing Steel (CARES) have proven the strength of the union after testing multiple samples to destruction. Ultimate failure was in the re-bar and not the joint, with forces as high as 630 Newton’s being applied to break the bar. The CARES technical approval certificate can be seen at ukcares.com/.
Hy-Ten (hy-ten.co.uk) has already tested and obtained approval for bar diameters from 16 to 40mm with tests on 50mm bar pending. The company began offering the new system in August and has already noted strong interest from construction contractors and consultants. “Productivity improvement and significant cost saving are driving contractor interest,” commented Richard Webster. “Importantly, the material savings make this system a more economic alternative for 25mm bars and larger, as the friction welded joint is cheaper than the corresponding lap length,” he concluded.
High resolution images on the web at ainsmag.co.uk/.
Information on Friction Welding
Friction welding (FW) is a solid state welding process that uses mechanical interaction between components and a lateral force to generate localised heat to weld them together. During the localised heating there is some displacement of plasticised material, but no actual melt of metal occurs. Technically therefore the process is not welding but forging.
Material can be joined in a fraction of the time required compared to tradition gas or arc welding. Moreover, because heating and plasticisation is extremely localised and there is no actual melt the metallurgical properties of the materials remain largely unaffected and their inherent strength is maintained.
Friction welded couplings are widely used in high rise buildings in areas of the world subject to earthquake. Applications in aerospace involve the jointing of dissimilar metals in components, copper and aluminium for example. In car manufacture the valve heads and stems in pushrods are commonly jointed this way.