green credentials have been attributed to the procedure as the salt can be recycled and the by- products (CO/CO2) are released in smaller amounts than traditional methods. In addition, pre-alloyed powders can be produced straight from the reduction process which has allowed previously difficult alloys (e.g. Ti-W alloys) to be fabricated. Consequently, the next step is to establish a robust supply chain for meltless Ti alloy powders.
An important message echoed throughout the conference was the significance of recycling as materials wastage can be as high as 70 percent when machining complex geometries. Near-net shaping manufacturing techniques were presented by Bill Swale, RTI International (superplastic forming) and Jon Meyer, EADS (additive layer manufacturing). They explained how these processes can be used to reduce production time, hence reduce the costs, and improve the quality of a component. Additive Layer Manufacturing (ALM) has been identified as a method to reduce
the amount of material wastage as the component is built up directly from powder form then consolidated using an electron beam. Any material not sintered can be recycled several times before being disposed of. This method can be used to create detailed features on large forgings such as landing gear, negating the requirement for expensive intricately designed dies.
Similarly, Richard Freeman (TWI) described how friction welding (linear, friction stir and stationary shoulder) can be used to reduce the amount of material wasted by machining. Instead of cutting complex geometries from a sheet of material, the complex component can be broken down into its constituent parts and cut separately. Then the appropriate friction welding technique can be used to join the pieces together. The company has been very successful with this method, producing welds with a high surface finish and mechanical properties akin to the parent material.
Recycling was also addressed by Achin Papendick (ThyssenKrupp VDM) who explained that since March 2008 the company has been using an Electric Beam Cold Hearth Remelting Furnace (EBCHR) to produce ingots and slabs not only from titanium sponge, but also scrap (chips, cobbles, feedstock, solids). The chemical compositions of the end-products (ingot/slab) are carefully controlled and therefore little or no difference can be found when compared to those formed from non-recycled titanium. Consequently, over the last three years, through the optimisation of this process, the company has seen profits around $1 million.
Jeremy Allen (The Metals Improvement Company) highlighted the benefits of peening (shot or laser) to increase the life of titanium products. Both laser and shot peening are based on the principle of imparting a layer of residual compressive stress underneath the metals surface.
This is done via blasting the component with small spherical media (shot peening) or a high energy laser. Since it is difficult for cracks to initiate or propagate within a compressively stressed region, the surface treatment provides improved resistance to fatigue, fretting, and stress corrosion cracking.
Other topics that were covered in detail during the conference included microstructure, texture and processing of titanium, along with Arc and EB welding techniques.
The European Titanium Conference is held every 2-3 years, and with the level of interest that NAMTEC has already received, it is expected to be just as good, if not better than the previous years.
The event was time and money well spent
Kyrre Haugen, Proplan International Ltd
organised event which I found very informative and useful
Thank you for the
opportunity to present. It was extremely useful for a small company like TISICS to get access to the range of delegates there
Stephen Kyle-Henney, TISICS
Tel: +44(0)1709 724990 www.namtec.co.uk
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