WCA March 2020

wire 2020 The proportional-pulse control system design produces a stable thermal cycle that is key to achieving 90 to 100 per cent spheroidisation, which leads to greater die life and better flow during the cold forming process. The company uses a 100 per cent hydrogen protective atmosphere, and a patented AC/APEx™ control system to ensure surface quality, free of decarburisation. Rad-Con, Inc www.rad-con.com Rautomead Ltd will be exhibiting its sealed lid continuous casting RSL technology, designed for processing progressive alloy rods such as copper chrome zirconium. The single-furnace multi-chamber design accurately controls and maintains the target composition by varying the feed rate of each of the constituent elements. The liquid metal is protected from the atmosphere by being enclosed within an argon gas environment. Rautomead Ltd Stand: 10 B52

Redies Stand: 09 B25

For drawing fine copper wire, diamond-based materials are state of the art, but there is a distinction between tools using polycrystalline diamonds and tools with monocrystalline diamonds. Using optical microscopy to inspect a polished polycrystalline diamond (PCD) yields a perfectly smooth surface, but SEM-micrographs reveal the granular structure of the material). This is to be expected, as PCD is made from diamond powder – microscopically small monocrystalline grains of diamond that are sintered into a die in a process involving a catalyst (eg cobalt) at temperatures around 1,400°C and pressures of 60 kbar. The result is a contiguous structure of interconnected monocrystalline diamond-grains, the PCD. Diamond consists of cubically arranged carbon atoms, a material with directional physical properties (anisotropy). Directional differences of hardness in diamonds have been measured to have a ratio of 1:9. Since hardness is the same as resistance to wear, natural diamond (ND) wears in certain directions. When drawing wire in tools using ND, carbon atom layers are stripped off the surface of the diamond in the “softer” directions. The cylindrical part of the drawing die geometry becomes oval while the atomic surface stays solid and smooth. In contrast, the random orientation of diamond grains in a PCD die suggest the material’s hardness to be isotropic. The paradox is that wear of a PCD is higher by weight, but its service life is longer. Because the mechanical polishing of diamond (eg supported with ultrasonic sound) can only be done using diamond powder, making this endeavour nothing but guided wear, the surface diamond grains’ points are smoothed off, but the crystalline structure remains. It is yet to be settled whether these depressions on the surface – the softer flanks of the formerly single crystals – have a beneficial impact on the effect of the lubricant, perhaps like “lubrification pockets”. As to the choice of which material – ND or PCD – would be better suited, apart from the question of price, the following is true in practice: wire drawing dies with natural diamonds provide the best wire surface, but with higher likelihood of non-circularity; and wire drawing dies

with PCD give a rougher wire surface, but longer tool life. With the achievable smoothness of PCD wire drawing dies made with MANT with a grain size of 1µm, it is possible in practice to set up multi-die drawing machines without ND wire drawing dies. The period of use of PCD MANT wire drawing dies, eg for end-dies with 0.15mm, is claimed to be around two to four times higher than that of wire drawing dies with ND. Redies Deutschland GmbH & Co KG www.redies.com ❍ The polished surface of a PCD of type MANT with a grain size of 1µm – the wavelength of infrared light RichardsApex, a manufacturer of wet lubricants for the ferrous, non-ferrous and alloy wire and tube industries, will be displaying the latest technology on its stand. For wire drawing, tube drawing and hot-rolling applications, RichardsApex provides semi-synthetic, fully synthetic and straight oil form compounds for wet drawing of non-ferrous and ferrous wire, as well as protective coatings, cleaners and corrosion inhibitors for all non-ferrous and ferrous alloys, for both wire and tube applications. The company’s core products can be made at all of its manufacturing locations in the USA, Europe, Australia and Mexico. RichardsApex has an established global sales network to service customers throughout the world, including on-site support and technical sales assistance. The company has subsidiaries located in both the UK (RichardsApex Europe) and Australia (RichardsApex AustralAsia), and representatives in Canada, China, Greece, India, Italy, Japan, Korea, Malaysia, Mexico, Peru, Poland, Russia, Taiwan, Thailand, Turkey, Venezuela and RichardsApex, Inc Stand: 09 F06-05

❍ RSL 1400 model

Rautomead will also be exhibiting its conventional open furnace model continuous casting machines, which are used for the production of high-purity, high-quality oxygen-free copper wire rods and also conductor alloy rods such as CuMg, CuAg and CuSn. This continuous cast rod material benefits manufacturers of enamelled wires, superfine wires, LAN cables, wiring harnesses, railway wires, shaped, contact wires, CTC and transformer strips. Equipment is available for the production of 1,000 to 12,000 tonnes per year in the diameter range 8 to 30mm. Sample coils can be manufactured to order and produced on the continuous casting equipment installed at the Rautomead facility in Dundee, UK. Rautomead Ltd www.rautomead.com

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