Iron based abrasive discs and wire beads

Citation

(1998), "Iron based abrasive discs and wire beads", Industrial Lubrication and Tribology, Vol. 50 No. 1. https://doi.org/10.1108/ilt.1998.01850aab.010

Iron based abrasive discs and wire beads

Iron based abrasive discs and wire beads

Diamond impregnated circular saws, designed for use in the stone and construction markets, and diamond impregnated wire beads used in stone quarries and construction used to rely heavily on cobalt.

For 50 years cobalt has provided a metallic matrix in which to suspend the particles of diamond abrasive and has been used as an effective bonding agent for some 50 years. First cold-pressed into shape, the tools are then hot-pressed in graphite moulds to their final density and shape. Recently, the proven technical effectiveness of cobalt has been compromised by its listing as a suspected carcinogen, which necessitates stringent precautions during manufacture and use and also by its price.

Cobalt is an inherently expensive material compounded by instability of the market.

Finding an environmentally-friendly, less vulnerably-priced but equally effective alternative was the daunting challenge handed to the group's diamond research team at Boart Longyear Technical Centre (BLTC) in Limerick. The team of scientists soon identified several alternative candidate materials; however, most were quickly eliminated on the grounds of cost or technical unsuitability. Eventually, the list was whittled down to two materials ­ nickel or iron ­ both chemically similar to cobalt and in plentiful supply. But nickel, too, had been identified as a carcinogen, and so the substitute of choice was iron.

Two years of intensive research ensued, developing expertise in iron powder technology from their base in Ireland, and conducting in-plant and on-site trials around the globe. Encouraging performance data using iron as a cobalt substitute was evident at the outset and now the full extent of its success can be disclosed.

Added to the cost-savings associated with dependable supply channels and stable material prices, iron-bonded products are not just meeting the performance standards of cobalt, but in most cases are exceeding them:

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  In South Africa, hot-pressed iron beads for diamond wire applications have been shown to outperform their cobalt-based counterparts, in both life and cutting speed. Tests in both South African and Norwegian quarries have yielded a 25 per cent improvement in wire life.

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  In Celle, Germany, a series of high-speed dry cut blades has been developed, enabling Boart Longyear to regain competitive advantage ­ through cutting speed and life ­ in a market where margins were increasingly slim due to mounting price pressures.

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  In the USA, saw blades containing iron have proved successful in cutting asphalt, concrete and other difficult materials. Iron shows a marked increase in reactivity with the diamond, thus giving superior adhesion and providing equal ­ or greater ­ performance compared to equivalent and more costly cobalt bonds. Boart Longyear Diamond Products in South Africa has already converted more than half of its cobalt-bonded products to iron, and all future diamond products will be iron-based.

Boart Longyear is a leading supplier of tools, equipment and services to the international mining, quarrying, construction, industrial, geotechnical and environmental markets. Comprising over 60 companies, the group employs some 9,000 people, based in 30 countries on all five continents.

Longyear Industrial Europe manufactures and markets diamond drilling and sawing equipment, industrial bits and saw blades.

More details from: Longyear Industrial Europe GmbH, Celle, Germany. Tel: +49 51 41 996-0; Fax: +49 51 41 996200.