NEW WELDING PROCESS

Gisborne Times, Volume XXIV, Issue 1937, 20 November 1906, Page 3

NEW WELDING PROCESS

The Ohristohuroh Tramway Board, siooe the linos havo boon oonstruoted under their own supervision, have adopted several improvements in order to facilitate the laying of the motals. Ssvoral members of the Board witnessed a trial of a new weldiDg process they are about io adopt. Tno thermit, or heat unit, used in tho experiment, consisted of a powder of oxide of iron and aluminium, mixed in proper proportions. This was then placed in a oruciblo, or furnace, rntdo from maoganese ore. A heat equal to melting stool was requited before tho thermit oould bo ignited, and this was derived by placing a small amount of powdered aluminium on tho top of tho thorrni*. In tbe meuutimo tho ends of the rails had betn drawn dose together by moans of a damp specially made for thß purpose, and a mould piaood round tbo ends So be united and well paoked with damp sand. The cruoible was then placed over tho mould, tho powdered aluminium was ignited, and in a few seoonds the little furnace was roaring with flame and wbiio hot, emitting epaiks in groat volume. Tho oruoibla alter tho roaotion was complete contained at the bottom the mohen steel covered with a quantity of molten aluminium slag. By easing up a small bar of iron at the bottom of the crucible the whole was allowed to flow info the mould, tbe thermit steel and molten aluminium bringing the ends io tbo mould to a heat sufficient to weld if. Within about thirty stoonds the clamps were screwed up and the whole waß left for foity minutes when tho moulds and clamps were removed and the joint trimmed with files. The joint is said to beso strong that tho rail under a steam hammer would break beioru tho wold would give way. Tho plant necessary for the process could j almost be oariied on a bicycle, ]