| 摘要 |
<p>A method for the reduction and sintering of moulded bodies containing or consisting of reducible metal compounds is characterized in that the reduction is carried out in two or more steps in each of which the temperature is increased and for a predetermined period of time maintained within predetermined limits for permitting the escape of gases evolved in the reduction process to take place so slowly as to avoid formation of cracks in the body being treated. The moulded body, having the shape of the finished article, is dried and reduced in a continuous operation either by a reducing gas or by a reducing agent mixed with the reducible compound or by both methods simultaneously. The furnace used may allow continuous passage of the bodies being treated. Plasticizers such as hydroxides, e.g. manganic hydrate or iron hydrate may be incorporated with the reducible compound to be moulded and moulding may be carried out by pressing in dies, extrusion, rolling or moulding on a carrier of paper or other combustible material. Sufficient carbonaceous material for carburizing the product may be incorporated with the raw material. Subsequent to the reduction, presintering and final reduction operation may be carried out at a higher temperature followed by compacting and final sintering a temperature 50-150 DEG C higher than the presintering temperature and not lower than 80 per cent of the melting temperature of the metal concerned. Compacting may be carried out by forging, pressing, hammering or rolling in the hot or cold state. Specification 3926/97, [Class 72], is referred to.</p> |
