Abstract
The philosophy of “Total Quality Control” is introduced by describing the special problems associated with the applications of hard-metals. There are no simple direct tests to measure the important parameters. These have to be assessed and controlled in an indirect way; nevertheless, experience has shown that the system of quality control described is most effective.
Hard-metal is very expensive and this factor alone provides a special incentive for manufacturers to supervise quality, not only to satisfy customers but also to reduce their own scrap costs. The manufacturing process should be capable of yielding the required quality under simply maintained operating conditions. A high degree of involvement on the part of operating and supervising personnel is required. The manufacturing method is illustrated with flow sheets and described only in sufficient detail to indicate the significance and relevance of the quality-control tests. Emphasis is placed on chemical purity, precise carbon control, and grain-size control, all means towards obtaining quality in the sintered product, particularly in terms of freedom from porosity. The most important stage is the examination of test-pieces made from each batch of powder, particularly metallographic examination; No powder is used for production until the tests have shown the quality to be acceptable.
It is concluded that the effectiveness of quality control may be judged by balancing costs against complaints and is a matter to be resolved individually by every manufacturer.
Get full access to this article
View all access options for this article.