Zero-defect and ppm strategy for semi-finished steel products, bars, wire rod and wire from the point of view of the steel manufacturers

Several fundamental ideas on the problem of certain "zero-defect" expectati ons on the part of customers are presented against the background of the cu rrent technical and economic reality of steel production and are discussed on the basis of practical examples. The zero-defect strategy starts out from the premise that, with careful pre liminary planning, inspection and assurance of process parameters, products supplied by the steel-producing and further-processing industries will be free from defects. This article defines remaining defects and highlights th e conditions under which they may occur or stay undetected. Theoretical con siderations which presuppose, in a steel heat, a certain number of uniforml y distributed, undetected remaining defects that cannot be altered by follo w-on processing stages are also presented. With practical examples sewing a s a basis, it is illustrated that remaining defects can, with a high probab ility, be detected at a suitable further-processing stage by means of 100% inspection. Processors and fabricators have the decisive possibility here t o help move closer toward the common goal of zero-defects.