Machine tap DIN 371-B

The machine tap consists of cobalt alloyed and vaporised heavy-duty high-speed steel. For through threads and bottoming threads in unalloyed and alloyed steels up to a strength of 1000 N/mm², stainless steel. The thread is cut in one operation. By "vaporisation" is meant the evaporation of a non-metallic oxide film. Vaporisation acts as a separating layer and reduces the occurrence of cold welding. In cold welding there are workpiece chips that build up on the flanks of the tap and damage the finished thread. Consequences of cold welding are torn and dirty flanks. VAP improves the adhesion of lubricants to the tool surface.