Abstract: Improved machinability of stainless steels, as determined by production-type operation of automatic screw machines, is obtained: by providing globular inclusions in the steel, which comprise essentially sulfur and selenium or tellurium, in combination with manganese, and which maintain globular character through extensive reduction as by hot rolling, the proportions of such elements being controlled to produce the inclusions, very preferably with a specific, relatively low and economical addition of selenium or tellurium; and also by controlling the actual presence of aluminum oxide in the steel, including the control of deoxidation practice, to provide production of stainless steel having not more than a critically very low content of aluminum oxide. In martensitic grades, the improved stainless steels are further enhanced in machinability, e.g. as to chip characteristics, by special heat treatment, including heating between the A.sub.1 and A.sub.3 critical points of temperature.