Process for improving magnetic performance in a free-machining ferritic stainless steel

Abstract

A method for making a corrosion resistant, ferritic steel alloy, with reduced magnetic coercivity is disclosed. The process includes the step of providing an intermediate form of a ferritic alloy consisting essentially of, in weight percent, about ______________________________________ Carbon 0.02 max. Manganese 1.5 max. Silicon 3.0 max. Phosphorus 0.03 max. Sulfur 0.1-0.5 Chromium 8-20 Nickel 0.60 max. Molybdenum 1.5 max. Copper 0.3 max. Cobalt 0.10 max. Aluminum 0.01 max. Titanium 0.01 max. Nitrogen 0.02 max. Iron Balance ______________________________________ The intermediate form of the alloy is given an annealing heat treatment at a first temperature in the range of about 700.degree.-900.degree. C. for at least about 2 hours. After the penultimate annealing step, the intermediate form is cold worked to reduce its cross-sectional area by about 10-25%, thereby providing an elongated form of said alloy. The elongated form is then given a final annealing heat treatment at a second temperature in the range of about 750.degree.-1050.degree. C. for at least about 4 hours. Parts prepared in accordance with the disclosed process are fully ferritic and exhibit a coercivity significantly less than 2.0 Oe.

Dependencies are inferred from the claim text.