Stainless steel has demonstrated a reduced tendency to gall. The corrosion resistance of iron-chromium alloys was first recognized in 1821 by French metallurgist Pierre Berthier, who noted their resistance against attack by some acids and suggested their use in cutlery. Metallurgists of the 19th century were unable to produce the combination of low carbon and high chromium found in most modern stainless steels, and the high-chromium alloys they could produce were too brittle to be practical. In 1872, the Englishmen John T. Woods and John Clark patented a "Water Resistant" alloy in Britain, that would today be considered a stainless steel. In
Corrugated stainless steel tubing and FAC tubing does not have a plastic sheath. On FAC tubing the corrugations are visible. CSST’s plastic sheath covers its corrugations. CSST is used as an alternative to the older standard “black iron” (steel) gas pipe. The inner stainless steel layer of typical residential CSST is .2 to .3 mm thick while the wall thickness of typical residential “black iron” gas pipe is 3 to 4 mm thick. CSST is more expensive than “black iron” gas pipe. However, CSST requires fewer joints, may be safer during earthquakes, and may be easier to install. CSST is alleged to have an