Quick History: Stainless steel was initially discovered at the turn of the last century by a Mr. Harry Brearley, a metallurgist in Sheffield, England who was investigating new steel compositions in an attempt to make the internal bores of gun barrels more resistant to heat. While testing different materials, he was astute enough to notice that samples of material with increased chromium content were harder and more difficult to etch with acid. This led to further investigation in his lab, stainless steel was born and people throughout the world have been eternally grateful ever since!
Composition: Stainless steels are actually iron alloys that normally contain a minimum chromium content of about 10.5%. The chromium forms a protective self-healing oxide film over the outer/exposed surface of the material. When scratched, a “new” surface layer, is exposed and the chromium content throughout the material allows a new oxide layer to form, with the result that the material effectively “heals itself”. Stainless steel is therefore inherently corrosion resistant, unlike carbon or low alloy steels which need to be protected from corrosion by secondary surface coatings or processes.
Grades of Stainless: There are many different made types/grades/series of stainless alloys, however for the purpose of discussing clamps, materials used are typically 200 series or 300 series, with sub-designations such as 201, 301 etc. in each. Corrosion resistance increases as the numerical designation goes up, with 316 series generally considered to have the highest degree of corrosion resistance for clamp band and housings. 316 is more costly to manufacture due both to it’s greater chromium content, and the fact that is somewhat more difficult to process.
Great. Why should we care? Well, the reason that this is important is twofold. First, it is important to select the correct series of stainless for your application(s), to make sure that you are getting the degree of corrosion resistance that you need. Secondly, the clamp marketplace is being inundated with clamps that are being called “stainless”, which in fact are at or below the very lowest chromium content for a given series of material. These clamps tend to be either unusually soft or brittle and prone to corrosion, which is why we are now having people come to us with questions on stainless on a weekly basis. We’ve got the answer – when you are looking for the best quality stainless steel clamps – look no further than Ideal Hose Clamps. Give us a call today at 800-626-4132 or feel free to send us an email at [email protected]
Next: We are going to do a side-by-side comparison of a high quality hose clamps with other “stainless” clamps of questionable material. The names however, will be changes to protect the not-so-innocent…