Today, eyewear manufacturers around the world can take advantage of lots of materials to make eyeglass frames. Regular plastics and metals are most commonly and traditionally used, such as cellulose acetate, propionate and nylon. And now there are also available new types of plastics and metals, like memory metal and memory plastic. There are still various unusual frame materials, including wood, bone, buffalo horn, and even stone. Among all these materials possible to make eyeglass frames, stainless steel is a regular but special one. This material has exclusive features or advantages. Stainless eyeglasses just refer to spectacles that have a stainless frame.
Widely used in the eyewear industry, stainless steel features lightness, low toxicity and strength. In addition, most of the stainless steel frames are nickel-free and thus hypoallergenic. Also known as inox steel, stainless steel is exactly a steel alloy with a minimum of 10.5 or 11% chromium. In typical, the content of chromium ranges from 10 to 30 percent. Of course, the major ingredient is steel. And in some cases, other elements may be added. In addition to the above features, stainless eyeglasses have also excellent resistance to corrosion, abrasion and heat. Why is this material able to provide such valuable features or benefits? Well, it is the chromium that exactly matters. This ingredient added to regular steel makes this material stain-proof. To a high degree, this is considered as the most valuable advantage boasted by this alloy. Some people even call it corrosion-resistant steel or CRES, when the alloy type and grade are not stated.
Since the major element is regular steel, stainless steel has all of the properties of steel. Those extra benefits or attributes are contributed by the added ingredient. This great advantage was first discovered by English metallurgist Harry Brearly, who accidentally discovered that adding chromium to low carbon steel brought stain resistance, while he was working on a project to improve rifle barrels. Modern stainless eyeglasses can take three major types of materials, including Austenitic, Ferritic and Martensitic.