Introduction 1.- What are Stainless Steels? 2.- Classification 3.- Properties 4.- Mechanical Properties 5.- Phase Diagrams 6.- Microstructures 7.- Applications 8.-Lyfecycle & Reciclability Sources
Stainless steels are said to be stainless because they resist corrosion and they don’t stain as easily as ordinary steel, but they are not stain proof.The stainless character occurs when the concentration of chromium exceeds amount a 11% of weight. There are different grades and surface finishes of stainless steel to suit the environment to which thematerial will be subjected in its lifetime
It is achieved by dissolving sufficient chromium in the iron to produce a coherent, adherent, insulating and regenerating chromium oxide protectivefilm on the surface. It is not surprising that they are used in the harsh environments of the chemical, oil production and power generation industries, and in utility goods where aesthetic appearanceand corrosion resistance are important criteria.
Stainless steel differs from carbon steel by the amount of chromium present. Carbon steel rusts when exposed to air and moisture. This ironoxide film is active and accelerates corrosion by forming more iron oxide. Stainless steels have sufficient amounts of chromium present so that a passive film of chromium oxide forms which preventsfurther surface corrosion and blocks corrosion from spreading into the metal's internal structure.
More than 200 comertially available stainless steel compositions.
All have different properties(heat treatetment, composition, production).
Chromium content must be within the ranges of 11% up to 30% .
- Chromium content of 11.5 % - Most FSS are binary alloys. (chromium andsteel) - Cheap.
- High carbon content. - Lots of components, thus more quenchable. - Higher strength, higher resistance to corrosion.
Small amount of carbon. 18% Chromium Most common alloy...