TYPES OF STAINLESS STEEL-
There are three different types of stainless steel based on their microstructure
Ferritic stainless steel
Austenitic stainless steel
Martensitic stainless steel
What is ferritic, austenitic and martensitic?
These are nothing but various state of steel on their microstructure. Ferritic has body centered cubic structure, Austenite has a face centered cubic structure and Martensite has a body centered structure
Ferritic stainless steel-
This is straight chromium stainless steel that contains approx 14 to 27% chromium. Because of the very high chromium content they have superior corrosion resistance. Due to low in carbon and high in chromium, these steel are not heat treatable. These are generally soft material and are no heat treatable. Some example of it SS405, SS430, SS446 etc.
Austenitic stainless steel- these are alloy of chromium, nickel and molybdenum. SS304 and SS316 are commonly used austenitic stainless steel. These are para magnetic material. These are non heat treatable alloy.
This stainless steel is commonly used stainless steel where general corrosion resistance is required at moderately high temperature. This alloy is easily wieldable and can be made available in any required form (casting, rolling, forging and drawing etc.).
Stabilized grade stainless steel SS321/ SS347 is used in furnace tubes. These alloys provide excellent corrosion resistance against sulphur bearing compound in crude.
Martensitic stainless steel- are the straight chromium steel containing between 11.5 % to 18% chromium. Some important example of this group are SS410, 416,420,440A,440Band 440C.
Martensitic stainless steel is magnetic in nature. These steel are heat treatable. It has very hard microstructure. Hardness is in range of 60 HRC. The material is made soft by giving a tempering heat treatment.
Based on tempering temperature and tempering time the final hardness of the component can be decided to suit a given application. For example SS410 material is used to manufacture of heat exchanger tubes, turbine blades and corrosion resistance casting.
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WHAT IS STAIN AND WHAT IS STAINLESS STEEL AND WHY STAINLESS STEEL CALL STAINLESS STEEL- CLICK HERE