WHAT IS STAINLESS STEEL ?
Stainless steel is an iron-containing alloy with a 10,5% (and more) chromium and 1,2% (and less) carbon content that is resistant against corrosions due to a thin self-repairing passive layer on its surface.
A BRIEF HISTORY STAINLESS STEEL
Stainless steel was invented as a product of the individual and joint efforts of the European steel producers in the early 1900s before the First World War, and patented in 1912. Since then, stainless steel has passed through various stages and provided a wide range use and brought ease and economic contribution to the industry and daily life. It is mainly used for products and plants that require high level of hygiene. The increasing wide-spread use of stainless steel, which has become an important culture today, is the indication of quality and economical values.
GRADES AND QUALITIES OF STAINLESS STEEL
The stainless steel adventure that began in 1912 with patenting of two qualities as V2A the current Cr 18 Ni 8) and V4A (the current Cr 20 Ni 10 Mo 2), has today expanded to a wide range of utilization areas with more than 120 quality types. They are usually classified as ferritic, austenitic, martensitic and duplex (austenitic-ferritic).
Each group has different internal structural properties and crystal structures, and resistance levels based on different fields of use. The qualities must be selected according to the resistance properties required in the relevant field of use.
STAINLESS STEEL PROPERTIES
In cases where demands for resistance against utilization environment cannot be met by other more cost-effective metals or substances, stainless steel is an indispensable and reliable material. In addition, stainless steel contains the necessary features and contents to meet the hygiene requirements for air, water, liquid and other chemicals, food and beverage industry.
Basic characteristics of stainless steel:
• Resistance against corrosion,
• Esthetic appeal,
• Heat resistance,
• Low life cycle cost (Life Cycle Cost / LCC),
• Fully recyclable,
• Biologically neutral ,
• Easy production and cleaning ,
• Weight / endurance ratio
STAINLESS STEEL APPLICATION AREAS
|
ASTM KOD |
SPECIFICATIONS |
APPLICATIONS |
|
304 |
Base kind of stainless steel. For mechanical strength and oxidation up 400°C. |
Household goods, hollow-ware, catering equipment, food and process industry equipment, dairy equipment, nitrogen and hydrogen tanks, metal furniture, car parts and other vehicles, etc. |
|
304L |
Same as 304 with low carbon (better formability). |
Thick-walled welded structures, strongly oxidizing envoirements as nitric acid, lining for coal hoppers, liquid fertilizer spray tanks, tomato paste storage tanks, etc. |
|
321 |
Useful in higher temperatures and with the content of titan higher corrosion resistance. |
Thick-walled welded structures, strongly oxidizing envoirements as nitric acid, lining for coal hoppers, liquid fertilizer spray tanks, tomato paste storage tanks, etc. |
|
316 |
For mechanical strength and oxidation up to 600 °C. Excellent ductility, formability and toughness. Due to the content of Mo resistant to high oxidation and acid. |
Textile-brewery-paper-medical and fatty acid industry, acetic acid compounds, etc. |
|
316L |
Same as 316 with low carbon but resistant up to 400°C. |
Thick-walled welded structures in the same scope of application as 316. |
|
316Ti |
The version of 316, Ti alloyed, resistant to higher temperatures and oxidations. |
Thick-walled welded structures in corroding environments, high temperature applications, developed for highly corrosive environments in the chemical and process industries and for sea water applications. |
|
309S |
At 1050 °C higher oxidation resistance. |
High temperature applications. |
|
310 |
At 1100 °C higher oxidation resistance. |
High temperature applications, blast furnace parts, chemical and petro-chemical industries. |
|
310S |
Same as 310 slightly higher resistance. |
Same as 310. |
|
|
STAINLESS STEEL SURFACE STANDARDS
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|
|||
|
KOD |
LANATIONS |
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|
ASTM |
EN |
DIN |
|
|
1 |
1D |
c2/lla |
Hot rolled, annealed, pickled. |
|
2D |
2D |
h/lllb |
Cold rolled, annealed, pickled |
|
2B |
2B |
n/llc |
Cold rolled, annealed, pickled and lightly rolled on polished rolls. |
|
3 |
2G |
o/IV |
Cold rolled, annealed, pickled and polished |
|
4 |
2J |
p/V |
Cold rolled, annealed, pickled and brush-polished |
|
BA |
BA |
m/lld |
Cold rolled, annealed, polished |
|
|
HL |
|
Scotch Brite (Brushed surface) |
STAINLESS STEEL STANDARDS AND CHEMICAL VALUES
