Stainless steel, or stainless steel, is used in much of our lives today, from spoons, forks and kitchen utensils to the major chemical and pharmaceutical industries.
1.4021 stainless steel, also known as 420, has magnetic properties and is used in parts of pumps, turbines and the like.
Stainless steel 1.4301, also known as 304, is a non-stainless steel. (It has no magnetic properties.)
304 stainless steel is used in food, medical and laboratory industries. This steel is weldable.
In addition to being stainless, 316 or 1.4401 stainless steel has anti-acid properties. 316L steel and 316Ti steel are similar to 316 stainless steels, and with a slight change in the amount of alloying elements (such as chromium, nickel and molybdenum), some of their properties change.
Obviously, due to its anti-acid properties, 316 steel is most used in the manufacture of petrochemical equipment and acid tanks.
This steel is also produced and marketed in different sections such as pipes, rebars and sheets.
Definition and marking of stainless steels:
Stainless steel is actually a type of steel that contains at least 12% cream, but most stainless steel castings, in terms of chemical composition, go beyond this simple definition and become more complex. To be.
Stainless alloy steels generally contain other alloying elements such as nickel, molybdenum, copper, columbine, nitrogen and in addition to having at least 12% cream.
The addition of these alloying elements is done to create the desired mechanical properties and proper structure.
Stainless alloy steels are generally marked with a chemical composition. Here’s a description of the system used by the Alloy Casting Association.
The first letter in the system indicates the type of corrosive environment, the letter C for corrosive environments including liquids, the letter H for corrosive environments or high temperatures. The second letter indicates the amount of cream and nickel in these parts.
As the percentage of nickel increases, the second letter in the ACI classification changes from A to Z.
The next number indicates the maximum amount of carbon in a corrosion-resistant alloy of 100 x. If alloying elements are present in the steel in addition to chromium and nickel, they indicate its presence by adding another letter in the ACI system;
For example, CF-8M is an alloy that contains 19% cream, 9% nickel and a maximum of 0.08% carbon as well as molybdenum.
History of the discovery of stainless steels
When iron combines with oxygen in the air, red iron oxide (which is iron rust) is produced. There is also a type of steel that does not rust.
The English metallurgist Harry Brearley was the first to discover the alloy.
In fact, it was in the years before World War I that gun production increased dramatically, and Breirley began testing an alloy of steel that was highly resistant to high temperature erosion in weapons. Of different directions
Reaching the desired alloy. He began to increase the amount of worm in the steel and compared it to standard carbon steels.
The man left all the metals in his lab warehouse after a series of tests and no results were obtained, and left in despair.
After months, he suddenly realized that there was a metal among these metals that, despite the rusting of all the metals, did not rust or oxidize.
After careful testing, Breirley found that the piece was an alloy of steel with 14% chromium. Today, it is known as “stainless steel” or “steel”.