Difference between Steel and Stainless Steel

Key Difference: Steel is an alloy, which means that it is created by mixing various different elements together. The primarily base element in steel is iron. Stainless Steel is a special type of steel. It has all the properties of steel. However, it is also non-corrosive, which basically means that it cannot rust.

Steel Steel is a popular material for use, primarily because it is cheap and easily available. Also, because it tends to have a very high tensile strength making it very versatile in its use. Hence, steel is often used for construction as well as in variety of other applications.

Steel is an alloy, which means that it is created by mixing various different elements together. The primarily base element in steel is iron. Many different elements can be added, however, the second most common element is carbon, which can contribute up to 2.1% of the alloy’s weight.

Each manufacturer can have its own recipe for making steel, however, in order to be considered steel, the alloy must meet certain requirements, such as the base element is iron, it contains carbon, and has a very high tensile strength. Modifying the ingredients in the steel alloy can affect the hardness, ductility, and tensile strength of the steel.

Steel is widely used in constructions, especially as a major component in buildings, infrastructure, tools, ships, automobiles, machines, appliances, and weapons.

Stainless Steel is a special type of steel. It has all the properties of steel. However, it is also non-corrosive, which basically means that it cannot rust. This is achieved by adding at least 10.5% or more chromium in the steel alloy. Chromium has a high resistance to corrosion, due to the oxide film that it results in. This naturally occurring chromium-rich oxide film ends up coating the surface of the steel, and when the steel is damaged, which exposes the metal to oxygen, this film tends to repair itself and cover the exposes part, thus saving it from oxidation.

It should be noted that despite of its name, stainless steel is not stain proof. It is highly resistant to staining, corroding, or rusting, however it is not impervious to it, and if not properly maintained, it may stain, corrode, or rust.

Stainless steel has a wide variety of implications, such as in construction, household items, etc. It is commonly used for cookware and cutlery, such as knives, forks, and spoons. It is also commonly used in household hardware, surgical instruments, major appliances, industrial equipment as well as an automotive and aerospace structural alloy and construction material in large buildings.

Comparison between Steel and Stainless Steel:

	Steel	Stainless Steel
Type	Alloy	Alloy, special type of steel
Dates back to	17^th century	19th century
Materials	Iron and other elements, primarily between 0.02% and 1.7% percent carbon.	Iron and other elements, contains 10.5% or more chromium
Implication	Widely used in construction and other applications	Widely used in construction, household items, etc.
Uses	Major component in buildings, infrastructure, tools, ships, automobiles, machines, appliances, and weapons.	Commonly used for cookware and cutlery, such as knives, forks, and spoons. Also used in household hardware, surgical instruments, major appliances, industrial equipment and as an automotive and aerospace structural alloy and construction material in large buildings.
Properties	High Tensile Strength	High Tensile Strength High Resistance To Corrosion
Cost	Low cost
Rust	Likely to rust	Less likely to rust
Types	Carbon steel - the most common type, but it must be painted or covered or it will rust Stainless steel - which will usually not rust much, the "stain" in the name is the red colour of rust Galvanized steel - which is steel covered with zinc, to prevent rust	Defined by its crystalline structure: Austenitic, or 200 and 300 series - have an austenitic crystalline structure, which is a face-centered cubic crystal structure. Ferritic stainless - better engineering properties than austenitic grades, but have reduced corrosion resistance Martensitic stainless steels - not as corrosion-resistant but are extremely strong and tough, as well as highly machinable, and can be hardened by heat treatment. Duplex steel stainless steels - have a mixed microstructure of austenite and ferrite Precipitation-hardening martensitic stainless steels -have corrosion resistance comparable to austenitic varieties, but can be precipitation hardened to even higher strengths

Reference: Wikipedia (Steel and Stainless Steel),
Simple Wikipedia (Steel and Stainless Steel), ASSDA
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