What is the Difference Between Mild Steel and Stainless Steel?
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The first metal used by man was bronze, an alloy of copper, tin and perhaps some additives, which started the metal age of the history. Hunting and gathering community of Stone Age got gradually replaced by more civilized community of metal age. The essential developments throughout history have occurred in Iron age, with the manufacture and use of iron and its popular alloy called steel.
Steel is an iron-based alloy having a carbon content less than that of cast iron and more than that of wrought iron. Steel is the most suitable metallic building material. As a structural material, steel offers high strength, stiffness and elasticity.
Steel has qualities of strength, hardness and elasticity which vary according to composition and heat treatment. Based on the carbon content, other alloying elements and heat treatment, a desired combination of hardness, ductility and strength can be obtained in steel.Steel is used for light and heavy structural framing, as well as a wide range of building products such as window, doors, hardware and fastenings.
Most of the steel used for construction has low to medium carbon content and it is relatively mild, tough and strong, fairly easy to work by cutting, punching, riveting and welding. Mild steel is the type of carbon steel containing a small percentage of carbon. It is also called Soft Steel.
Out of all alloy steels, the chromium-nickel alloy steel, known as stainless steel, is most popular in construction industry.
Let us, discuss the difference between mild steel and stainless steel.
Comparison: Mild Steel Vs Stainless Steel
- According to ‘Christopher Gorse’, ‘David Johnston’ and ‘Martin Pritchard’ (Author of Oxford Dictionary of Construction, Surveying & Civil Engineering), Mild steel is a type of steel containing not more than 2 % carbon content and very few additional alloying elements. It is also called Low Carbon Steel or soft steel.
- According to ‘Christopher Gorse’, ‘David Johnston’ and ‘Martin Pritchard’ (Author of Oxford Dictionary of Construction, Surveying & Civil Engineering), Stainless steel is a type of steel with excellent resistance to corrosion and degradation due to the high chromium content.
- According to ‘Francis D. K. Ching’ (Author of Building Construction Illustrated), Carbon Steel is unalloyed steel, which contains elements such as carbon, manganese, phosphorus, Sulphur and silicon. Mild steel is a type of carbon steel which contains 0.15 to 0.25 % carbon.
- According to ‘J. R. Davis’ (Author of Alloy Digest Sourcebook: Stainless Steel), Stainless steel is an alloy steel which contains a minimum of about 12 % chromium (Cr). Other elements added to improve particular characteristics include nickel, manganese, molybdenum, copper, titanium, silicon, niobium, aluminium, Sulphur and selenium.
- Mild steel has a fibrous structure.
- Stainless steel has silver-white appearance.
04. Major Constituents
- Iron and carbon are significant constituents of mild steel.
- Chromium and nickel are significant constituents of stainless steel, over and above iron.
- The strength of mild steel is less than that of stainless steel.
- The strength of stainless steel is more than that of mild steel.
- The hardness of mild steel is less than stainless steel.
- The hardness of stainless steel is more than mild steel.
- The toughness of mild steel is less than stainless steel.
- The toughness of stainless steel is more than mild steel.
- The ductility of mild steel is less than stainless steel.
- The ductility of stainless steel is more than mild steel.
- The elasticity of mild steel is less than stainless steel.
- Stainless steel is more elastic than mild steel.
- Mild steel can be permanently magnetized.
- Stainless steel may not be magnetized. Generally, ferritic stainless steel is magnetized.
- Mild steel rusts easily and rapidly.
- Stainless steel does not rust easily.
12. Corrosion Resistance
- The corrosion resistance of mild steel is less than stainless steel.
- The corrosion resistance of Stainless steel is more than mild steel.
Mild Steel is used in the form of
- Rolled sections
- Reinforcing bars
- Roof coverings
- Sheet piles
- Railway tracks
Stainless steel is widely used for making
- Household utensils
- Railings for stairs and balcony
- Grills for window
- Vessels to store acids
- Dairy pharma plant equipment etc.
- Their relative inertness and finish-retention qualities also make them useful in surgical equipment and kitchen applications such as sinks, kitchen countertops etc.
Advantages of mild steel
- Mild steel can be bent, cut and twisted to create the desired shape compared to other metals.
- While working on a low budget, mild steel proves to be economical.
- Mild steel is elastic material and can be easily cut, machined, punched or drilled, welded, forged and rolled.
Advantages of stainless steel
- Due to high corrosion resistance, it is suitable for extreme environment.
- Fire and heat resistance allow it to retain shape at high temperature.
- Easy cleaning ability of stainless steel makes it the primary choice for applications that require strict hygiene control, such as in hospitals, kitchens and in other food processing plants.
- Its aesthetic appearance is providing a modern and attractive look to metal applications.
- Ease of fabrication and use of modern steel-making techniques, allow stainless steel to be cut, machined, fabricated, and welded.
- It is suitable when resisting impact on high-temperature variations.
- Long-term value is created due to its long useful life. It is less expensive material compared to mild steel in a long run.
Disadvantages of mild steel
- It rusts easily.
- It is light in weight. Therefore, the ability to resist penetration by a harder body is less compared to stainless steel.
Disadvantages of stainless steel
- Initial cost is high, especially when compared to alternative metals.
- Difficult to fabricate stainless steel without using the high technology machines and proper techniques.
- The cost of final polishing and finishing of stainless steel is high.
To summarize, mild steel and stainless steel are different types of Iron. Mild steel, also called as Carbon steel is ordinary steel with low carbon whereas Stainless steel is special alloyed steel wherein certain alloys like Nickel and Chromium added to improve its qualities. Since they differ in their constituents, they differ in their properties and uses too. With alloys, stainless steel has higher strength, hardness, elasticity, and corrosion resistance. It is therefore widely used now a days. Mild steel is used where toughness and ductility are needed particularly when working with low budget.