Stainless steel and carbon steel are extensively utilized for various industrial and domestic purposes. There are certain core differences between these two materials, and this article will provide an extensive comparison.
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What is Stainless Steel?
Stainless steel is mainly made of iron and carbon. Stainless steel differs from general carbon steel due to the presence of Chromium. In addition to Chromium, Nickel may also be included.
Chromium is added to prevent corrosion. Anti-corrosion properties are a major factor that differentiates stainless steel from carbon steel. Iron, the essential component of any steel, is artificially processed to make steel. However, the artificial processed form of iron is unstable and reacts with moisture and oxygen to undergo corrosion.
To prevent this, chromium is added, and the product is called stainless steel. Chromium reacts with oxygen and moisture to develop a layer of chromium oxide over the steel surface, preventing rust from damaging it.
To classify any steel as “stainless steel” it must contain a minimum of 10.5% of chromium. There are different grades of stainless steel based on its composition, which are grouped into different types such as Austenitic, Ferritic, Martensitic, and Duplex stainless steel.
An Introduction to Carbon Steel
Carbon steel is undoubtedly among the most highly utilized steel variants being manufactured worldwide. The concentration of carbon in carbon steel ranges between 0.05 to 2.1%. American Steel Institute (ASI) states that carbon steel consists mainly of iron and carbon, with almost no additional alloying element required.
A comparison of stainless steel and carbon steel reveals that stainless steel must contain chromium. No such requirement is necessary for carbon steel. Carbon steel is categorized into low-carbon or mild steel, medium-carbon steel, and high-carbon steel.
Stainless Steel vs Carbon Steel: The Major Differences
The comparison of major properties of stainless steel vs. carbon steel reveals that stainless steel has a major edge being highly corrosion resistant. The protective layer formed on the surface of stainless steel protects it from corrosion and makes stainless steel a viable choice for applications where machinery parts are subjected to high moisture content.
The appearance of stainless steel is much glossier, giving off a smooth, bright silver look. Carbon steel, on the other hand, is much duller and mostly black, so stainless steel wins the battle versus carbon steel when it comes to aesthetic appearance.
The analysis of stainless steel vs carbon steel for robustness has revealed stainless steel to be more durable. Stainless steel is much more robust, but it has a lower resistance to wear and tear. However, in comparison to carbon steel, it is much less brittle.
The table below provides a brief overview of stainless steel vs carbon steel:
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TABLE OF COMPARISON OF STAINLESS STEEL VS CARBON STEEL
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PROPERTIES
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STAINLESS STEEL VS CARBON STEEL
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Material Properties
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Iron, Chromium, and Carbon
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Corrosion Resistance
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Stainless steel vs carbon steel has high corrosion and rust resistance
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Temperature Resistance
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Stainless steel vs carbon steel can withstand high and low temperatures for extended amounts of time with high performance
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Weldability
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Stainless steel vs carbon steel is much more complex; welding carbon steel is a simple task
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Lifespan
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20 years for both steels
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Hygienic
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Stainless steel vs. carbon steel rejects bacteria and other pathogens and is much easier to clean; Carbon steel is nontoxic but gets unclean easily
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Cost
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Stainless steel vs carbon steel is much more expensive to manufacture
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Recyclability
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100% Recyclable steels
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A Comparison of Properties of Stainless steel vs carbon steel. Information Source: Mead Metals https://www.meadmetals.com/blog/stainless-steel-vs-carbon-steel
Additive Manufacturing (AM) of Stainless Steel vs Carbon Steel
Wire arc additive manufacturing (WAAM) is an additive manufacturing technique efficient for the fabrication of different types of steel. Researchers have published a research article recently in the journal Materials, where they used gas metal arc welded (GMAW) based AM to fabricate mild carbon steel (G3Si1) and austenitic stainless steel (SS304). The properties of stainless steel vs carbon steel produced by additive manufacturing were compared.
The material property comparison of stainless steel vs carbon steel by the researchers revealed a higher value of strength in stainless steel in both the longitudinal and transverse directions in the range of 240-260 HV. The hardness value of stainless steel was higher than carbon steel by about 80 HV.
A comparison of residual stresses generated was also performed for stainless steel vs carbon steel. Longitudinal stresses in stainless steel were tensile with a value of 90MPa. For carbon steel, both the longitudinal and transverse residual stresses were compressive, ranging from 50 to 80 MPa.
Fracture Study of Stainless Steel vs Carbon Steel Bolts
Bolts are used to fasten two mechanical parts in complex machinery, and the failure of bolts leads to failure of the complete joint, which may cause severe damage. Therefore, the study of fracture characteristics of bolted connections is essential. Most bolts are made either of stainless steel or carbon steel.
In the latest article published in the Journal of Constructional Steel Research, researchers performed a detailed experimental study of fracture attributes of Grade A4–80 austenitic stainless steel bolts and carbon steel 8.8 bolts, along with developing comprehensive numerical modeling for predicting the failure.
Researchers performed 24 tensile tests. The numerical as well as experimental setup results confirmed that the A4-80 stainless steel bolts were more ductile than the 8.8 bolts. It was determined that the number of threads between the parts being fastened has a considerable influence on the bolts' reaction.
In short, the clear winner in stainless steel vs carbon steel depends on the application. For applications where corrosion resistance is a necessity, stainless steel must be preferred over carbon steel. However, where regular welding is required, such parts should be manufactured using carbon steel. Both types of steel have distinct advantages and shortcomings, which must be assessed beforehand for any particular project.
More from AZoM: Metal Recycling and the Circular Economy
References and Further Reading
Anderson, M., 2023. Stainless Steel Vs. Carbon Steel: What's The Difference?. [Online]
Available at: https://www.meadmetals.com/blog/stainless-steel-vs-carbon-steel
Burnett, C., 2023. What Is Stainless Steel? Part I. [Online]
Available at: https://www.thermofisher.com/blog/metals/what-is-stainless-steel-part-i/
John, 2023. Stainless Steel vs Carbon Steel. [Online]
Available at: https://mellowpine.com/blog/stainless-steel-vs-carbon-steel/
Zhejiang Seamless Pipe CO., LTD, 2023. The Difference Between Stainless Steel And Carbon Steel. [Online]
Available at: https://www.linkedin.com/pulse/difference-between-stainless-steel/
Rani, K. et. al. (2022). Wire Arc Additive Manufactured Mild Steel and Austenitic Stainless Steel Components: Microstructure, Mechanical Properties and Residual Stresses. Materials 15(20). 7094. Available at: https://doi.org/10.3390/ma15207094
Yapici, O. et. al. (2023). Comparative study on fracture characteristics of carbon and stainless steel bolt material. Journal of Constructional Steel Research, 210, 108102. Available at: https://doi.org/10.1016/j.jcsr.2023.10810
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