Stainless steel is an iron-based alloy primarily known for its corrosion-resistance properties. It is a huge family consisting of various grades of this commodity. Stainless steel is mainly categorize into five different families, martensitic, austenitic, duplex, and precipitation hardening. The one key element that these families share is a minimum of 10.5% chromium by mass. The alloy also consists of other elements, such as nickel and molybdenum, to yield desirable properties. Stainless steel has a valuable niche market and is applicable across various industries.
Stainless steel is highly durable and affordable and is known for its versatility. The success of stainless steel is generally attribute to its corrosion-resistance properties. The chromium in the stainless steel shows a great affinity for oxygen. It combines with oxygen on the steel’s surface to develop a molecular-level film of chromium oxide that can effectively resist corrosion. The thin layer protects the underlying metal from external agents and further oxygen/chrome oxidation. This layer is self-healing; chromium can reform the oxide layer “automatically.” Thus, this layer is known to be passive, tenacious, and self-renewing.
Type 321 belongs to the austenitic stainless-steel family and is one of the most widely used grades. It is a basic austenitic 18/8 steel stainless steel stabilize using a certain percentage of Titanium. The Titanium (Ti) content must be five times more than the Carbon content. Type 321 offers excellent resistance to intergranular corrosion and enhanced creep resistance. You can buy 321 stainless steel tubes for chemical processing equipment, jet engine parts, heat exchangers, expansion joints, welded equipment, and aircraft exhaust stacks.
The development of Stainless Steel
Harry Brearley of Sheffield, UK, is regard as the inventor of the first true stainless steel in the year 1913. He had added chromium to molten iron to produce metal that did not rust. He created a steel grade with a composition of 12.8% chromium and 0.24% carbon, arguing it to be the first-ever ‘rustless’ steel.
Common uses of Stainless Steel
Stainless Steel is available in pipes, tubes, bars, plates, and sheets. It serves the following common uses:
- Automotive and Transportation: Stainless Steel is deploye for manufacturing motor vehicles and various structural components in this industry. Stainless steel shows energy absorption properties and can have mechanical properties over an extensive temperature range that renders it valuable. It is useful in all forms of transportation, including road tankers, ship containers, and refuse vehicles.
- Medical Use: Stainless steel upholds hygienic properties, making it ideal for medical use. You can sterilize it easily, and it is helpful in the construction of surgical and dental instruments, operating tables, and various medical equipment. Surgical implants and joints replacement also brings stainless steel to use.
- Offshore Technology: Offshore oil and gas industry uses stainless steel as it offers corrosion resistance, reduced weight, and increased strength. It finds use in submerged components such as pipework for water, oil, and sewage, heat exchangers for ships, and risers for oil platforms. The seawater pipe systems use stainless steel to transport hydrocarbons and petrochemicals.
- Energy and Heavy Industries: Stainless steel has a high strength-to-weight ratio. It helps form powerful and stable structures and is suitable for constructing storage tanks, valves, and pipes. Thus, it finds extensive use in heavy industries in energy production and refining, nuclear power, hydroelectric, and long-distance energy transmission.
- Architecture and Construction: The concerned industry uses stainless steel extensively. Stainless steel alloyed with molybdenum shows enhanced corrosion resistance. Thus the architectural and landscape design and structural engineering firms use it for locations that suffer greater exposure to corrosive media.
Beneficial Properties of Stainless Steel
- Corrosion Resistance: The most distinguishing property of stainless steel is its ability to resist corrosion. Different grades have varied compositions that enable them to withstand the corrosive effects of various environments. Grades with higher Chromium, Molybdenum, and Nickel content shows enhanced corrosion resistance.
- Coefficient of friction: It offers lower friction as compared to cement-lined carbon steel pipes. Thus, the manufacturer can reduce the pipe’s internal diameter, which contributes to cost savings.
- Cryogenic (Low Temperature) Resistance: Austenitic stainless steel family shows excellent toughness and increased tensile strength at sub-zero temperatures.
- Hygiene: Stainless steels are inert in water which makes them hygienic. Since it is biologically inert, it is ideal for kitchen appliances and medical equipment. The leaching of the alloys such as chromium and nickel within stainless steel is within safe limits.
- Yield strength: Depending on the grade, it tends to show low strength and high elongation or high strength and low elongation properties. Compared to carbon steel, it has higher yield strength.
- Ductility: The ductility property differs across various grades. Stainless steel grades with higher ductility are suitable for strenuous deep drawing processes.
These are a few things you should know about stainless steel. It is a valuable material known for its corrosion resistance, low maintenance, high tensile strength, durability, and temperature resistance. A wide range of industries use this materialto fulfill industrial operations and applications.