Stainless steel pipe is considered to be an alloy, which is said to be a mixture of two components, one of which should be metallic. To make things more clear, the two components that make steel are carbon and iron. In its simplest form, stainless steel, or inox steel, is carbon steel mixed with chromium.
Stainless steel pipe can be made to exhibit a spectrum of mechanical and physical properties. The five main families of stainless steel are Austenitic stainless steel, Duplex stainless steel, Ferritic stainless steel, Martensitic stainless steel, and Precipitation Hardening stainless steel.
Stainless steel is a bit of a misnomer, as stainless steel pipe can rust. However, it is far less likely to rust than any other steel. As mentioned earlier, stainless steel is basically carbon plus chromium. The chromium has two dramatic effects on the steel: appearance and corrosion resistance. The chromium gives the stainless steel it’s mirror-like appearance. The cosmetic appeal of stainless steel is showcased in the kitchen and with knives. Stainless steel does oxidize, however, not with iron but with chromium. Chromium bonds to oxygen more readily than iron. The result is chromium oxide. The oxidation of stainless steel creates a layer of chromium oxide on the pipe, which prevents the steel from rusting.
Standard Stainless Steel Grades and Finishes
Stainless steel pipe is known for its corrosion resistance and its stain resistance. There are more than 150 grades of stainless steel. There are only 15 grades of steel that are commonly used. Some grades of stainless steel are more resistant to corrosion than others. The level of resistance varies depending on the stainless steel product’s chromium content. In addition to its corrosion and stain resistance, stainless steel pipe is popular because of its strength, low maintenance requirements and aesthetic appeal.
Stainless steel is also available in many shapes and sizes and presents a luster that gives it a cosmetic purpose. Standard stainless steel finishes include:
No. 0: Thicker, hot-rolled, annealed
No. 1: Rough, dull and non-uniform
No. 2D: Dull, silver-grey
No. 2B: Matte finish
No. 2BA: Mirror-like with some cloudiness and imperfections
No. 3: Somewhat coarse, parallel polishing lines
No. 4: Brushed finish
No. 5: Satin finish
No. 6: Dull, silver-white finish
No. 7: Reflective finish
No. 8: Mirror finish
No. 9: Bead blast finish
No. 10: Heat colored finish
2B matte finish is among the least expensive of all stainless steel finishing options.
Popular Applications of Stainless Steel
Stainless steel is often used for construction materials and industrial equipment. It is also used to make major appliances, cutlery, and kitchenware. Because stainless steel does not require protective coating and is easy to clean and sterilize, it is ideal for commercial kitchens, storage tanks, and surgical supplies. Popular applications for stainless steel pipe include beer brewing, wine making, food processing and meat processing.
The aesthetic properties of stainless steel make it popular in architecture. Stainless steel type 316 was used in the exteriors of some of the world’s most famous skyscrapers. Stainless steel has also been used in the construction of many well-known bridges, monuments, sculptures.
Which Type of Steel is Best?
It really depends on your application and budget. Different specs and grades of stainless steel have different properties. The type of steel or stainless steel pipe needed for a specific project depends largely on the environment the steel materials must endure. For instance, stainless steel Type 304 has the properties suitable for handling a strong acid like formic acid but rarely for sulfuric acid. Meanwhile, stainless steel Type 316 is ideal for storing and handling acetic acids. Neither stainless steel types should be used with hydrochloric acid, while both Type 304 and 316 are standard materials for applications involving water, such as water treatment and plumbing.
One major role that plays a big part in the decision process is the budget for each kind of steel. An engineer can help stainless steel customers decide which steel is best suited for their specific application.
Recycled Stainless Steel
Stainless steel offers a long service life, but on top of that, it promises 100 percent recyclability. Recycled stainless steel is economically viable because it contains valuable raw materials, such as chromium and nickel. Stainless steel, unlike numerous industrial and engineering materials, is capable of returning to its original quality in the supply chain without experiencing degradation.
Recyclers from around the world collect and process scrap (recycled stainless steel) for remelting. The use of stainless steel scrap is a fundamental part of the steelmaking process. The two types of stainless steel scraps are: 1) reclaimed scrap (old scrap), and 1) industrial scrap (new scrap).
Reclaimed stainless steel scrap includes a variety of items that have reached the end of their service life, like old refrigerators, washing machines, industrial equipment and tanks. Industrial stainless steel scrap, on the other hand, includes returns and offcuts from manufacturing sources, like industrial engineering and fabrication.
Currently, stainless steel is comprised of approximately 60% recycled content. This includes: 25% reclaimed scrap, 35% industrial scrap and 40% new raw materials.
Specialised technology is used to separate and prepare each type of alloy for remelting during the recycling process. First, the scrap is shredded into smaller pieces. Then, the shredded pieces are gathered by stainless steel type. The scraps, along with other raw materials, are blended, based on customer requirements, and placed into an electric furnace. Impurities are removed after melting. Once the molten metal is refined, it is chemically analyzed, and adjustments are made until the specified type of stainless steel is achieved. They are then casted into slabs and billets before being manufactured into stainless steel products, like kitchen sinks, pots and pans, cutlery and more.
Benefits of Stainless Steel Pipe
Stainless steel pipe offers a wide range of benefits. It is often compared with regular steel but stainless steel offers greater cryogenic toughness, a higher work hardening rate, increased strength, greater ductility, lower maintenance costs, and a more attractive appearance. With all this being said, stainless steel has many uses in modern construction. It can be seen on the exterior cladding of large, high impact buildings but also can be seen inside of those buildings used as a form of handrails, countertops, backsplashes, and more. Stainless steel pipe can be used in automotive through car exhaust systems, trims, and grills. It is also seen in the medical field through surgical and dental instruments, kidney dishes, and operating tables. One more popular use of stainless steel pipe is through the food and catering industry. It is used for items to be molded into shapes such as cookers, grills, sinks, and saucepans. The steel can also be used as a finish for refrigerators, freezers, countertops, and dishwashers. Stainless steel is best suited for a wide range of industries that can be used for many different products.