Stainless steel is a versatile material composed of a steel alloy and a small amount of chromium. The addition of chromium increases the material's corrosion resistance, a property that gives stainless steel its name. Because stainless steel is also low-maintenance, resistant to oxidation, and does not affect other metals it comes in contact with, it is often used in a variety of applications, especially in pipe, tube, and fitting manufacturing. Stainless steel pipes are divided into several categories based on the end use of the pipes.
Different types of steel pipes and stainless steel pipes:
Pipes are sometimes difficult to classify and are often distinguished based on function. In addition to these classifications, stainless steel is also distinguished by type and grade.
1.304 stainless steel pipe
For pipe and duct applications, Type 304 stainless steel is a common choice because of its high degree of chemical and corrosion resistance. However, Type 304 stainless steel is not suitable for applications with temperatures between 800 and 1640 degrees Fahrenheit (F) because it is prone to carbide precipitation, a result of the material's 0.08% carbon content limit. Type 304L stainless steel avoids this problem because it has lower carbon content limits, allowing for welding and higher temperature applications. Other types of stainless steel often contain additives (such as nickel or molybdenum) that enhance the properties needed in a specific application.
2. Stainless steel pipe with general corrosion resistance
This general category of steel is suitable for applications where corrosion resistance is required over other properties. Ferritic or martensitic types of steel (those containing the most chromium) are manufactured by heat treating or annealing them. Austenitic stainless steels (stainless steels with high chromium and nickel content) are more resistant and can be used under the same general conditions as ferritic and martensitic types.
3. Stainless steel pressure pipe
This type of stainless steel pipe is made from solid chromium or a combination of chromium and nickel. Types of stainless steel pressure pipe include seamless and welded pipe, electrofusion welded pipe for high pressure applications, large diameter welded pipe for corrosive or high temperature applications, and seamless and welded ferritic and austenitic stainless steel pipe.
4. Stainless steel sanitary pipe
For applications where stainless steel pipe or pipe must come into contact with food and other sensitive products, hygiene is a top priority. Stainless steel sanitary pipe is used in such applications because it is highly resistant to corrosion, does not discolor, and is easy to keep clean. For specific applications, different tolerances can be achieved. The grade commonly used for these applications is ASTMA270.
5. Stainless steel mechanical pipe
Stainless steel mechanical tubing is commonly used in applications such as cylinders, bearings and other hollow formed parts. In addition to the more traditional circular tube cross-sections, tubes can also be controlled to have various cross-sectional shapes, such as square and rectangular. Typically, ASTMA 511 and A554 grades are used for mechanical tubing applications.
6. Stainless steel aircraft pipe
In highly specific aircraft applications, chromium and nickel type stainless steels are used due to their heat and corrosion resistance. In applications requiring high strength, stainless steel aircraft tubing can be work-hardened or welded, but work-hardened pieces should not be used with certain corrosive substances. Low-carbon types of stainless steel are a common choice for welded parts.
For applications requiring larger sizes (1.6 to 125 mm OD) seamless and welded pipe, aircraft structural pipe is available - this type of stainless steel is manufactured to the Aerospace Materials Specification (AMS) or Military Specification (MIL Specification) .
7. Aircraft hydraulic pipeline
Another type of aircraft tubing, aircraft hydraulic line tubing, is used in aerospace applications as fuel injection lines and hydraulic systems and tends to be smaller. It is typically made from 304 or 304 L stainless steel due to its high strength, corrosion resistance, and ductility.
