Stainless SUS201 is one of the most widely used grades in the 200 series austenitic stainless steel family. This article covers everything you need to know about SUS201 stainless steel tubes, from chemical composition and key properties to common applications and fabrication processes.
What Is Stainless SUS201?
SUS is a naming system for stainless steel that comes from Japan’s Industrial Standards (JIS). The letters stand for “Steel Use Stainless.” This naming system is widely used across the stainless steel industry in Asia. Stainless SUS201 belongs to the 200 series austenitic stainless steel group. It was designed to use manganese and nitrogen in place of some of the nickel content. This keeps the austenitic structure intact while bringing down material costs.
In the stainless steel tube industry, SUS201 is a popular and affordable grade. It works well in situations where extreme corrosion resistance is not required, but good strength and formability are still important.
Chemical Composition of Stainless SUS201 Tubes
To understand how SUS201 stainless steel tubes perform, it helps to start with what they are made of. Here is a breakdown of the main elements and their composition ranges.
| Element | Composition Range |
| Chromium (Cr) | 16.00 – 18.00% |
| Manganese (Mn) | 5.50 – 7.50% |
| Nickel (Ni) | 3.50 – 5.50% |
| Nitrogen (N) | ≤ 0.25% |
| Carbon (C) | ≤ 0.15% |
| Silicon (Si) | ≤ 1.00% |
SUS201 uses higher levels of manganese and nitrogen to partially replace nickel. Nickel is one of the more expensive elements in stainless steel. By reducing nickel and adding manganese and nitrogen instead, SUS201 keeps its austenitic structure at a lower cost. This makes it a practical alternative to 300 series stainless steel tubes in many applications.
Each element plays a specific role in tube performance. Chromium is the key element for corrosion resistance. A chromium content above 16% forms a thin protective oxide layer on the tube surface. Manganese helps improve strength and also makes the material easier to process at high temperatures. Nitrogen adds further strength and helps stabilize corrosion resistance. Low carbon content reduces the risk of carbide precipitation during welding, which is good for overall weldability.
Key Properties of Stainless SUS201 Tubes
Now that we have covered the chemical composition, let us look at how stainless SUS201 tubes actually perform. The following sections cover physical properties, mechanical properties, corrosion resistance, formability, and magnetic behavior.
Physical Properties
SUS201 stainless steel tubes have a density of 7.86 g/cm³. The thermal conductivity is 16.3 W/mK at 100°C. The thermal expansion coefficient is 16.6 µm/m°C, measured between 20°C and 100°C.
Mechanical Properties
The data below is based on tests carried out in the annealed condition.
| Property | Value |
| Tensile Strength (Transverse) | 685 MPa |
| Tensile Strength (Longitudinal) | 696 MPa |
| Yield Strength (Transverse) | 292 MPa |
| Yield Strength (Longitudinal) | 301 MPa |
| Elongation (Longitudinal) | 56% |
| Elongation (Transverse) | 62.5% |
| Elastic Modulus | 197 GPa |
| Hardness (HRB) | 85 |
The elongation values are notably high. This means SUS201 tubes can handle a good amount of plastic deformation without breaking. It makes them well suited for cold drawing and cold rolling processes.
Corrosion Resistance
Stainless SUS201 tubes offer moderate corrosion resistance. They perform well in indoor settings and normal atmospheric conditions. This is sufficient for most structural and decorative tube applications. In high-humidity environments, coastal areas, or places with high chloride exposure, the corrosion resistance of SUS201 is more limited. It is worth considering the actual environment before choosing this grade.
Formability
SUS201 has good formability. It can be processed using the same cold drawing and cold rolling methods used for 300 series stainless steel tubes. It adapts well to standard tube manufacturing and secondary processing.
Magnetic Behavior
In its annealed state, SUS201 is essentially non-magnetic. This is typical of austenitic stainless steel. After cold working, such as cold drawing or bending, some of the austenite transforms into martensite. This causes the tube to become slightly magnetic. This is a normal material characteristic and does not affect how the tube performs in use.
Main Applications of Stainless SUS201 Tubes
Stainless SUS201 tubes offer a good combination of strength, formability, and cost efficiency. These qualities make them a practical choice across several industries.
Decorative Tubes
SUS201 stainless steel tubes are widely used in building decoration. Common applications include indoor handrails, stair railings, door frames, and decorative trims. After polishing or brushing, the surface looks clean and attractive. This makes SUS201 tubes a reliable option for indoor decorative projects.
Furniture Tubes
In the furniture industry, SUS201 stainless steel tubes are commonly used for chair frames, table legs, storage racks, and display stands. The high tensile strength supports good load-bearing capacity. The formability makes bending and welding straightforward during production.
Light Structural Tubes
SUS201 tubes are also used in light structural applications. These include window and door frames, light support structures, and exhibition booths. In dry indoor environments where strong corrosion resistance is not a priority, SUS201 is a practical and cost-effective tube material.
Heat Treatment & Fabrication of Stainless SUS201 Tubes
Understanding the fabrication process helps get the best performance out of stainless SUS201 tubes. Here are the key process points to keep in mind.
Forming
SUS201 stainless steel tubes can be processed through cold drawing, bending, and roll forming. Because of the lower nickel content, the material is slightly less ductile than SUS304. More forming force or specialized equipment may be needed during bending or deep drawing. For tubes with complex shapes, intermediate annealing during forming is recommended. This helps release internal stress and reduces the risk of cracking.
Welding
SUS201 tubes have good weldability. Standard fusion welding and resistance welding methods both work well. During welding, pay attention to the heat-affected zone, as it can become sensitized under certain conditions. Controlling heat input and using filler materials helps prevent hot cracking.
Annealing
The standard annealing temperature range for SUS201 stainless steel tubes is 1010°C to 1093°C. After annealing, the tubes should be water quenched or rapidly air cooled. This prevents carbide precipitation and protects the corrosion resistance of the material. The temperature should not exceed the upper limit. Going over 1093°C increases the risk of surface scaling, which affects the tube finish.
Conclusion
Stainless SUS201 tubes offer a solid balance of mechanical strength, formability, and affordability. They are a reliable choice for decorative, furniture, and light structural applications, especially in indoor and normal atmospheric environments where extreme corrosion resistance is not required.
If you are looking for SUS201 stainless steel decorative and architectural tubes for your project, feel free to contact us for detailed product specifications and pricing.