Which Precision Stainless Steel Tubing Grade Is Best for Your Needs
Do you frequently encounter the problem of not knowing how to choose the right materials when advancing your projects? Today, we'll introduce you to the unique characteristics of popular stainless steel pipes: 304, 316, 321, 410, and 904L. Understanding these characteristics will help you choose the appropriate stainless steel pipe for your needs.
Key Takeaways
To select the appropriate grade of stainless steel pipe based on the specific requirements of the project, the following factors should be considered: corrosion resistance, mechanical strength, and cost.
l If your project requires highly corrosion-resistant steel pipes, then the 300 series, such as 304 and 316, is a cost-effective option
l If you require higher strength and wear resistance, the 400 series is a better choice. 410 stainless steel precision tubes can have their strength increased through heat treatment.
l If your operating environment involves strong acids or chloride stress corrosion cracking, 904L is a good choice.
In any case, you need to confirm the product form and standards, as well as the specifications of the tubing.
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Precision Stainless Steel Tubing Grades Overview
We have listed several series that you may encounter, which are also commonly used. Each series has its own unique characteristics, and we will help you understand these differences and characteristics to choose the right material for you.
300 Series (Austenitic)
300 series austenitic stainless steel tubes are widely used in various industries due to their excellent corrosion resistance, formability, and weldability. Please note that they are generally non-magnetic in the annealed state, but may become slightly magnetic after extensive cold working.
400 Series (Martensitic/Ferritic)
400 series stainless steel is "pure chromium" stainless steel and is typically ferromagnetic. Martensitic stainless steel TP410 can have its strength and hardness increased through heat treatment, and is therefore frequently used in wear-resistant and mechanical applications.
Super austenitic stainless steel Stube
Super austenitic stainless steel pipe 904L is designed for extremely corrosive environments. This super stainless steel pipe has enhanced corrosion resistance due to its high nickel/molybdenum content and the addition of copper.
Grade Comparison
|
Grade
|
Key alloying feature
|
Corrosion resistance
(relative)
|
Strength
(relative)
|
Magnetic?
|
Common tubing/pipe standards
(examples)
|
|
304 / 304L
|
18Cr-8Ni (baseline austenitic)
|
Good (general service)
|
Moderate
|
Usually no*
|
Tube: ASTM A269; Sanitary tube: ASTM A270; Pipe: ASTM A312
|
|
316 / 316L
|
Mo addition improves chloride pitting resistance
|
Very good (chlorides)
|
Moderate
|
Usually no*
|
Tube: ASTM A269; Sanitary tube: ASTM A270; Pipe: ASTM A312
|
|
321
|
Ti-stabilized to reduce sensitization
|
Good; strong at high temp
|
Moderate
|
Usually no*
|
Tube: ASTM A269 / ASTM A213 (heat-exchanger service)
|
|
410
|
Heat-treatable martensitic
|
Fair (mild environments)
|
High (after heat treat)
|
Yes
|
Tube: ASTM A268; Welded mech tube: ASTM A554 (when applicable)
|
|
904L
|
High Ni/Mo + Cu (superaustenitic)
|
Superior (reducing acids / chlorides)
|
Moderate
|
No
|
Confirm grade availability in your required product spec (e.g., ASTM A269/A213 for tubing, or ASTM A312 for piping).
|
Application Examples
|
Application scenario
|
Typical conditions
|
Shortlist grade
(s)
|
Why / standard cue
|
|
General industrial tubing (instrumentation, frames, indoor equipment)
|
Mild atmosphere, general corrosion; forming/welding as needed
|
304/304L
|
Cost-effective baseline; common under ASTM A269 for general-service tubing.
|
|
Coastal / chloride exposure (marine, outdoor, salt spray)
|
Chlorides; risk of pitting/crevice corrosion
|
316/316L
|
Mo improves pitting/crevice resistance vs 304; often chosen when chlorides are present.
|
|
High-temperature welded service (exhaust/heat exposure)
|
Welded fabrication + prolonged 425–815°C exposure
|
321/321H (or 347 for filler)
|
Ti-stabilized to reduce sensitization and intergranular corrosion risk after heat exposure.
|
|
Food & beverage / hygienic lines
|
Cleanability + surface finish requirement; sanitary fittings
|
304L or 316L (sanitary)
|
Sanitary tubing is commonly specified to ASTM A270 (dairy/food; pharma quality as a supplementary requirement).
|
|
Wear / mechanical parts where corrosion is secondary
|
Need hardness/wear; may heat treat
|
410
|
Martensitic; heat treatable for higher strength/hardness; use when environment is mild.
|
|
Acidic / aggressive chemical service (e.g., dilute sulfuric/phosphoric)
|
Reducing acids; possible chlorides + SCC risk
|
904L (or higher alloys)
|
High Ni/Mo with Cu improves resistance in some reducing acids—confirm with corrosion engineer and project spec.
|
Summary of Requirements:
We have summarized several key factors you need to consider when choosing the right stainless steel tubing for your project:
1. Environmental Factors: Exposure to chloride, salt spray, acids, or other chemicals.
2. Mechanical Requirements: Mechanical properties, wear resistance, and whether heat treatment is required to enhance strength.
3. Manufacturing Process: Seamless or welded tubing, bending requirements, and limitations regarding post-weld heat treatment.
4. Standards and Compliance: Compliance with project standards and surface treatment requirements.
5. Total Cost: Material price, yield rate, and long-term maintenance and service life.
How to Choose the Right Grade of Precision Stainless Steel Tubing
TORICH is a company with 25 years of industry experience. We have extensive industry experience in steel pipe selection through hundreds of projects. If you are having trouble finding the right precision stainless steel tubing for your project, please contact us immediately. Upon receiving your inquiry, we will contact you promptly to discuss and design the steel pipes you need.
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