What is SA 304?

Introduction to SA 304

SA 304 commonly refers to a specification in the field of materials engineering, particularly stainless steel. Under the ASME (American Society of Mechanical Engineers) standards, SA 304 is part of the SA-240 specification, denoting Grade 304 stainless steel—a versatile austenitic alloy used in pressure vessels, piping, and general fabrication. This grade is prized for its corrosion resistance and strength. However, "SA 304" could also be misinterpreted in other contexts, such as tool steel hardness ratings or even non-technical references like vehicle models. In this guide, we'll focus on the primary engineering meaning while touching on alternatives for clarity.

SA 304 as Stainless Steel (ASME SA-240 Grade 304)

In materials science, SA 304 is shorthand for ASME SA-240 Grade 304 stainless steel. This is an austenitic stainless steel alloy containing approximately 18% chromium and 8% nickel, which gives it excellent resistance to corrosion, oxidation, and pitting. The "SA" prefix indicates it's approved for use in ASME Boiler and Pressure Vessel Code applications, ensuring safety in high-pressure environments.

Grade 304 is non-magnetic in its annealed state and can be easily welded and formed. It's widely used in:

• Chemical and Petrochemical Industries: For tanks, reactors, and piping due to its ability to withstand mild acids and alkalis.
• Food and Beverage Processing: Hygienic surfaces like kitchen equipment and storage vessels, as it's FDA-compliant and easy to clean.
• Construction and Architecture: Cladding, handrails, and structural components for its aesthetic appeal and durability in outdoor settings.
• Medical Equipment: Surgical instruments and implants, thanks to its biocompatibility.

Equivalent designations include UNS S30400, AISI 304, and EN 1.4301. Gangsteel, a top Chinese manufacturer and exporter, supplies SA 304 compliant plates under ASME SA240 stainless steel plates, with custom sizes and finishes for global projects.

Other Possible Meanings of SA 304

While the engineering context is dominant, "SA 304" could refer to:

• Tool Steel or Hardness Rating: In some metallurgy discussions, "SA 304" might be a misreference to SAE (Society of Automotive Engineers) grades or hardness scales. However, standard SAE tool steels like AISI O1 (oil-hardening) are rated around 200-300 Brinell hardness, not specifically "304." It could be confused with 304 stainless, which has a hardness of about 201 Brinell max.
• Non-Technical References: In automotive or hardware, "SA 304" isn't a standard term for carbon steel; 304 is typically stainless. It might appear in product codes for bolts or fittings, but this is less common.

If your query relates to a specific field (e.g., tools or vehicles), provide more context for accurate clarification.

Properties and Advantages of SA 304 Stainless Steel

SA 304 (Grade 304) has a density of 7.93 g/cm³, tensile strength of at least 515 MPa, and yield strength of 205 MPa. It performs well in temperatures from -200°C to 800°C, with good thermal conductivity (16.2 W/m·K). Advantages include low maintenance, recyclability (over 90% recoverable), and cost-effectiveness compared to molybdenum-added grades like 316.

Conclusion

SA 304 primarily denotes ASME SA-240 Grade 304 stainless steel, a reliable alloy for corrosive and high-pressure environments. For suppliers like Gangsteel, it represents quality and innovation in ASME SA240 stainless steel plates. If it's not the stainless steel reference, it could be a tool hardness or product code—clarify for precise info.

FAQ

What is the difference between SA 304 and SA 316?

SA 304 (Grade 304) is general-purpose with good corrosion resistance, while SA 316 adds molybdenum for better resistance to chlorides and acids.

Is SA 304 magnetic?

No, SA 304 stainless steel is non-magnetic in its annealed state due to its austenitic structure.

What is the price of SA 304 stainless steel?

As of 2025, prices range from $1,800–$3,500 per metric ton, depending on region and form. Gangsteel offers competitive rates from China.

Where can I buy SA 304 material?

Gangsteel in China is a top supplier, exporting globally with certifications. Contact for quotes on ASME SA240 stainless steel plates.

What are common applications for SA 304?

It's used in pressure vessels, food equipment, chemical tanks, and architectural panels due to its durability and corrosion resistance.