What is 304 Stainless Steel?

304 is the most common stainless steel used globally. It is chosen for its excellent corrosion resistance and value for money.

304 and other austenitic steels also offer a balance of strength and workability.

304L is the extra low carbon form of 304 which has improved resistance to pitting and crevice corrosion in chloride bearing environments.

The most common form of 304 is 18/8 – which contains 18% chromium and 8% nickel.

304 machinability

Stainless steel 304 has good machinability. We recommend the following when machining 304:

• Keep cutting edges sharp as dull edges cause excess work hardening
• Light cuts but deep enough to prevent work hardening by riding on the surface of the material
• Use of chip breakers to assist in ensuring swarf remains clear of the work
• Use of coolants and lubricants in large quantities due to low thermal conductivity which can result in heat concentrating at the cutting edges

You may also see 304 referred to as:

• 18/8
• 1.4301/304
• 1.4307/304L
• S30400
• 304S15
• 304S16
• 304S31
• EN58E
• S11

Main attributes

• Can withstand corrosion from most oxidising acids
• Easy to sanitize due to its durability
• Excellent toughness
• Susceptible to corrosion from chloride solutions and saline environments
• Aesthetically pleasing
• Ease of cleaning
• Outstanding welding characteristics
• Good heat resistance – oxidation resistance in intermittent use up to 870°c and continuous use up to 925°c, however continuous use at 425-860°c is not recommended. In this instance, 304L is recommended.

UK stock sizes

Here are the standard stock sizes/colours for 304 in the UK. Please note we do not supply stock material, the information provided is purely for design and research purposes.

Example Stainless 304 Stock Sizes

Stock sizes will vary depending on supplier. Please get in contact to discuss further.

304 Round Bar

4mm - 300mm

304 Round Tube

Outside diameter: 10mm - 152.4mm

Wall thickness: 1.2mm - 3mm

304 Flat Bar

Thickness: 3mm - 12mm

Width: 12mm - 150mm

304 Square Bar

8mm - 120mm

304 Sheet

Thickness: 0.5mm - 3mm

Width: 1000mm - 2000mm

Length: 2000mm - 4000mm

304 Plate

Thickness: 3mm - 12mm

Width: 1000mm - 2000mm

Length: 2000mm - 4000mm

Common applications

• Food processing machinery & equipment
• Building & architectural products
• Tanks, containers & pressure vessels
• Piping, tubing & fittings
• Chemical processing & storage equipment
• Heat exchangers, heatsinks & coolers
• Domestic tools & utensils
• Panelling & fascias

Technical properties

Physical properties

Mechanical properties

Typical chemical composition (weight %)