304L Stainless Steel Hot Rolled Coil and Sheet: Properties, Processing and Applications
Dec 05, 2025
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What Is 304L Hot Rolled Stainless Steel Coil and Sheet?
304L is the low-carbon version of the austenitic stainless steel grade 304, designated UNS S30403 and covered by ASTM A240/A240M. Its carbon content is limited to a maximum of 0.030%, which suppresses the precipitation of chromium carbides at grain boundaries during welding and reduces the risk of intergranular corrosion in the heat-affected zone. Hot rolled coil and sheet are produced by rolling reheated slabs at temperatures above the recrystallization point, followed by annealing and pickling to restore the corrosion-resistant surface.
Hot rolled 304L is normally supplied in thicknesses from about 3.0 mm to 14.0 mm and widths up to 2000 mm, with a No.1 or pickled finish. It is the preferred starting material for tanks, pressure vessels, structural sections and heavy industrial equipment where the corrosion resistance of the 304 family is required in thicker gauges.
Chemical Composition per ASTM A240
| Element | Content (wt%) |
|---|---|
| Carbon (C) | ≤ 0.030 |
| Manganese (Mn) | ≤ 2.00 |
| Phosphorus (P) | ≤ 0.045 |
| Sulfur (S) | ≤ 0.030 |
| Silicon (Si) | ≤ 0.75 |
| Chromium (Cr) | 18.00 – 20.00 |
| Nickel (Ni) | 8.00 – 12.00 |
| Nitrogen (N) | ≤ 0.10 |
The limits above are taken from ASTM A240/A240M, the standard specification for chromium and chromium-nickel stainless steel plate, sheet and strip for pressure vessels and general applications.
Mechanical Properties (Annealed)
| Property | Value |
|---|---|
| Tensile strength | ≥ 485 MPa (70 ksi) |
| Yield strength (0.2% offset) | ≥ 170 MPa (25 ksi) |
| Elongation in 50 mm | ≥ 40% |
| Hardness | ≤ 217 HBW |
| Density (typical) | ≈ 7.93 g/cm³ |
| Modulus of elasticity | ≈ 193 GPa at 20 °C |
Hot Rolling Process and Surface Finish
Hot rolling is carried out at temperatures around 1000 – 1200 °C, which allows large reductions and economical production of thick coil and sheet. After rolling, the material is annealed and descaled. The common finishes are:
No.1 finish: hot rolled, annealed and pickled, with a dull grey surface used where a cosmetic appearance is not critical.
2D finish: cold rolled, annealed and pickled, giving a smoother matte surface for further processing.
Pickled surface: chemically descaled and ready for grinding, polishing or coating operations.
Thickness and flatness tolerances follow ASTM A480/A480M for flat-rolled stainless steel products. Hot rolled coil can be further processed by slitting, cut-to-length, leveling, edge trimming and surface grinding, which gives fabricators a flexible supply of sheet, strip and plate in custom sizes.
Applications of 304L Hot Rolled Coil and Sheet
Because 304L combines the corrosion resistance of 304 with resistance to sensitization after welding, it is widely specified for:
Storage tanks and process vessels in the food, beverage and chemical industries
Heat exchangers and pressure equipment that require welded thick sections
Architectural and structural components such as columns, beams and cladding supports
Railway, truck and container structures exposed to atmospheric corrosion
Pharmaceutical and dairy equipment where cleanability and hygiene are essential
FAQs About 304L Hot Rolled Coil and Sheet
What is the difference between 304 and 304L?
The main difference is carbon content. 304 allows up to 0.08% carbon, while 304L limits it to 0.030%. The lower carbon content of 304L prevents chromium carbide precipitation during welding, so welded assemblies are less prone to intergranular corrosion. Mechanical strength is slightly lower, with a minimum yield strength of 170 MPa instead of 205 MPa, which is normally acceptable for welded fabrications.
Can 304L hot rolled coil be welded?
Yes. 304L has excellent weldability with TIG, MIG, MMA and resistance welding processes. Because of its low carbon content, no post-weld heat treatment is normally required to restore corrosion resistance. Matching filler metal such as ER308L is typically selected to keep the weld metal carbon level low.
What is the No.1 hot rolled finish?
No.1 is a hot rolled, annealed and pickled surface with a dull, grey and uniform appearance. It is the standard finish for thicker sheets and plates used in tanks, vessels and industrial equipment where a bright decorative surface is not required.
Is 304L stainless steel magnetic?
304L is austenitic and essentially non-magnetic in the annealed condition. Cold working such as bending, shearing or rolling can transform part of the austenite into martensite and introduce slight magnetism, which is normal and does not affect corrosion resistance.
What sizes are available in hot rolled coil?
Typical hot rolled coil is supplied in thicknesses of 3.0 – 14.0 mm and widths of 1000 – 2000 mm, and can be cut to length or slit into narrower strip. Custom thickness, width and length combinations are arranged per project specifications, with tolerances in accordance with ASTM A480.
How should 304L hot rolled sheet be stored?
Store the material under cover in a dry and ventilated area, keep the surface protected with interleaving paper or plastic film, and avoid contact with carbon steel tools, chains or slings that can deposit rust particles and cause surface contamination.
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