304L Stainless Steel (UNS S30403)
304 with carbon held to 0.030 percent so welds and heat-affected zones do not sensitize — the choice for welded assemblies and parts that will be heated in service.
What 304L Stainless is.
Type 304L is 304 with the carbon limited to 0.030 percent. Low carbon means chromium carbides cannot precipitate at grain boundaries when the steel is heated into the 800 to 1500 °F range, so welded parts keep their corrosion resistance without a post-weld anneal. The price is a slightly lower minimum strength in the annealed bar: 70 ksi against 75 ksi for 304.
For fasteners the two grades are usually dual certified, because most 304 bar today meets the 304L carbon limit while still meeting 304 strength. We machine 304L bolts, studs and components from dual-certified A276 bar and supply them to F593 Group 1 conditions.
Chemical composition.
| Element | Symbol | Min % | Max % |
|---|---|---|---|
| Carbon | C | — | 0.030 |
| Manganese | Mn | — | 2.00 |
| Phosphorus | P | — | 0.045 |
| Sulfur | S | — | 0.030 |
| Silicon | Si | — | 1.00 |
| Chromium | Cr | 18.0 | 20.0 |
| Nickel | Ni | 8.0 | 12.0 |
Values per ASTM A276/A276M-17 Tables 1 and 2 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team.
Mechanical properties.
| Condition and nominal diameter (in.) | Tensile strength, min (ksi) | Yield strength 0.2% offset, min (ksi) | Elongation, min (%) | Reduction of area, min (%) | Hardness |
|---|---|---|---|---|---|
| Condition A (annealed), hot finished — all | 70 | 25 | 40 | 50 | — |
| Condition A, cold finished — ½ and under | 90 | 45 | 30 | 40 | — |
| Condition A, cold finished — over ½ | 70 | 25 | 30 | 40 | — |
| Condition B (cold worked) — ¾ and under | 125 | 100 | 12 | 35 | — |
| Condition B — over ¾ to 1 | 115 | 80 | 15 | 35 | — |
| Condition B — over 1 to 1¼ | 105 | 65 | 20 | 35 | — |
| Condition B — over 1¼ to 1½ | 100 | 50 | 24 | 45 | — |
| Condition B — over 1½ to 1¾ | 95 | 45 | 28 | 45 | — |
| Condition S (strain hardened) — 2 and under | 95 | 75 | 25 | 40 | — |
| Condition S — over 2 to 2½ | 90 | 65 | 30 | 40 | — |
| Condition S — over 2½ to 3 | 80 | 55 | 30 | 40 | — |
Values per ASTM A276/A276M-17 Tables 1 and 2 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team. Condition B and S limits are shared with 304 and 316.
| F593 condition · marking | Nominal diameter (in.) | Tensile strength (ksi) | Yield strength, min (ksi) | Rockwell hardness |
|---|---|---|---|---|
| AF (annealed after forming) · F593A | ¼ to 1½ | 65 to 85 | 20 | B85 max |
| A (annealed) · F593B | ¼ to 1½ | 75 to 100 | 30 | B65 to B95 |
| CW1 (cold worked) · F593C | ¼ to ⅝ | 100 to 150 | 65 | B95 to C32 |
| CW2 (cold worked) · F593D | ¾ to 1½ | 85 to 140 | 45 | B80 to C32 |
| SH1 (strain hardened) · F593A | ¼ to ⅝ | 120 to 160 | 95 | C24 to C36 |
| SH2 (strain hardened) · F593B | ¾ to 1 | 110 to 150 | 75 | C20 to C32 |
| SH3 (strain hardened) · F593C | 1⅛ to 1¼ | 100 to 140 | 60 | B95 to C30 |
| SH4 (strain hardened) · F593D | 1⅜ to 1½ | 95 to 130 | 45 | B90 to C28 |
Values per ASTM F593-24 Table 2, full-size tests (verified against the specification). Yield is 0.2 % offset; hardness is Rockwell. Machined-specimen limits differ slightly.
Specifications that apply.
How 304L Stainless ships from Houston.
- Hex and heavy hex bolts and cap screws
- Full-thread studs and threaded rod
- Socket head cap and set screws
- Hex, jam and lock nuts
- Washers and spacers
- Machined components from certified bar
304L Stainless fasteners we make.
Every item is manufactured to your drawing or standard in 304L Stainless, imperial or metric, with an EN 10204 3.1 certificate.
What is 304L stainless steel?
304L is the low-carbon variant of 304. Carbon above about 0.03 percent will combine with chromium at grain boundaries when the steel sits between 800 and 1500 °F, as it does beside a weld, and the chromium-depleted zone then corrodes preferentially. Holding carbon to 0.030 percent removes the problem. Everything else about the alloy, its structure, magnetism, cryogenic toughness and machinability, is the same as 304.
When to specify 304L
- Any part that will be welded or brazed, or that sits near a weld.
- Service between 800 and 1500 °F where sensitization would otherwise occur over time.
- Where a purchaser's specification calls for L grades on all austenitic stainless, common in refining and pharmaceuticals.
- Not needed for high strength: use 304 Condition B, or B8 Class 2, where the cold-worked strength matters.
Testing, certification and marking
- Tensile and hardness tested per lot on the finished product
- Grade or marking symbol F593A to F593D and manufacturer's identification on every piece
- EN 10204 3.1 material test report with heat number and chemistry; 3.2 witness available
- PMI verification and intergranular corrosion testing (ASTM A262) arranged on request
304 Stainless Steel (UNS S30400)
The general-purpose 18-8 stainless: 75 ksi annealed bar, cold-worked bolts to 160 ksi, non-magnetic, and resistant to water, food and most mild chemicals.
ASTM A276 bar · ASTM F593 bolts316L Stainless Steel (UNS S31603)
316 with carbon held to 0.030 percent for welded and heated service in chloride environments — the standard grade for pharmaceutical, chemical and offshore skids.
ASTM A193 / ASME SA-193ASTM A193 Grades B8LN and B8MLN (304LN / 316LN)
304LN and 316LN bolting — low carbon for weld-zone corrosion resistance, nitrogen to recover the strength that low carbon gives away.