304 / 304L Stainless Steel Pipe
304 / 304L stainless steel pipe is a versatile,widely used austenitic chromium-nickel alloy (also known as “18-8” stainless steel) known for its excellent corrosion resistance and formability.The “L” in 304L denotes a low-carbon version that offers enhanced weldability and resistance to intergranular corrosion,especially in heavy-gauge welded sections.
Heat Treatment of 304 / 304L Stainless Steel Pipe
Solution Annealing
- Heating Temperature:
1010°C – 1120°C (1850°F – 2050°F). - Soak Time:
Ensure workpieces are thoroughly heated through.For thick-walled components (e.g., over 25mm),it is generally recommended to soak for 60-90 minutes per 25mm of thickness. - Cooling Method:
Rapid cooling is mandatory.Water quenching is recommended for heavy components;thin sections may use forced air cooling.Cooling must rapidly traverse the critical temperature range of 427°C – 816°C (800°F – 1500°F) to prevent re-precipitation of chromium carbides (sensitization),which causes intergranular corrosion.
Stress Relieving
- Low-temperature Stress Relief:
Typically performed below 400°C – 450°C,followed by air cooling after holding.This lower temperature range avoids sensitization. - High-temperature Stress Relief:
For 304L,this can be conducted at 450°C – 600°C with relatively low risk.However,standard 304 stainless steel must never be held in this temperature range for extended periods,as it may develop severe intergranular corrosion susceptibility.
Forging/Hot Working
- Initial Temperature:
1149°C – 1260°C (2100°F – 2300°F). - Final Temperature:
Should not be lower than 927°C (1700°F). - Post-Processing Treatment:
Solution treatment is recommended immediately after hot working to ensure optimal corrosion resistance.
Differences in Heat Treatment Between 304 and 304L
- Post-weld Treatment:
304L has an extremely low carbon content (≤0.03%),typically maintaining excellent intergranular corrosion resistance without requiring heat treatment after welding.In contrast,standard 304 may need solution treatment post-weld to restore performance in severe corrosion environments. - Hardening Methods:
Both grades can only increase strength and hardness through cold working (cold rolling, cold drawing).Heat treatment will only soften them and increase ductility.
304 / 304L Stainless Steel Pipe Chemical Composition
| Element (%) | 304 (S30400) | 304L (S30403) |
|---|---|---|
| C | ≤ 0.08 | ≤ 0.03 |
| Cr | 8.0 – 12.0 | 10.0 – 14.0 |
| Mo | 18.0 – 20.0 | 18.0 – 20.0 |
| Ni | 8.0 – 10.5 | 8.0 – 12.0 |
| Mn | ≤ 2.00 | ≤ 2.00 |
| Si | ≤ 0.75 | ≤ 0.75 |
| P | ≤ 0.045 | ≤ 0.045 |
| S | ≤ 0.030 | ≤ 0.030 |
| N | ≤ 0.10 | ≤ 0.10 |
| Fe | Balance | Balance |
304 / 304L Stainless Steel Pipe Chemical Composition
| Property | 304 (S30400) | 304L (S30403) |
|---|---|---|
| Tensile Strength, min. | 75 ksi (515 MPa) | 70 ksi (485 MPa) |
| Yield Strength (0.2% Offset), min. | 30 ksi (205 MPa) | 25 ksi (170 MPa) |
| Elongation (in 2 in. or 50mm), min. | 35% – 40% | 35% – 40% |
| Hardness, max. | 92 HRB (192 HBW) | 92 HRB (192 HBW) |
Kaysuns offers stainless steel pipes that simultaneously meet the mechanical properties of 304 and the low-carbon requirements of 304L. These products carry dual 304/304L certification.Please feel free to contact us if you have any needs.
What We Do
- Plate
- Sheet
- Forgings
- Round Bar
- Flange
- Pipes
- Fittings
- Customized
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Manufacturing Standards for 304/304L Stainless Steel Pipe
- ASTM A312 / ASME SA312:
The most common standard in North America, covering seamless and welded austenitic stainless steel pipes for high-temperature and general corrosion service. - ASTM A240 / ASME SA240:
Standard for stainless steel plates;however,when producing welded pipes,the raw material plates and strips must meet these chemical composition and performance requirements. - EN 10217-7:
European standard specifying technical delivery conditions for welded stainless steel pipes. - JIS G3459:
Japanese Industrial Standard specifying stainless steel pipes for corrosion-resistant,cryogenic,and high-temperature applications (designated as SUS304TP/SUS304LTP - GB/T 14976: Chinese National Standard defining requirements for seamless stainless steel pipes used in fluid conveyance.
Manufacturing and Supplying Capacity
| Product | Stainless Steel Pipes and tubes |
| Grade | 304 | 1.4301 ，304 | 1.4307 |
| Dimension | 1/2” ~ 24” for smls, 6” ~ 104” for EFW pipe The dimensions of stainless steel pipes comply with ASME B36.19/B36.10 standards. |
| Schedule | SCH10S, SCH20, SCH30, SCH40, STD, SCH80, XS, SCH60, SCH80, SCH120, SCH140, SCH160, XXS |
| Type | Seamless / Welded |
| Manfaucturing Craft | Cold Drawn,Cold Rolled (ERW/EFW for welded) |
| Pipe End | Plain End, Beveled End, Treaded |
| Delivery Condtions | Solution Annealing, Bright Annealing |
Features
- Corrosion Resistance
- Fabrication & Welding
- Temperature Versatility
- Hygiene & Aesthetics
- Cost-Effectiveness
Applications
- Food & Beverage Processing
- Chemical & Petrochemical Industry
- Water Treatment & Supply Systems
- Architecture & Construction
- Medical & Pharmaceutical Equipment
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Get In Touch
- RM901 No.22 Tangjiaqiao Road Wenzhou China
- +86 577 8551 1171
- [email protected]
- https://www.kaysuns.com/
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