Short answer: Use 316L for mild chloride service; step up to duplex 2205 for higher strength or higher chloride levels, and to super duplex 2507 for seawater. Huabo Pipe Industry Co., Ltd. (HuaboPipe) supplies both, plus 304/304L, 310S, 321 and 2507, as fittings and flanges to order. Standard sizes DN15 to DN1200; larger sizes are made to drawing, up to DN3000. Lead time and MOQ are confirmed with the inquiry.
HuaboPipe was founded in 2004, with the company in Wenzhou. The factory is in Lishui, Zhejiang, and makes butt-weld fittings and forged flanges. Stainless steel pipe is also supplied. Factory address: No. 102 Longqing Road, Liandu District, Lishui, Zhejiang. This page is for buyers and engineers who need a material decision, not a slogan.
Comparison
| Item | 304 / 304L | 316 / 316L | Duplex 2205 |
|---|---|---|---|
| What it is | 18Cr-8Ni | Mo-bearing austenitic, better vs chlorides | Duplex microstructure, higher strength |
| Use when | Clean water, air, mild process service | Mild chloride service, most chemical lines; not the default for seawater | Higher corrosion, higher pressure, or thinner wall |
| Avoid when | Seawater, chlorinated cooling water, coastal yards | Strong reducing acids or extreme chloride + heat (needs calculation) | Simple 304 service where duplex cost is wasted |
| Match the pipe | 304 pipe → 304 fittings | 316L pipe → 316L fittings; do not mix in one joint | Follow the spec; welding consumables must match |
| HuaboPipe supply | Yes, to order | Yes, to order | Yes, to order |
Use the L grades (304L / 316L) for welded fittings unless the drawing says otherwise. We do not change the grade on the PO.
How to decide
- Read the fluid and temperature before the price. 304 is cheaper. Chloride pitting on the wrong elbow costs more than the alloy upgrade.
- Keep fittings in the same alloy family as the pipe. Do not weld 304 elbows onto a 316L header.
- 316L is not the default choice for seawater: its pitting resistance (PREN about 24) is low for chloride service, especially at crevices and in warm or stagnant water. For seawater and high-chloride service, duplex 2205 or super duplex 2507 is usually specified; the final grade follows the project material specification. If you are unsure, send medium, concentration, temperature and pressure.
- Step up to 2205 when 316L is not enough: higher chlorides, higher design stress, or a duplex spec. Super duplex 2507 is for more severe pitting duty, to drawing.
- Large sizes follow the drawing. Standard sizes DN15 to DN1200; larger sizes are made to drawing, up to DN3000. DN3000-class flanges are made to drawing. They are not catalog items.
Product pages:
What HuaboPipe can supply
- Grades: 304/304L, 316/316L, 310S, 321, 2205, 2507
- Products: BW elbows (45°/90°/180°), tees, reducers, crosses, caps, stub ends, SO/WN/LWN/blind and non-standard blinds
- Size: DN15 to DN1200; larger to drawing, up to DN3000
- Standards: EN 10253, DIN, JIS; non-standard to drawing
- OEM from drawings or samples
- Inspection: PMI inspection available; hydro, PT/UT/RT and MTR as agreed on the order. Heat treatment: solution annealing. Surface treatment: polishing, pickling, sand blasting and sand tumbling.
- Lead time and MOQ: confirmed on inquiry
Send medium, temperature, pressure, size/schedule, standard, quantity, and whether you need MTR or NDT. Email lucas@hbpipe.com, Tel/WhatsApp +86 152 1057 8298.
Certificates are listed on the certificate page: Special Equipment Production License TS2733H03-2027, ISO 9001/14001/45001, DNV, BV, PED, plus business license and related Chinese certificates. Company facts: About.
FAQ
Can we use 316L instead of 2205 to save cost?
Often yes, if chloride level, temperature and design stress stay within 316L. If the datasheet already specifies duplex, do not substitute.
Do you stock 2205 elbows?
We supply to order. MOQ and lead time are confirmed with the inquiry.
Will you mix 316L fittings onto a 2205 line?
No. Match the pipe grade and the welding procedure. Send the spec if you need a written confirmation.
Is a DN3000 flange a catalog item?
No. Large-diameter pieces are made to drawing.
What inspection comes with the order?
MTR as standard when agreed. Hydro and PT/UT/RT follow the PO. Ask in the inquiry.
Request a quote on the contact page. Chinese site: cnhuabo.cn.
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