Short answer: Use 316/316L for most chloride, seawater and chemical lines. Move to duplex 2205 when you need higher strength, higher pitting resistance, or the spec already calls for duplex. Zhejiang Huabo Pipe Co., Ltd. (HuaboPipe) supplies both — plus 304/304L, 310S and 2507 — as fittings and flanges to order, DN15–DN3000. Lead time and MOQ are confirmed with the inquiry. We do not publish stock lists or fictitious SKUs.
HuaboPipe has manufactured stainless industrial pipe, fittings and flanges in Lishui, Zhejiang, China since 2004. 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 | Chlorides, seawater, most chemical lines | 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. A 316L header with 304 elbows is a leak waiting at the weld.
- Default to 316L for seawater, chlorinated cooling water and coastal plants. If you are unsure, send medium, concentration, temperature and pressure. We reply within 24 hours.
- 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, not a catalog daydream. Our published range is DN15–DN3000. DN3000-class flanges are made to drawing. They are not sold as ASME B16.5 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–DN3000
- Standards: ASME B16.9, GB/T 12459 and others; non-standard to drawing
- Factory direct OEM from drawings or samples
- Inspection: hydro, PT/UT/RT and MTR as agreed on the order
- Lead time and MOQ: confirmed on inquiry — not a fixed number on this page
Send medium, temperature, pressure, size/schedule, standard, quantity, and whether you need MTR or NDT. Email lucas@huabopipe.com, Tel/WhatsApp +86 189 8973 8576. We reply within 24 hours.
Certificates are listed on the certificate page: Special Equipment Production License TS2733H08-2027, ISO 9001/14001/45001, DNV, BV, PED, plus business license and related Chinese certificates. Company facts: About.
Recent supply of similar fittings and flanges
Taken from HuaboPipe’s qualification file. Industry, owner and product type only — contract values are not published. The Projects page is unchanged; this table is material-selection evidence, not a case-study gallery.
| Year | Industry | Owner | Supply |
|---|---|---|---|
| 2022 | Pulp & paper | Nine Dragons Paper (Hubei); Shan Ying Paper (Guangdong / Zhejiang) | Fittings, flanges |
| 2022 | Wastewater | Jilin Origin Water | Fittings, flanges |
| 2022–2023 | High-purity silicon / semiconductor materials | Inner Mongolia Daqo New Energy | Fittings, flanges |
| 2023 | Pharma | Zhejiang Huahai Chengke Pharmaceutical | Fittings |
| 2023 | Chemicals (coatings / solvents) | Runtai Chemical (Taixing) | Fittings, flanges |
| 2023 | Lithium battery | Dalian Huayi Lithium | Fittings, flanges |
| 2023–2024 | Paper chemicals / new materials | Xianhe New Materials (Guangzhou, Guangxi) | Fittings, flanges |
| 2024 | Pharma | Shandong New Time Pharmaceutical | Fittings, flanges |
| 2024 | Hydrogen energy | Changchun Green Hydrogen | Fittings, flanges |
| 2024 | Polysilicon | United Solar Polysilicon | Fittings, flanges |
| 2025 | Pulp & paper | Nine Dragons Paper (Hubei) | Fittings, flanges |
These jobs show fittings and flanges in paper, water, pharma, chemical, lithium, hydrogen and silicon service. The grade on each job follows that drawing. Do not assume a named owner always uses 316L or always uses 2205.
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 an ASME B16.5 item?
No. B16.5 covers smaller NPS. 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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