303 Stainless Steel Pipe – The World’s Most Machinable Stainless Steel Piping Solution
When your production line needs to run faster, 303 Stainless Steel Pipe delivers. With 0.15–0.35 % sulfur deliberately added, this free-machining grade offers 2–3× higher machining speeds than standard 304 or 316 while still providing good corrosion resistance for mild-service applications. The coil-to-pipe process maintains the same chip-breaking advantage, allowing automatic screw machines and CNC lathes to produce precision fittings, shafts, and instrumentation tubing at maximum throughput. Whether you need bright-polished hydraulic lines or custom-machined valve bodies, 303 Stainless Steel Pipe gives you the productivity of brass with the prestige and corrosion resistance of stainless steel.
303 Stainless Steel Pipe & Stainless Steel 303 Pipe Fittings – Ultra-Machinable Grade for High-Volume Production
Key Features & Benefits
- Free-machining sulfur 0.15–0.35 % – 90 % machinability rating vs 45 % for 304
- Excellent chip break-up – longer tool life, lower production cost
- Good corrosion resistance for indoor, food-zone, and mild chemical environments
- Non-galling / non-seizing – ideal for moving screw-machine parts
- Non-magnetic in annealed condition; low permeability after cold work
- Available in both seamless and welded forms; precision honed ID possible
- Full ASTM A895, EN 1.4305, AMS 5640 compliance
- 100 % recyclable, RoHS compliant
Technical Specifications
Table 1 – Chemical Composition (ASTM A895)
| Element | 303 % | 303Se % |
|---|---|---|
| Cr | 17.0–19.0 | 17.0–19.0 |
| Ni | 8.0–10.0 | 8.0–10.0 |
| S | 0.15–0.35 | ≤0.060 |
| Se | — | ≥0.15 |
| C | ≤0.15 | ≤0.15 |
| Mn | ≤2.00 | ≤2.00 |
| Si | ≤1.00 | ≤1.00 |
| Fe | Balance | Balance |
Table 2 – Mechanical & Machining Data vs 304/316
| Property | 303 Pipe | 304 Pipe | 316 Pipe |
|---|---|---|---|
| Tensile Strength | ≥620 MPa | ≥515 MPa | ≥515 MPa |
| Yield Strength (0.2 %) | ≥310 MPa | ≥205 MPa | ≥205 MPa |
| Elongation in 2" | ≥35 % | ≥40 % | ≥40 % |
| Hardness HRB | 90–100 | ≤92 | ≤95 |
| Machinability Rating | 90 % (excellent) | 45 % (good) | 45 % (good) |
| Chip Break-Up | Superior | Fair | Fair |
| Weldability | Poor* | Excellent | Excellent |
*Welding not recommended due to hot-cracking risk; use 304/347 for welded joints and bolt on 303 parts.
Size Range & Types
Full range from 1/8" to 12" – seamless and 321 stainless steel welded pipe.
| NPS | OD (mm) | Sch | WT (mm) | Length (m) | Type |
|---|---|---|---|---|---|
| 1/8" | 10.3 | 10S/40S/80S | 1.24–2.24 | 6 | Seamless |
| 1/2" | 21.3 | 10S/40S/80S | 1.65–3.73 | 6 | Seamless |
| 3" | 88.9 | 10S/40S/80S | 2.11–7.62 | 6/12 | Smls / Welded |
| 6" | 168.3 | 10S/40S/80S | 2.77–7.11 | 6/12 | Smls / Welded |
| 12" | 323.8 | 10S/40S/80S | 3.96–12.7 | 6/12 | Welded (ERW) |
Custom lengths, honed ID, and precision cut-to-size available.
Product Range & Market Info
As one of the largest producers of china 303 stainless steel pipe, we operate a 100 000 t/year mill with three continuous mandrel mills and six ERW lines dedicated to 303 stainless steel pipe and 303 se stainless steel pipe. Our 150 000 m² facility keeps 30 000 t of ready stock, ensuring immediate availability for 303 stainless steel pipe suppliers and global distributors. Whether you need one bundle of 3" Sch 40S or a full container of 6" × 6 m seamless pipe, our mill-direct pricing and EN 10204 3.1/3.2 MTC give you the competitive edge. Contact our export team today for the latest china 303 stainless steel pipe quotation and downloadable mill test certificates.
Specialty products include complete stainless steel 303 pipe fittings – elbows, tees, reducers, and caps manufactured in-house under ASTM A403 WP-S.
303Se Stainless Steel Pipe – Selenium Grade for Even Better Chip-Breaking & Surface Finish on Swiss-Type Lathes
Main Applications
- Precision machined components: nuts, bolts, shafts, bushings
- Automatic lathe parts: fittings, connectors, adapters
- Valve bodies, pump trim, pneumatic cylinders
- Instrumentation tubing, sensor housings
- Food-processing equipment parts requiring extensive machining
- Stainless steel 303 pipe fittings for low-pressure dairy lines
- Electrical connectors, terminal blocks, RF shields
Why Choose Us – Mill-Direct Advantages
- ISO 9001 & PED certified mill – EN 10204 3.1 & 3.2 MTC supplied
- 100 000 ton annual capacity – 5-day lead time for standard sizes
- In-house stainless steel 303 pipe fittings production – elbows, tees, caps ½"–12"
- Precision cutting, honing, threading – lengths 3–12 m, tolerances ±0.2 mm
- Same-day shipment from 30 000 t stock – real-time 303 stainless steel pipe portal
- Global export to 70+ countries – fumigation-free crates, vessel booking, insurance
China 303 Stainless Steel Pipe – Massive Stock, Mill-Direct Prices, Fast Global Delivery
Grade Comparison Table: 303 vs 303Se vs 304 vs 316 vs 416 vs 430F
| Grade | S/Se % | Mo % | Machinability | Weldability | Magnetic | Relative Cost | Best Use |
|---|---|---|---|---|---|---|---|
| 303 | S 0.15–0.35 | 0 | 90 % | Poor | No* | 1.0× | High-speed machining |
| 303Se | Se ≥0.15 | 0 | 95 % | Poor | No* | 1.1× | Ultra-smooth finish |
| 304 | ≤0.030 | 0 | 45 % | Excellent | No* | 0.95× | General corrosion |
| 316 | ≤0.030 | 2–3 | 45 % | Excellent | No* | 1.35× | Marine chloride |
| 416 | S ≥0.15 | 0 | 95 % | Poor | Yes | 0.9× | Magnetic fasteners |
| 430F | S ≥0.15 | 0 | 90 % | Poor | Yes | 0.8× | Non-corrosive shafts |
*Non-magnetic in annealed condition; slight magnetism possible after cold work.
FAQ – 303 Stainless Steel Pipe
-
What is the machinability rating of 303?
90 % (excellent) vs 45 % for 304; chip break-up is superior, tool life 2–3× longer. -
Can 303 pipe be welded?
Welding is not recommended due to hot-cracking risk; use 304 or 347 for welded joints and bolt on 303 parts. -
Difference between 303 and 303Se?
303Se contains ≥0.15 % selenium instead of sulfur, providing even better chip breaking and smoother surface finish. -
What is current china 303 stainless steel pipe pricing?
Mill-direct FOB China USD 2.40–2.80/kg depending on sulfur additive and nickel surcharge; fixed for 48 h. -
What sizes are available for stainless steel 303 pipe fittings?
Elbows, tees, reducers, caps from ½" to 12" manufactured in-house under ASTM A403 WP-S. -
How do I check current 303 stainless steel pipe stock?
Login to our portal – live tonnage, coil ID, location, and certificate number updated every 30 minutes. -
Which countries receive your china 303 stainless steel pipe?
More than 70 countries including USA, Germany, India, Brazil, UAE, South Korea, and Australia. -
What certificates accompany the shipment?
EN 10204 3.1/3.2 MTC, ISO 9001, PED 2014/68/EU, and third-party inspection (SGS/TÜV/BV).
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Stop paying trader margins. Contact the largest china 303 stainless steel pipe producer today for the most competitive price, immediate access to 303 se stainless steel pipe stock, and same-day cutting of any stainless steel 303 pipe fittings.