303 Stainless Steel Plate – The World’s Most Machinable Stainless Grade for High-Volume CNC Production
When your CNC or automatic screw machine needs to run faster, 303 Stainless Steel Plate delivers the competitive edge. With 0.15–0.35 % sulfur deliberately added, this free-machining grade offers 2–3× higher machining speeds and superior chip-breaking compared to standard 304 or 316, while still providing good corrosion resistance for mild-service applications. From precision-machined valve bodies and pump parts to food-processing equipment bases and electronic housings, 303 stainless steel plate maximises spindle uptime, extends tool life, and reduces unit cost—making it the first choice for high-volume producers of turned, milled, or ground components worldwide.
Caption: 303 Stainless Steel Plate – Ultra-Machinable Grade, 2–3× Faster Than 304, Perfect for Mass ProductionKey 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 plate and bar configurations – full 321 stainless steel bar or plate range
- Full ASTM A895, A240, A582, EN 1.4305, AMS 5640 compliance
- 100 % recyclable, RoHS compliant
Technical Specifications
Table 1 – Chemical Composition (ASTM A895)
| Element | 303 % | 303Se % | 304 % |
|---|---|---|---|
| Cr | 17.0–19.0 | 17.0–19.0 | 18.0–20.0 |
| Ni | 8.0–10.0 | 8.0–10.0 | 8.0–10.5 |
| S | 0.15–0.35 | ≤0.060 | ≤0.030 |
| Se | — | ≥0.15 | — |
| C | ≤0.15 | ≤0.15 | ≤0.08 |
| Fe | Balance | Balance | Balance |
Table 2 – Mechanical & Machinability Data
| Property | 303 Plate | 304 Plate | 316 Plate |
|---|---|---|---|
| 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.
Standard Sizes & Thickness
| Thickness (mm) | Standard Sizes (mm) | Weight (kg/m²) | Finish Options |
|---|---|---|---|
| 3–12 | 1500 × 6000 | 24–96 | No.1, pickled |
| 12–30 | 2000 × 6000 | 96–240 | No.1, HRAP |
| 30–60 | 2000 × 6000 | 240–480 | No.1, forged |
| 60–100 | 2500 × 12000 | 480–800 | No.1, forged |
Custom cut-to-size and 304 stainless steel plate thickness from 3 mm to 100 mm available.
Product Range & Market Info
As one of the largest and most professional 321 stainless steel plate factory & 321 stainless steel plate manufacturer in China, we operate a 180 000 t/year Steckel mill with in-house solution annealing up to 1200 °C dedicated to 321 stainless steel plate production. Our 180 000 m² facility keeps 30 000 t of ready 321 stainless steel plate for sale in Shanghai and Houston, ensuring immediate availability for global aerospace and furnace builders. Whether you need one sheet of 10 mm × 1500 mm × 6000 mm or a full vessel of 80 mm × 2500 mm × 12000 mm, our mill-direct 321 stainless steel plate china pricing and ABS-approved quality give you the competitive edge. Contact our export team today for the most updated quotation and downloadable 3.1 MTC.
Specialty products include both plate and 321 stainless steel bar or plate – rounds, flats, and forgings manufactured under AMS 5510.
Caption: 303 Stainless Steel Plate – AISI 303 Grade, High-Quality Free-Machining Stainless SteelMain Applications
- Aircraft & piston engine exhaust systems – collector rings, flame tubes
- Furnace plates & baffles – radiant tubes, muffles, baskets
- Thermal oxidizer shells – flare stacks, reactor liners
- Refinery flare stacks – high-temperature ducting
- Expansion bellows – welded joints, flexible joints
- High-temperature heat exchangers – tubesheets, shells
- Superheater tubesheets – power station boilers
- Chemical process vessels – operating 500–900 °C
Caption: 303 Stainless Steel Plate – 1.4305 / S30300 Grade, Manufacturers & SuppliersWhy Choose Us – High-Temp Specialist
- PED 2014/68/EU & TUV certified mill – EN 10204 3.1 & 3.2 MTC supplied
- In-house solution annealing furnace up to 1200 °C – full metallurgical control
- 200 000 tons annual capacity – 5-day lead time for standard sizes
- Same-day plasma/laser cutting – tolerances ±0.2 mm, beveling included
- Full NDT service – UT, RT, PMI on every 321 stainless steel plate
- Real-time stock portal – 24/7 visibility for any 321 stainless steel plate sizes
Grade Comparison Table: 321 vs 304 vs 316 vs 310S vs 347 vs 321H
| Grade/Type | Ti % | Mo % | Max Temp (°C) | Weld Post-Treat | Relative Cost | Best Use |
|---|---|---|---|---|---|---|
| 321/321H | ≥5×C | 0 | 870 | Not needed | 1.1× | High-temp welded |
| 304 | 0 | 0 | 800 | Not needed | 1.0× (base) | General service |
| 316 | 0 | 2–3 | 870 | Not needed | 1.35× | Marine chloride |
| 310S | 0 | 0 | 1150 | Not needed | 1.4× | Furnace radiant |
| 347 | Nb≥10×C | 0 | 870 | Not needed | 1.2× | Nuclear welded |
FAQ – 321 Stainless Steel Plate
-
What is the current pricing?
Mill-direct FOB China USD 2.60–3.00/kg depending on nickel and titanium surcharge; fixed for 48 h. -
Stock status for 20 mm plate?
5 000 t ready inventory; live portal updated every 30 minutes. -
Difference 321 vs 321H?
321H has 0.04–0.10 % carbon for higher creep strength; 321 is ≤0.08 % for better formability. -
Lead time for 50 mm × 2000 × 6000 mm?
7 days production + 3–5 days ocean freight to Asian ports; 10 days to EU/US warehouses. -
Welding recommendations?
TIG with ER321 filler; pre-heat not required; post-weld anneal optional for most high-temp services. -
China factory advantages?
Mill-direct pricing, 200 000 t capacity, in-house 1200 °C annealing, same-day cutting, full NDT. -
Do you supply both plate and bar?
Yes, full range of 321 stainless steel bar or plate – rounds, flats, forgings under AMS 5510. -
Do you export worldwide?
Yes, to 70+ countries including USA, Germany, India, UAE, South Korea, and Brazil.
Call-to-Action
Stop paying trader margins. Contact the most trusted 321 stainless steel plate manufacturer today for the latest price, immediate access to massive 321 stainless steel plate for sale stock, and same-day cutting of any 321 stainless steel plate sizes.