AISI 303Se Stainless Steel Plate | 303Se China steel mill-Direct Supply
What is AISI 303Se Stainless Steel Plate?
As a professional China steel mill-Direct Supply and stainless steel plate supplier, SHH STEEL is pleased to present AISI 303Se Stainless Steel Plate.
AISI 303Se (UNS S30323) is a free-machining austenitic stainless steel based on the classic 18-8 composition. Instead of (or in addition to) sulfur, selenium is intentionally added to improve machinability. Selenium forms inclusions that act as chip breakers during cutting, delivering high machining speeds, good tool life and a superior surface finish compared with the standard sulfur-bearing AISI 303.
The grade retains good corrosion resistance in mild environments, excellent toughness and non-magnetic properties in the annealed condition. It is particularly preferred when both high machinability and a cleaner surface finish are required. Typical applications include precision-turned parts, shafts, fittings, valve components and fasteners that demand extensive machining.
SHH STEEL supplies AISI 303Se as true China steel mill-Direct Supply, sourcing directly from major Chinese stainless steel mills. This model delivers competitive mill pricing, consistent quality, complete heat traceability and reliable delivery. SHH STEEL offers AISI 303Se in plate and related forms with surface finishes suitable for subsequent precision machining.
AISI 303Se is frequently compared with a240 304, a240 304l and a240 316l when projects require an optimal balance of machinability and corrosion performance. SHH STEEL provides technical support to help customers select the most suitable free-machining grade.
Material Specification
| Specification Element | Requirement | SHH STEEL Compliance |
|---|---|---|
| Grade | AISI 303Se / UNS S30323 | Confirmed |
| Related Standards | ASTM A240, ASTM A582, ASME, JIS, EN related | Available |
| Product Form | Plate, Sheet, Bar (related) | Available |
| Delivery Condition | Annealed | Standard |
| Thickness Range | 0.5 mm – 50 mm (thicker available on request) | Custom sizes supported |
| Width | Up to 1500–2000 mm | Available |
| Length | Up to 6000 mm or cut-to-length | Available |
| Surface Finish | 2B, No.1, and others on request | Available |
| Certification | EN 10204 3.1 / Mill Test Certificate | Available |
SHH STEEL can supply AISI 303Se dual-certified to relevant ASTM/ASME specifications when required by the project.
Chemical Composition
Typical Chemical Composition of AISI 303Se (UNS S30323):
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.15 |
| Silicon (Si) | ≤ 1.00 |
| Manganese (Mn) | ≤ 2.00 |
| Phosphorus (P) | ≤ 0.20 |
| Sulfur (S) | ≤ 0.06 |
| Selenium (Se) | ≥ 0.15 |
| Chromium (Cr) | 17.00 – 19.00 |
| Nickel (Ni) | 8.00 – 10.00 |
| Iron (Fe) | Balance |
The intentional selenium addition is the key feature that provides the free-machining characteristics of AISI 303Se. Selenium generally produces a cleaner machining surface and slightly better corrosion resistance than the sulfur-bearing version of 303. SHH STEEL carefully controls composition to ensure both excellent machinability and consistent quality.
Mechanical Properties
Annealed Condition (typical values)
| Property | Value |
|---|---|
| Tensile Strength | ≥ 515 MPa (75 ksi) |
| Yield Strength (0.2%) | ≥ 205 MPa (30 ksi) |
| Elongation (in 50 mm) | ≥ 40% |
| Hardness | ≤ 217 HB |
AISI 303Se offers mechanical properties similar to Type 304 and standard 303 in the annealed condition. The selenium inclusions improve chip breaking during machining without significantly affecting strength. SHH STEEL supplies material with consistent mechanical properties suitable for precision machining applications.
Physical Properties
- Density: 7.93 g/cm³
- Magnetic Response: Non-magnetic in the annealed condition
- Melting Range: approximately 1400–1420°C
Material Comparison
| Grade | Free-Machining Element | Machinability | Surface Finish | Corrosion Resistance | Typical Preference |
|---|---|---|---|---|---|
| AISI 303 | Sulfur | Excellent | Good | Good | General free-machining |
| AISI 303Se | Selenium | Excellent | Better | Slightly better | Precision machining + better finish |
| AISI 304 | None | Moderate | Excellent | Better | General purpose |
| AISI 304L | None | Moderate | Excellent | Better | Welded constructions |
| AISI 316L | None | Moderate | Excellent | Excellent | Chloride environments |
AISI 303Se is preferred when both high machinability and a superior surface finish are required. When better corrosion resistance or weldability is needed, SHH STEEL recommends upgrading to a240 304 or a240 304l. For higher corrosion resistance in chloride environments, a240 316l is the common selection.
Corrosion Resistance
AISI 303Se offers good resistance to atmospheric corrosion, fresh water, food products and many mild chemical environments. The selenium-bearing inclusions generally result in slightly better corrosion performance and a cleaner surface compared with sulfur-bearing AISI 303.
Corrosion resistance remains lower than that of a240 304 in more aggressive media, particularly in chloride-containing environments. AISI 303Se is therefore best suited for indoor or mildly corrosive service where machining productivity and surface quality are priorities. SHH STEEL advises careful evaluation of the service environment before selecting 303Se for critical corrosion applications.
For better pitting resistance, a240 316l or a240 2205 should be considered.
Weldability
AISI 303Se has limited weldability. The selenium additions that improve machinability can increase the risk of hot cracking and porosity in the weld zone. Welding is generally not recommended for critical applications.
When welding cannot be avoided, low heat input and appropriate filler metals should be used, followed by careful post-weld cleaning. For components that require both machining and welding, SHH STEEL often recommends machining from a240 304l or using a combination of free-machining and weldable grades.
Heat Treatment
AISI 303Se is normally supplied in the annealed condition by SHH STEEL.
Recommended Solution Annealing Parameters
- Temperature range: 1010 – 1120°C
- Cooling: Rapid cooling (water quench preferred)
Annealing softens the material after cold working and optimizes corrosion resistance. SHH STEEL controls heat treatment to ensure consistent properties for machining stock.
Surface Finishes
| Finish | Description | Typical Use / Keywords |
|---|---|---|
| 2B | Cold-rolled, annealed, pickled, skin-passed | AISI 303Se 2B – general fabrication and machining |
| No.1 | Hot-rolled, annealed and pickled | AISI 303Se No.1 – industrial plate |
| Special | Ground or custom finishes | AISI 303Se Special – precision machining stock |
SHH STEEL regularly supplies AISI 303Se in 2B and No.1 finishes suitable for subsequent precision machining operations.
Tolerances
Dimensional tolerances for AISI 303Se Stainless Steel Plate supplied by SHH STEEL generally conform to ASTM A480 practices.
Typical available size range:
- Thickness: 0.5 mm – 50 mm
- Width: up to 1500–2000 mm
- Length: up to 6000 mm or cut-to-length
SHH STEEL provides precise dimensional control and can support tighter tolerances when required for machining stock.
Equivalent Material Grades
Applications
AISI 303Se is specifically chosen for precision components that require excellent machinability and a high-quality surface finish. Typical applications of AISI 303Se include:
| Industry / Sector | Typical Components / Equipment (with keywords) |
|---|---|
| Precision Machining | AISI 303Se shafts, spindles, fittings, valve components |
| Fasteners & Hardware | AISI 303Se screws, bolts, nuts, high-quality threaded parts |
| Automotive & Transportation | AISI 303Se machined fittings and precision parts |
| Food & Beverage Equipment | AISI 303Se machined components in mild environments |
| General Engineering | AISI 303Se bushings, connectors, instrument parts |
| Pump & Valve Industry | AISI 303Se valve stems, seats and precision machined bodies |
| Medical & Instrument | AISI 303Se precision-turned instrument components |
SHH STEEL supplies AISI 303Se for these free-machining applications with consistent quality and good surface characteristics. For related industry solutions, see our equipment manufacturing and machinery industry pages. Supporting services include steel cutting services and cnc steel machining services.
Why Choose SHH STEEL
SHH STEEL is a China steel mill-Direct Supply specializing in stainless steel plate and sheet. By working directly with major Chinese stainless steel mills, SHH STEEL supplies AISI 303Se with the following advantages:
- Genuine China steel mill-Direct Supply pricing
- Consistent quality and complete heat traceability
- Full Mill Test Certificates (EN 10204 3.1)
- Material optimized for free-machining performance and surface quality
- Flexible dimensions and surface finishes (including AISI 303Se 2B and AISI 303Se No.1)
- Technical support for selection between selenium-bearing and sulfur-bearing free-machining grades
- Value-added services including steel cutting services, cnc steel machining services and worldwide shipping service
For more information about our company and full product range, please visit China steel Mill Agent-SHH STEEL.
FAQ
- What is the main advantage of AISI 303Se over standard AISI 303?AISI 303Se uses selenium instead of sulfur, which generally provides a better surface finish after machining and slightly improved corrosion resistance. SHH STEEL recommends 303Se when surface quality is important.
- How does AISI 303Se compare with AISI 304 in corrosion resistance?AISI 303Se has slightly lower corrosion resistance than 304 because of the free-machining additions. SHH STEEL advises using 304 or 316L when corrosion performance is critical.
- Can AISI 303Se be welded?Welding is possible but not recommended for critical applications due to the risk of hot cracking. SHH STEEL suggests alternative grades when welding is required.
- Is AISI 303Se magnetic?Non-magnetic in the annealed condition. SHH STEEL supplies fully annealed material as standard.
Conclusion
AISI 303Se Stainless Steel Plate is a selenium-bearing free-machining austenitic stainless steel designed for excellent machinability combined with a superior surface finish and good corrosion resistance in mild environments. It is the preferred choice for precision shafts, fittings, fasteners, valve components and other parts that require extensive high-quality machining.
As a professional China steel mill-Direct Supply, SHH STEEL provides high-quality AISI 303Se Stainless Steel Plate with competitive pricing, full certification and complete technical support.
Contact SHH STEEL today for stock availability, surface finish options (including AISI 303Se 2B and AISI 303Se No.1), or a competitive quotation.
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