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Overview
303 stainless steel is a free-machining austenitic grade designed for applications where high productivity and excellent surface finish are essential. Its enhanced sulfur content significantly improves machinability compared to standard 300-series grades, making it the preferred material for precision-turned components and complex parts requiring tight tolerances.
Kormax supplies grade 303 stainless steel in a range of profiles, including round bar and custom-cut components. With fast turnaround, batch certifications and technical support, we help manufacturers achieve reliable, consistent performance in demanding machining environments.
303 stainless steel suppliers recommend this grade where rapid machining efficiency, dimensional accuracy and dependable corrosion resistance are required.
Common Applications
Precision machined shafts and pins
Threaded fasteners and fittings
Vavle stems and pump components (non-corrosive service)
Instrumentation and electronic hardware
Bushings, spacers and collars
General industrial and commercial hardware
Key Features
Excellent machinability: Sulphur addition produces short chips, smooth finishes, and reduced tool wear.
Good corrosion resistance: Suitable for dry, mild environments; slightly lower resistance than 304 stainless.
High-temperature oxidation resistance: Performs well up to 870 °C intermittently; not suited for continuous high-temperature service.
Good toughness: Maintains good toughness, though slightly reduced compared to 304 stainless steel.
303 Stainless Steel Material Properties
Material Profile
The properties of 303 stainless steel make it versatile for both hygienic environments and structural applications.
Chemical Composition
The chemical balance of grade 303 stainless steel explains its durability. The chromium and nickel mix ensures corrosion resistance and dependable performance.
(Typical Composition %)
| Element | Symbol | Value |
| Carbon | C | 0.0–0.10 |
| Chromium | Cr | 17.00–19.00 |
| Manganese | Mn | 0.0–2.00 |
| Silicon | Si | 0.0–1.00 |
| Phosphorus | P | 0.0–0.05 |
| Sulfur | S | 0.15–0.35 |
| Nickel | Ni | 8.00–10.00 |
| Copper | Cu | 0.0–1.00 |
| Nitrogen | N | 0.0–0.11 |
| Iron | Fe | Balance |
Mechanical Properties
The mechanical properties of 303 stainless steel make it suitable for tanks, pressure vessels and structural work.
| Property | Value |
| Tensile Strength | 500–750 MPa |
| Yield Strength | 190 MPa (proof) |
| Elongation | ≥35% (A50 mm) |
| Hardness | ≤230 HB |
Tolerances Chart
Kormax supplies 303 stainless steel to precise dimensional tolerances, ensuring reliability in engineering applications. All material conforms to ASTM A276 / A479 and meets ISO dimensional standards, aligning with our broader engineered materials solutions.
| Diameter (mm) Range | Tolerance Class | Tolerance (mm) |
| All Sizes | H9 | +0 / -0.036 |
Conforms to ASTM A276 / A479 and dimensional tolerances as per ISO standards.
Sizes & Availability
303 Stainless Steel Round Bar
Kormax stocks stainless steel 303 round bars in a wide range of diameters. Standard lengths are available for supply, with custom sizes and grades available upon request.
| Diameter (mm) | KG per Metre | Tolerance | Length (m) |
| 8.00 | 0.41 | H9 | 3 |
| 15.88 | 1.59 | H9 | 3 |
| 19.05 | 2.28 | H9 | 3 |
| 25.40 | 4.05 | H9 | 3 |
| 31.75 | 6.82 | H9 | 3 |
*Custom grades and sizes available by request.
Explore More Stainless Steel Grades
Looking for an alternative? Explore our broader range of stainless steel materials, including:
Kormax is your reliable stainless steel supplier, helping engineers choose the right material for lasting performance.
Resources
Data Sheet
Stainless Steel 303
Blog
A Guide to the Grades of Aluminium: Choosing the Right Alloy
Resource
Engineering Metal Bar Manufacturing Methods
PDF (298 KB)
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Quality Management
Quality materials, delivered to standard.
Kormax is ISO certified for ISO 9001, ISO 14001, and ISO 45001.
All Kormax products come with batch certifications.
Why Choose Kormax for 303 Grade Material
As a fourth-generation family-owned business, Kormax brings over 75 years of foundry and engineering metals experience to your project.
We operate in various sectors worldwide, utilising our leading engineering, manufacturing and global distribution capabilities to offer world-class solutions for engineers.
Expert Advice
Trusted advice on metal and profile selection for your application, backed by our engineered materials solutions.
Unique Range
Unique range of quality products, in industry-specific profiles and sizes, including casting alloys.
Top-tier Foundries
Global top-tier supply network with the ability to source specific sizes and metals through trusted stainless steel supplier partnerships.
Supply Security
For anyone working with critical materials like 304 stainless steel, we offer custom supply options to enhance continuity.
Quality Management
With ISO 9001, ISO 14001 and ISO 45501 certification, our quality systems include complete batch traceability across all stainless steel grades.
Competitive Pricing
With a wide supplier network, Kormax can balance quality and value, supporting long-term partnerships with 304 stainless steel suppliers worldwide.