Q: Is SUS303 the same as SS303 and AISI 303?
Yes. SUS303 is the Japanese JIS designation, SS303 is a common trade abbreviation, and AISI 303 is the American standard. They all refer to the same free-machining austenitic stainless steel grade.
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SS303 / SUS303 Stainless Steel Round Bar Supplier — Cut to Size & Full Length
E Steel Sdn. Bhd. is a supplier of SS303 and SS303Cu stainless steel round bars (also known as : free-machining stainless stee) in Malaysia, supplying customers across Malaysia and weekly truck to Singapore. We stock full-length bars in a wide range of diameters up to DIA140mm, and we don't only supply full length — we offer precision bandsaw cut-to-size service, so you only pay and carry away the length you actually need.
No minimum order required.
What Is 303 / 303Cu Stainless Steel Round Bar?
SS303 is a free-machining austenitic stainless steel. It is essentially a 304-type composition with added sulphur, which forms manganese sulphide inclusions that act as internal chip-breakers — dramatically improving machinability compared to standard 304.
This makes 303 the go-to grade for parts produced on CNC lathes and screw machines: fittings, fasteners, shafts, bushings, valve components, and precision turned parts.
SS303Cu takes this further by adding copper (typically 2-4%) to the composition. The copper addition improves chip control and surface finish even more, reduces tool wear, and allows higher cutting speeds — making 303Cu the preferred choice for high-volume, high-speed precision machining shops.
303Cu Stainless Steel is sometimes referred to under mill-specific trade names or as "1.4305 + Cu" on certificates.
303 vs 304 — Why Choose 303?
- Free-machining — significantly faster cutting speeds and better chip control on CNC lathes
- Lower corrosion resistance than 304 due to sulphur content — not recommended for aggressive corrosive or welded applications
- The standard choice wherever the part is turned/milled rather than welded
303 vs 303Cu — Which One Do You Need?
- SS303 / SUS303 — standard free-machining grade, widely available, suitable for most turned components
- SS303Cu / SUS303Cu — enhanced machinability with copper addition, better chip-breaking and surface finish, preferred for high-speed automatic lathes and tighter tolerance work.
Grade Equivalents — All the Ways Customers Search for 303
Customers often search using different material code systems depending on their industry standard or drawing requirement.
The table below covers common equivalents:
| Standard | 303 Grade |
|---|---|
| American (AISI / SAE) | AISI 303 / SS303 |
| Japanese (JIS) | SUS303 |
| European (EN) | EN 1.4305 |
| German (DIN) | DIN 1.4305 |
| European Chemical Symbol | X8CrNiS18-9 |
| American UNS | UNS S30300 |
| Chinese (GB) | Y1Cr18Ni9 |
| ISO | X8CrNiS18-9 |
Our 303 / 303Cu Round Bar Stock — in Diameter (Ø)
We stocked 303/303Cu stainless steel round bars from different mills & origins in the following range :
Cut to size is available too for major sizes.
| Parameter | Details |
|---|---|
| Diameter Range | Up to maximum DIA140mm |
| Origin Mill |
|
| Form Supplied | Full-length bar, or bandsaw cut-to-size to your cutting list |
| Mill Test Certificate | 3.1 MTC per EN 10204 |
Need a size not listed? Call or WhatsApp us — we will source non-standard diameters through our global procurement network with short lead times.
Not Just Full-Length Bars — We Supply Bandsaw Cut-to-Size Too
Not only supplying in full length, E Steel supplies both bandsaw cut-to-size, down to the exact lengths on your cutting list — across diameters up to DIA140mm.
Chemical Composition of 303/303Cu Stainless Steel Round Bars
| Element | 303 (S30300) | 303Cu (Cu-Enhanced) |
|---|---|---|
| Carbon (C) | ≤ 0.15% | ≤ 0.15% |
| Chromium (Cr) | 17.0 – 19.0% | 17.0 – 19.0% |
| Nickel (Ni) | 8.0 – 10.0% | 8.0 – 10.0% |
| Manganese (Mn) | ≤ 2.0% | ≤ 2.0% |
| Silicon (Si) | ≤ 1.0% | ≤ 1.0% |
| Phosphorus (P) | ≤ 0.20% | ≤ 0.20% |
| Sulphur (S) | ≥ 0.15% | 0.15 – 0.35% |
| Copper (Cu) | — | ~2.0 – 4.0% (added) |
| Molybdenum (Mo) | ≤ 0.60% (optional) | ≤ 0.60% (optional) |
Mechanical Properties of 303/303Cu Stainless Steel Round Bars
| Property | 303 | 303Cu |
|---|---|---|
| Tensile Strength | 515 – 720 MPa | 515 – 720 MPa |
| Yield Strength 0.2% (min) | 205 MPa | 205 MPa |
| Elongation (min) | 35% | 35% |
| Hardness (max) | 262 HBW / 28 HRC | 262 HBW / 28 HRC |
Note: 303Cu mechanical values are broadly comparable to standard 303 — the copper addition primarily improves machinability and chip control rather than altering core mechanical properties.
Why Choose E Steel Sdn Bhd for Your Stainless Steel SS303 / SS303Cu Round Bars?
✅ Ready Stock in Malaysia
No long lead times. Our 303/303Cu round bars are in stock at our Malaysia warehouse, ready to cut and deliver.
✅ Serving Malaysia & Singapore + Southeast Asia Markets
We supply customers across Malaysia, Singapore and Southeast Asia Market — twice a week to Singapore markets.
✅ Full Length or Cut to Size — Your Choice
Order a full-length bar, or send us your required size and we bandsaw cut it to your exact lengths, up to DIA140mm.
✅ No Minimum Order Quantity (MOQ)
Whether you need one piece cut to size or a full-length bar, we accommodate all order sizes — ideal for prototyping, R&D, and small-batch production.
✅ Multiple Origin Options
Not only one origin for SS303 stainless steel round bars, but we do stock for few origins for different sizes.
✅ Material Traceability
Every bar comes with a Mill Test Certificate (MTC) traceable to the original mill.
Frequently Asked Questions for SS303 SS303Cu Stainless Steel Round Bars | Full Length . Cut To Size
Q: What is the difference between EN 1.4305 and AISI 303?
They are equivalent grades. EN 1.4305 (also written as DIN 1.4305 or X8CrNiS18-9) is the European designation for AISI 303. Chemical composition and mechanical properties are essentially the same.
Q: What is the difference between 303 and 303Cu?
303Cu has copper added to the standard 303 composition, further improving chip-breaking, surface finish, and tool life during high-speed CNC machining. Core mechanical properties remain broadly similar.
Q: Where does E Steel source its 303/303Cu round bars from?
We stock 303/303Cu round bars from Viraj Profiles in India, Olarra in Spain, and Valbruna in Italy, giving customers a choice based on their project's needs.
Q: What is the maximum diameter available?
We stock and cut 303/303Cu round bars up to a maximum diameter of DIA140mm.
Q: Do you only sell full-length bars?
No. We supply full-length bars and bandsaw cut-to-size. Send us your cutting list (lengths and quantity) and we will provide a quotation.
Q: Do you supply to Singapore / Thailand / Vietnam or Indonesia?
Yes. We regularly supply stainless steel round bars to customers in Singapore via freight forwarding, and export to ASEAN countries too.
Q: What is the minimum order?
There is no strict minimum order quantity. We supply from a single cut piece to full-length bars and bulk orders.
Q: Can you provide Mill Test Certificates (MTC)?
Yes. All our round bars come with 3.1 MTCs traceable to the original mill, compliant with EN 10204.
Q: What is 303/303Cu round bar typically used for?
Precision CNC-turned components such as fittings, fasteners, shafts, bushings, and valve parts — anywhere fast machining speed and good surface finish matter more than maximum corrosion resistance.
Inquiry - SS303 SS303Cu Stainless Steel Round Bars | Full Length . Cut To Size
