SUS403 Stainless Steel Round Bar | SS403 Round Bar Supplier & Stockist

E Steel Sdn. Bhd. is the leading supplier of SUS403 / SS403 (AISI 403, UNS S40300, DIN 1.4024) stainless steel round bars in Malaysia, supplying customers across Selangor, Kuala Lumpur, Johor, Penang, and Singapore, and exporting to Indonesia, Brunei, and other ASEAN countries.
We stock full-length round bars and rods, 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 (MOQ) required.

Looking for SS403 in plate form? We propose SS410 as the recommended plate-form alternative — contact us for details.
SS410 Plates | https://www.ecarbonsteel.com/showproducts/productid/3293112/cid/327502/sus410-stainless-steel-ss410-stainless-steel-plates-cut-to-size/

What Is SUS403 / SS403 Stainless Steel Round Bar?

SS403 is the basic martensitic stainless steel. Like most non-stainless engineering steels — and unlike the austenitic grades (304, 316, 310, 321) — it can be hardened by a quench-and-temper heat treatment. It contains a minimum of 11.5% chromium, just sufficient to provide corrosion resistance, and achieves maximum corrosion resistance once hardened, tempered, and polished.

SUS403 is a general-purpose grade often supplied in the hardened but still machinable condition, for applications where high strength and moderate heat and corrosion resistance are required. Martensitic stainless steels like SUS403 are optimised for high hardness and strength; corrosion resistance is correspondingly lower than the austenitic grades, and also lower than 17%-chromium ferritic grades such as SUS430.

A Note on SUS416

You may also see SUS403 referenced alongside SUS416 in some material listings. While related, they are not the same grade — SUS416 is a free-machining martensitic variant with added sulphur for improved machinability.  If your application requires fast CNC turning rather than maximum toughness, SUS416 may be worth asking us about as an alternative.

Grade Equivalents — All the Ways Customers Search for SUS403

Customers often search using different national or industry standard codes.
The table below covers the common equivalents and designations for this grade:

Our SUS403 Round Bar Stock — Origin & Sizes

We stocked SUS403/SS403 stainless steel round bars as per below table: 

Need a size not listed? Call or WhatsApp us — we 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

E Steel supplies both full-length bar and bandsaw cut-to-size, down to the exact lengths on your cutting list.
This means you don't need to buy a full-length bar and cut the remainder yourself, and you don't need to source a separate cutting service. 

We operate multiple bandsaw cutting machines at our Klang warehouse, dedicated to cold-cutting stainless steel bar. Bandsaw cutting is our preferred method — and the method we recommend to customers — because it delivers:

• ✅ Clean, burr-minimal cut face — ready for machining or direct use
• ✅ No heat-affected zone (HAZ) — the cut stays cold, so it does not disturb the bar's hardness or temper condition at the cut end
• ✅ No surface discoloration or oxide scale — unlike thermal or friction-based cutting methods
• ✅ Consistent, square cut face — minimal distortion even on larger diameters
• ✅ Efficient and fast — quick turnaround even for complex multi-length cutting lists
• ✅ No minimum order quantity — from a single cut piece to a full cutting list

Chemical Composition of SUS403 / SS403 Stainless Steel Round Bars

Typical/nominal composition for AISI 403 stainless steel:

Mechanical Properties of SUS403 / SS403 Stainless Steel Round Bars

Corrosion Resistance of SUS403

SUS403 resists dry atmosphere, fresh water, mild alkalies and acids, food, steam, and hot gases. It must be hardened for maximum heat and corrosion resistance, and performs best with a smooth surface finish. Corrosion resistance is lower than the austenitic grades (such as 304, 316), and also lower than 17%-chromium ferritic alloys such as SUS430 — SUS403 is selected primarily for strength and hardness, with corrosion resistance as a secondary benefit.

Applications of SUS403 / SS403 Stainless Steel Round Bar

• Bolts & nuts
• Screws
• Bushings
• Pump and valve parts and shafts
• Steam and gas turbine parts
• Petroleum fractionating tower components
• Mine ladder rungs

Why Choose E Steel for Your SUS403 Round Bars?

✅ Stockist in Malaysia
Our SUS403 round bars, sourced from Japan, are either in Malaysia Warehouse or overseas warehouse. 

✅ Serving Malaysia & Singapore + Southeast Asia Markets
We supply and export to Singapore, Indonesia, Brunei, and other ASEAN countries — including express air freight for urgent orders.

✅ Full Length or Cut to Size — Your Choice
Order a full-length bar, or send us your cutting list and we bandsaw cut it to your exact lengths.

✅ 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.

✅ Material Traceability
Every bar comes with a Mill Test Certificate (MTC) traceable to the original mill.
 

Frequently Asked Questions for SUS403 SS403 Stainless Steel Round Bars

Q: Is SUS403 the same as SS403 and AISI 403?
Yes. SUS403 is the Japanese JIS designation, SS403 is a common trade abbreviation, and AISI 403 is the American standard. They all refer to the same basic martensitic stainless steel grade.

Q: Is SUS403 the same as SUS416?
No, though they're closely related.
SUS416 is a free-machining variant of the 400-series martensitic family, with added sulphur for better machinability. SUS403 is the standard grade without that addition.

Q: Can SUS403 be hardened?
Yes. Unlike austenitic stainless grades, SUS403 can be hardened by quench-and-temper heat treatment, and achieves maximum corrosion resistance once hardened, tempered, and polished.

Q: Do you supply SS403 in plate form?
Our SS403 stock is focused on round bar / rod.
If your requirement is plate, we propose SS410 as the recommended alternative — contact us for details.

Q: Is SUS403 as corrosion resistant as 304 or 316?
No. SUS403 has lower corrosion resistance than austenitic grades like 304/316, and also lower than 17%-chromium ferritic grades like SUS430. It is selected primarily for strength and hardness rather than maximum corrosion resistance.

Q: What is SUS403 round bar commonly used for?
Common applications include bolts and nuts, screws, bushings, pump and valve parts and shafts, steam and gas turbine parts, petroleum fractionating tower components, and mine ladder rungs.