303 Stainless Steel Bar: Machining, Sizes & Supplier Guide

303 stainless steel bar: A Practical Buying Guide

Looking for a reliable 303 stainless steel bar supplier? Huaxiao Stainless keeps 100,000 tons of inventory, ships in 15 days, and is certified to ISO/TS16949. Before you request a quote, here is what actually matters when specifying and sourcing 303 stainless steel bar.

Why Choose 303 Stainless Steel Bar

303 stainless steel bar is the free-machining version of 304: small, controlled additions of sulphur (and sometimes selenium) turn it into the easiest austenitic grade to cut. Those inclusions break the chip, reduce built-up edge and extend tool life, which is exactly what high-volume CNC turning and automatic screw machines need. The trade-off is slightly lower corrosion resistance and reduced weldability versus 304, so 303 is specified for parts that are heavily machined but not exposed to aggressive corrosion.

For any component that will be turned, threaded or milled in volume – fasteners, fittings, bushings, spacers – 303 is usually the most economical grade once you factor in cycle time and tool cost.

Specifications, Sizes & Surface Condition

We supply 303 (UNS S30300) bar to ASTM A276 / A479 and EN 10088-3. Diameters run from 3 mm to 400 mm, in 3 m and 6 m lengths or cut to your drawing, and also as hexagonal and square profiles.

• Condition: cold drawn, peeled, or centreless ground
• Surface: bright, pickled, or polished to Ra 0.4
• Tolerance: h9 / h11 on cold drawn, k12 on hot rolled
• Machining: optimised for automatic screw machines and CNC lathes

Typical properties: tensile 515 MPa minimum, yield 205 MPa minimum, elongation 35% minimum, hardness HB 228 maximum. Sulphur is held in the 0.15-0.35% range to guarantee machinability.

303 Stainless Steel Bar Price Factors

The 303 stainless steel bar price per kg sits close to 304 (both are 18-8 nickel grades) with a small free-machining premium for the sulphur addition. As always, nickel (8-10.5%) and chromium (17-19%) drive the base, and LME nickel passes through to the quote.

• Processing: centreless ground bar costs more than cold drawn, which costs more than hot rolled
• Diameter: very small (under 6 mm) and very large (over 250 mm) bars both carry premiums
• Tolerance: tighter than h9 requires extra grinding
• Quantity: full-bundle pricing beats piece-cut pricing significantly

Tell us the machined diameter you actually need and we will advise the most economical starting stock size to reduce swarf loss and cycle time.

Common Applications

303 bar is machined into screws, bolts and nuts, bushings and spacers, hydraulic and pneumatic fittings, valve components, instrument parts, fasteners for electronics enclosures, and high-volume turned components on automatic screw machines. It is the default choice wherever a part is mostly metal-removal rather than corrosion-critical.

How to Choose a Reliable Supplier

With 303 the single most important check is the sulphur content: too low and you lose the machinability benefit; too high and corrosion and hot-working suffer. Confirm 0.15-0.35% S on the mill certificate, and verify the chromium and nickel ranges match 303. As with all stainless, demand PMI verification and full heat traceability.

A dependable 303 stainless steel bar supplier delivers both the certificate and the consistency your CNC cells depend on. Huaxiao Stainless maintains 100,000 tons of stainless stock, ships within 15 days, and holds ISO/TS16949 certification with full heat traceability from mill to your dock.

Frequently Asked Questions About 303 stainless steel bar

Get a Quote for 303 stainless steel bar

303 stainless steel bar in stock: 100,000 tons available, 15-day delivery, certified to ISO/TS16949. Browse our 303 stainless steel bar product page or contact us for a quote to get a competitive price today.