303 Stainless Steel Bar (1.4305)

Grade 303/1.4305 Stainless bar is a non-magnetic, austenitic, free machining stainless steel that is a modification of the basic 18Cr – 8Ni stainless steel. The addition of sulphur (S) and, in some cases, selenium (Se) produces excellent machining characteristics while maintaining good mechanical and corrosion-resistant properties and high resistance to oxidation. The high sulphur content that dramatically increases cutting speeds also reduces the grade’s formability, making type 303 not readily cold workable. Sharp bending should be avoided.

303/1.4305 Stainless Bar is austenitic at all temperatures and cannot be hardened by heat treatment. Free machining grades are not generally recommended for welding. Typical applications include nuts & bolts, switchgear components, bushings, shafts and gears.

To view 303 Stainless Bar chemical analysis, specification or shapes & sizes, please click on the tabs below.

Colour Code:
Colour Code
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Rounds (mm)
4.00
5.00
6.00
7.00
8.00
9.00
10.00
11.00
12.00
13.00
14.00
15.00
16.00
20.00
22.00
25.00
28.00
30.00
35.00
40.00
45.00
50.00
55.00
60.00
65.00
70.00
75.00
80.00
85.00
90.00
95.00
100.00
105.00
110.00
115.00
120.00
125.00
130.00
135.00
140.00
145.00
150.00
155.00
Rounds (inch)
3⁄32
9⁄64
5⁄32
3⁄16
1/4
9/32
5/16
11/32
3/8
13/32
7/16
31/64
1/2
9/16
5/8
11/16
3/4
7/8
1
1 1/8
1 1/4
1 3/8
1 1/2
1 5/8
1 3/4
2
2 1/4
2 1/2
3
3 1/2
4
6
7
8
Hexagons (mm)
8.00
10.00
13.00
14.00
19.00
32.00
41.00
50.00
Hexagons (inch)
3⁄16
1⁄4
5⁄16
3⁄8
7⁄16
1⁄2
5⁄8
7⁄8
1
1 3⁄16
1 1⁄4
1 5⁄16
1 3⁄8
1 7⁄16
1 1⁄2
1 5⁄8
1 7⁄8
2

This is our standard size range. If you do not see the shape, size or grade you require, please contact us as we will be happy to assist you with reaching your requirements.

303 stainless steel bar (EN 1.4305 / AISI 303) is a free-machining austenitic stainless steel grade supplied for high-speed turning and precision components.

303 Stainless Steel Bar (1.4305)

303 stainless steel bar (EN 1.4305 / AISI 303) is a free-machining austenitic stainless steel designed for high-speed turning and precision-machined components. 303 stainless bar is widely chosen for applications where fast, consistent machining is the priority, while still maintaining good general corrosion resistance for typical engineering environments.

Overview
303 stainless bar, also referred to as 1.4305 stainless bar, achieves its excellent machinability through a sulphur addition that improves chip breaking and supports higher cutting speeds. This makes it a strong option for CNC turning, drilling and milling, particularly in repeat production work where efficiency and surface finish matter. It is commonly supplied as stainless steel round bar and hex bar, depending on the part geometry and machining requirements.

Key benefits

  • Excellent machinability for CNC turning and high-volume production
  • Good general corrosion resistance for general engineering use
  • Non-magnetic in the annealed condition (may become slightly magnetic after cold work)
  • Suitable for precision parts, fasteners and machined fittings

Limitations
Because of the sulphur addition, 303 is not generally recommended for welding and it has reduced formability compared to 304/304L. Sharp bending should be avoided. As an austenitic grade, it cannot be hardened by heat treatment, so it is not typically selected when higher hardness is required through heat treatment. If your application involves welding or significant forming, 304/304L is usually a more suitable alternative.

Typical applications
303 / 1.4305 stainless steel bar is commonly used for:

  • Nuts, bolts and threaded components
  • Bushings, spacers and couplings
  • Shafts, pins and gears
  • Switchgear and precision-machined parts

Supply note
Below is our standard range for 303 stainless bar in round and hex. As a stockist and supplier Ireland customers rely on, Impact Ireland can support standard sizes and help source non-standard sizes, quantities, or requirements. If you do not see the shape, size or grade you need, contact our team and we will help with availability, lead times and a quote.

EN NumberSymbolAISIUNSBS 970 1983Material Standard
1.4305X8CrNiS18-9303S30300303S31EN 10088-3
CMnSiPSCrNiFe
1.5 max2.0 max1.0 max.2 max.15-3517-198-10Bal

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