Stainless Steel
303 BS EN 10088-3
Description
Grade 303 stainless steel 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 the excellent machining characteristics while maintaining good mechanical and corrosion-resistant properties and a high resistance to oxidation.The high sulphur content that dramatically increases cutting speeds also reduces the grades formability making type 303 not readily cold workable. Sharp bending should be avoided.
Stainless Steel type 303 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.
Colour Code
| Steel Number | Steel Name | Grade | UNS | BS 970 1983 |
|---|---|---|---|---|
| 1,4305 | X8CrNiSI8-9 | 303 | S30300 | 303S31 |
| C | Mn | Si | P | S | Cr | Ni | Fe |
|---|---|---|---|---|---|---|---|
| 1.5 max | 2.0 max | 1.0 max | .2 max | .15-35 | 17-19 | 8-10 | Bal |
![]() |
![]() |
|---|---|
| Rounds | Rounds |
| (mm) | (mm) |
| 2.00 | 50.00 |
| 4.00 | 55.00 |
| 5.00 | 60.00 |
| 6.00 | 65.00 |
| 7.00 | 70.00 |
| 8.00 | 75.00 |
| 9.00 | 80.00 |
| 10.00 | 85.00 |
| 11.00 | 90.00 |
| 12.00 | 95.00 |
| 13.00 | 100.00 |
| 14.00 | 105.00 |
| 15.00 | 110.00 |
| 16.00 | 115.00 |
| 20.00 | 120.00 |
| 22.00 | 125.00 |
| 25.00 | 130.00 |
| 28.00 | 135.00 |
| 30.00 | 140.00 |
| 35.00 | 145.00 |
| 40.00 | 150.00 |
| 45.00 | 155.00 |
![]() |
![]() |
|---|---|
| Rounds | Rounds |
| (inch) | (inch) |
| 1⁄16 | 11⁄4 |
| 3⁄32 | 13⁄8 |
| 1⁄8 | 11⁄2 |
| 9⁄64 | 15⁄8 |
| 5⁄32 | 13⁄4 |
| 3⁄16 | 2 |
| 1⁄4 | 21⁄4 |
| 9⁄32 | 21⁄2 |
| 5⁄16 | 3 |
| 11⁄32 | 31⁄2 |
| 3⁄8 | 4 |
| 13⁄32 | 6 |
| 7⁄16 | |
| 31⁄64 | |
| 1⁄2 | |
| 9⁄16 | |
| 5⁄8 | |
| 11⁄16 | |
| 3⁄4 | |
| 7⁄8 | |
| 1 | |
| 11⁄8 |
![]() |
![]() |
Hexagons | Hexagons |
|---|---|
| (mm) | (inch) |
| 8.00 | 3⁄16 |
| 10.00 | 1⁄4 |
| 13.00 | 5⁄16 |
| 14.00 | 3⁄8 |
| 19.00 | 7⁄16 |
| 32.00 | 1⁄2 |
| 41.00 | 5⁄8 |
| 50.00 | 7⁄8 |
| 1 | |
| 13⁄16 | |
| 11⁄4 | |
| 15⁄16 | |
| 13⁄8 | |
| 17⁄16 | |
| 11⁄2 | |
| 15⁄8 | |
| 17⁄8 | |
| 2 |
For further technical information or additional sizes on this product or any other product or service please contact us.
Disclaimer
All data provided is for information and guidance only. Information above is not for design purposes and comes without warranty or guarantee with respect to the subject matter or fitness for purpose.

