SS 303 Hexagonal Bar
Stainless Steel 303 Hexagonal Bars are free-machining austenitic stainless steel products engineered for high-speed, high-volume machining operations. With a six-sided profile, these hex bars combine good corrosion resistance with excellent machinability, making them ideal for precision-turned components, fasteners, and fittings. The addition of sulfur improves chip formation and reduces tool wear during machining, distinguishing SS 303 from standard 304-series grades, though this comes at some cost to weldability and corrosion resistance.
What is SS 303 Hexagonal Bar
SS 303 Hexagonal Bars are a free-machining variant of 18-8 austenitic stainless steel, modified with added sulfur (and sometimes selenium) to improve machinability significantly over standard 304. This makes SS 303 the preferred choice for parts requiring extensive lathe or CNC machining, such as fittings, valve components, and precision fasteners, where cycle time and tool life matter. The trade-off is reduced corrosion resistance and weldability compared to 304, so SS 303 is best suited to components that are machined complete rather than welded.
Specifications of SS 303 Hexagonal Bar
| Parameter | Specification |
|---|---|
| Size Range | 6mm to 200mm |
| Length | 1m to 6m (custom cut lengths available) |
| Standards | ASTM A276, ASTM A479, ASME SA276, SA479 |
| Finish | Bright, Black, Polished, Peeled |
| Tolerance | h11, h10 as per ISO standards |
| Heat Treatment | Annealed & Pickled / Bright Annealed |
| Form | Hexagonal (6-sided bar) |
| Density | 8.0 g/cm³ |
Chemical Composition of SS 303 Hexagonal Bar
| Element | SS 303 (%) |
|---|---|
| Carbon (C) | ≤ 0.15 |
| Manganese (Mn) | ≤ 2.00 |
| Silicon (Si) | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.20 |
| Sulfur (S) | 0.15 min |
| Chromium (Cr) | 17.00 – 19.00 |
| Nickel (Ni) | 8.00 – 10.00 |
| Molybdenum (Mo) | ≤ 0.60 (optional) |
| Iron (Fe) | Balance |
Mechanical Properties of SS 303 Hexagonal Bar
| Property | SS 303 |
|---|---|
| Tensile Strength (MPa) | 515 min |
| Yield Strength (0.2% offset, MPa) | 205 min |
| Elongation (%) | 40 min |
| Hardness (Brinell HB) | ≤ 262 |
| Modulus of Elasticity (GPa) | 193 |
| Melting Point (°C) | 1400 – 1450 |