Automotive
Automotive economics reward whatever machines fastest and forms most consistently at volume. Free-machining 303 dominates turned parts, ferritic 409 and 439 handle exhaust systems at lower cost than austenitics, and 304 covers trim and fuel system components. Material substitution here is usually a cost exercise rather than a corrosion one.
What gets specified in automotive
Ordered by how commonly they are called for in this sector.
- UNS S30300303PREN 18
304 with sulphur added for machinability. The free-machining austenitic.
- UNS S40900 / S41000 / S43000400 SeriesPREN 17
Ferritic and martensitic chromium grades. Magnetic, nickel-free, hardenable.
- UNS S30400 / S30403304 / 304LPREN 19
The default austenitic stainless. 18% chromium, 8% nickel, no molybdenum.
- UNS S31600 / S31603316 / 316LPREN 25
304 plus 2–3% molybdenum. The standard answer to chlorides and mild acids.
- UNS S1740017-4 PHPREN 20
Martensitic PH grade. Machine soft, then age to tensile strengths above 1300 MPa.
Applications
06- Exhaust manifolds and systems
- Fuel system components
- Turned shafts and spindles
- Fasteners and fixings
- Trim and decorative parts
- Sensor and injector housings
Governing standards
03- ASTM A276
- ASTM A554
- EN 10088-3
Verification available
10- Spectrometer
- Chemical Testing Laboratory
- Positive Material Identification (PMI)
- Spectro Test
- Tensile Testing Machine
- Hardness Testing Machine
- Portable Hardness Tester
- Flattening Test
- Reverse-Bend Test
- Hydrostatic Test Machine
What automotive buys
Other industries
Supplying into automotive?
Send the specification and service conditions. We will confirm the grade, the availability and the documentation you will need.