Automotive

Stainless steel in vehicles splits into two groups: heat-resistant (exhaust systems) and decorative. Brand systems and their acceptance standards differ, and mixing them costs you either money or a failure.

Describe Your Application View Products

Common Parts and Material Selection

Part	Grade	Surface / Size	Watch Out For
Exhaust manifold / downpipe	409 / 441	2B / 1D, 1.2–2.0 mm	High-temperature oxidation, thermal fatigue
Muffler / exhaust pipe	409 / 436L	8–1.5 mm	Condensate corrosion
Trim / bright trim	304 / 430	BA / 8K, 0.3–0.8 mm	Surface grade, cracking during bending
Fuel tank / filler neck	304 / 441	0–2.0 mm	Formability, spot weldability
Seat frame	301 / 304	High-strength sheet 0.5–1.2 mm	Yield ratio, fatigue

These are typical configurations.The actual choice depends on environment, temperature and welding method— the same part can move from 304 to 316L or 2205. Describing the service conditions is more useful than naming a steel grade.

There are three real constraints in this industry

An exhaust system is not "the more expensive, the better"

409 is titanium-stabilized, inexpensive and adequate; 441 adds Nb+Ti for higher heat. Both mistakes are common: 304 cracks at welds in the exhaust due to thermal expansion, 409 scales in the hot section.

Deep drawability depends on the r value, not hardness

Decorative parts require high r and low Δr. The same grade behaves completely differently under different rolling schedules — always run a drawability test before the batch, don't just read the mill certificate.

Electrode life determines cycle time

Stainless steel has high resistance and low conductivity, so spot welding electrodes wear quickly. Schedule electrode replacement by weld count and control oil film and incoming flatness.