Is 430 stainless steel?

Yes, at 16–18% chromium. But the word "stainless" covers very different levels of performance: a 430 in a marine atmosphere pits where a 316L lasts for years.

Because its structure is ferritic, like ordinary steel, rather than austenitic. The nickel in 304 and 316 stabilises austenite, which is not magnetic. It is a simple way to tell the two families apart by hand.

Can it be used for an exhaust?

On cold sections, yes — that is common in volume automotive production. On manifolds, no: temperature there calls for a 321 or a 310S.

GRADE PROFILE

430 — S43000 / X6Cr17

430 is a ferritic grade at 16–18% chromium, with no nickel. Magnetic and economical, it belongs to appearance and structure rather than process. It is not an industrial piping grade, and its place in the catalogue rests on specific uses.

Ferritic
PREN 16–18
Cost index 55

When to choose it

On decorative and structural tube indoors, domestic appliances and furniture, cold sections of automotive exhausts. And where nickel is excluded, on cost or contact grounds.

It is a grade of appearance and form, not of performance. It earns its place where the environment is dry and clean and the budget governs.

When not to choose it

In process piping, full stop. 430 has no circuit application in aggressive media, and offering it on an industrial network would be a category error.

In chlorinated media, even weakly: at PREN 17 it performs worse than a 304L.

Outdoors, in marine or polluted urban atmospheres, where it pits and stains quickly.

On heavy welded sections without precautions: grain grows in the heat-affected zone, and ASTM A268 notes the susceptibility of high-chromium ferritics to notch brittleness on slow cooling.

Composition

ASTM A268/A268M−10, tableau 1
Element	%
C	≤ 0.12
Mn	≤ 1
P	≤ 0.04
S	≤ 0.03
Si	≤ 1
Cr	16–18

EN 10088
Element	%
C	≤ 0.08
Mn	≤ 1
P	≤ 0.04
S	≤ 0.015
Si	≤ 1
Cr	16–18
N	≤ 0.03

Mechanical properties

Mechanical properties
Standard	Form	Rm (MPa)	Rp0.2 (MPa)	A (%)	Hardness
ASTM A268/A268M−10, tableau 3	tube soudé et sans soudure, paroi 8 mm	≥ 415	≥ 240	≥ 20	≤ 190 HBW · ≤ 90 HRB

Designations and standards

Equivalent normative designations
Reference	Designation
EN (numeric)	1.4016
EN (symbolic)	X6Cr17
ASTM / AISI	TP430
UNS	S43000
JIS	—
AFNOR	Z8C17

Tube product standards :

ASTM A268/A268M
ASME SA268

Availability

Available in welded and seamless tube to ASTM A268. Structured dimensional data for this grade is not yet documented in our reference set: send us your sizes. EN 10204 3.1 material certificates supplied with the goods.

Related grades

444 (S44400) — the molybdenum-bearing ferritic, PREN 25, which is the genuine ferritic circuit grade.
304L (1.4307) — the austenitic reference, better performing and more universal.

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Frequently asked questions

Is 430 stainless steel?: Yes, at 16–18% chromium. But the word "stainless" covers very different levels of performance: a 430 in a marine atmosphere pits where a 316L lasts for years.
Why is it magnetic?: Because its structure is ferritic, like ordinary steel, rather than austenitic. The nickel in 304 and 316 stabilises austenite, which is not magnetic. It is a simple way to tell the two families apart by hand.
Can it be used for an exhaust?: On cold sections, yes — that is common in volume automotive production. On manifolds, no: temperature there calls for a 321 or a 310S.