430 vs 304 Stainless Steel: Which Should You Choose?

Two Popular Grades, Two Different Families

Stainless steel must contain at least 10.5% chromium by weight to develop the self-healing chromium oxide film that provides corrosion resistance. Within that definition, grade 430 and grade 304 take very different paths. Type 430 (UNS S43000, EN 1.4016) is a ferritic grade with 16–18% chromium and no nickel addition. Type 304 (UNS S30400, EN 1.4301) is the austenitic 18-8 workhorse with 17.5–19.5% chromium and 8.0–10.5% nickel. Both are classified in the AISI numbering system and specified in ASTM A240 for plate, sheet and strip.

Chemical Composition (Per ASTM A240)

Element (wt %)	430 (S43000)	304 (S30400)
Carbon (C)	≤ 0.12	≤ 0.08
Manganese (Mn)	≤ 1.00	≤ 2.00
Phosphorus (P)	≤ 0.040	≤ 0.045
Sulfur (S)	≤ 0.030	≤ 0.030
Silicon (Si)	≤ 1.00	≤ 0.75
Chromium (Cr)	16.0 – 18.0	17.5 – 19.5
Nickel (Ni)	≤ 0.75	8.0 – 10.5
Nitrogen (N)	-	≤ 0.10

Mechanical Properties (ASTM A240 Minimums)

Property	430	304
Tensile strength	≥ 450 MPa	≥ 515 MPa
Yield strength	≥ 205 MPa	≥ 205 MPa
Elongation (in 50 mm)	≥ 20%	≥ 40%
Hardness	≤ 88 HRB	≤ 92 HRB
Magnetism	Magnetic (ferritic)	Essentially non-magnetic (austenitic)

Corrosion Resistance and Weldability

304 resists a broad range of corrosive media: atmospheric exposure, food acids, most organic and inorganic acids, alkaline solutions and mild chloride environments. Its 8% nickel content stabilizes the austenite and prevents the grain-growth problems that limit ferritic grades. 430 is adequate in nitric acid, mild organic acids and clean atmospheric conditions, but it is susceptible to pitting and crevice attack in chlorides and to intergranular corrosion near welds.

Weldability follows the same pattern. 304 welds readily by TIG, MIG or resistance methods with no preheat and usually no post-weld heat treatment. 430 is difficult to weld without stabilizing elements because the heat-affected zone can suffer grain growth and loss of ductility; where welded 430 is required, the stabilized variants 430Ti or 430LX (titanium or niobium added, carbon reduced) are preferred, and low heat input is essential.

Cost and Application Selection

The decisive commercial difference is nickel. 430 contains none, so its price tracks chromium and steel-market fundamentals and is typically 10–20% below 304 on an equal-weight basis in normal market conditions. Select 430 for kitchen utensils, appliance trim, dishwasher liners, burner parts, decorative panels, automotive trim and magnetic components. Select 304 for food processing equipment, beverage and dairy lines, chemical storage, architectural cladding, medical devices and any service involving chlorides, acids or hygiene requirements.

Common Misconceptions

"430 rusts easily everywhere." In dry interior and mild atmospheric service 430 performs well; failures occur when it is used in chloride or acid environments that require 304 or 316.

"304 is always non-magnetic." Heavy cold work can make 304 weakly magnetic through strain-induced martensite.

"304 can be welded directly to plain carbon steel with no precautions." Dissimilar welding is possible but requires austenitic filler and attention to dilution; carbon steel contamination of the stainless surface is a known cause of rust.

Frequently Asked Questions

Which is stronger, 430 or 304?

304 has a higher minimum tensile strength (515 MPa vs 450 MPa) and much higher elongation (40% vs 20%), reflecting its tougher austenitic structure.

Is 430 cheaper than 304?

Yes. 430 is nickel-free, so it is significantly less expensive; the gap widens when nickel prices rise.

Is 430 food safe?

For dry and mildly acidic contact it is accepted; for prolonged acidic, salty or high-hygiene service, 304 or 316 is recommended.

Can 430 be used outdoors?

In moderate climates it performs acceptably for architectural trim, but coastal chloride exposure favors 304 or a coated finish.

How can I tell 430 and 304 apart?

A magnet test is a quick first check (430 attracts, annealed 304 does not), but positive identification requires composition analysis, e.g., PMI testing.

Which grade is better for a deep-drawn kitchen sink?

304 or the high-nickel 305 are preferred for deep draws; 430 is used for shallower, lower-cost pressings.