What's the difference between 310 and 310S?

310S has lower carbon than 310, which limits carbide precipitation after welding. In practice, 310S is the variant almost always offered today; pure 310 is rarer.

Does PREN matter when choosing a heat-resistant grade?

No, not for this family's main use. PREN measures pitting resistance in a chlorinated aqueous environment; heat-resistant grades are selected for their hot oxidation resistance, a different property.

Do these grades also hold up to cold corrosion?

To some extent, but that isn't this family's selection criterion. For a mainly aqueous, room-temperature use, a standard austenitic grade will generally be sufficient and less costly.

My heat-resistant grade isn't listed — what should I do?

This family covers many more variants beyond the examples cited — 1.4828, 1.4841 and others depending on the mill. Send us your exact designation via a quote request and we will check availability with our partners.

GRADE FAMILY

Heat-resistant grades

Heat-resistant grades are stainless steels with a high chromium and silicon content, designed to resist oxidation and carburisation at very high temperature rather than aqueous corrosion. Furnaces, incineration, cement plants and heat treatment are their natural territory — as is motorsport exhaust, where temperature outweighs everything else.

What is a heat-resistant grade?

A heat-resistant grade is a stainless steel with a high chromium and silicon content, which forms a stable oxide layer on its surface even at very high temperature. This family is selected to resist oxidation, carburisation and sulphidation at high temperature — not for aqueous corrosion resistance, which is not its territory.

When to choose this family — and when not to?

Choose it for continuous high-temperature service — furnaces, incinerators, cement plants, heat treatment — where oxidation resistance outweighs everything else. Avoid it for room-temperature service in aqueous or chlorinated environments: a standard austenitic or duplex grade will be more suitable and less costly.

Grades in this family

The grades listed are examples, never a closed catalogue — every grade belongs to one of the nine families, which is what makes this claim reliable.

Examples in the heat-resistant grades family (familles-nuances.json), EN and PREN filled in from nuances-inox.json when the entry exists — not a closed catalogue
Grade (example)	EN	Indicative PREN
310/310S	1.4845	24–28 †
314	—	—
253 MA	1.4835	22–25 †
1.4828	—	—
1.4841	—	—

† PREN is calculable but not the deciding factor for this grade, see the note below.

PREN caveats (†)

310/310S: ⚠️ PREN is NOT the relevant criterion for a heat-resistant grade. 310S is designed for hot oxidation resistance, not aqueous corrosion: without molybdenum, it isn't suited to chlorinated environments.
253 MA: ⚠️ As with 310S, PREN is not the relevant criterion for a heat-resistant grade: 253 MA is designed for hot oxidation resistance, not aqueous corrosion, and its pitting resistance in aqueous environments is lower than standard austenitics.

Typical applications for this family: Furnaces · Incineration · Cement plants · Heat treatment · Motorsport exhaust.

My grade isn't listed →

Available forms and dimensions

Tubes, fittings, flanges and bars depending on the grade selected and the supplier. Precise dimensions are not yet documented in our structured reference data for this family: send us your requirement (diameter, wall thickness, length) via a quote request — we check with our partner mills and confirm within 2 to 3 business days.

Applicable standards

EN 10095
EN 10296-2
EN 10297-2
ASTM A312/A312M
ASTM A213/A213M
ASTM A240/A240M

Frequently asked questions

What's the difference between 310 and 310S?: 310S has lower carbon than 310, which limits carbide precipitation after welding. In practice, 310S is the variant almost always offered today; pure 310 is rarer.
Does PREN matter when choosing a heat-resistant grade?: No, not for this family's main use. PREN measures pitting resistance in a chlorinated aqueous environment; heat-resistant grades are selected for their hot oxidation resistance, a different property.
Do these grades also hold up to cold corrosion?: To some extent, but that isn't this family's selection criterion. For a mainly aqueous, room-temperature use, a standard austenitic grade will generally be sufficient and less costly.
My heat-resistant grade isn't listed — what should I do?: This family covers many more variants beyond the examples cited — 1.4828, 1.4841 and others depending on the mill. Send us your exact designation via a quote request and we will check availability with our partners.