304 vs 310 Stainless Steel: High-Temperature Performance

304 and 310 are both austenitic stainless steels and both are non-magnetic in the annealed condition, but they serve very different temperature ranges. Grade 304 is the workhorse 18/8 alloy used across general fabrication, while grade 310 is a high-nickel, high-chromium heat-resisting grade built for furnace and high-temperature service. Selecting the wrong one is usually discovered only after scaling, distortion or premature failure in service.

304 and 310 Stainless Steel at a Glance

304 - UNS S30400, EN 1.4301, 18% chromium and 8% nickel. General purpose, excellent formability and weldability, service up to about 870 degrees C.

310 - UNS S31000, EN 1.4841, 25% chromium and 20% nickel. Heat resisting, superior oxidation and scaling resistance, service up to about 1100 degrees C.

310S - UNS S31008, EN 1.4845, the low-carbon version of 310 with carbon capped at 0.08%. It is the preferred variant for cyclic high-temperature duty and for welded furnace components.

A common point of confusion is that 310 and 310S carry different EN and UNS numbers. Grade 310 is EN 1.4841 and UNS S31000, while 310S is EN 1.4845 and UNS S31008 with the designation X8CrNi25-21. Quoting the correct number matters when a specification calls for a low-carbon heat-resisting grade.

Chemical Composition Comparison

The difference in high-temperature performance comes directly from the composition: 310 contains substantially more chromium and nickel and a higher silicon level than 304.

Element (wt%)	304 (UNS S30400)	310 (UNS S31000)	310S (UNS S31008)
Chromium (Cr)	18.0 - 20.0	24.0 - 26.0	24.0 - 26.0
Nickel (Ni)	8.0 - 10.5	19.0 - 22.0	19.0 - 22.0
Carbon (C)	0.07 max	0.25 max	0.08 max
Manganese (Mn)	2.00 max	2.00 max	2.00 max
Silicon (Si)	0.75 max	1.50 max	1.50 max
Phosphorus (P)	0.045 max	0.045 max	0.045 max
Sulfur (S)	0.030 max	0.030 max	0.030 max

The higher chromium and nickel content of 310 stabilises the austenitic structure and slows the diffusion processes that cause oxide scale growth, while the higher silicon level supports a dense, adherent protective oxide. These three elements together are what allow 310 to survive thermal cycling that would destroy 304.

High-Temperature Oxidation and Scaling Resistance

In continuous service 304 is normally limited to about 870 degrees C, and its useful ceiling drops further in cyclic duty because repeated thermal expansion and contraction spall the protective oxide and expose fresh metal. Grade 310 pushes the practical ceiling to about 1100 degrees C, and 310S extends that capability to welded and cyclically loaded furnace parts.

Service condition	304	310 / 310S
Continuous service limit	about 870 degrees C	about 1100 degrees C
Oxidation and scaling resistance	Moderate	Excellent
Cyclic thermal shock	Poor above limit	Good, best with 310S
Creep and stress rupture	Limited	Superior
Sulfur-bearing furnace atmospheres	Not recommended	Use with caution

At ambient temperature the two grades behave quite differently in the opposite direction. Both resist atmospheric corrosion well, but 304 generally performs better in mildly corrosive aqueous media and acidic solutions, while 310 is selected for its high-temperature behaviour rather than for aqueous corrosion duty.

Mechanical Properties Compared

At room temperature the strength of the two grades is broadly similar, although 304 is slightly more ductile and 310 retains its strength better as temperature rises.

Property	304 SS	310 SS
Tensile strength	515 - 720 MPa	515 - 655 MPa
Yield strength	205 - 310 MPa	205 - 310 MPa
Elongation	40 - 60%	about 40%
Hardness	about 200 HB	about 217 HB
Elevated temperature strength retention	Moderate	Good to high

Both grades are readily welded by the common arc processes. Grade 304 needs no special precautions beyond normal austenitic practice, whereas 310 and 310S should be welded with matching high-alloy filler and low heat input to preserve the high-temperature properties of the joint. Grade 310S is preferred for welded furnace assemblies because its lower carbon level reduces the risk of sensitisation during thermal exposure.

Grade Selection and Typical Applications

304 SS - kitchen and catering equipment, food processing plant, architectural panels, chemical storage vessels, sanitary pipework and general-purpose fabrication.

310 SS - furnace parts, radiant tubes, heat exchangers, kiln liners, muffles and other components held at high temperature.

310S SS - the same furnace and heat-treating duties where frequent thermal cycling or welded construction is involved.

The selection rule is simple. If the working temperature stays below roughly 800 to 870 degrees C and aqueous corrosion resistance matters, 304 is the economical and correct choice. If the component must survive repeated heating above that level, particularly in oxidising atmospheres, the high chromium and nickel content of 310 or 310S is essential.

Frequently Asked Questions

Q: What is 310 stainless steel equivalent to?
Grade 310 is UNS S31000 and EN 1.4841, while its low-carbon variant 310S is UNS S31008 and EN 1.4845, also written as X8CrNi25-21.

Q: What is the difference between 304 and 310 stainless steel?
310 contains far more chromium and nickel, so it resists oxidation and scaling up to about 1100 degrees C while 304 is limited to roughly 870 degrees C.

Q: Which grade is better for high-temperature applications?
310 and 310S are preferred because their higher alloy content provides superior oxidation resistance. For welded or cyclically heated parts, 310S is the usual selection.

Q: Are 304 and 310 stainless steel corrosion resistant?
Both resist normal atmospheric corrosion. Grade 304 performs better in mildly corrosive aqueous media, while 310 excels against high-temperature oxidation and scaling.

Q: Is 310 stainless steel magnetic?
In the annealed condition it is essentially non-magnetic. Cold working or welding can create small amounts of magnetic phases in the affected zones.

Q: Can 304 and 310 stainless steel be welded together?
They can be joined, but a high-alloy nickel-based or 310-type filler should be used to avoid a low-alloy dilution zone that would fail first at temperature.