What Is the Difference Between 1.4401 and 1.4310 Stainless Steel?

Two Alloys Built for Different Jobs

Grade 1.4401 and grade 1.4310 are both austenitic stainless steels, but they are engineered for opposite purposes. Grade 1.4401, the EN designation for type 316, is a molybdenum-bearing corrosion alloy intended for chemical, marine and pharmaceutical service. Grade 1.4310, the EN designation for type 301, is a low-nickel, higher-carbon alloy designed to work-harden to high strength in springs, clips and structural fasteners. Comparing them on strength alone, or on corrosion resistance alone, misses the point of each grade.

Chemical Composition

Element, %	1.4401 / 316 (S31600)	1.4310 / 301 (S30100)
Carbon (C)	0.08 max	0.15 max
Silicon (Si)	0.75 max	0.75 max
Manganese (Mn)	2.00 max	2.00 max
Phosphorus (P)	0.045 max	0.045 max
Sulfur (S)	0.030 max	0.030 max
Chromium (Cr)	16.0 - 18.0	16.0 - 18.0
Nickel (Ni)	10.0 - 14.0	6.0 - 8.0
Molybdenum (Mo)	2.00 - 3.00	-
Nitrogen (N)	0.10 max	0.10 max

Values are those of ASTM A240 for the equivalent American grades. EN 10088-2 applies narrower ranges to 1.4401 than ASTM applies to 316, specifying chromium of 16.5 to 18.5 %, nickel of 10.0 to 13.0 % and molybdenum of 2.00 to 2.50 %, and it requires 1.4310 to carry carbon in the range 0.05 to 0.15 % to guarantee the work-hardening response. Both grades are fully austenitic in the annealed condition.

Mechanical Properties and Work Hardening

Property	1.4401 / 316	1.4310 / 301
Tensile strength, annealed, min	515 MPa	515 MPa
Yield strength 0.2 %, annealed, min	205 MPa	205 MPa
Elongation, annealed, min	40 %	40 %
Work-hardening response	Moderate	High

In the annealed condition the two alloys look similar, and that is where the similarity ends. Grade 1.4310 work-hardens far more aggressively because its lower nickel and higher carbon content make the austenite less stable, so cold rolling converts part of the structure to martensite and drives strength upward. ASTM A666 recognises this by defining a series of tempers from quarter hard through full hard, each with its own minimum tensile strength and elongation. In practical terms, cold-rolled 1.4310 strip used for springs reaches tensile strength in the 1000 MPa class and above, while 1.4401 in the same cold-worked condition settles at a much lower level and cannot approach spring tempers without cracking. The exact minima for each temper depend on the temper class and thickness and should be taken from the applicable standard rather than from a general figure.

Corrosion Resistance

The roles reverse on corrosion. The 2 to 3 % molybdenum in 1.4401 lifts pitting resistance and gives the grade useful performance in chlorides, seawater splash zones, chemical process streams and pharmaceutical cleaning regimes. Grade 1.4310 has no molybdenum, so it pits in chloride service and is not selected for wet marine or chemical exposure. It is reserved for mildly corrosive or indoor atmospheres, and its corrosion resistance in the cold-worked tempers is further reduced by the martensite formed during forming.

A second difference is magnetic behaviour. Grade 1.4401 remains essentially non-magnetic in service even after moderate forming, which matters for instrument and sensor applications. Cold-worked 1.4310 becomes distinctly magnetic, which is acceptable for springs but disqualifies it from applications where magnetic permeability is controlled.

Welding, Forming and Availability

Grade 1.4401 is welded with 316L filler metal and is one of the most weldable stainless steels in general engineering use. Grade 1.4310 is weldable but is normally welded only in the annealed condition, because the cold-worked tempers can crack under welding stresses, and the weld zone reverts to annealed properties, creating a soft band in an otherwise strong spring component. Both grades form readily; 1.4401 suits deep drawing and spinning, while 1.4310 is used where forming is followed by a deliberate strength increase.

Both are supplied as sheet, plate, coil, strip, bar, wire and tube. Grade 1.4310 is most commonly seen as precision strip and spring wire, and 1.4401 as sheet, plate, tube and bar for process equipment.

Applications Side by Side

1.4401 is found in chemical and petrochemical pipework, heat exchangers, food and pharmaceutical equipment, architectural components in coastal areas, marine hardware and medical instruments. 1.4310 is found in springs of every kind, spring washers, retaining rings, clips, conveyor belt fasteners, structural brackets and components requiring high strength with only moderate corrosion exposure, such as interior vehicle and appliance parts.

Frequently Asked Questions

Q: Is 1.4401 the same as 316 stainless steel?
A: Yes. Grade 1.4401 is the EN designation for type 316, UNS S31600. Grade 1.4404 corresponds to 316L with a maximum carbon content of 0.030 %. The molybdenum addition in the 316 family is what separates it from type 304.

Q: Why does 1.4310 reach much higher strength than 1.4401?
A: Because of its work-hardening behaviour. Lower nickel and higher carbon make the austenite less stable, so cold rolling forms martensite and raises strength sharply. ASTM A666 defines the resulting tempers from quarter hard to full hard with progressively higher minimum tensile strengths.

Q: Which grade should be used for springs in a corrosive environment?
A: Neither is ideal in isolation. Grade 1.4310 gives the spring force but has no molybdenum and will pit in chlorides, while 1.4401 resists corrosion but has limited spring strength. For chloride-bearing service, a precipitation-hardening or higher-alloy spring material is normally selected instead.

Q: Is 1.4310 magnetic?
A: In the annealed condition it is essentially non-magnetic, but cold working to spring temper forms martensite and the material becomes clearly magnetic. Grade 1.4401 stays essentially non-magnetic in service.

Q: Can the two grades be welded?
A: Grade 1.4401 welds readily with 316L filler metal. Grade 1.4310 is welded in the annealed condition only, because welding a cold-worked spring part cracks it and leaves an annealed, low-strength zone in the joint.

Q: Do the two grades cost the same?
A: No. Grade 1.4401 carries 10 to 14 % nickel and 2 to 3 % molybdenum, so it is significantly more expensive per tonne than 1.4310, which contains 6 to 8 % nickel and no molybdenum. Material selection should follow the corrosion duty and the strength requirement rather than a general preference.