Steel ER312
UNS S31380
ER312 is a high-chromium/nickel stainless welding wire (S31380) whose duplex ferrite-austenite deposit tolerates heavy dilution from the base metal.
Reference datasheet — ER312 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the AW condition
ER312 tempers and conditions
ER312 is supplied in 2 conditions, soft to hard. AW is the default FabDigit quotes; the values on this page are for it.
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As-welded then stress relieved | Pick when the base metal mandates PWHT; keep hold time short because prolonged exposure embrittles the high-ferrite deposit. | 550 | 750 | 22 | 23 HRC | 2.2 % IACS |
AWDefault As-welded deposit | Standard condition for all-position joining of dissimilar/unknown steels and for buffer layers under hardfacing. | 570 | 780 | 25 | 24 HRC | 2.2 % IACS |
Supply forms, finishes and certifications
Ways ER312 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
WIRE-CD | Wire | Supply form |
What is ER312?
ER312 is a high-chromium/nickel stainless welding wire (S31380) whose duplex ferrite-austenite deposit tolerates heavy dilution from the base metal. It is used to join dissimilar, unknown or hard-to-weld steels and to butter or buffer surfaces before hardfacing, and is supplied as cold-drawn GTAW/GMAW wire; as-welded strength reaches 570 MPa yield and 780 MPa tensile at 25 % elongation and 250 HB (24 HRC). Elongation, machinability and corrosion resistance are lower than for austenitic fillers, and high-ferrite deposits should be limited above about 315 °C; ER309L is the usual choice for routine carbon-to-stainless joints. ER312 has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 93% of steel grades. It melts at 1,400°C (2,552 °F). ER312 has a yield strength of 570 MPa (82.7 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 74% of steel grades. Elongation at break is 25% and the elastic modulus is 200 GPa (29 Msi).
What is ER312 used for?
- dissimilar metal welding
- cast iron to steel joints
- tool steel repair
- buffer/buttering layers
Advantages
- Good corrosion resistance — 55/100, better than 99% of steel grades
- Readily welded — 90/100, better than 90% of steel grades
- Ductile — tolerates forming and impact — 25%, better than 77% of steel grades
Limitations
- Poor heat conductor — 16 W/m·K (9.24 BTU/hr·ft·°F), worse than 98% of steel grades
- Low electrical conductivity — 2.2 % IACS, worse than 98% of steel grades
- High embodied carbon — 4.6 kg CO₂/kg, worse than 96% of steel grades
- Difficult to machine — 25/100, worse than 93% of steel grades
ER312 properties
Typical room-temperature values for ER312-AW; bars are the position among steel grades.
Physical3
ER312 has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 93% of steel grades. It melts at 1,400°C (2,552 °F).
Mechanical17
ER312 has a yield strength of 570 MPa (82.7 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 74% of steel grades. Elongation at break is 25% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
ER312 is rated for continuous service to 315°C (599 °F). It conducts heat at 16 W/m·K (9.24 BTU/hr·ft·°F), worse than 98% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
ER312 conducts electricity at 2.2 % IACS, worse than 98% of steel grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), better than 99% of steel grades.
Sustainability4
Producing a kilogram of ER312 takes about 55 MJ of energy and emits 4.6 kg of CO₂ — more than 94% of steel grades. Typical recycled content is 55%.
Manufacturability7
ER312's machinability is poor (25/100, worse than 93% of steel grades); weldability excellent (90/100); formability poor (30/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. ER312 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with ER312
Is ER312 easy to machine?
Deposits are hard, tough and strongly work-hardening — use rigid setups, sharp carbide, low speed/heavy positive feed, or grind; expect much slower rates than 308L.
Can ER312 be welded?
Very tolerant of dilution and contamination: run low heat input, stringer beads, interpass below ~150 °C, no preheat needed on most steels; limit thickness of high-ferrite deposits in service above ~315 °C.
Can ER312 be formed, bent or molded?
Not a wrought product form — the cold-drawn wire is only bent/coiled for feeding; deposits have limited cold ductility and should not be cold formed.
ER312 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| C | ≤ 0.15 | 0.1 |
| Cr | 28 – 32 | 30 |
| Ni | 8 – 10.5 | 9 |
| Mn | 1 – 2.5 | 1.8 |
| Si | 0.3 – 0.65 | 0.45 |
| Moresidual | ≤ 0.75 | |
| Curesidual | ≤ 0.75 | |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Fe | balance |
What surface finishes work on ER312?
Grind or machine buffer layers flat before hardfacing; deposit takes a passive film but polishes/pickles less uniformly than austenitic weld metal due to the two-phase structure.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel ER312 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- S31380
How much does ER312 cost?
ER312 is a high-cost steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
ER312 — frequently asked
What is ER312 used for?
ER312 is typically used for dissimilar metal welding, cast iron to steel joints, tool steel repair and buffer/buttering layers. In short: most dilution-tolerant stainless filler; standard buffer-layer wire; high-strength duplex deposit.
What is the yield strength of ER312?
ER312 has a typical yield strength of 570 MPa (82.7 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 74% of steel grades. Strength varies by condition: see the 2 listed tempers.
Is ER312 easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% of steel grades). Deposits are hard, tough and strongly work-hardening — use rigid setups, sharp carbide, low speed/heavy positive feed, or grind; expect much slower rates than 308L.
Can ER312 be welded?
Yes — weldability is rated excellent (90/100). Very tolerant of dilution and contamination: run low heat input, stringer beads, interpass below ~150 °C, no preheat needed on most steels; limit thickness of high-ferrite deposits in service above ~315 °C.
What surface finishes work on ER312?
Grind or machine buffer layers flat before hardfacing; deposit takes a passive film but polishes/pickles less uniformly than austenitic weld metal due to the two-phase structure.
Can ER312 be formed, bent or molded?
Not a wrought product form — the cold-drawn wire is only bent/coiled for feeding; deposits have limited cold ductility and should not be cold formed.
What is the maximum service temperature of ER312?
ER312 is rated for continuous use to about 315°C (599 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ER312-AW and ER312 AW-SR?
AW is the default condition — standard condition for all-position joining of dissimilar/unknown steels and for buffer layers under hardfacing. AW-SR: pick when the base metal mandates PWHT; keep hold time short because prolonged exposure embrittles the high-ferrite deposit. Yield strength is 570 MPa in AW versus 550 MPa in AW-SR.
How much does ER312 cost?
ER312 is a high-cost steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- AWS A5.9/A5.9M — Bare Stainless Steel Welding Electrodes and Rods — American Welding Society (2017)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering — ASM International (1993)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ER312 / 312 stainless filler metal weld-metal property sheets — Böhler Welding / Lincoln Electric / ESAB (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.