Stainless Steel E33-31
UNS W33310
E33-31 is a super-austenitic 33Cr-31Ni type filler metal (W33310) matching Alloy 33 base material (R20033), with high nitrogen contributing to strength and pitting resistance.
Reference datasheet — E33-31 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
E33-31 tempers and conditions
E33-31 is supplied in 3 conditions, soft to hard. AW is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Weldment solution annealed ~1120–1180 °C and quenched | Choose when the fabricated component can be re-solution-annealed to dissolve interdendritic precipitates and restore maximum ductility and acid resistance. | 410 | 790 | 45 | 210 HB | 1.9 % IACS |
AWDefault As-welded deposit | Standard stocked condition: covered-electrode deposit used in the as-welded state for acid-service fabrication and repair. | 480 | 760 | 33 | 21 HRC | 1.9 % IACS |
AW-GTAW/GMAW | Pick for root passes, thin-wall and high-purity acid-service welds where the cleaner, slightly tougher bare-wire deposit is required. | 500 | 780 | 38 | 225 HB | 1.9 % IACS |
What is E33-31?
E33-31 is a super-austenitic 33Cr-31Ni type filler metal (W33310) matching Alloy 33 base material (R20033), with high nitrogen contributing to strength and pitting resistance. It is used where 316 and Alloy 20 fillers corrode — concentrated sulfuric and phosphoric acid and acid dew-point service — and is supplied as coated electrodes and GTAW rod. The deposit is the strongest of this filler group at 480 MPa yield, 760 MPa tensile, 33 % elongation and 235 HB (98 HRB), with a corrosion rating of 88 and service to 550 °C. High nitrogen brings severe work hardening and poor machinability; E320LR is the lower-cost step down. E33-31 has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,350°C (2,462 °F). E33-31 has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 75% of stainless steel grades. Elongation at break is 33% and the elastic modulus is 196 GPa (28.4 Msi).
What is E33-31 used for?
- phosphoric acid production
- sulfuric acid dew-point equipment
- super-austenitic pressure vessels
Advantages
- Good corrosion resistance — 88/100, better than 97% of stainless steel grades
- High strength — 480 MPa (69.6 ksi), better than 75% of stainless steel grades
Limitations
- Difficult to machine — 20/100, worse than 98% of stainless steel grades
- Poor heat conductor — 12 W/m·K (6.93 BTU/hr·ft·°F), worse than 93% of stainless steel grades
- High embodied carbon — 6.5 kg CO₂/kg, worse than 93% of stainless steel grades
- Low electrical conductivity — 1.9 % IACS, worse than 84% of stainless steel grades
E33-31 properties
Typical room-temperature values for E33-31-AW; bars are the position among stainless steel grades.
Physical3
E33-31 has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,350°C (2,462 °F).
Mechanical16
E33-31 has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 75% of stainless steel grades. Elongation at break is 33% and the elastic modulus is 196 GPa (28.4 Msi).
Thermal6
E33-31 is rated for continuous service to 550°C (1,022 °F). It conducts heat at 12 W/m·K (6.93 BTU/hr·ft·°F), worse than 93% of stainless steel grades. Thermal expansion is 14.5 µm/m·K (8.06 µin/in·°F).
Electrical3
E33-31 conducts electricity at 1.9 % IACS, worse than 84% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is excellent (88/100), better than 97% of stainless steel grades.
Sustainability4
Producing a kilogram of E33-31 takes about 90 MJ of energy and emits 6.5 kg of CO₂ — more than 94% of stainless steel grades. Typical recycled content is 30%.
Manufacturability7
E33-31's machinability is poor (20/100, worse than 98% of stainless steel grades); weldability very good (70/100); formability fair (40/100).
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 stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. E33-31 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with E33-31
Is E33-31 easy to machine?
Very poor machinability — high N content gives severe work hardening; use rigid setups, sharp positive-rake carbide, low speed with heavy positive feed and flood coolant.
Can E33-31 be welded?
Weld with low heat input, stringer beads and interpass temperature below ~120 °C; keep electrodes dry (re-bake per producer instruction) and use Ar or Ar+He shielding — avoid N-free backing gas losses and never use oxidising/CO₂-rich mixtures.
Can E33-31 be formed, bent or molded?
Deposit is strong and heavily work hardening; cold straightening of wire/weldment is limited — prefer solution annealing before any significant cold work.
E33-31 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 |
|---|---|---|
| Clow carbon for acid service | ≤ 0.02 | 0.01 |
| Cr | 31 – 35 | 33 |
| Ni | 30 – 33 | 31 |
| Mo | 0.5 – 2 | 1.6 |
| Cuaids sulfuric acid resistance | 0.3 – 1.2 | 0.6 |
| Naustenite stabiliser and strengthener | 0.3 – 0.6 | 0.4 |
| Mn | ≤ 2 | 0.6 |
| Si | ≤ 0.8 | 0.4 |
| P | ≤ 0.02 | |
| S | ≤ 0.01 | |
| Febalance, approx. 30 % | balance |
What surface finishes work on E33-31?
Grind off all weld oxide/tint, then pickle and passivate (HNO₃-HF type) to restore the Cr-rich passive film before acid service; can be polished to a bright finish.
Surface treatments FabDigit runs on stainless 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).
Passivation
Organic Coating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel E33-31 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- W33310
- Also called
- AWS A5.4 E33-31
- Similar grades
- R20033
How much does E33-31 cost?
E33-31 is a high-cost stainless 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.
E33-31 — frequently asked
What is E33-31 used for?
E33-31 is typically used for phosphoric acid production, sulfuric acid dew-point equipment and super-austenitic pressure vessels. In short: strongest deposit in family; super-austenitic acid resistance; poor machinability.
What is the yield strength of E33-31?
E33-31 has a typical yield strength of 480 MPa (69.6 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 75% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is E33-31 easy to machine?
Not especially — machinability is rated poor (20/100, worse than 98% of stainless steel grades). Very poor machinability — high N content gives severe work hardening; use rigid setups, sharp positive-rake carbide, low speed with heavy positive feed and flood coolant.
Can E33-31 be welded?
Yes — weldability is rated very good (70/100). Weld with low heat input, stringer beads and interpass temperature below ~120 °C; keep electrodes dry (re-bake per producer instruction) and use Ar or Ar+He shielding — avoid N-free backing gas losses and never use oxidising/CO₂-rich mixtures.
What surface finishes work on E33-31?
Grind off all weld oxide/tint, then pickle and passivate (HNO₃-HF type) to restore the Cr-rich passive film before acid service; can be polished to a bright finish.
Can E33-31 be formed, bent or molded?
Deposit is strong and heavily work hardening; cold straightening of wire/weldment is limited — prefer solution annealing before any significant cold work.
What is the maximum service temperature of E33-31?
E33-31 is rated for continuous use to about 550°C (1,022 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between E33-31-AW and E33-31-SA?
AW is the default condition — standard stocked condition: covered-electrode deposit used in the as-welded state for acid-service fabrication and repair. SA: choose when the fabricated component can be re-solution-annealed to dissolve interdendritic precipitates and restore maximum ductility and acid resistance. Yield strength is 480 MPa in AW versus 410 MPa in SA.
How much does E33-31 cost?
E33-31 is a high-cost stainless 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 A5.4/A5.4M — Specification for Stainless Steel Electrodes for Shielded Metal Arc Welding — American Welding Society (2012)
- AWS A5.9/A5.9M — Bare Stainless Steel Welding Electrodes and Rods — American Welding Society (2017)
- ASTM B625 / A240 (UNS R20033 requirements) — ASTM International (2021)
- VDM Alloy 33 (Nicrofer 3033) material data sheet — VDM Metals (2018)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering (stainless filler metals) — ASM International (1993)
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.