Stainless Steel ER420-ANN (Annealed)
Heat-treated state
UNS S42080
Use when the whole repaired part is fully annealed for extensive machining before final hardening.
Values for the ANN condition
Other ER420 tempers and conditions
ER420 is listed in 6 conditions; see the grade overview at ER420.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNThis page Annealed | Use when the whole repaired part is fully annealed for extensive machining before final hardening. | 450 | 760 | 18 | 215 HB | — |
PWHT 600–700 °C | Choose when the repair must be machined or when a tougher, less crack-sensitive deposit is required at moderate hardness. | 850 | 1,050 | 13 | 33 HRC | — |
PWHT 350–450 °C | Compromise temper for tools needing ~45 HRC; avoid holding near 475 °C where embrittlement and carbide sensitisation begin. | 1,250 | 1,500 | 7 | 45 HRC | 3.2 % IACS |
AWDefault As-welded deposit | Default condition straight off the arc — maximum hardness for wear surfacing, but brittle and crack-prone until tempered. | 1,350 | 1,650 | 3 | 50 HRC | — |
PWHT 200–300 °C | Pick when maximum wear hardness must be kept but hydrogen/quench stresses need relieving on hardfaced surfaces. | 1,450 | 1,700 | 5 | 49 HRC | 3.1 % IACS |
Q&T | Full re-heat-treatment of the welded assembly to restore uniform cutlery/die hardness of 52–56 HRC. | 1,550 | 1,850 | 4 | 54 HRC | — |
What is ER420-ANN?
ER420-ANN is ER420 heat treated to ANN — use when the whole repaired part is fully annealed for extensive machining before final hardening. ER420-ANN has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 70% of stainless steel grades. Elongation at break is 18% and the elastic modulus is 200 GPa (29 Msi). ER420-ANN has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,450°C (2,642 °F). AW is the default condition FabDigit quotes; ANN is available on request or by drawing note.
Advantages
- High electrical conductivity — 3.1 % IACS, better than 99% of stainless steel grades
- Polishes to a fine finish — 80/100, better than 89% of stainless steel grades
- Conducts heat well — 24.9 W/m·K (14.4 BTU/hr·ft·°F), better than 87% of stainless steel grades
Limitations
- Low fracture toughness — 20 MPa·√m (18.2 ksi·√in), worse than 100% of stainless steel grades
- Needs corrosion protection — 30/100, worse than 99% of stainless steel grades
- Difficult to weld — 35/100, worse than 86% of stainless steel grades
- Limited ductility — 18%, worse than 83% of stainless steel grades
ER420-ANN properties
Typical room-temperature values for ER420-ANN; 12 are specific to this condition. Other listed values are ER420 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
ER420-ANN has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,450°C (2,642 °F).
Mechanical16
ER420-ANN has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 70% of stainless steel grades. Elongation at break is 18% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
ER420-ANN is rated for continuous service to 600°C (1,112 °F). It conducts heat at 24.9 W/m·K (14.4 BTU/hr·ft·°F), better than 87% of stainless steel grades. Thermal expansion is 10.3 µm/m·K (5.72 µin/in·°F).
Electrical3
ER420-ANN conducts electricity at 3.1 % IACS, better than 99% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is poor (30/100), worse than 99% of stainless steel grades.
Sustainability4
Producing a kilogram of ER420-ANN takes about 53 MJ of energy and emits 4.6 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 55%.
Manufacturability7
ER420-ANN's machinability is fair (42/100, better than 79% of stainless steel grades); weldability fair (35/100); formability fair (35/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ER420-ANN
Is ER420 easy to machine?
As-welded deposit at ~50 HRC is essentially grind-only; high-temper (650 °C) or full anneal first if turning/milling is needed, then re-harden.
Can ER420 be welded?
GTAW/GMAW/SAW on 410/420 base metal; preheat and interpass 200–300 °C, slow cool, then temper or anneal immediately to avoid hydrogen cracking — never leave untempered overnight.
Can ER420 be formed, bent or molded?
Not a wrought product form — supplied as spooled wire or cut TIG rod; the martensitic deposit has no useful cold formability.
What surface finishes work on ER420?
Grind and polish to a fine finish for wear/sealing surfaces, then passivate (nitric or citric) to restore the chromium oxide film; hard chrome or nitriding may be added for extra wear life.
ER420 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 |
|---|---|---|
| CAWS A5.9 ER420 | 0.25 – 0.4 | 0.32 |
| Cr | 12 – 14 | 13 |
| Mn | ≤ 0.6 | 0.45 |
| Si | ≤ 0.5 | 0.35 |
| Ni | ≤ 0.75 | 0.3 |
| Mo | ≤ 0.75 | 0.2 |
| Cu | ≤ 0.75 | 0.15 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Fe | balance | — |
ER420-ANN — frequently asked
What is ER420-ANN used for?
ER420-ANN is typically used for cutlery and blade repair welding, hardenable tool component joining, die and mould weld build-up, plastic-mould steel repair, wear surface overlay on 420 shafts and valve seat and sealing face rebuilding. In short: hardest martensitic stainless filler; 50 HRC as-welded; grind-only after welding.
What is the yield strength of ER420-ANN?
ER420-ANN has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 70% of stainless steel grades. Strength varies by condition: see the 6 listed tempers.
Is ER420-ANN easy to machine?
Not especially — machinability is rated fair (42/100, better than 79% of stainless steel grades). As-welded deposit at ~50 HRC is essentially grind-only; high-temper (650 °C) or full anneal first if turning/milling is needed, then re-harden.
Can ER420-ANN be welded?
With care — weldability is rated fair (35/100). GTAW/GMAW/SAW on 410/420 base metal; preheat and interpass 200–300 °C, slow cool, then temper or anneal immediately to avoid hydrogen cracking — never leave untempered overnight.
What surface finishes work on ER420-ANN?
Grind and polish to a fine finish for wear/sealing surfaces, then passivate (nitric or citric) to restore the chromium oxide film; hard chrome or nitriding may be added for extra wear life.
Can ER420-ANN be formed, bent or molded?
Not a wrought product form — supplied as spooled wire or cut TIG rod; the martensitic deposit has no useful cold formability.
What is the maximum service temperature of ER420-ANN?
ER420-ANN is rated for continuous use to about 600°C (1,112 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ER420-AW and ER420-ANN?
AW is the default condition — default condition straight off the arc — maximum hardness for wear surfacing, but brittle and crack-prone until tempered. ANN: use when the whole repaired part is fully annealed for extensive machining before final hardening. Yield strength is 1,350 MPa in AW versus 450 MPa in ANN.
Sources
- AWS A5.9/A5.9M — Bare Stainless Steel Welding Electrodes and Rods — American Welding Society (2017)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
- ASM Handbook Vol.6 — Welding, Brazing and Soldering — ASM International (1993)
- Martensitic stainless filler metal ER420 data sheets — Böhler Welding / Metrode / Lincoln Electric (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.