Steel ER70S-A1
UNS K11235
ER70S-A1 (K11235) is a carbon-molybdenum (0.5 Mo) alloyed solid filler wire for GMAW and GTAW, part of the low-alloy steel filler family and matched to C-Mo base metals.
Reference datasheet — ER70S-A1 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
ER70S-A1 tempers and conditions
ER70S-A1 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 |
|---|---|---|---|---|---|---|
PWHT | Standard condition for C-Mo pressure piping and boilers; softens the deposit, restores ductility and stabilises creep performance. | 460 | 550 | 28 | 165 HB | — |
AWDefault As-welded deposit | Use for as-deposited joints where PWHT is not mandated; highest strength and hardness, lowest ductility. | 500 | 590 | 25 | 12 HRC | 8.5 % IACS |
What is ER70S-A1?
ER70S-A1 (K11235) is a carbon-molybdenum (0.5 Mo) alloyed solid filler wire for GMAW and GTAW, part of the low-alloy steel filler family and matched to C-Mo base metals. Engineers use it where elevated-temperature creep resistance beyond plain carbon deposits is needed: typical weld metal gives 500 MPa yield, 590 MPa tensile, 25 % elongation and 185 HB (90 HRB), with service to 450 °C; it is supplied as copper-coated spooled wire and cut TIG rod. The deposit has no corrosion resistance and heavy sections require preheat and code post-weld heat treatment. For 1.25Cr-0.5Mo piping such as P11/P12, ER80S-B2 is the nearest alternative. ER70S-A1 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F). ER70S-A1 has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 590 MPa (85.6 ksi) — stronger than 63% of steel grades. Elongation at break is 25% and the elastic modulus is 205 GPa (29.7 Msi).
What is ER70S-A1 used for?
- carbon-moly steel pipe welding
- power plant piping
- refinery process piping
- elevated temperature service welds
Advantages
- Readily welded — 88/100, better than 87% of steel grades
- High service temperature — 450°C (842 °F), better than 86% of steel grades
- Ductile — tolerates forming and impact — 25%, better than 77% of steel grades
ER70S-A1 properties
Typical room-temperature values for ER70S-A1-AW; bars are the position among steel grades.
Physical3
ER70S-A1 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F).
Mechanical17
ER70S-A1 has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 590 MPa (85.6 ksi) — stronger than 63% of steel grades. Elongation at break is 25% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
ER70S-A1 is rated for continuous service to 450°C (842 °F). It conducts heat at 41 W/m·K (23.7 BTU/hr·ft·°F), worse than 62% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
ER70S-A1 conducts electricity at 8.5 % IACS, better than 63% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (13/100), better than 66% of steel grades.
Sustainability4
Producing a kilogram of ER70S-A1 takes about 26 MJ of energy and emits 2.1 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 25%.
Manufacturability7
ER70S-A1's machinability is fair (52/100, better than 52% of steel grades); weldability excellent (88/100); formability fair (50/100).
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. ER70S-A1 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with ER70S-A1
Is ER70S-A1 easy to machine?
Weld caps machine like a normalized C-Mo steel (~60 % of AISI 1212); PWHT first to avoid hard as-welded zones.
Can ER70S-A1 be welded?
GMAW with Ar+(5–25 %)CO₂ or GTAW with Ar; preheat 100–200 °C on heavy C-Mo sections and PWHT at 605–635 °C per code.
Can ER70S-A1 be formed, bent or molded?
Supplied as drawn copper-coated wire or cut TIG rod; keep feed rolls and liners clean to avoid arc instability.
ER70S-A1 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 A5.28 max | ≤ 0.12 | 0.09 |
| Mn | ≤ 1.3 | 1.1 |
| Si | 0.4 – 0.7 | 0.55 |
| Mocreep-strengthening addition | 0.4 – 0.65 | 0.5 |
| P | ≤ 0.03 | 0.01 |
| S | ≤ 0.04 | 0.01 |
| Cuincludes any copper coating | ≤ 0.35 | 0.2 |
| Fe | balance |
What surface finishes work on ER70S-A1?
Deposit rusts like plain steel — grind, wire-brush and paint or insulate; no anodizing, plating only for special service.
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 ER70S-A1 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- K11235
- Other
- ER49S-A1
How much does ER70S-A1 cost?
ER70S-A1 is a standard-cost steel ($$), cheaper than about 71% 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.
ER70S-A1 — frequently asked
What is ER70S-A1 used for?
ER70S-A1 is typically used for carbon-moly steel pipe welding, power plant piping, refinery process piping and elevated temperature service welds. In short: creep-resistant C-Mo deposit; entry-level alloy pipe filler; service to 450 °C.
What is the yield strength of ER70S-A1?
ER70S-A1 has a typical yield strength of 500 MPa (72.5 ksi) and a tensile strength of 590 MPa (85.6 ksi) — stronger than 63% of steel grades. Strength varies by condition: see the 2 listed tempers.
Is ER70S-A1 easy to machine?
Reasonably — machinability is rated fair (52/100, better than 52% of steel grades). Weld caps machine like a normalized C-Mo steel (~60 % of AISI 1212); PWHT first to avoid hard as-welded zones.
Can ER70S-A1 be welded?
Yes — weldability is rated excellent (88/100). GMAW with Ar+(5–25 %)CO₂ or GTAW with Ar; preheat 100–200 °C on heavy C-Mo sections and PWHT at 605–635 °C per code.
What surface finishes work on ER70S-A1?
Deposit rusts like plain steel — grind, wire-brush and paint or insulate; no anodizing, plating only for special service.
Can ER70S-A1 be formed, bent or molded?
Supplied as drawn copper-coated wire or cut TIG rod; keep feed rolls and liners clean to avoid arc instability.
What is the maximum service temperature of ER70S-A1?
ER70S-A1 is rated for continuous use to about 450°C (842 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ER70S-A1-AW and ER70S-A1 PWHT620?
AW is the default condition — use for as-deposited joints where PWHT is not mandated; highest strength and hardness, lowest ductility. PWHT620: standard condition for C-Mo pressure piping and boilers; softens the deposit, restores ductility and stabilises creep performance. Yield strength is 500 MPa in AW versus 460 MPa in PWHT620.
How much does ER70S-A1 cost?
ER70S-A1 is a standard-cost steel ($$), cheaper than about 71% 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 A5.28/A5.28M — Low-Alloy Steel Electrodes and Rods for Gas Shielded Arc Welding — American Welding Society (2020)
- ASME BPVC Section II Part C / Part D — ASME (2023)
- ASM Handbook Vol.6 — Welding, Brazing and Soldering — ASM International (1993)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- C-Mo solid wire product data (ER70S-A1 class) — Lincoln Electric / ESAB / Böhler (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.