Steel ER70S-3-SR (Stress relieved)
Heat-treated state
EN G2Si1 · JIS YGW11 · GB ER50-3
For code-mandated PWHT on pressure parts or thick sections: strength drops ~40 MPa, ductility and toughness improve and residual stress/hardness fall.
Values for the SR condition
Other ER70S-3 tempers and conditions
ER70S-3 is listed in 4 conditions; see the grade overview at ER70S-3.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SRThis page Stress relieved | For code-mandated PWHT on pressure parts or thick sections: strength drops ~40 MPa, ductility and toughness improve and residual stress/hardness fall. | 400 | 505 | 30 | 145 HB | 10.5 % IACS |
As-welded, submerged arc with neutral flux | Same chemistry supplied as EL12/EM12-class SAW wire; properties depend strongly on flux basicity and heat input, values below are for a neutral agglomerated flux. | 420 | 530 | 28 | 155 HB | 10 % IACS |
As-welded, GTAW/TIG cut lengths under argon | Use 1.6–3.2 mm cut rods with pure Ar for thin sheet, root passes and pipe roots; cleanest, toughest deposit of the three processes. | 430 | 525 | 30 | 150 HB | 10 % IACS |
AWDefault As-welded deposit | Default all-weld-metal condition: 0.8–1.2 mm copper-coated spool wire run with 75–80 % Ar / balance CO₂, spray or short-arc. | 460 | 550 | 28 | 160 HB | — |
What is ER70S-3-SR?
ER70S-3-SR is ER70S-3 heat treated to SR — for code-mandated PWHT on pressure parts or thick sections: strength drops ~40 MPa, ductility and toughness improve and residual stress/hardness fall. ER70S-3-SR has a yield strength of 400 MPa (58 ksi) and a tensile strength of 505 MPa (73.2 ksi) — weaker than 60% of steel grades. Elongation at break is 30% and the elastic modulus is 205 GPa (29.7 Msi). ER70S-3-SR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,470°C (2,678 °F). AW is the default condition FabDigit quotes; SR is available on request or by drawing note.
Advantages
- Readily welded — 95/100, better than 97% of steel grades
- Forms and bends easily — 85/100, better than 96% of steel grades
- Ductile — tolerates forming and impact — 30%, better than 93% of steel grades
- High electrical conductivity — 10.5 % IACS, better than 89% of steel grades
- Easy to machine — 62/100, better than 89% of steel grades
ER70S-3-SR properties
Typical room-temperature values for ER70S-3-SR; 22 are specific to this condition. Other listed values are ER70S-3 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
ER70S-3-SR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,470°C (2,678 °F).
Mechanical16
ER70S-3-SR has a yield strength of 400 MPa (58 ksi) and a tensile strength of 505 MPa (73.2 ksi) — weaker than 60% of steel grades. Elongation at break is 30% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
ER70S-3-SR is rated for continuous service to 425°C (797 °F). It conducts heat at 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
ER70S-3-SR conducts electricity at 10.5 % IACS, better than 89% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of ER70S-3-SR takes about 32 MJ of energy and emits 2.4 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 25%.
Manufacturability8
ER70S-3-SR's machinability is good (62/100, better than 89% of steel grades); weldability excellent (95/100); formability excellent (85/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ER70S-3-SR
Is ER70S-3 easy to machine?
Deposits machine like hot-rolled 1018 (≈60 % of AISI 1212); expect gummy chips, use sharp tools and flood coolant, and dress weld crowns before finish cuts to avoid hard spots in the HAZ.
Can ER70S-3 be welded?
Run DCEP on Ar–CO₂ or CO₂ (GMAW), pure Ar (GTAW) or neutral flux (SAW); base metal must be reasonably free of mill scale, rust and oil because the modest Si content gives limited deoxidation and porosity resistance versus ER70S-6.
Can ER70S-3 be formed, bent or molded?
Supplied as cold-drawn copper-coated spooled wire or straight rods; keep feed-roll pressure and liner condition good since the softer low-Si wire shaves easily and causes birdnesting.
What surface finishes work on ER70S-3?
Deposits rust readily — grind/blast to remove spatter and mill scale, then apply zinc-rich primer, paint, phosphate or galvanizing; not anodizable, and copper coating residue should be cleaned before painting.
ER70S-3 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 A5.18 ER70S-3 | 0.06 – 0.15 | 0.09 |
| Mn | 0.9 – 1.4 | 1.1 |
| Silower than ER70S-6 (0.80–1.15) | 0.45 – 0.75 | 0.6 |
| P | ≤ 0.03 | 0.01 |
| S | ≤ 0.04 | 0.02 |
| Niresidual | ≤ 0.15 | 0.03 |
| Crresidual | ≤ 0.15 | 0.03 |
| Moresidual | ≤ 0.15 | 0.02 |
| Vresidual | ≤ 0.03 | 0.01 |
| Cuincludes copper coating | ≤ 0.5 | 0.2 |
| Febalance; total other elements ≤0.50 % | balance | — |
ER70S-3-SR — frequently asked
What is ER70S-3-SR used for?
ER70S-3-SR is typically used for general fabrication, machine building, TIG filler rod for mild steel and submerged arc welding. In short: cleaner deposits than ER70S-6; multi-process MIG/TIG/SAW wire; needs clean base metal.
What is the yield strength of ER70S-3-SR?
ER70S-3-SR has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 505 MPa (73.2 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is ER70S-3-SR easy to machine?
Reasonably — machinability is rated good (62/100, better than 89% of steel grades). Deposits machine like hot-rolled 1018 (≈60 % of AISI 1212); expect gummy chips, use sharp tools and flood coolant, and dress weld crowns before finish cuts to avoid hard spots in the HAZ.
Can ER70S-3-SR be welded?
Yes — weldability is rated excellent (95/100). Run DCEP on Ar–CO₂ or CO₂ (GMAW), pure Ar (GTAW) or neutral flux (SAW); base metal must be reasonably free of mill scale, rust and oil because the modest Si content gives limited deoxidation and porosity resistance versus ER70S-6.
What surface finishes work on ER70S-3-SR?
Deposits rust readily — grind/blast to remove spatter and mill scale, then apply zinc-rich primer, paint, phosphate or galvanizing; not anodizable, and copper coating residue should be cleaned before painting.
Can ER70S-3-SR be formed, bent or molded?
Supplied as cold-drawn copper-coated spooled wire or straight rods; keep feed-roll pressure and liner condition good since the softer low-Si wire shaves easily and causes birdnesting.
What is the maximum service temperature of ER70S-3-SR?
ER70S-3-SR is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ER70S-3-AW and ER70S-3-SR?
AW is the default condition — default all-weld-metal condition: 0.8–1.2 mm copper-coated spool wire run with 75–80 % Ar / balance CO₂, spray or short-arc. SR: for code-mandated PWHT on pressure parts or thick sections: strength drops ~40 MPa, ductility and toughness improve and residual stress/hardness fall. Yield strength is 460 MPa in AW versus 400 MPa in SR.
Sources
- AWS A5.18/A5.18M — Carbon Steel Electrodes and Rods for Gas Shielded Arc Welding — American Welding Society (2021)
- ISO 14341 / EN ISO 14341-A G3Si1-G2Si1 — ISO (2020)
- JIS Z 3312 YGW11 — Japanese Industrial Standards Committee (2009)
- 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)
- Solid wire ER70S-3 all-weld-metal data (Lincoln Electric / Hobart / typical values) — various producers (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.