FabDigitFabDigit

Steel ER70S-6 PWHT

Heat-treated state

EN G3Si1 · JIS YGW12 · GB ER50-6

PWHT = post-weld heat treated

Choose when the weldment is stress-relieved per code; strength drops slightly, ductility and toughness improve.

Budget cost $
Request a quote in ER70S-6 PWHTER70S-6 overview

Values for the PWHT condition

What is ER70S-6 PWHT?

ER70S-6 PWHT is ER70S-6 heat treated to PWHT — choose when the weldment is stress-relieved per code; strength drops slightly, ductility and toughness improve. ER70S-6 PWHT has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 53% of steel grades. Elongation at break is 30% and the elastic modulus is 205 GPa (29.7 Msi). ER70S-6 PWHT 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).

Advantages

  • Readily welded — 95/100, better than 97% 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
  • Conducts heat well — 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades
  • Tough — resists crack growth — 120 MPa·√m (109.2 ksi·√in), better than 81% of steel grades

Limitations

  • Hard to polish — 45/100, worse than 84% of steel grades

ER70S-6 PWHT properties

Typical room-temperature values for ER70S-6 PWHT; 9 are specific to this condition. Other listed values are ER70S-6 reference data and may not represent this condition. Bars are the position among steel grades.

Physical3

ER70S-6 PWHT 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).

Density7.85 g/cm³0.28 lb/in³
Melting Point (Solidus)1,470°C2,678 °F
Liquidus Temperature1,520°C2,768 °F

Mechanical16

ER70S-6 PWHT has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 53% of steel grades. Elongation at break is 30% and the elastic modulus is 205 GPa (29.7 Msi).

Elastic (Young's) Modulus205 GPa29.7 Msi
Shear Modulus80 GPa11.6 Msi
Bulk Modulus160 GPa23.2 Msi
Poisson's Ratio0.29
Tensile Strength (Ultimate)520 MPa75.4 ksi
Yield Strength (0.2% offset)420 MPa60.9 ksi
Elongation at Break30%
Reduction in Area70%
Compressive Strength460 MPa66.7 ksi
Shear Strength340 MPa49.3 ksi
Fatigue Strength (Endurance Limit)240 MPa34.8 ksi
Fracture Toughness (K_IC)120 MPa·√m109 ksi·√in
Charpy V-Notch Impact (RT)150 J111 ft·lbf
Hardness, Brinell148 HB
Hardness, Rockwell B80 HRB
Hardness, Vickers156 HV

Thermal6

ER70S-6 PWHT 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).

Thermal Conductivity49 W/m·K28.3 BTU/hr·ft·°F
Specific Heat Capacity480 J/kg·K0.11 BTU/lb·°F
Thermal Expansion (CTE, 20–100 °C)12 µm/m·K6.7 µin/in·°F
Latent Heat of Fusion270 J/g116 BTU/lb
Max Service Temperature (continuous)425°C797 °F
Min Service Temperature-30°C-22 °F

Electrical3

ER70S-6 PWHT conducts electricity at 10.5 % IACS, better than 89% of steel grades.

Electrical Conductivity10.5 % IACS
Electrical Resistivity1.6×10⁻⁷ Ω·m6.3 µΩ·in
Magnetic Responseferromagnetic

Chemical & Environmental3

Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.

Galvanic Potential (seawater, vs SCE)-0.65 V
Corrosion ResistanceNot recommended10/100
Chemical Resistance SummaryRusts freely in moist air, seawater and acids; needs paint, galvanizing or other coating. Resists dry hydrocarbons and caustic at ambient temperature.

Sustainability4

Producing a kilogram of ER70S-6 PWHT takes about 28 MJ of energy and emits 2.1 kg of CO₂ — less than 56% of steel grades. Typical recycled content is 25%.

Embodied Energy (primary production)28 MJ/kg12,038 BTU/lb
Embodied Carbon (primary production)2.1 kg CO₂/kg
Embodied Water45 L/kg5.4 gal/lb
Typical Recycled Content25%

Manufacturability7

ER70S-6 PWHT's machinability is good (58/100, better than 75% of steel grades); weldability excellent (95/100); formability good (60/100).

MachinabilityGood58/100
Machinability Rating (AISI 1212 = 100 %)65%
WeldabilityExcellent95/100
Formability (cold)Good60/100
Brazeability / SolderabilityGood65/100
PolishabilityFair45/100
Anodizing Responsen/a — ferrous alloy; use paint, zinc plating or hot-dip galvanizing

Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.

Working with ER70S-6 PWHT

Is ER70S-6 easy to machine?

Weld deposits machine like 1018/1020 but are gummy and may contain hard spots at fusion lines; use sharp carbide and generous feed.

Can ER70S-6 be welded?

Run 0.8–1.6 mm wire in 100 % CO₂ (short arc/globular) or 75–82 % Ar mix (spray/pulse); high Mn-Si tolerates mill scale and light rust, keep interpass ≤300 °C on structural steel.

Can ER70S-6 be formed, bent or molded?

Supplied as cold-drawn copper-coated spool wire with controlled cast/helix; weldments in this filler bend and cold-form comparably to Q235/A36 base metal.

What surface finishes work on ER70S-6?

No corrosion resistance of its own — grind flush and paint, zinc-rich prime or hot-dip galvanize; deposits accept plating after proper cleaning.

ER70S-6 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.

ElementSpec limit (wt %)Nominal
C0.06 – 0.150.08
Mndeoxidizer / strength1.4 – 1.851.55
Sihigh Si for wetting on rusty plate0.8 – 1.150.9
P≤ 0.030.01
S≤ 0.040.02
Ni≤ 0.15—
Cr≤ 0.15—
Mo≤ 0.15—
V≤ 0.03—
Cuincludes copper coating≤ 0.50.2
Febalance—

ER70S-6 PWHT — frequently asked

What is ER70S-6 PWHT used for?

ER70S-6 PWHT is typically used for structural steel welding, automotive fabrication, general shop MIG welding and pipe and tank fabrication. In short: default mild-steel MIG wire; best tolerance of mill scale; widest availability, lowest cost.

What is the yield strength of ER70S-6 PWHT?

ER70S-6 PWHT has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 53% of steel grades.

Is ER70S-6 PWHT easy to machine?

Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Weld deposits machine like 1018/1020 but are gummy and may contain hard spots at fusion lines; use sharp carbide and generous feed.

Can ER70S-6 PWHT be welded?

Yes — weldability is rated excellent (95/100). Run 0.8–1.6 mm wire in 100 % CO₂ (short arc/globular) or 75–82 % Ar mix (spray/pulse); high Mn-Si tolerates mill scale and light rust, keep interpass ≤300 °C on structural steel.

What surface finishes work on ER70S-6 PWHT?

No corrosion resistance of its own — grind flush and paint, zinc-rich prime or hot-dip galvanize; deposits accept plating after proper cleaning.

Can ER70S-6 PWHT be formed, bent or molded?

Supplied as cold-drawn copper-coated spool wire with controlled cast/helix; weldments in this filler bend and cold-form comparably to Q235/A36 base metal.

What is the maximum service temperature of ER70S-6 PWHT?

ER70S-6 PWHT 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.

Sources

  1. AWS A5.18/A5.18M — Carbon Steel Electrodes and Rods for Gas Shielded Arc Welding — American Welding Society (2021)
  2. EN ISO 14341 — Wire electrodes for gas shielded metal arc welding (G3Si1/G42 3 M21 3Si1) — ISO (2020)
  3. Solid GMAW wire ER70S-6 datasheets — Lincoln Electric / ESAB / Kobelco / (2023)
  4. ASM Handbook Vol.6 Welding, Brazing and Soldering; Vol.1 Properties of Carbon Steels — ASM International (1993)

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.