Steel EM12K PWHT
Heat-treated state
PWHT = post-weld heat treated
Choose when the fabrication receives code-required stress relief; strength drops slightly and ductility/toughness rise.
Values for the PWHT condition
Other EM12K tempers and conditions
EM12K is listed in 2 conditions; see the grade overview at EM12K.
- PWHT
- AW
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
PWHTThis page Post-weld heat treated | Choose when the fabrication receives code-required stress relief; strength drops slightly and ductility/toughness rise. | 420 | 520 | 30 | 155 HB | 10.5 % IACS |
AWDefault As-welded deposit | Default condition: deposit tested in the as-welded state with a neutral agglomerated/fused flux for structural and plate fabrication. | 450 | 550 | 28 | 165 HB | 10 % IACS |
What is EM12K PWHT?
EM12K PWHT is EM12K heat treated to PWHT — choose when the fabrication receives code-required stress relief; strength drops slightly and ductility/toughness rise. EM12K 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). EM12K PWHT has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,500°C (2,732 °F). AW is the default condition FabDigit quotes; PWHT is available on request or by drawing note.
Advantages
- Readily welded — 95/100, better than 97% of steel grades
- Easy to machine — 70/100, better than 96% of steel grades
- Forms and bends easily — 84/100, better than 94% of steel grades
- Ductile — tolerates forming and impact — 30%, better than 93% of steel grades
- Conducts heat well — 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades
EM12K PWHT properties
Typical room-temperature values for EM12K PWHT; 23 are specific to this condition. Other listed values are EM12K reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
EM12K PWHT has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,500°C (2,732 °F).
Mechanical16
EM12K 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).
Thermal6
EM12K PWHT is rated for continuous service to 425°C (797 °F). It conducts heat at 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
EM12K PWHT 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 EM12K PWHT 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
EM12K PWHT's machinability is very good (70/100, better than 96% of steel grades); weldability excellent (95/100); formability very good (84/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with EM12K PWHT
Is EM12K easy to machine?
As-welded deposit machines like AISI 1018 (~65 % of 1212); use sharp carbide and expect some hardness scatter across weld/HAZ boundaries.
Can EM12K be welded?
Designed for submerged arc (single/multi-wire, DCEP or AC) with neutral or slightly active fluxes; keep flux dry, control heat input to protect toughness, and select flux to hit F7A2 vs F7P2 requirements.
Can EM12K be formed, bent or molded?
Supplied as cold-drawn coiled wire; the silicon-killed, low-carbon chemistry drawn to 2.0–6.4 mm feeds smoothly with minimal cast/helix issues.
What surface finishes work on EM12K?
Copper coating aids current pickup and shelf life; finished weldments must be painted, primed or galvanized as bare deposits rust readily.
EM12K 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 A5.17 EM12K | 0.05 – 0.15 | 0.1 |
| Mn | 0.8 – 1.25 | 1.05 |
| Sisilicon-killed | 0.1 – 0.35 | 0.22 |
| S | ≤ 0.03 | 0.02 |
| P | ≤ 0.03 | 0.02 |
| Cuincluding any copper coating | ≤ 0.35 | 0.15 |
| Fe | balance | — |
EM12K PWHT — frequently asked
What is EM12K PWHT used for?
EM12K PWHT is typically used for submerged arc welding of plate, pressure vessels, structural fabrication and shipbuilding. In short: general-purpose SAW wire; neutral-flux plate workhorse; leanest-alloy SAW option.
What is the yield strength of EM12K PWHT?
EM12K 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. Strength varies by condition: see the 2 listed tempers.
Is EM12K PWHT easy to machine?
Yes — machinability is rated very good (70/100, better than 96% of steel grades). As-welded deposit machines like AISI 1018 (~65 % of 1212); use sharp carbide and expect some hardness scatter across weld/HAZ boundaries.
Can EM12K PWHT be welded?
Yes — weldability is rated excellent (95/100). Designed for submerged arc (single/multi-wire, DCEP or AC) with neutral or slightly active fluxes; keep flux dry, control heat input to protect toughness, and select flux to hit F7A2 vs F7P2 requirements.
What surface finishes work on EM12K PWHT?
Copper coating aids current pickup and shelf life; finished weldments must be painted, primed or galvanized as bare deposits rust readily.
Can EM12K PWHT be formed, bent or molded?
Supplied as cold-drawn coiled wire; the silicon-killed, low-carbon chemistry drawn to 2.0–6.4 mm feeds smoothly with minimal cast/helix issues.
What is the maximum service temperature of EM12K PWHT?
EM12K 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.
What is the difference between EM12K-AW and EM12K PWHT?
AW is the default condition — default condition: deposit tested in the as-welded state with a neutral agglomerated/fused flux for structural and plate fabrication. PWHT: choose when the fabrication receives code-required stress relief; strength drops slightly and ductility/toughness rise. Yield strength is 450 MPa in AW versus 420 MPa in PWHT.
Sources
- AWS A5.17/A5.17M — Carbon Steel Electrodes and Fluxes for Submerged Arc Welding — American Welding Society (2019)
- ASME BPVC Section II Part C, SFA-5.17 — 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)
- SAW wire/flux combination all-weld-metal data (Lincoln Electric, ESAB, Hobart) — Various filler metal 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.