Steel E120C-K4 PWHT
Heat-treated state
PWHT = post-weld heat treated
Pick when code or thick-section stress relief is mandatory — expect roughly 60–100 MPa loss in strength and possible drop below the 120 ksi class.
Values for the PWHT condition
Other E120C-K4 tempers and conditions
E120C-K4 is listed in 2 conditions; see the grade overview at E120C-K4.
- 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 | Pick when code or thick-section stress relief is mandatory — expect roughly 60–100 MPa loss in strength and possible drop below the 120 ksi class. | 730 | 810 | 19 | 23 HRC | 7.3 % IACS |
AWDefault As-welded deposit | Standard classification condition — use when joining Q&T high-strength plate where full 120 ksi weld strength must be retained. | 800 | 880 | 17 | 27 HRC | — |
What is E120C-K4 PWHT?
E120C-K4 PWHT is E120C-K4 heat treated to PWHT — pick when code or thick-section stress relief is mandatory — expect roughly 60–100 MPa loss in strength and possible drop below the 120 ksi class. E120C-K4 PWHT has a yield strength of 730 MPa (106 ksi) and a tensile strength of 810 MPa (117 ksi) — stronger than 83% of steel grades. Elongation at break is 19% and the elastic modulus is 205 GPa (29.7 Msi). E120C-K4 PWHT has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,425°C (2,597 °F). AW is the default condition FabDigit quotes; PWHT is available on request or by drawing note.
Advantages
- High strength — 730 MPa (106 ksi), better than 83% of steel grades
- Readily welded — 80/100, better than 79% of steel grades
Limitations
- High embodied carbon — 2.5 kg CO₂/kg, worse than 82% of steel grades
E120C-K4 PWHT properties
Typical room-temperature values for E120C-K4 PWHT; 23 are specific to this condition. Other listed values are E120C-K4 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
E120C-K4 PWHT has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical14
E120C-K4 PWHT has a yield strength of 730 MPa (106 ksi) and a tensile strength of 810 MPa (117 ksi) — stronger than 83% of steel grades. Elongation at break is 19% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
E120C-K4 PWHT is rated for continuous service to 425°C (797 °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).
Electrical2
E120C-K4 PWHT has an electrical resistivity of 2.35×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is not recommended (14/100), better than 70% of steel grades.
Sustainability4
Producing a kilogram of E120C-K4 PWHT takes about 32 MJ of energy and emits 2.5 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 40%.
Manufacturability5
E120C-K4 PWHT's machinability is fair (42/100, worse than 73% of steel grades); weldability very good (80/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with E120C-K4 PWHT
Is E120C-K4 easy to machine?
Weld deposit runs ~250–300 HB as-welded; machine with rigid setups and coated carbide at reduced speed, or stress-relieve first to ease finishing.
Can E120C-K4 be welded?
Spray or pulsed GMAW with 75–80 % Ar / balance CO₂ (or 100 % CO₂ with reduced properties); use low-hydrogen practice, preheat/interpass per plate thickness (typically 100–150 °C) and cap heat input around 2.0 kJ/mm to hold the 120 ksi level.
Can E120C-K4 be formed, bent or molded?
Not a wrought product — the wire itself is drawn and spooled; deposited metal is essentially unformable and should be designed to final shape.
What surface finishes work on E120C-K4?
Weld metal rusts like carbon steel: grind/blast to SA 2.5 and apply epoxy or zinc-rich primer; avoid electroplating without post-bake because of hydrogen embrittlement risk in the 120 ksi range.
E120C-K4 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 -K4 classification range | 0.05 – 0.15 | 0.1 |
| Mn | 1.2 – 2.25 | 1.7 |
| Si | 0.2 – 0.8 | 0.5 |
| Ni | 1.2 – 2.6 | 1.9 |
| Cr | 0.2 – 0.6 | 0.4 |
| Mo | 0.2 – 0.65 | 0.45 |
| V | ≤ 0.03 | 0.01 |
| P | ≤ 0.02 | 0.01 |
| S | ≤ 0.02 | 0.01 |
| Fe | balance | — |
E120C-K4 PWHT — frequently asked
What is E120C-K4 PWHT used for?
E120C-K4 PWHT is typically used for HY-130 class steel welding, ultra-high-strength structural steel, submarine hull fabrication and heavy-duty crane booms. In short: 120 ksi cored deposit; highest strength K4 grade; for HY-130 class steel.
What is the yield strength of E120C-K4 PWHT?
E120C-K4 PWHT has a typical yield strength of 730 MPa (106 ksi) and a tensile strength of 810 MPa (117 ksi) — stronger than 83% of steel grades. Strength varies by condition: see the 2 listed tempers.
Is E120C-K4 PWHT easy to machine?
Not especially — machinability is rated fair (42/100, worse than 73% of steel grades). Weld deposit runs ~250–300 HB as-welded; machine with rigid setups and coated carbide at reduced speed, or stress-relieve first to ease finishing.
Can E120C-K4 PWHT be welded?
Yes — weldability is rated very good (80/100). Spray or pulsed GMAW with 75–80 % Ar / balance CO₂ (or 100 % CO₂ with reduced properties); use low-hydrogen practice, preheat/interpass per plate thickness (typically 100–150 °C) and cap heat input around 2.0 kJ/mm to hold the 120 ksi level.
What surface finishes work on E120C-K4 PWHT?
Weld metal rusts like carbon steel: grind/blast to SA 2.5 and apply epoxy or zinc-rich primer; avoid electroplating without post-bake because of hydrogen embrittlement risk in the 120 ksi range.
Can E120C-K4 PWHT be formed, bent or molded?
Not a wrought product — the wire itself is drawn and spooled; deposited metal is essentially unformable and should be designed to final shape.
What is the maximum service temperature of E120C-K4 PWHT?
E120C-K4 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 E120C-K4-AW and E120C-K4 PWHT?
AW is the default condition — standard classification condition — use when joining Q&T high-strength plate where full 120 ksi weld strength must be retained. PWHT: pick when code or thick-section stress relief is mandatory — expect roughly 60–100 MPa loss in strength and possible drop below the 120 ksi class. Yield strength is 800 MPa in AW versus 730 MPa in PWHT.
Sources
- AWS A5.28/A5.28M — Low-Alloy Steel Electrodes and Rods for Gas Shielded Arc Welding — American Welding Society (2020)
- AWS A5.29/A5.29M — Low-Alloy Steel Electrodes for Flux Cored Arc Welding — American Welding Society (2010)
- 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)
- High-strength metal-cored wire datasheets (Lincoln Electric / ESAB / voestalpine Böhler) — various (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.