Steel E120C-K4
E120C-K4 is the highest-strength Ni-Cr-Mo composite cored electrode in the K4 group, depositing about 120 ksi weld metal — 800 MPa yield, 880 MPa tensile, 17 % elongation.
Reference datasheet — E120C-K4 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
E120C-K4 tempers and conditions
E120C-K4 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 |
|---|---|---|---|---|---|---|
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?
E120C-K4 is the highest-strength Ni-Cr-Mo composite cored electrode in the K4 group, depositing about 120 ksi weld metal — 800 MPa yield, 880 MPa tensile, 17 % elongation. It is chosen for very high strength quenched-and-tempered steel joints such as HY-130 class plate, and is supplied as spooled cored wire for gas-shielded GMAW/FCAW in AW or PWHT condition. Deposit hardness of about 270 HB (27 HRC) and a machinability score of 35 make finish machining slow, service is capped near 400 °C, and hydrogen control is critical at this strength level. E110C-K4 is the lower-strength alternative when toughness margin matters more than yield. E120C-K4 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). E120C-K4 has a yield strength of 800 MPa (116 ksi) and a tensile strength of 880 MPa (128 ksi) — stronger than 86% of steel grades. Elongation at break is 17% and the elastic modulus is 205 GPa (29.7 Msi).
What is E120C-K4 used for?
- HY-130 class steel welding
- Ultra-high-strength structural steel
- Submarine hull fabrication
- Heavy-duty crane booms
Advantages
- High strength — 800 MPa (116 ksi), better than 86% of steel grades
- Readily welded — 80/100, better than 79% of steel grades
Limitations
- Difficult to machine — 35/100, worse than 84% of steel grades
- High embodied carbon — 2.5 kg CO₂/kg, worse than 82% of steel grades
E120C-K4 properties
Typical room-temperature values for E120C-K4-AW; bars are the position among steel grades.
Physical3
E120C-K4 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 has a yield strength of 800 MPa (116 ksi) and a tensile strength of 880 MPa (128 ksi) — stronger than 86% of steel grades. Elongation at break is 17% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
E120C-K4 is rated for continuous service to 400°C (752 °F). It conducts heat at 40 W/m·K (23.1 BTU/hr·ft·°F), worse than 64% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical2
E120C-K4 has an electrical resistivity of 2.4×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is not recommended (14/100), better than 70% of steel grades.
Sustainability4
Producing a kilogram of E120C-K4 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's machinability is fair (35/100, worse than 84% of steel grades); weldability very good (80/100); formability poor (25/100).
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. E120C-K4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with E120C-K4
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.
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 |
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.
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 E120C-K4 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- AWS E120C-K4AWS E83C-K4
How much does E120C-K4 cost?
E120C-K4 is a premium-cost steel ($$$), cheaper than about 51% 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.
E120C-K4 — frequently asked
What is E120C-K4 used for?
E120C-K4 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?
E120C-K4 has a typical yield strength of 800 MPa (116 ksi) and a tensile strength of 880 MPa (128 ksi) — stronger than 86% of steel grades. Strength varies by condition: see the 2 listed tempers.
Is E120C-K4 easy to machine?
Not especially — machinability is rated fair (35/100, worse than 84% 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 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?
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 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?
E120C-K4 is rated for continuous use to about 400°C (752 °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.
How much does E120C-K4 cost?
E120C-K4 is a premium-cost steel ($$$), cheaper than about 51% 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)
- 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; 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.