Steel E90C-K3 PWHT
Heat-treated state
PWHT = post-weld heat treated
Apply post-weld stress relief at 605–620 °C for 1 h on thick-wall joints needing dimensional stability and toughness; check that the softened 545 MPa yield still meets the 90 ksi class.
Values for the PWHT condition
Other E90C-K3 tempers and conditions
E90C-K3 is listed in 3 conditions; see the grade overview at E90C-K3.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
PWHTThis page Post-weld heat treated | Apply post-weld stress relief at 605–620 °C for 1 h on thick-wall joints needing dimensional stability and toughness; check that the softened 545 MPa yield still meets the 90 ksi class. | 545 | 640 | 25 | 14 HRC | 8.2 % IACS |
As-welded, 100 % CO₂ shielding | Choose 100 % CO₂ shielding to lower cost when slightly reduced alloy recovery is acceptable; as-welded strength falls to 580 MPa yield and low-temperature impact values drop. | 580 | 660 | 21 | 18 HRC | 8 % IACS |
AWDefault As-welded deposit | Use the as-welded, M21 mixed-gas all-weld-metal condition tested to AWS A5.28 as the standard supply and acceptance state for most high-strength steel structural welds. | 610 | 690 | 22 | 20 HRC | — |
What is E90C-K3 PWHT?
E90C-K3 PWHT is E90C-K3 heat treated to PWHT — apply post-weld stress relief at 605–620 °C for 1 h on thick-wall joints needing dimensional stability and toughness; check that the softened 545 MPa yield still meets the 90 ksi class. E90C-K3 PWHT has a yield strength of 545 MPa (79 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 70% of steel grades. Elongation at break is 25% and the elastic modulus is 205 GPa (29.7 Msi). E90C-K3 PWHT has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F). AW is the default condition FabDigit quotes; PWHT is available on request or by drawing note.
Advantages
- Tough — resists crack growth — 130 MPa·√m (118.3 ksi·√in), better than 89% of steel grades
- Readily welded — 82/100, better than 81% of steel grades
- Ductile — tolerates forming and impact — 25%, better than 77% of steel grades
E90C-K3 PWHT properties
Typical room-temperature values for E90C-K3 PWHT; 23 are specific to this condition. Other listed values are E90C-K3 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
E90C-K3 PWHT has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F).
Mechanical15
E90C-K3 PWHT has a yield strength of 545 MPa (79 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 70% of steel grades. Elongation at break is 25% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
E90C-K3 PWHT is rated for continuous service to 425°C (797 °F). It conducts heat at 39 W/m·K (22.5 BTU/hr·ft·°F), worse than 67% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
E90C-K3 PWHT conducts electricity at 8.2 % IACS, better than 61% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (16/100), better than 79% of steel grades.
Sustainability4
Producing a kilogram of E90C-K3 PWHT takes about 32 MJ of energy and emits 2.4 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 30%.
Manufacturability7
E90C-K3 PWHT's machinability is fair (47/100, worse than 58% of steel grades); weldability very good (82/100); formability fair (42/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with E90C-K3 PWHT
Is E90C-K3 easy to machine?
As-welded deposit is about 200–230 HB and cuts with coated carbide tooling; set cutting speeds as for quenched-and-tempered 4140. Machinability improves slightly after PWHT.
Can E90C-K3 be welded?
GMAW with metal-cored wire under M21 shielding (75–80 % Ar + CO₂) or straight CO₂, spray or pulsed transfer. On Q&T high-strength steel preheat 100–150 °C according to base-metal carbon equivalent, keep interpass ≤250 °C and control heat input to 1.0–2.5 kJ/mm to balance strength and toughness.
Can E90C-K3 be formed, bent or molded?
No forming step applies to a filler metal; feedability is good and deposition rate is higher than solid wire, which suits semi-automatic and robotic welding and multi-pass thick-plate grooves.
What surface finishes work on E90C-K3?
Remove silicon islands and grind the weld. Finished assemblies must be painted, thermal-sprayed with zinc or plated for corrosion protection; anodizing is not possible.
E90C-K3 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 K3 class | ≤ 0.15 | 0.07 |
| Mn | 0.75 – 2.25 | 1.5 |
| Si | ≤ 0.8 | 0.45 |
| P | ≤ 0.03 | 0.01 |
| S | ≤ 0.03 | 0.01 |
| Ni | 1.25 – 2.6 | 1.9 |
| Cr | ≤ 0.15 | 0.05 |
| Mo | 0.25 – 0.65 | 0.45 |
| V | ≤ 0.05 | 0.01 |
| Cuincludes copper coating | ≤ 0.35 | 0.1 |
| Fe | balance | — |
E90C-K3 PWHT — frequently asked
What is E90C-K3 PWHT used for?
E90C-K3 PWHT is typically used for high-strength structural steel, offshore platform fabrication, heavy machinery frames and pressure vessel repair. In short: best low-temperature toughness here; ni-Cr-Mo 90 ksi deposit; high deposition cored wire.
What is the yield strength of E90C-K3 PWHT?
E90C-K3 PWHT has a typical yield strength of 545 MPa (79 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 70% of steel grades. Strength varies by condition: see the 3 listed tempers.
Is E90C-K3 PWHT easy to machine?
Reasonably — machinability is rated fair (47/100, worse than 58% of steel grades). As-welded deposit is about 200–230 HB and cuts with coated carbide tooling; set cutting speeds as for quenched-and-tempered 4140. Machinability improves slightly after PWHT.
Can E90C-K3 PWHT be welded?
Yes — weldability is rated very good (82/100). GMAW with metal-cored wire under M21 shielding (75–80 % Ar + CO₂) or straight CO₂, spray or pulsed transfer. On Q&T high-strength steel preheat 100–150 °C according to base-metal carbon equivalent, keep interpass ≤250 °C and control heat input to 1.0–2.5 kJ/mm to balance strength and toughness.
What surface finishes work on E90C-K3 PWHT?
Remove silicon islands and grind the weld. Finished assemblies must be painted, thermal-sprayed with zinc or plated for corrosion protection; anodizing is not possible.
Can E90C-K3 PWHT be formed, bent or molded?
No forming step applies to a filler metal; feedability is good and deposition rate is higher than solid wire, which suits semi-automatic and robotic welding and multi-pass thick-plate grooves.
What is the maximum service temperature of E90C-K3 PWHT?
E90C-K3 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 E90C-K3-AW and E90C-K3 PWHT?
AW is the default condition — use the as-welded, M21 mixed-gas all-weld-metal condition tested to AWS A5.28 as the standard supply and acceptance state for most high-strength steel structural welds. PWHT: apply post-weld stress relief at 605–620 °C for 1 h on thick-wall joints needing dimensional stability and toughness; check that the softened 545 MPa yield still meets the 90 ksi class. Yield strength is 610 MPa in AW versus 545 MPa in PWHT.
Sources
- AWS A5.28/A5.28M — Low-Alloy Steel Electrodes and Rods for Gas Shielded Arc Welding — American Welding Society (2020)
- 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)
- Metal-cored low-alloy wire datasheets (E90C-K3 class) — Lincoln Electric / ESAB / Kobelco (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.