Steel E90C-B9 PWHT-EXT
Heat-treated state
Choose for thick headers/pipe or repeated PWHT cycles: softer, tougher weld metal at the cost of some room-temperature strength.
Values for the PWHT-EXT condition
Other E90C-B9 tempers and conditions
E90C-B9 is listed in 4 conditions; see the grade overview at E90C-B9.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
PWHT-EXTThis page 760 °C, 4–8 h (heavy-section / multiple thermal cycles) | Choose for thick headers/pipe or repeated PWHT cycles: softer, tougher weld metal at the cost of some room-temperature strength. | 545 | 660 | 22 | 19 HRC | 2.9 % IACS |
Normalized and tempered | Used when the whole weldment can be re-normalized (shop-fabricated components) to fully restore a uniform tempered-martensite structure. | 580 | 700 | 22 | 21 HRC | 2.9 % IACS |
PWHT760Default PWHT | Standard delivery/service condition: the AWS A5.29 classification properties are measured after this temper, and code work requires it. | 600 | 710 | 20 | 23 HRC | — |
As-welded deposit | Interim condition only — never leave 9Cr-1Mo-V weld metal in service as-welded; hardness and residual stress are far too high. | 900 | 1,150 | 9 | 43 HRC | — |
What is E90C-B9 PWHT-EXT?
E90C-B9 PWHT-EXT is E90C-B9 heat treated to PWHT-EXT — choose for thick headers/pipe or repeated PWHT cycles: softer, tougher weld metal at the cost of some room-temperature strength. E90C-B9 PWHT-EXT has a yield strength of 545 MPa (79 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 70% of steel grades. Elongation at break is 22% and the elastic modulus is 217 GPa (31.5 Msi). E90C-B9 PWHT-EXT has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 93% of steel grades. It melts at 1,425°C (2,597 °F). PWHT760 is the default condition FabDigit quotes; PWHT-EXT is available on request or by drawing note.
Advantages
- High service temperature — 600°C (1,112 °F), better than 98% of steel grades
- Good corrosion resistance — 30/100, better than 95% of steel grades
- Tough — resists crack growth — 115 MPa·√m (104.7 ksi·√in), better than 77% of steel grades
Limitations
- High embodied carbon — 2.9 kg CO₂/kg, worse than 91% of steel grades
- Poor heat conductor — 26.5 W/m·K (15.3 BTU/hr·ft·°F), worse than 86% of steel grades
- Difficult to machine — 40/100, worse than 77% of steel grades
E90C-B9 PWHT-EXT properties
Typical room-temperature values for E90C-B9 PWHT-EXT; 23 are specific to this condition. Other listed values are E90C-B9 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
E90C-B9 PWHT-EXT has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 93% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical15
E90C-B9 PWHT-EXT has a yield strength of 545 MPa (79 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 70% of steel grades. Elongation at break is 22% and the elastic modulus is 217 GPa (31.5 Msi).
Thermal6
E90C-B9 PWHT-EXT is rated for continuous service to 600°C (1,112 °F). It conducts heat at 26.5 W/m·K (15.3 BTU/hr·ft·°F), worse than 86% of steel grades. Thermal expansion is 10.8 µm/m·K (6 µin/in·°F).
Electrical2
E90C-B9 PWHT-EXT has an electrical resistivity of 5.9×10⁻⁷ Ω·m.
Chemical & Environmental3
Corrosion resistance is poor (30/100), better than 95% of steel grades.
Sustainability4
Producing a kilogram of E90C-B9 PWHT-EXT takes about 38 MJ of energy and emits 2.9 kg of CO₂ — more than 91% of steel grades. Typical recycled content is 25%.
Manufacturability6
E90C-B9 PWHT-EXT's machinability is fair (40/100, worse than 77% of steel grades); weldability fair (45/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with E90C-B9 PWHT-EXT
Is E90C-B9 easy to machine?
Machine only after PWHT (≤265 HB); as-welded martensite at ~400 HB needs carbide or CBN tooling and rigid setups.
Can E90C-B9 be welded?
Preheat 200–250 °C, interlayer max ~300 °C, Ar-CO₂ shielding, cool to 80–100 °C to transform, then mandatory temper at 750–770 °C for 2 h min; avoid dissimilar dilution with austenitic or Ni-rich fillers.
Can E90C-B9 be formed, bent or molded?
Not applicable — deposited weld metal; joint preparation and pipe bending are done on the base metal before welding.
What surface finishes work on E90C-B9?
Grind/blast and apply high-temperature aluminium-silicone paint or insulate; the alloy is not stainless and will rust during outages.
E90C-B9 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 |
|---|---|---|
| C | 0.08 – 0.13 | 0.1 |
| MnMn+Ni typically limited to 1.40–1.50 % max | 0.4 – 1.2 | 0.8 |
| Si | ≤ 0.5 | 0.3 |
| P | ≤ 0.01 | 0.01 |
| S | ≤ 0.01 | 0.01 |
| Cr | 8 – 10.5 | 9 |
| Mo | 0.85 – 1.2 | 1 |
| V | 0.15 – 0.3 | 0.2 |
| Nbcolumbium | 0.02 – 0.1 | 0.05 |
| NN/Al ratio controlled for creep strength | 0.02 – 0.07 | 0.05 |
| Nikept low to keep Ac1 high | ≤ 1 | 0.5 |
| Al | ≤ 0.04 | 0.01 |
| Cu | ≤ 0.25 | 0.05 |
| Fe | balance | — |
E90C-B9 PWHT-EXT — frequently asked
What is E90C-B9 PWHT-EXT used for?
E90C-B9 PWHT-EXT is typically used for P91/T91 boiler tubing, advanced ultra-supercritical power plants, high-temperature steam piping and petrochemical high-temperature vessels. In short: P91-grade 600 °C deposit; highest creep strength in family; requires strict PWHT control.
What is the yield strength of E90C-B9 PWHT-EXT?
E90C-B9 PWHT-EXT has a typical yield strength of 545 MPa (79 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 70% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is E90C-B9 PWHT-EXT easy to machine?
Not especially — machinability is rated fair (40/100, worse than 77% of steel grades). Machine only after PWHT (≤265 HB); as-welded martensite at ~400 HB needs carbide or CBN tooling and rigid setups.
Can E90C-B9 PWHT-EXT be welded?
With care — weldability is rated fair (45/100). Preheat 200–250 °C, interlayer max ~300 °C, Ar-CO₂ shielding, cool to 80–100 °C to transform, then mandatory temper at 750–770 °C for 2 h min; avoid dissimilar dilution with austenitic or Ni-rich fillers.
What surface finishes work on E90C-B9 PWHT-EXT?
Grind/blast and apply high-temperature aluminium-silicone paint or insulate; the alloy is not stainless and will rust during outages.
Can E90C-B9 PWHT-EXT be formed, bent or molded?
Not applicable — deposited weld metal; joint preparation and pipe bending are done on the base metal before welding.
What is the maximum service temperature of E90C-B9 PWHT-EXT?
E90C-B9 PWHT-EXT is rated for continuous use to about 600°C (1,112 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between E90C-B9 PWHT760 and E90C-B9-AW?
PWHT760 is the default condition — standard delivery/service condition: the AWS A5.29 classification properties are measured after this temper, and code work requires it. AW: interim condition only — never leave 9Cr-1Mo-V weld metal in service as-welded; hardness and residual stress are far too high. Yield strength is 600 MPa in PWHT760 versus 900 MPa in AW.
Sources
- AWS A5.29/A5.29M — Low-Alloy Steel Electrodes for Flux Cored Arc Welding — American Welding Society (2010)
- ASME BPVC Section II Part C (SFA-5.29) and Part D (Grade 91 physical properties) — ASME (2023)
- ASTM A335/A335M — Seamless Ferritic Alloy-Steel Pipe (Grade P91) — ASTM International (2022)
- ASM Handbook Vol.6 — Welding, Brazing and Soldering (Cr-Mo steels) — ASM International (1993)
- Metal-cored / flux-cored 9Cr-1Mo-V welding consumable datasheets — Böhler Welding / Lincoln Electric / 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.