Steel ER70S-B2L PWHT-745
Heat-treated state
UNS K20500
PWHT-745 = high-temperature temper 730–760 °C
Use when the fabrication receives repeated or extended PWHT (wet H2S / HTHA service) requiring maximum softening and hardness well under 200 HB.
Values for the PWHT-745 condition
Other ER70S-B2L tempers and conditions
ER70S-B2L is listed in 3 conditions; see the grade overview at ER70S-B2L.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
PWHT-745This page High-temperature temper 730–760 °C | Use when the fabrication receives repeated or extended PWHT (wet H2S / HTHA service) requiring maximum softening and hardness well under 200 HB. | 410 | 520 | 28 | 150 HB | 8.2 % IACS |
PWHT | Standard condition for ASME code Cr-Mo piping: tempers the weld metal, restores toughness and brings hardness below typical 225 HB / 22 HRC limits. | 450 | 560 | 26 | 165 HB | — |
AWDefault As-welded deposit | Pick for tack welds, thin-wall or code-exempt joints where PWHT is impractical — the low-carbon B2L chemistry keeps as-welded hardness and cracking risk down. | 520 | 620 | 22 | 18 HRC | — |
What is ER70S-B2L PWHT-745?
ER70S-B2L PWHT-745 is ER70S-B2L heat treated to PWHT-745 — use when the fabrication receives repeated or extended PWHT (wet H2S / HTHA service) requiring maximum softening and hardness well under 200 HB. ER70S-B2L PWHT-745 has a yield strength of 410 MPa (59.5 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 57% of steel grades. Elongation at break is 28% and the elastic modulus is 205 GPa (29.7 Msi). ER70S-B2L PWHT-745 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,490°C (2,714 °F). AW is the default condition FabDigit quotes; PWHT-745 is available on request or by drawing note.
Advantages
- High service temperature — 550°C (1,022 °F), better than 95% of steel grades
- Ductile — tolerates forming and impact — 28%, better than 89% of steel grades
- Readily welded — 78/100, better than 78% of steel grades
Limitations
- High embodied carbon — 2.8 kg CO₂/kg, worse than 90% of steel grades
ER70S-B2L PWHT-745 properties
Typical room-temperature values for ER70S-B2L PWHT-745; 22 are specific to this condition. Other listed values are ER70S-B2L reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
ER70S-B2L PWHT-745 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,490°C (2,714 °F).
Mechanical15
ER70S-B2L PWHT-745 has a yield strength of 410 MPa (59.5 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 57% of steel grades. Elongation at break is 28% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
ER70S-B2L PWHT-745 is rated for continuous service to 550°C (1,022 °F). It conducts heat at 43 W/m·K (24.8 BTU/hr·ft·°F), better than 51% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
ER70S-B2L PWHT-745 conducts electricity at 8.2 % IACS, better than 61% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (18/100), better than 83% of steel grades.
Sustainability4
Producing a kilogram of ER70S-B2L PWHT-745 takes about 36 MJ of energy and emits 2.8 kg of CO₂ — more than 89% of steel grades. Typical recycled content is 35%.
Manufacturability6
ER70S-B2L PWHT-745's machinability is good (57/100, better than 71% of steel grades); weldability very good (78/100); formability good (55/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ER70S-B2L PWHT-745
Is ER70S-B2L easy to machine?
Machine the deposit after PWHT — as-welded bainitic/martensitic weld metal is abrasive on HSS; use carbide at moderate speed with rigid setup.
Can ER70S-B2L be welded?
GTAW/GMAW of P11/P12 with 150–250 °C preheat, ≤300 °C interpass, dry argon shielding, and PWHT at 690–730 °C; the low-carbon grade tolerates short delays before PWHT better than ER70S-B2.
Can ER70S-B2L be formed, bent or molded?
Supplied only as drawn wire or cut rod; no cold forming of the deposit — bend tests should follow PWHT.
What surface finishes work on ER70S-B2L?
Weld metal rusts readily: grind/blast and prime, or insulate for hot service; no anodizing applicable and plating is rarely used on the joint.
ER70S-B2L 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 |
|---|---|---|
| Clow-carbon 'L' grade | ≤ 0.05 | 0.04 |
| Mn | 0.4 – 0.7 | 0.55 |
| Si | 0.4 – 0.7 | 0.55 |
| Cr | 1.2 – 1.5 | 1.35 |
| Mo | 0.4 – 0.65 | 0.52 |
| P | ≤ 0.03 | 0.01 |
| S | ≤ 0.03 | 0.01 |
| Cuincluding any copper coating | ≤ 0.35 | 0.15 |
| Fe | balance | — |
ER70S-B2L PWHT-745 — frequently asked
What is ER70S-B2L PWHT-745 used for?
ER70S-B2L PWHT-745 is typically used for P11/P12 chrome-moly pipe welding, hydrocracker piping, power generation steam lines and petrochemical process piping. In short: low-carbon Cr-Mo filler; reduced underbead cracking risk; softer as-welded than B2.
What is the yield strength of ER70S-B2L PWHT-745?
ER70S-B2L PWHT-745 has a typical yield strength of 410 MPa (59.5 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 57% of steel grades. Strength varies by condition: see the 3 listed tempers.
Is ER70S-B2L PWHT-745 easy to machine?
Reasonably — machinability is rated good (57/100, better than 71% of steel grades). Machine the deposit after PWHT — as-welded bainitic/martensitic weld metal is abrasive on HSS; use carbide at moderate speed with rigid setup.
Can ER70S-B2L PWHT-745 be welded?
Yes — weldability is rated very good (78/100). GTAW/GMAW of P11/P12 with 150–250 °C preheat, ≤300 °C interpass, dry argon shielding, and PWHT at 690–730 °C; the low-carbon grade tolerates short delays before PWHT better than ER70S-B2.
What surface finishes work on ER70S-B2L PWHT-745?
Weld metal rusts readily: grind/blast and prime, or insulate for hot service; no anodizing applicable and plating is rarely used on the joint.
Can ER70S-B2L PWHT-745 be formed, bent or molded?
Supplied only as drawn wire or cut rod; no cold forming of the deposit — bend tests should follow PWHT.
What is the maximum service temperature of ER70S-B2L PWHT-745?
ER70S-B2L PWHT-745 is rated for continuous use to about 550°C (1,022 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- AWS A5.28/A5.28M — Low-Alloy Steel Electrodes and Rods for Gas Shielded Arc Welding — American Welding Society (2020)
- ASME BPVC Section II Part C / Part D (SFA-5.28; 1.25Cr-0.5Mo physical properties) — ASME (2023)
- Chrome-moly solid wire weld-metal property sheets (ER70S-B2L class) — Lincoln Electric / ESAB / Böhler Welding (2023)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering (Cr-Mo steels) — ASM International (1993)
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.