UNS K30960, ER90S-B3, ER62S-B3
UNS K30960 is used in applications involving high temperatures and pressure, such as:
- Chemical and petrochemical reactors
- High-temperature pipelines
- Power boiler components
- Pressure vessels operating up to 1100°F (590°C)
Its creep strength and resistance to hydrogen embrittlement make it suitable for severe service environments.
What is UNS K30960, ER90S-B3, ER62S-B3?
UNS K30960 is a chromium-molybdenum low-alloy steel welding wire classified under AWS A5.28/A5.28M:2022 as ER90S-B3 (imperial) and ER62S-B3 (metric). This creep-resistant filler metal is designed for gas shielded arc welding processes and is commonly used in high-temperature applications in the chemical, petrochemical, and power generation industries.
Standards and Specifications
- AWS: A5.28 ER90S-B3 / A5.28M ER62S-B3
- UNS: K30960
- ASME: SFA-5.28/SFA-5.28M
- Base Metal: SA 387 Grade 22 (UNS K21590)
UNS K30960 is a high-performance welding consumable designed for joining and repairing 2.25Cr-1Mo steel components in high-temperature service. Proper welding procedures, including preheat, interpass temperature control, and PWHT, are essential to ensure weld integrity and performance.
Applications
UNS K30960 is a high-performance welding consumable designed for joining and repairing 2.25Cr-1Mo steel components in high-temperature service. Proper welding procedures, including preheat, interpass temperature control, and PWHT, are essential to ensure weld integrity and performance.Chemical Composition (%)
The chemical composition of UNS K30960 conforms to the requirements for AWS ER90S-B3/ER62S-B3 electrodes and rods:
| Element | Content (%) |
|---|---|
| C | 0.07–0.12 |
| Mn | 0.40–0.70 |
| Si | 0.40–0.70 |
| P | ≤ 0.025 |
| S | ≤ 0.025 |
| Cr | 2.30–2.70 |
| Mo | 0.90–1.20 |
| Ni | ≤ 0.20 |
| Cu | ≤ 0.35 |
| Other Elements | ≤ 0.50 |
Its composition is nearly identical to SA 387 Grade 22 (UNS K21590), making it an ideal match for welding similar base materials.
Material Properties
UNS K30960 weld metals exhibit the following minimum tensile properties per AWS A5.28:
- Tensile Strength: 90,000 psi (620 MPa)
- Yield Strength: 78,000 psi (540 MPa)
- Elongation: 17%
These high-strength properties make it suitable for high-pressure and high-temperature service.
Processing Performance
Welding Considerations
Due to its alloy content and high strength, UNS K30960 requires careful welding practices:
- Preheat Temperature: 375–425°F (190–220°C)
- Interpass Temperature: 375–425°F (190–220°C)
- Post-Weld Heat Treatment (PWHT): Typically performed at 1275°F (690°C) for at least 1 hour to reduce residual stresses and temper the weld metal.
Welding in the as-welded condition requires special attention to avoid cracking due to high strength and residual stresses.
Base Metal Compatibility
UNS K30960 is commonly used to weld ASTM SA 387 Grade 22 (UNS K21590) steel, a 2.25% Cr-1% Mo low-alloy steel widely used in pressure vessels and piping systems.
Shielding Gas Requirements
Welding must be performed using a shielding gas mixture such as Argon with 1–5% Oxygen (Classes SG-AO-1 through SG-AO-5 per AWS specification).