Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
Durehete in Gas Turbine Bolting — Compressor and Turbine Casing Bolting
Gas turbine bolting splits between compressor casing (operating <450°C, often Cr-Mo-V at the lower end) and turbine casing (operating 540°C+ on heavy-duty industrial frames, requiring Cr-Mo-V-Ti-B). Durehete 1055 and 950 cover both bands.
Compressor Casing Bolting
Compressor casing bolts on industrial gas turbines run in Durehete 950 / Alloy T31 for service to 480°C. Bolt diameters typically 24-72 mm. Stress-rupture envelope covers the 100,000-hour design life at compressor exit temperature.
Turbine Casing Bolting
Heavy-duty industrial frame turbine casing bolts run in Durehete 1055 / Alloy T41 at 540-565°C casing skin temperature. The Ti+B microalloying maintains the creep-rupture envelope across the 8,000-hour fired-hour service interval typical for industrial gas turbines.
Expansion-Joint Bolting
Expansion-joint bolting between the compressor and turbine modules sees both thermal cycling and high preload. Durehete 1055 is specified to handle the combined fatigue plus creep loading.
Certification
Major gas-turbine OEMs accept EN 10269 type 3.1 / 3.2 inspection certificates with optional VdTÜV Werkstoffblatt 350 dual certification when AD 2000-Merkblatt acceptance is required for German installation sites.
Frequently Asked Questions
Which Durehete grade is specified for gas turbine bolting?
The grade depends on service temperature. Durehete 1055 (T41 / 1.7729) covers up to 565 degrees Celsius; Durehete 950 (T31 / 1.7711) covers up to 540 degrees Celsius; Durehete 900 (T22 / 42CrMoV5-6) covers up to 500 degrees Celsius.
What standard governs gas turbine bolting?
EN 10269 is the controlling European bolting-steel standard. ASTM A193 Grade B16 is the closest US equivalent for the lower-temperature grades (Durehete 950 and 900).
Are dual certificates available?
Yes. TorqBolt supplies the Durehete grades with EN 10269 type 3.1 / 3.2 inspection certificates plus ASTM A193 dual certification when the procurement specification requires it.
What is the typical lead time?
Lead time depends on size and quantity. Stock sizes ship within a week; custom-machined fasteners run 4-8 weeks from heat traceability through to delivery.
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