Shree Impex Steel manufactures high temperature buttweld fittings for power plants, refineries, and petrochemical plants operating above 427°C. WP91, WP22, WP11, WP9, SS 321, SS 347H — all creep-resistant grades. IBR approved. ASME B16.9. Mumbai India.
Above 427°C (800°F), standard carbon steel WPB loses its strength through a phenomenon called creep — slow deformation under sustained load at elevated temperature. Creep-resistant alloy grades are mandatory for high temperature service.
| Grade | Max Temp | Application | Key Property |
|---|---|---|---|
| WPB Carbon Steel | 427°C (800°F) | General service | Standard carbon steel |
| WP11 (1.25Cr-0.5Mo) | 540°C (1000°F) | Medium temp steam | Chrome-moly addition |
| WP22 (2.25Cr-1Mo) | 565°C (1050°F) | Subcritical power, refinery | Higher Cr-Mo content |
| WP91 (9Cr-1Mo-V) | 620°C (1150°F) | Ultra-supercritical power | V, Nb additions — superior creep |
| SS 321 (Ti stabilized) | 650°C (1200°F) | Stainless high temp | Ti prevents sensitization |
| SS 347H (Nb stabilized) | 700°C (1290°F) | Superheater, reheater | Highest creep SS grade |
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