Filler metal composition and method for overlaying low NOx power boiler tubes
US8568901B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 19, 2007 |
| Grant date | Oct 29, 2013 |
| Priority date | — |
| Expiry date | Mar 10, 2031 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/13
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
An alloy for use as a welding overlay for boiler tubes in a low NOx coal-fired boiler comprising in % by weight: 36 to 43% Cr, 0.2 to 5.0% Fe, 0-2.0% Nb, 0-1% Mo, 0.3 to 1% Ti, 0.5 to 2% Al, 0.005 to 0.05% C, 0.005 to 0.020% (Mg+Ca), 0-1% Mn, 0-0.5% Si, less than 0.01% S, balance substantially Ni and trace additions and impurities. The alloy provides exceptional coal ash corrosion resistance in low partial pressures of oxygen. The alloy also increases in hardness and in thermal conductivity at service temperature over time. The increased hardness improves erosion resistance of the tubes while the increased thermal conductivity improves the thermal efficiency of the boiler and its power generation capabilities.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.