Site conditions thick-wall P92 pipe local heat treatment method
US9663841B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 31, 2012 |
| Grant date | May 30, 2017 |
| Priority date | — |
| Expiry date | Dec 25, 2032 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B30/00
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The present invention published a large walled field conditions P92 long pipeline local heat treatment processes. Firstly, according to the specific conditions for the on-site grade heat-resistant steel (P92 pipe), combining of the finite element method and test, the Heated Band (HB) width and Gradient Control Band (GCB) was calculated. The pipe was then locally heated using the flexible ceramic resistive heater. When the temperature reaches 80-100° C., the pipe was heated to constant temperature at 80-100° C. for 2 h. The pipe was heated to 300° C. at the rate of 150° C./h. When the temperature reaches 300° C., rising the temperature to 765° C. at the rate of 80° C./h. Holding time is calculated by the wall thickness (5 min/mm, no less than 4 h). Lowering the temperature to 300° C. at the rate of 100° C./h and then natural cooling to room temperature, finally removing the heating device. Finally, the local heat treatment process can be obtained. The present invention can effectively decrease the temperature difference between the outer and inner wall, the residual stress in the welded joints. Thus the service properties can be guaranteed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.