B31.3 - Preheating

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Last updated: Nov 26, 2019 by Former user (Deleted)
2 min read

ASME B31.3 provides material preheating requirements when welding piping to be used in the process industry.

 

The requirements apply to materials of various P-Numbers and to all types of welding including; tack welds, repair welds, and seal welds. The P-No. that B31.3 provides preheat temperatures for are 1, 3, 4, 5A, 5B, 6, 9A, 9B, 10I, 15E, as well as a required minimum temperature for all other materials.

  • P-No. 1 can be specified to have a percent Carbon concentration greater than 0.30 which will increase the required minimum preheat temperature. This will show up as a checkbox in the PQR window.

  • P-No. 5B can be specified to have a percent Chromium concentration greater than 6.0, which would increase the required minimum preheat temperature. This will show up as a checkbox in the PQR window.

 

In ProWrite, when creating a WPS from a PQR that specifies Section IX and B31.3 as the applicable code, this minimum preheat temperature will be determined from the materials being welded and their respective thickness. This required minimum preheat temperature is shown in the ASME Section IX WPS window and in the printed WPS report.