# -10 Postweld heat treatment.

**Citation:** 49 CFR 179.100-10  
**Type / status:** regulation / current  
**Agency:** Pipeline and Hazardous Materials Safety Administration  
**Effective:** 2026-08-18  
**Published:** Not stated

(a) After welding is complete, steel tanks and all attachments welded thereto must be postweld heat treated as a unit in compliance with the requirements of AAR Specifications for Tank Cars, appendix W (IBR, see § 171.7 of this subchapter).

(b) For aluminum tanks, postweld heat treatment is prohibi

## Document text

(a) After welding is complete, steel tanks and all attachments welded thereto must be postweld heat treated as a unit in compliance with the requirements of AAR Specifications for Tank Cars, appendix W (IBR, see § 171.7 of this subchapter).

(b) For aluminum tanks, postweld heat treatment is prohibited.

(c) Tank and welded attachments, fabricated from ASTM A 240/A 240M (IBR, see § 171.7 of this subchapter), Type 304L or Type 316L materials do not require postweld heat treatment, but these materials do require a corrosion resistance test as specified in § 179.100-7(c)(2).

[Amdt. 179-10, 36 FR 21345, Nov. 6, 1971, as amended by Amdt. 179-47, 58 FR 50238, Sept. 24, 1993; Amdt. 179-52, 61 FR 28679, June 5, 1996; 67 FR 51660, Aug. 8, 2002; 68 FR 75758, 75759, Dec. 31, 2003]

## Provenance

- Official: Yes
- Source: <https://www.ecfr.gov/on/2026-08-18/title-49/section-179.100-10>
- Source ID: `ecfr`
- SHA-256: `6e3ab639abb386e055ca8d2c62fc35a96198fab4f718001408d09cea0c3062d8`
- Retrieved: 2026-08-20T05:46:20.606Z
- Exported: 2026-08-25T16:07:22.058Z
- Document slug: `49-cfr-179-100-10`

### Source metadata

```json
{
  "cfrTitle": 49,
  "part": "179",
  "section": "179.100-10",
  "subpart": "Subpart C—Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120)",
  "corpusVersion": "2026-08-18",
  "jurisdiction": "US"
}
```