Short answer
DENUE lists 137 welded structures plants with 11 or more staff in Aguascalientes, Guanajuato, Querétaro and San Luis Potosí. 31 have 51 or more staff, and 3 of those match an IMMEX program on exact name and postal code. Guanajuato has the most, with 51. Each plant still needs its own checks.
Key facts
- Activity codes (SCIAN)
- 332310
- Plants, 11+ staff
- 137
- Data
- INEGI DENUE bulk files, 25 Sep 2026; IMMEX directory, August 2026 edition
About welded structures
Structural metal shops cut, weld and finish frames, brackets and assemblies. Their capacity is set by floor space, fixtures and lifting, more than by machines.
The numbers by state
| State | Plants, 11+ staff | With 51+ staff | With an IMMEX match |
|---|---|---|---|
| Guanajuato | 51 | 9 | 0 |
| San Luis Potosí | 37 | 9 | 1 |
| Querétaro | 32 | 11 | 2 |
| Aguascalientes | 17 | 2 | 0 |
| Four states | 137 | 31 | 3 |
| Staff band | Plants |
|---|---|
| 11 to 30 | 91 |
| 31 to 50 | 15 |
| 51 to 100 | 15 |
| 101 to 250 | 12 |
| 251 or more | 4 |
What to ask a welded structure supplier
Registries show that a plant exists and exports. These questions cover what they cannot.
- Welding procedures and the welder qualifications behind them.
- Fixture capacity and how fixtures are validated.
- Largest and heaviest assembly they can handle.
- Paint, powder coat or plating: in house or outsourced.
- Dimensional inspection and how weld quality is checked.
Checks before you approach a plant
- Confirm the plant in DENUEName, address, activity code and staff band.
- Check its IMMEX programStatus and type, matched on legal name and postal code.
- Search the SAT 69-B listBy RFC where you have it, otherwise by exact name.
The verification guide explains each step and where it stops.
Frequently asked questions
How many welded structures plants are in the Bajío?
INEGI’s DENUE lists 137 welded structures plants with 11 or more staff across Aguascalientes, Guanajuato, Querétaro and San Luis Potosí. 31 of them have 51 or more staff. Testigo counted these from INEGI’s bulk files on 25 September 2026.
Which Bajío state has the most welded structures plants?
Among the four states Testigo counted, Guanajuato has the most welded structures plants in DENUE, with 51 of 137, followed by San Luis Potosí (37). Plants elsewhere in Mexico are outside Testigo’s pilot, and counts are establishments in INEGI’s directory as of 25 September 2026.
Do welded structures plants in the Bajío export under IMMEX?
Some do. 3 of the 137 plants match an IMMEX program on exact name and postal code, and 3 of the 31 with 51 or more staff. A plant with no match may still export through a shelter company’s program, so ask which entity holds it.