| ASTM B594 | Ultrasonic Inspection of Aluminum-Alloy Wrought Products. *NOTE* NGAS ASPL approval is required when testing is performed by a secondary source other than the primary mill. | Non-Destructive Testing |
| Supercedes: None | Superceded By: None |
| Number | Name | State | Country |
| 90048519 | Aerospace Testing Lab, Inc. | CT | United States |
| 90048601 | Howmet Aerospace Inc.Cleveland Operations | OH | United States |
| 90051187 | Kaiser Aluminum/Chemical Company | WA | United States |
| 90043905 | Mistras Group dba Mistras Services | CA | United States |
| 90051777 | Mitchell Laboratories Inc | CA | United States |
| 90077007 | ND Testing Inc. | CA | United States |
| 90055777 | Weber Metals Inc | CA | United States |