AWS C7.4/C7.4M

This specification addresses processing and quality control requirements for electron beam welding. Processing includes both high- and low-voltage welding equipment and high and medium vacuum variations.

Materials.

This specification covers all major engineering alloys including:

Ferrous Alloys (steels and stainless steels)

Aerospace Alloys (Al alloys, Ti alloys, superalloys)

Heat-Resisting Alloys (refractory metal alloys)

Other Metals (Cu alloys, Be alloys, precious metals)

Qualification Categories. There are three categories to which welds may be qualified: Class A, B, or C.

Class A—Critical Applications.

Critical weldments include those where a failure of any portion would cause loss of system, loss of major component, loss of control, unintentional release of critical stores (such as fuel or cargo), or endangerment of personnel.

Class B—Semicritical Applications.

Semicritical weldments include those where a failure would reduce the overall efficiency of the system but loss of the system or endangerment of personnel would not be experienced.

Class C—Noncritical Applications.

Noncritical weldments include those where a failure would not affect the efficiency of the system or endanger personnel.