AWS C7.4:2017

This specification on laser beam welding discusses applicable specifications, safety, requirements, fabrication, quality examination, equipment calibration and maintenance, approval of work, and delivery of work.
Scope : 1.1 Scope. This specification covers the preparation, the process control, and quality control requirements for laser beam welding. Welding equipment includes Gas Lasers (CO2) and Solid-State Lasers (Nd:YAG, Yb:YAG, Nd:Glass, Diode, Ruby, Disk and Fiber) in pulsed, continuous wave (CW), and quasi-continuous wave (QCW) output as defined in AWS A3.0M/A3.0, Standard Welding Terms and Definitions. Tutorial information regarding techniques of welding or details of equipment setup or operation is beyond the scope of this specification. For more information on this subject and recommended practices, refer to the latest published version of AWS C7.2, Recommended Practices for Laser Welding, Cutting, and Allied Processes. 1.1.1 Materials. This specification covers all major engineering alloys including: (1) Ferrous Alloys (e.g., Carbon steels, stainless steels, etc.); (2) Nonferrous Alloys (e.g., Alloys of Al, Ni, Ti, etc. and Super-alloys); (3) Heat-Resisting and Refractory Metal Alloys (e.g., Alloys of Mo, Ta, W, etc.); (4) Other Alloys (e.g., Be and Cu alloys, precious metals); (5) Nonmetals (Plastics, polymers, etc.). 1.1.2 Qualification Categories. There are three categories to which welds may be qualified: Class A, B, or C. Classification levels are intended to delineate inspection level and process control. Examples of acceptance criteria, which may be applied to the classification levels, are presented in Annex D. 1.1.2.1 Class Aâ??Critical Applications. Critical weldments include those where a failure of any portion of a weldment 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. 1.1.2.2 Class Bâ??Semicritical Applications. Semicritical weldments include those where a failure of any portion of a weldment would reduce the overall efficiency of the system, but loss of the system or endangerment of personnel would not be experienced. 1.1.2.3 Class Câ??Noncritical Applications. Noncritical weldments include those where a failure of any portion of a weldment would not affect the efficiency of the system or endanger personnel. 1.2 Units of Measure. This standard makes use of both U.S. Customary Units and the International System of Units (SI). The latter are shown within brackets [ ] or in appropriate columns in tables and figures. The measurements may not be exact equivalents; therefore, each system must be used independently. 1.3 Safety. Safety and health issues and concerns are beyond the scope of this standard; some safety and health information is provided, but such issues are not fully addressed herein. Safety and health information is available from the following sources: American Welding Society:(1) ANSI Z49.1, Safety in Welding, Cutting, and Allied Processes (2) AWS Safety and Health Fact Sheets (3) Other safety and health information on the AWS website Laser Institute of America (LIA): ANSI Z136.1, Safe Use of Lasers Material or Equipment Manufacturers: (1) Safety Data Sheets supplied by materials manufacturers (2) Operating Manuals supplied by equipment manufacturers 2. Normative References The following standards contain provisions which, through reference in