AWS D8.8M:2014 pdf download.Specification for Automotive Weld Quality - Arc Welding of Steel
3. Terms and Definitions
All of the terms in this clause are used in various parts of this document and require definition for correct interpretation of the instructions. The terms used in this specification shall be interpreted in accordance with the definitions given in the lat-est edition of AWS A3.0M/A3.0, Standard Welding Terms and Definitions Including Terms for Adhesive Bonding, Brazing,Soldering, Thermal Cutting, and Thermal Spraying. Some of the terms are listed in AWS A3.0M/A3.0 but their definitions have been enhanced to clarify their use in this document. For the purposes of this document, the following definitions apply:
burn-through. A case of excessive melt-through in which the weld pool cannot be supported resulting in a hole through the base metals joined.
effective weld length. The portion of a weld meeting all the minimum acceptance requirements of the specification. In a curved weld, the length is measured longitudinally along the axis.
gap. The distance between two base components of the joint to be welded (see Figure 1). NOTE: This distance is typi-cally referred to as the root opening in nonautomotive applications.
hybrid welding. Combination of two or more welding processes applied and controlled simultaneously. Designated by HW-XXX/XXX with the dominant process listed first (e.g.. HW-LBW/GMAW).
meltback. This occurs where the base metal melts back from the edge, but does not become part of the weld. This con-dition leaves a void between the weld deposit and the base metal (sce Figure 2).
notching. A weld heat related burn back of material at the end of the joint resulting in a notch (see Figure 3).OEM. Original Equipment Manufacturer: one producing a product from components which may or may not be bought from other manufacturers.
4.3.2.2 To ensure consistent weld quality in fllet welds, the joint gap should not exceed 0.3T where T is the thickness of the thinnest part. Additionally, the gap should not exceed the diameter of the filler wire. This should be true for all thicknesses in the range from 2 mm to 5 mm for single arc processes. For tandem arc welding, the range from 2 mm to 5 mm material thickness would allow a maximum gap of 2.0 mm. NOTE: This size gap only applies for welding done in the flat or horizontal positions. For lap penetration joints with high power density processes such as hybrid laser, the joint gap should not exceed 0.2 mm. The specific range of gap values listed above is dependent on the welding process and joint configuration. Larger gaps than specified can adversely affect structural performance or fatigue life.AWS D8.8M pdf download.