Welding is a common, effective and economical joining method in the modern manufacturing industry. Choosing the proper filler metal for welding requires an understanding of all aspects involving the base metals, welding process, and the desired outcome. This article introduces the welding rod labeling methods for various materials.
The American Welding Society (AWS) has issued a labeling system for welding filler metals. This system groups filler metals into 5 categories according to the type of base metal, joint design, and current or welding process to be used:
1. Filler Metal Groups & Classification Codes
The AWS uses a letter code to designate the base metal or metals to be welded together. The base metal categories are then designated by their material corresponding letter codes. The AWS has proposed several standard ASME classification codes for welding filler metals in each group: A, B, C, etc. The Classification Codes are appended with a “-” (a dash) followed by a number that identifies the welding process, electrode core, and chemical constituents of the filler metal to be used. For example, an F-7a classification code indicates that the filler metal is suitable for use with an electric arc welding process and an a (arc) core wire chemical composition.
2. Number System
The AWS D1-series of specifications for welding standards use a numerical designation for filler metals. The numerical system consists of two or three digits that indicate the type and composition of the filler metal. The numbering system is divided into service classifications, chemical composition designations, AWS classification, and filler metal group numbers.
The first number indicates the type of filler metal, such as a rod (1), electrode (2), wire (3), flux (4) etc. The second and third numbers indicate the base metal group of the filler material and the filler metal group number. For instance, 7018 indicates the filler metal is perfect for use with an electric arc welding process on an E-70XX base metal group.
3. AWS Standard & Grade Markings
The AWS standard and grade markings indicate the type of material or alloy used in the welding process. This is essential when performing welding repairs on components that use various alloys and metals. The grade is a two-letter designation that indicates the service condition, strength, and methodology used in the welding process. The AWS standard and grade markings are used to differentiate the alloys and metals being welded.
4. Manufacturer’s Symbols
Manufacturer’s symbol markings are used to denote the manufacturer’s suggested wire gauging, contact tips, and other technical information for individual companies’ components. Knowing the manufacturer’s symbols is important for reading and interpreting welding process data, including metallurgy and filler metals.
Additionally, markings are used to indicate the overall welding characteristics of the welding rod. This includes information such as welding current and electrode positions as well as welding speed and electrode diameter expressions.
In summary, the welding rod labeling method helps reduce confusion and error due to the wide variety of welding processes and base materials available. Knowing the labeling methods of filler metals helps welders identify the right filler rods for a specific job at hand. By combining the information obtained from the AWS labeling methods and manufacturer’s symbols, welders are able to accurately select the right welding rod and process for each application.
