The ISO 2553 standard are made up of a series of symbols that convey welding instruction. The ISO 2553 standard exist to create a universal language for welder from any region of the world. Since welders from any region of the world may be required to reading a blueprint, the ISO 2553 standard ensure that all individual can read a blueprint accurate.
Should a welder misread the welding symbol, they could end up welding the wrong part of a beam, leading to costs and wasted material for the construction project. The reference line for welding symbol is the most important part of the welding symbol. The placement of the welding symbol in relation to the reference line determine where the weld should be placed on the metal piece.
How to Read ISO 2553 Welding Symbols
If the welding symbol is placed below the reference line, welders must place the weld on the side of the metal piece that the arrow is pointing to. If the welding symbol is placed above the reference line, welders must place the weld on the opposite side of the metal piece different than that which the arrow is pointing. The geometry of the metal pieces that are to be welded together will determine the welding symbol that should be used.
Joint between metal pieces require specific welding symbol. A butt joint is one type of joint where the metal pieces are placed in the same plane. Depending on the thickness of the metal pieces, different type of butt joints are used.
If the metal pieces are thin, a square groove weld is used. If the metal pieces are thick, a V-groove or a U groove is used for the joint. These grooves are used for allowing the weld to penetrate deep into the metal piece.
The choice of groove type impact the strength of the joint and how much filler metal must be use to complete the weld. A fillet weld is a triangular weld shape that is used for T-joints and lap joints. Fillet weld dont require any special preparation of the edge of the metal pieces.
The fillet weld does, however, require specific dimension for the weld. The number to the left of the fillet weld symbol specify the leg size of the weld. The leg size is important because the size of the leg determine the load that the weld can take.
If the leg size of the fillet weld is too small, there will not be enough internal thickness of the weld to evenly distribute the load to the metal pieces. This can result in the weld breaking or failing. Other marks on a welding symbol add to the precision of the welding requirement.
A circle located at the junction of the arrow and the reference line mean that the weld must be performed around the joints perimeter. A small flag next to a welding symbol mean that the weld should be performed in the field instead of in a shop. These marks prevent error during the welding process.
The tail of the welding symbol contain other technical specification for the weld. The tail of the welding symbol also indicate the welding process that will be used to complete the weld. Codes can be found in the tail of the welding symbol.
Code 131 in the tail indicate that the welding process will be MIG welding. Code 141 in the tail indicate that the welding process will be TIG welding. The tail of the welding symbol remove the guesswork for welders regarding which welding process to use.
The tail of the welding symbol will also include information regarding the welding process specification that will be followed in a professional welding environment. This specification is legally binding and describe the legal welding process for each weld on a metal piece. Understanding the welding symbol will allow welders to translate the blueprint of a metal structure to be built into a calculated connection of metal piece.
Should welders understand these welding symbol, the final product will accurately match the blueprint of the original design.
