The weld height standard of stainless steel duct welding mainly depends on the following aspects:

First, the purpose and pressure grade of the air duct

General ventilation system: For general ventilation system, the requirement of weld height is relatively low. In general, the height of the weld should not be less than 0.7 times of the thickness of the parent metal, and should not be less than 3 mm. This can ensure that the air duct has sufficient tightness and strength under normal ventilation pressure.

Air-conditioning system: In air-conditioning system, the standard of weld height will be improved accordingly due to the higher control requirements of air flow and pressure. Generally speaking, the height of the weld should not be less than 0.8 times the thickness of the parent material, so as to ensure that the air duct will not leak air during the air conditioning operation, which will affect the air conditioning effect.

High-pressure system: For some high-pressure ventilation systems, such as high-pressure gas transmission pipelines in industrial ventilation, the requirements for weld height are more stringent. The height of the weld should usually not be less than the thickness of the base metal, and even higher requirements may be required to withstand the pressure of high-pressure gas.

Second, the welding method and technology

Manual arc welding: Manual arc welding is a common welding method, but it is relatively difficult to control the weld height. In manual arc welding, the weld height should generally be between 3mm and 6mm, depending on the welder's technical level and the control of welding process parameters.

Argon arc welding: Argon arc welding is a high-quality welding method, which can obtain a more uniform and beautiful weld. In argon arc welding, the weld height can be controlled accurately, generally between 2mm and 4mm, depending on the welding current, welding speed and argon flow rate.

Automatic welding: automatic welding equipment can achieve high-precision welding, and the consistency of weld height is good. In automatic welding, the weld height can be accurately controlled according to the design requirements, generally between 1.5mm and 3 mm.

III. Relevant Standards and Specifications

National standard: The national standard clearly stipulates the weld height of stainless steel air duct welding. For example, the Code for Acceptance of Construction Quality of Ventilation and Air Conditioning Engineering (GB 50243-2016) stipulates that the weld height of stainless steel air duct should meet the design requirements, and shall not be less than 0.7 times the thickness of parent material.

Industry standard: Different industries may have their own standards and specifications, and there will be specific requirements for the weld height of stainless steel air duct welding. For example, in the food processing industry, there is a higher requirement for the airtightness of air ducts, and there may be stricter regulations on the height of welds.

Design requirements: In practical engineering, the design unit usually puts forward specific design requirements for weld height according to the service requirements and pressure grade of air duct. The construction unit shall conduct welding in strict accordance with the design requirements to ensure that the weld height meets the standards.

In a word, the weld height standard of stainless steel air duct welding should be determined according to the purpose, pressure grade, welding method and technology of air duct and relevant standards and specifications. In the process of construction, the height of weld should be strictly controlled to ensure the tightness and strength of air duct to meet the use requirements of the project.