The welding specification of bellows compensator mainly includes the following aspects:
Material selection and pretreatment：
The selection of welding materials shall comply with the design requirements and be verified by relevant tests.
The material should be properly pretreated before welding, such as cleaning, sanding, etc., to ensure the welding quality.
Welding process parameters：
Using DC positive power supply, tungsten electrode diameter, current intensity, hydrogen flow and other parameters are adjusted according to specific working conditions. For example, using a 0.6 mm tungsten electrode, the current is set between 60-80 A, and the hydrogen flow rate is controlled at 5-7 L/min.
Select suitable welding wire, such as HOCR19NI9TI (stainless steel material), and adjust the welding parameters as needed.
Process measures：
After joint positioning welding, the welding wire is covered by a specific method to protect the welding area.
Maintain the weld spot in the optimum position depending on the workpiece rotation, usually a 45-degree climb weld.
The swing mode of welding torch has an influence on the welding effect, and the bellows moves quickly, while other parts stay slightly.
Welding form and inspection：
The connection between the bellows and the end pipe is recommended in a butt form rather than a lap to withstand normal stress.
The welds must be subjected to rigorous non-destructive testing and no defects are allowed.
For large caliber or special requirements compensators, additional inspection steps such as airtightness testing, leak testing, coloring inspection, etc. may also be required.
Protective measures：
During the assembly process, protective measures should be taken for the bellows to avoid the welding arc directly contacting the bellows or the welding slag splashing on it.
The completed pressure-bearing weld shall be able to withstand the pressure test of 1.5 times the design pressure, and the pressure holding time shall be determined according to the volume size of the compensator.
Appearance and geometric inspection：
Before the compensator leaves the factory, cosmetic inspection, geometric measurement and necessary pressure testing are required to ensure that the product meets the specifications.
These are some basic specification points about bellows compensator welding. Specific welding standards may vary from manufacturer to manufacturer, so it is recommended to refer to the technical manual or relevant industry standards for specific products.