Bake the flux according to the specifications of the flux specification before use. This drying specification is accurate and quality-assured data is obtained based on testing and process inspection controls. This is an enterprise standard, and different companies require different specifications. According to the welding procedure of JB4709-2000 steel pressure vessel, the recommended flux drying temperature and holding time. Generally, when the flux is dry, the stack height does not exceed 5 cm. Consumables libraries are often less than one generation at a dry volume, and the stack thickness is thick and thin. Should be strictly managed to ensure the quality of the flux. Avoid thick build-up and ensure that the flux is dry by extending the drying time.

 

2 Flux site management and recycling control

 

Welding parts should be clean, and impurities must not be mixed into the flux. The flux used for the flux pad should be distributed according to regulations. It is best to use around 50 ° C. Flux should be recycled in time to avoid contamination. Sieve the flux with an 8-mesh and 40-mesh sieve to remove impurities and fines, and mix with three times the new flux. Before use, it must be dried and kept at 250-350 ° C for 2 hours. After drying, it should be stored in an incubator at 100-150 ° C for next use. Do not store in the open air. Complex or relatively high ambient humidity on site, timely management of the job site, keeping clean, conducting necessary flux resistance and mechanical mixing tests, controlling moisture absorption and mechanical inclusions to avoid mess and flux mixing.

 

3 Flux particle size and distribution requirements

 

The flux has certain particle size requirements, the particle size should be appropriate, the flux has a certain gas permeability, the welding process cannot penetrate continuous arcs, and can prevent air from forming holes in the molten pool. Fluxes are generally divided into two types, one type has a normal particle size of 2.5-0.45 mm (8-40 mesh), and the other type has a fine particle size of 1.43-0.28 mm (10-60 mesh). The fine powder smaller than the specified particle diameter is usually not larger than 5%, and the coarse powder larger than the specified particle diameter is usually larger than 2%. The particle size distribution of the flux must be tested and controlled to determine the welding current used. Attachment: the relationship between the particle size of the flux and the range of the welding current

 

Grain size / mm 2.5-0.45 0.28-1.43 Welding current / A <800 600-1200

 

4 Flux size and stack height control

 

If the flux layer is too thin or too thick, pits, spots and pores will form on the surface of the weld, forming an uneven weld shape. The thickness of the flux layer should be strictly controlled at 25-40 mm. Small, the height of the flux stack is 20% to 50% higher than the height of the molten flux stack. The larger the diameter of the welding wire, the larger the welding current and the larger the thickness of the flux layer. Due to the irregular operation of the welding process, the distribution of fine powder flux is unreasonable, and intermittent uneven pits may appear on the surface of the weld, so nondestructive testing can be performed. The appearance quality is affected, which partially weakens the thickness of the casing.

Aluminum Welding Wire