What are the factors that affect whether Stainless Steel Weld Tee annealing is bright?

1. Influence of protective atmosphere Liquid ammonia decomposition gas is used as protective atmosphere. Liquid ammonia will decompose above 800℃. 2NH3→3H2+N2 Hydrogen is the reducing gas, and liquid ammonia decomposition atmosphere is used as the protective gas, which can make the surface of the welded pipe white, bright and smooth.

2. Sealing of the furnace body To ensure the bright annealing of thin-walled stainless steel pipe fittings, the bright annealing furnace should be closed and isolated from the outside air.

3. Solution treatment temperature Solution treatment temperature is one of the important parameters of the solid-liquid treatment process. Too high or too low will directly affect the quality of the pipeline. Too high temperature will coarsen the welded pipe structure and reduce performance. Too low temperature will not completely dissolve and eliminate stress. 1080℃±10℃ is selected, and proper insulation is performed so that carbides can be fully dissolved.

4. Protective gas pressure In order to prevent micro-leakage, the protective gas in the furnace should maintain a certain positive pressure. If it is hydrogen protective gas, it is generally required to be above 20kBar. 5. Water vapor in the furnace. If the water vapor content in the furnace is too high, it will cause atmosphere destruction and affect the annealing brightness of thin-walled stainless steel pipe fittings. The water vapor comes from the furnace body material on the one hand, and from the residual water stains on the stainless steel pipe fittings entering the furnace on the other hand.