WELDED ALLOY STEEL CYLINDERS FOR ULTRA-HIGH PURITY MATERIALS

WELDED ALLOY STEEL CYLINDERS FOR ULTRA-HIGH PURITY MATERIALS (GASES)

Polishing, grinding, and high-temperature phosphating of the inner surface of the welded steel cylinders are carried out. The cylinders are filled with high-purity medium, with a purity of 99.9999% (6N) to 99.99999% (7N).

After polishing and grinding, the roughness Ra of the inner wall of the cylinder reaches 0.8 μm, and the minimum average value reaches 0.3 μm. After decontamination, the cylinder is cleaned and dried with high-temperature ultra-pure deionized water, purged with high-purity nitrogen, and finally heated and vacuumed to make the dew point value in the cylinder below -76 °C. All sealing points of the cylinder body are tested by the cumulative hydrogen leak detection method, and the leakage is 0 ppm. The dust and particulate matter in the cylinder are controlled by measuring the change in the resistance of the water flowing through the cylinder. Nitrogen is used for pressure performance testing under working pressure, and nitrogen is used as a protective gas during transportation.