how to control when the pipe change to black after picking

- Jan 22, 2018-

Stainless steel pipe in the pickling process exists black phenomenon, black attachments for hot-rolled material pressed into the deep oxide. Pickling black is the main reason for pickling solution concentration, temperature, pH value of rinse water and hot air dryer temperature is low and so on. For this purpose, the corresponding control measures to be taken in the pickling section are: glenflange

1, improve pickling solution concentration and temperature
Increasing the temperature or concentration of hydrochloric acid can improve the pickling effect, but in hydrochloric acid solution, the effect of increasing the concentration is better than increasing the temperature. When the acid concentration is increased from 2% to 2.5%, the pickling speed of hydrochloric acid is increased by 10 times. Therefore, hydrochloric acid concentration should be increased acid pickling tank.
By regularly cleaning the graphite heater heated pickling solution to reach the heating requirements of the graphite heater replacement, according to the requirements of the process control the temperature of each acid tank to improve pickling surface quality. glenflange

2, improve the rinse water PH value
Before each production of pickling squeeze rollers and cylinders were inspected on the presence of cracks, degumming, serious wear and tear immediately replace the squeeze roll to restore squeeze roll cylinder function, and according to different positions and different materials of the squeeze roll to develop Change the roll cycle, be replaced before scrapping to improve squeeze squeeze the drying effect, reducing the amount of acid into the rinse tank, increasing the rinse water PH value.

































3, to improve hot air drying temperature and blowing effect
Press through the newspaper heating steam pressure ≥ 0.4MPa, hot air dryer temperature above 120 ℃, and in the hot air drying unit, equipped with a pair of blow blowing compressed air blowing device will be stored in both sides of the raffinate liquid to The outer side of the strip is blown to make the edge of the strip easy to dry, which eliminates the problem of water bordering on the edge of the pickling strip.