Pickling passivation of stainless steel seamless pipe can remove all kinds of oil, rust, oxide, welding spots and other dirt, and the appearance becomes average Snow White after disposal, which can greatly improve the corrosion resistance of stainless steel seamless pipe. However, the pickling passivation process of stainless steel seamless pipe is not simple, the following stainless steel seamless pipe small series will introduce the process and steps of pickling passivation of stainless steel seamless pipe.
QQ picture 20180909113146_1.jpg
1. Prepare
2, chemical oil removal:
(1) Chemical degreasing is done by soaking in the tank. The degreasing tank is made of steel plate, and the inner wall is paved with PVC or polyethylene.
(2) Use 12~15% nitric acid (by volume) to stop chemical degreasing disposal, the temperature is 40℃~60℃, and the time is 2~ 4 hours.
(3) When the stainless steel seamless pipe is soaked in the tank, attention should be paid to the position of placement to prevent air in the pipe
(4) During the soaking process, the stainless steel seamless pipe should be moved up and down or turned over, so that the inner cavity solution is changed from time to time to improve the effect. If necessary, remove the stainless steel seamless pipe, rinse with water and then stop soaking.
(5) Chemical oil removal until the stainless steel seamless pipe surface is completely wet by water.
3, hot water rinsing:
(1) The stainless steel seamless pipe after oil removal is removed from the oil removal tank and soaked in a hot sink of about 40 ° C ~60 ° C for rinsing for 5 ~ 20 minutes.
(2) The hot sink is made of steel plate, and the inner wall is paved with PVC or polyethylene.
(3) The chloride ion content in water is less than 25ppm.
4. Rinse with water:
(1), water rinsed stainless steel seamless pipe pressure water (pressure P≥0.1Mpa) stop washing.
(2) The chloride ion content in water is less than 25ppm.
5. Passivation:
(1) The passivation is in the tank tank bubble mode, and the passivation solution formula and soaking time can be selected according to Table 2.3.
(2) Passivation channel steel plate manufacturing, the inner wall of the anti-acid plastic.
(3) When soaking in the tank, attention should be paid to the position of placement to prevent air in the stainless steel welding tube.
(4) During the soaking process, the stainless steel seamless pipe should be moved up and down or turned over, so that the inner cavity solution is changed from time to time to improve the effect. If necessary, remove the stainless steel seamless pipe, rinse with water and gas, and then stop soaking.
6. Boring:
The stainless steel seamless pipe after passivation should be dried with clean compressed air or nitrogen, and there must be enough time (at least 2 hours) for the stainless steel seamless pipe to be naturally passivated in the air.
7, inspection: stainless steel seamless pipe after passivation, should stop self-inspection, mutual inspection, and then submit to the inspector according to the request to stop acceptance.
8. Maintenance:
(1) If the exterior needs to stop painting the stainless steel seamless pipe, stop according to the painting request.
(2) Stainless steel seamless pipe after inspection, stainless steel seamless pipe manufacturers should use plastic plugs to seal, stop bandaging and maintenance with three anti-cloth, and stop marking.
