What Points Need to be Noted in the Use of the Vessel Dished Heads?

What points need to be noted in the use of the vessel dished heads? We Jetvision share something with you.

1. Please measure the outer circumference of the vessel dished head. If barrel processing is carried out beforehand, please ask the company for the size of the intended outer circumference.

2. Please divide the outer circumference of the vessel dished heads into 4 equal parts and mark the barrel and the vessel dished head.

3. Positioning welding is carried out and the positioning points for positioning welding are to be chosen by the customer according to the diameter and plate thickness.

4. After the positioning welding is completed, carry out welding. Pay attention to the protection of the surface of stainless steel vessel dished head. After group welding of vessel dished head and cylinder, clean up the welding slag, spatter and pollutants in and around the weld seam, heat affected zone in time and carry out PT inspection and surface pickling.

5. Prevent bumping and scratching on the surface of stainless steel vessel dished head.

6. Prevent direct contact with carbon steel and avoid iron ion pollution.

7. Do not store in the open air and prevent rain.

8. Avoid forced group welding. Structure design to prevent excessive constraint stress.

9. The chloride ion content of the water used in the hydraulic test must not be greater than 25mg/L, and blow dry in time after the test.

10. Stainless steel pickling can not use reducing acids such as hydrochloric acid.

11. Strictly comply with the medium compatibility specified in the "tolerance regulations". Note: For sub-stable austenitic stainless steel vessel vessel heads such as 0Cr18Ni9 and 304, it is easy to cause surface pitting corrosion due to improper surface protection. When superimposed with processing stress and welding stress, it leads to stress corrosion and intergranular corrosion. For this reason, customers are requested to pay special attention to the surface protection of such stainless steel.

Points to note on the occasions of vessel dished heads use.

1. Carbon steel vessel dished heads will crack under nitrate, ammonia, alkaline sodium, etc. Please specify the elimination of residual stress when ordering vessel dished heads.

2. Austenitic stainless steel will be subject to stress corrosion cracking in specific environments with chloride ions.

3. For carbon steel vessels to be hot-dip galvanised or aluminised, please apply heat treatment first to remove residual stresses.