The inspection of stainless steel tank can be divided into external inspection, internal regular inspection and all-round inspection. The inspection of the cycle time shall be determined according to the technical application standard of the storage tank.
Generally, the external inspection shall be conducted at least once a year, the internal inspection shall be conducted at least once every three years, and the comprehensive inspection shall be conducted at least once every six years. If the application period of the tank is about 15 years, the external environment inspection shall be carried out once every 2 years, and at least once a year if the application period is 20 years.
1、 Internal inspection
1. Whether the inner surface layer and manhole transfer storage tank are damaged by corrosive agent, and whether there are cracks in the joint area of welding, stainless steel head or other stress areas;
2. When the inner and outer surface of the tank is corroded, several accurate wall thickness measurements should be carried out to solve the problems. If the accurately measured thickness is lower than the small wall thickness of the design scheme, the compressive strength verification shall be carried out again, and the proposal of whether to reapply and allow high pressure shall be put forward clearly;
3. When there are decarbonization, stress corrosion, stress corrosion and fatigue crack in the inner cavity of the storage tank, metallographic inspection and surface strength measurement shall be carried out, and the test report shall be clearly put forward.
2、 External inspection
1. Check whether the anticorrosive coating, thermal insulation layer and equipment identification plate of stainless steel storage tank are damaged, and whether the safety notes and operation equipment are complete;
2. Whether the surface layer has cracks, deformation, partial overtemperature and other conditions;
3. Whether there is leakage in the transferred welding and stressed components, whether there is damage in tightening the anchor bolts, whether there is basically down shift, skew and other abnormal phenomena.
3、 All round inspection
1. The key welding or shell shall be inspected without damage, and the sampling length shall be 20% of the total welding length;
2. After the external environment inspection meets the standard, carry out the pressure test according to 1.25 times of the working pressure of the stainless steel tank design scheme and the air tightness test according to the working pressure of the tank design scheme. In the whole process of the inspection, there is no leakage in the storage tank and all welding, and the abnormal deformation of the storage tank without visible appearance is up to the standard;
After tank inspection, it is necessary to report the inspection, and point out the problems and reasons that can be re applied or can be re applied but need to be trimmed and can not be applied. The inspection sheet needs to be stored and kept for convenient maintenance and inspection.