93，precautions for tank pickling and passivation operation - doer equipment
classification：forum publishtime：2019-09-30 14:56:36
precautions for pickling and passivation of storage tank
pickling and passivation operation in storage tank only the pretreated containers or parts can be pickled and passivated.
pickling solution pickling is mainly used for the overall treatment of small unprocessed parts, which can be sprayed and brushed. when the solution temperature is 21-60 ℃, check it every 10 minutes or so until it shows a uniform white acid etching finish.
pickling paste pickling is mainly suitable for large containers or local treatment. evenly clean the outside of the pickling paste on the equipment (about 2-3mm thick) at room temperature. after staying for one hour, gently brush it with clean water or stainless steel wire brush until it presents a uniform white acid etching finish.
passivation solution is mainly applicable to the overall treatment of small containers or components. immersion or spray brushing can be used. when the solution temperature is 48-60 ℃, check it every 20 minutes, and when the solution is 21-47 ℃, check it every hour until a uniform passivation film is formed on the surface.
the passivation paste is mainly suitable for large containers or local treatment. apply the passivation paste evenly on the pickled container surface (about 2-3mm) at room temperature and check it after 1 hour until a uniform passivation film is formed on the surface.
the surface of pickling passivation container or parts must be washed with clean water. finally, test any part of the washing surface with acid litmus test paper to make the ph value between 6.5-7.5, and then wipe dry or blow dry with compressed air.
containers and parts shall be handled after pickling and passivation. it is forbidden to bump and scratch the passivation film during hoisting and storage.
matters needing attention
1 when preparing the solution, put the water into the acid resistant container in proportion, and then add the acid slowly in proportion to prevent splashing injury caused by too fast acid pouring speed.
2. for pickling and passivation treatment, the test shall be conducted on the local surface of small parts or similar materials for the first operation.
3. during pickling, operators must carefully observe the surface and prevent excessive corrosion. effective measures shall be taken for carbon steel parts to prevent corrosion.
4 after pickling, the stainless steel surface shall be free of obvious corrosion traces, uneven color spots, and oxidation color on the weld and hot working surface.
5 during operation, operators must wear acid resistant clothes, gloves, masks and protective eye masks. pickling in the container must be carried out under the supervision of a specially assigned person with a qualified gas mask.
6 austenitic stainless steel parts with anti-corrosion requirements shall be pickled and passivated after heat treatment according to the drawing requirements.
7. the above pickling and passivation formula and operation, concentration, volume ratio, liquid temperature and operation time can be adjusted in a small amount according to the situation. pickling passivation solution can be reused, but proper concentration and volume ratio must be ensured.
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