About the passivation of the stainless steel pipe fittings
In our today’s career stainless steel pipe fittings used to say very much, but you know that just get its hands on stainless steel pipe fittings is put into immediately to use oh, you know to forefathers sex passivation disposal? Any stainless steel parts, if no plating or other coating request, ordinary
At pre treatment (including pickling to black, polishing, etc.) through the passivation disposal, talents when products or disassembled into parts. Thermodynamics can be improved after passivation of stainless steel in medium volatility, prevention of stainless steel parts of the corruption, make stainless steel appearance has enough clean degree
And can also eliminate stainless steel exterior thermal oxide. The passivation technology of stainless steel can be pided into wet and dry process two kinds. Detailed and type can be pided into many varieties.
Here are bolden stainless steel pipe fittings for everybody introduced next wet down the pickling passivation operation method:
Washing is applied chemistry reaction in workpiece melting appearance lost rust, oxidation film, and other products, this method does not affect the matrix metal, the goal is to make the workpiece surface decontamination, to reach the goal of pollution. Passivation is the application of chemical reaction, in workpiece appearance constitute a dense oxide film
Methods. The goal is to make the workpiece appearance set oxide film or oxygen adsorption layer, thereby blocking electrochemistry corrupting stop, and progress of metal corrosion (electrochemical corrupt) function.
A construction procedures
1, preparation task
(1) before the pickling and passivation needed to tube sheet welding coated, splash, burrs, dirt, etc liquidation clean.
(2) pipe appearance of oil can be used to wipe clean gasoline, acetone and other inorganic solvents. On large areas of oil can be used for the sake of peace steam or 3 ~ 5% caustic soda solution (NaOH) washing, then wash clean with clear water and dry them. Pay attention to the use of water and CL – ion concentration limit
25 mg/l.
(3) prepare pickling and passivation homework required equipment, tools, and labor insurance supplies (three people work at the same time, for example).
1) equipment and tools
A. acid pickling and passivation bath A;
B. stainless steel wire brush or hard plastic nylon brush 3;
C. measuring cup, measuring cylinder and Taiwan said, stir bar each one;
D. acid mop to 3.
(2) maintenance supplies to rest
A. acid their rubber shoes 3 double;
B. acid-resistant rubber gloves 3 pay;
C. acid cap, mask 3 sets of tasks and mission;
D. glasses 3 pay.
2, pickling and passivation materials and preparation of pickling and passivation solution attention to matters
(1) the pickling and passivation materials preparation
(1) industrial nitric acid (HNO3, gamma = 1.42).
(2) industrial hydrochloric acid (HCL);
(3) industrial sulfuric acid (- H2SO4);
Ordinary stainless steel pipe fittings depends on both the passivation effects of passivation process, also depends on the stainless steel material itself, the influence of the detailed elements have stainless steel contains elements of metallographic structure, stainless steel, stainless steel processing forms, etc. In elements, chromium, nickel belongs to the passivation strong sex element, iron passivation followed, therefore, the higher the content of chromium, nickel, the stronger the passivation of stainless steel. Austenitic stainless steel, iron element size is average, but is passivation, markov shape through the heat treatment of stainless steel reinforcement, its microstructure is heterogeneous organization, so the passivation is not strong.
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