How to carry out protection and surface treatment in the manufacture of stainless steel pressure vessels

How to carry out protection and surface treatment in the manufacture of stainless steel pressure vessels

This paper discusses the problems existing in the manufacture of stainless steel pressure vessels and how to do a good job in protection and surface treatment. It has been proved that by adopting relevant specific technical measures and scientifically applying the surface treatment technology of pressure vessels, the appearance quality of vessels can be guaranteed and various corrosion resistance of the surface can be enhanced.

Stainless steel pressure vessel in the manufacture, the first should ensure that its wear resistance and corrosion resistance are relatively good, the surface of the stainless steel pressure vessel has a metallurgical organization, so in general, it can ensure that no strong chemical reaction with the medium is corroded, but not in any case can not be corroded. In a variety of causes and corrosive media coexist, stainless steel pressure vessels to avoid a variety of chemical reactions, to prevent the surface is prone to corrosion, resulting in pitting and other undesirable phenomena, of which the electrochemical reaction is the main cause of corrosion of stainless steel parts.

Stainless steel pressure vessel in the manufacture of surface analysis of the current situation

(A) In the stainless steel surface is easy to produce bad phenomena such as welding seams
Usually after this phenomenon, with manual direct processing, or mechanical grinding and other methods, these methods will cause surface unevenness, the surface of stainless steel is prone to inconsistencies. In the process of pickling passivation, the pickling paste will be unevenly applied, which makes the surface color is not uniform, and scratches easily appear on the surface of stainless steel, and it is difficult to remove. In the overall pickling passivation method, simply can not remove the various scratches produced in the processing engineering, because the scratch and other processes adhered to the surface of the stainless steel carbon steel and other impurities, but also difficult to remove, so that in the case of corrosive media, a series of electrochemical corrosion or chemical corrosion and other adverse reactions, eventually leading to rust.
(B) In the grinding and polishing passivation process of uneven problems
Generally in the manual grinding and polishing after a certain pickling passivation treatment, many workpieces are large areas, in the process of processing, it is difficult to complete uniform and consistent effect, therefore, can not make the surface is uniform enough and ideal, and in the stainless steel surface treatment in the limited pickling capacity and other undesirable problems. For pickling passivation paste, it is not a panacea, it is also difficult to remove the black oxide skin produced in the process of flame cutting and other phenomena.
(C) In the stainless steel surface treatment will produce some scratching phenomenon
In the process of lifting and transportation, welding arc, bumping and hammering and other human factors, will produce serious scratches, and therefore more difficult to do a good job of surface treatment, these phenomena are also key issues that make the surface rust and corrosion, and in the non-special equipment factors, in the process of cutting, coiling or bevel processing, the non-stainless steel processing equipment used, will cause scratches and oil stains, these are also rust and corrosion Important factors.

Stainless steel pressure vessels in the manufacturing process of protection measures taken

According to the stainless steel pressure vessel in the manufacturing process of various problems, take different measures.
(A) In the stainless steel container storage link to do protective measures
From the admission of stainless steel to the final packaging process, should be strictly black and white separation, to ensure that there can be no direct contact between stainless steel and ferrous metals. In the entire manufacturing process of stainless steel, the welding process will be disturbed by various factors, like oil and other forms of moisture, is the main reason, and seriously affect the mechanical properties of the weld and corrosion resistance. Therefore, in the stainless steel materials and components stored, should be placed in a convenient storage location for lifting, and isolated from other areas, should also take protective measures to avoid pollution caused by oil, rust and dust on the stainless steel, should be set up according to the actual situation in the field, such as steel plates and other different parts of the special bracket, not allowed to mix with any other ferrous materials.
(B) Lifting good protection in all aspects
When lifting stainless steel, first of all, you should use special lifting tools, can not use wire rope and other tools, making the surface of stainless steel scratches and other phenomena, and in lifting and placing stainless steel, to be rigorous bumping and other to prevent the surface is scratched. In the lifting stainless steel plate, all can not use any fixture with iron, hanging fixture and hook sling, etc. should be required, but also do a good job in the transport process of protection, in the transport of stainless steel parts, there should be a special platform or transport bracket, there should be a perfect isolation protection measures to avoid unnecessary oil and other pollutants contaminated stainless steel surface. In the processing area to do all the protection, special processing and manufacturing of stainless steel containers in the region, the region should be used to support the enclosed wall with relevant partitions plus angles, in each region should be laid rubber mat board or wooden square, stainless steel containers processing area must strengthen the placement management, to achieve civilized production, black and white separation of all types of tools at the work site, and construction personnel should take the dust-proof channel, production personnel in the walk before the stainless steel Should wear good protective shoe cover.
(C) Do a good job in the process of material protection
In the undercutting, should use shear, plasma cutting and other methods, should also be in the planer claw covered with soft cloth or matting, lathe and milling machine and other parts should take isolation measures, to do a good job in the forming process, the surface of the working stick of the rolling machine, must prevent pollution, do the relevant processing work, and join the stainless steel sleeve on the working stick, using seal welding or plug welding and roll connection, and In the work of the roll with a special protective film. Before welding must be carefully clear rust and dust and other debris, multi-layer welding, should also pay attention to control the temperature between the layers can not exceed 100 degrees, clear inter-layer slag, manual arc welding, should use fast welding or small current, to avoid oscillation, etc.; should be carefully resharpened weld joints, to ensure that the surface shall not have pores or unwelded defects. In the whole orthopedic process in all aspects of protection and processing, flame processing methods are simply not suitable for use in this process, not to mention repeated heating, orthopedic, mechanical devices should be used, can not use iron and other tools for direct knocking, etc., to prevent unnecessary damage to stainless steel parts.

Stainless steel pressure vessels in the process of post-welding surface treatment in the application of measures

(A) The method used in the cleaning process
After the damage should be polished, especially in contact with carbon steel parts caused by splash scratches, damage caused by cutting slag, or weld discoloration, etc., must be carefully cleaned and polished, and in polishing, must use the appropriate polishing tools, the requirements of the treatment must be comprehensive and uniform, etc., to avoid re-scratching or over-polishing and other phenomena. In the dust-proofing process should be in the stainless steel parts before pickling passivation, remove oil and other debris, paint and other impurities can be wiped off with acetone, or directly with a cloth for cleaning.
(B) On the rust spot treatment process used in the method
Iron tools and other accidental contact with the surface of stainless steel must be done in a timely manner, otherwise there will be a variety of rust spots on the surface of the steel plate, you can use the kind of non-ferrous fibre layer piece will be polished off, clean the surface. In the process of pickling passivation, the oxidation discoloration and weld discoloration of the hot processing head can be chemically cleaned by pickling method.
(C) The method used in the cleaning process
After pickling passivation, should be strictly rinsing and drying, etc., the residual acid completely removed, the method used in the protection process, should be done after processing the surface of the stainless steel parts, must do a good job of protection, to avoid dust, oil and other undesirable substances on the surface of the secondary pollution.

Concluding remarks

In this paper, the protection of stainless steel pressure vessel manufacturing and surface treatment content of the elaboration, can better solve all the quality problems in the manufacturing process of stainless steel pressure vessels, but also to ensure that after the completion of the container, stainless steel materials can maintain a good corrosion resistance. All kinds of adverse conditions also seriously affect the quality of product appearance, in the manufacturing process of pressure vessels, must take the necessary surface treatment technology and protection technology to better protect the quality of the product.

Author: Huang junchu

Source: China Pressure Vessels Manufacturer – www.secmachinery.com

www.secmachinery.com is one of the leading china filtration equipment & sanitary stainless steel pressure vessels manufacturer, with professional factory. We focus on the sanitary pressure vessels, filtration equipment research and development, manufacturing, sales and service since the company been established. Our products is widely used on bio-pharmaceutical, food and beverage, fine chemical industry. 

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