Application of new repair technology of the hottes

2022-10-22
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Application of new repair technology of steel barrel (Part 1)

in the production process of steel barrel, it is inevitable that there will be leakage of welds and upper and lower "big circles" (i.e. the joint of barrel bottom, barrel top and barrel body mechanical crimping). However, with the further development of the market economy, the ISO9000:2000 standard will focus on customers and mention it to the first place of the eight management principles of the standard. Meeting the requirements of customers has become the goal of steel barrel enterprises, otherwise the production and operation of enterprises will be in crisis

recently, I visited several barrel factories, and everyone complained about the increasingly high quality requirements of customers, saying that customers' requirements are too high. Steel barrels can all have no welding scars, and national standards allow the existence of welding scars. Why can't current users, etc. In fact, I encounter these problems every day in my work. At present, many customers require the steel barrel to have a dazzling appearance, and there are no welding scars, paint sagging, paint peeling and pits on the surface of the steel barrel. Even the weld repaired by argon arc welding machine (the weld scar is very small and can hardly be seen after grinding) is not needed, but at present, it is difficult to achieve "zero defects" in the products of barrel making enterprises, which are constantly optimizing the variety structure, mainly due to the limitation of the management level of enterprises in the industry. At present, the steel barrel industry cannot meet the requirements of zero defect production conditions in terms of personnel quality, equipment status and enterprise management level. Therefore, we are looking for a method that does not affect the appearance quality of the steel barrel and can prevent its leakage - bonding, which has been used by several steel barrel enterprises at present

most of the leakage of the steel barrel is at the bite of the barrel bottom, barrel top and barrel body mechanical crimping; The second is at the seam weld of the barrel body. A small part of the leakage is caused by the defects of the raw materials of the steel plate, such as sand holes, interlayer, etc. Bonding is divided into structural bonding and non structural bonding. The important characteristic of structural bonding is that the bonding place should bear mechanical load for a long time; Non structural bonding refers to sealing, packaging, positioning, repairing and other non mechanical bonding. Therefore, the bonding of steel drums belongs to metal non structural bonding. Next, let's discuss the bonding process and methods of steel barrels:

first, the selection of adhesive for steel barrel repair

to choose a reasonable and appropriate adhesive, we should first understand the properties and characteristics of the adhesive. Generally, the adhesives we use to bond steel barrels are synthetic adhesives. Synthetic adhesives can be divided into chemical reaction type and physical solidification type, or they can be divided into thermosetting and thermoplastic according to their state at different temperatures. Once the former is cured, it will not dissolve or melt, forming a cross-linked structure; The latter will soften with the increase of temperature. When the temperature is higher than a certain material characteristic temperature (such as crystallization temperature or glass transition temperature), they can flow viscous, and once the temperature is reduced, they will solidify again. Thermosetting adhesives are generally chemical reactive, while thermoplastic or thermosetting adhesives are generally chemical reactive, while thermoplastic or hot-melt adhesives are generally physically solidified

thermosetting adhesive has higher strength and stiffness, and less creep tendency; The thermoplastic adhesive has higher plasticity and toughness, and better fatigue performance

according to the characteristics of the adhesive and the service environment of the steel barrel, we usually use epoxy resin adhesive, abbreviated as epoxy adhesive, as the repair adhesive of the steel barrel

epoxy adhesive has high bonding strength, good processing performance, convenient preparation and use, small volume shrinkage after curing, stable product size, wide temperature range, and non-toxic to human body. Epoxy adhesives of various brands and properties can not only be bought from the market, but also be prepared by ourselves or modified according to needs. Therefore, epoxy adhesives are called "all-purpose adhesives"

II. Surface treatment before steel barrel repair

before steel barrel bonding, the most important difference from welding is that the surface of the bonded steel barrel is required to have a certain roughness and cleanliness, and at the same time, the surface of the bonded steel barrel is also required to have a certain chemical or physical reactivity, so as to ensure the bonding quality of the steel barrel. Therefore, before bonding, it is necessary to carry out the cleaning treatment and surface activation treatment of the steel barrel surface, which are collectively referred to as the pretreatment of the steel barrel surface

the common process methods of steel barrel surface treatment are as follows:

when carrying out the steel barrel surface treatment process, the following points should be considered:

1. The pollution of the steel barrel surface, including the thickness of the pollution layer, the tightness of the pollution layer, and the surface pollution. The basic feature of the universal experimental machine is that it can realize the types and properties of large tonnage objects at low cost. If the surface of the steel barrel is paint, electroplated coating or ore, why buy aluminum alloy cables? It's better to buy aluminum cable, vegetable oil, etc

2. Bonding is the most important. On the whole, the service performance requirements of the structure, such as no leakage in a short time, that is, emergency treatment or long-term no leakage, are required to reach the level of new steel barrels after all leaking steel barrels are treated by this method

3. Economy and necessity of materials used. That is to say, we should find out the best economic compromise between the types of the surface of the bonded steel barrel (paint barrel, electroplating barrel, galvanized barrel or cold plate white leather barrel), the types of adhesives, the performance requirements and the surface treatment process

generally, the following methods are commonly used in the surface treatment of steel barrels:

degreasing solution: trichloroethylene or gasoline

treatment solution: orthophosphoric acid (85%): ethanol =1:2 (weight ratio)

treatment method: 1. Solvent degreasing

2, medium coarse emery cloth roughening

3. Soak in the treatment solution at 60 ℃ for 10 minutes, then brush the surface pollution with nylon in running water, rinse with distilled water, and dry in air at 120 ℃ for 1 hour

this method is the most effective for the surface treatment of steel drums without spraying

(to be continued)

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