One section of outlet expansion joint

Jiangsu Shuguang: 0523-88680588! !

Expansion joint bidding unit contact information Serial number Unit contact phone fax Remarks 1 Qinhuangdao Development Nuoshi Pipe Industry Co., Ltd. Peng Gangfu 0335-8503632 0335-8518907 13313351820 Zhou Cheng 0335-8503632 0335-8518907 13016438159 2 Nanjing Aerospace Chenguang Co., Ltd. Zheng Yun 13888966401 0871-5330493 3 Wuxi Jinlong Corrugated Compensator Factory He Weigong 013861819293 0510-85590814 0510-85590729 4 Nantong AVIC Corrugated Pipe Co., Ltd. Xi’an Branch Zhang Li 029-83107062 029-83107062 013669202568

Wuxi Jinlong's expansion joints are better. Send them the conditions and let them calculate what kind of expansion joint to use. Try not to use multi-layer expansion joints.

It is recommended to use a single-wave expansion joint. The single-wave expansion joint is molded with an 8mm thick steel plate and has a large corrosion margin.

The people at Chenguang are awesome and the prices are also high. I am from Jiangsu Baixin, 13609315108.

Haha, I have used both the Shuguang and Chenguang models, and they are okay. The Chenguang model is the best in China! But I don’t know which place you live in. I can give you the contact information for Sichuan!

Briefly describe the use characteristics of compensators in sulfur acid production projects. In recent years, with the increase in social demand, sulfur acid production projects in my country's chemical industry have continued to emerge, and the projects have become larger and larger. From 150,000 tons/year to 300,000 tons/year to the current 800,000 tons/year. The compensator that matches it should follow several major characteristics of the sulfuric acid project in terms of design, selection, production, and use to produce a special compensator. 1. Characteristics of sulfur acid production project: The entire piping system layout of the sulfur acid production project is very compact, and fixed brackets or hangers are not suitable for many spatial locations. Compensators are often required to bear the weight of the piping system, which places higher requirements on the stiffness of the components of the compensator and the strength of the structural parts. In addition, in order to reduce heat loss, the compensator components are protected from corrosion by sulfur dioxide and sulfur trioxide in the air. Manufacturers basically do external insulation. General insulation materials contain chloride ions, so the corrugated components must be protected again. ； In addition, the temperature of the entire piping system is relatively high, and the medium contains a lot of corrosive gases such as sulfur dioxide and sulfur trioxide. Eliminating stress corrosion puts higher requirements on the material selection of the corrugated component parts. Because the temperature of each section varies greatly. Therefore, when doing external insulation, the thickness of the external insulation layer should also be different. ； It is also known that the actual service life of the compensator is greatly affected by stress corrosion, and corrosion is the main cause of compensator failure. Therefore, during the manufacturing of the compensator, the degree of residual stress elimination directly determines the service life of the compensator. 2. It is recommended to use a compensator protective cover. Recommended reasons for use: We mentioned earlier that chloride ions in the outer insulation layer will cause great damage to the components, so protective measures should be taken. I recommend using an outer protective cover. Its functions are as follows:: It can improve the strength of the compensator, reduce or even prevent the ring weld between the component and the end tube from being torn due to excessive tension during transportation, and can also reduce the deformation of the component due to impact. ； It can prevent damage caused by impact during installation and splashing slag and welding slag on the surface of components during system installation. Of course, it can also effectively prevent chloride ions in the insulation layer from adhering to the surface of components and reduce the resulting stress corrosion. 3. Selection of insulation layer thickness: Based on many years of practical experience of compensator manufacturers in sulfur acid production projects in the chemical industry, the general principles for selecting the thickness of the insulation layer (δ) are summarized.: When the temperature is lower than or equal to 350°C, the thickness is 200 mm. ； When the temperature is lower than 480℃ and higher than 350℃, the thickness should be 250℃ ； When the temperature is higher than or equal to 480°C, the thickness is 280 mm. 4. Based on the characteristics of sulfur projects, summarize the general principles that should be followed in design selection: The compensation amount of the compensator should be set larger and the margin should be larger, especially where there are branch pipes and valves nearby. ； Corrugated components should be single-layered and slightly thicker. ； For high positions, large lateral displacement, and small passage pipe sections, try not to use compound tie rods and use hinge types. Several questions about corrosion 1 What is corrosion? The phenomenon or process of deterioration and damage of objects due to the chemical or electrochemical action of external media is called corrosion. 2. What is intergranular corrosion? What causes intergranular corrosion? Corrosion penetrates deep into the interior along the intergranular surface, and there is no sign of corrosion on the surface. Intergranular corrosion is caused by the precipitation of impurities at the grain boundaries, or the increase or decrease of a certain element. Taking austenitic stainless steel as an example, 2 to 3 mm on both sides of the weld can be heated to 400°C to 910°C during welding. At this time, the complex at the grain boundary combines with carbon to form CR23C6, which precipitates out of the solid. Since the complex flows very slowly, it is difficult to diffuse from within the grain to the grain boundary, thus forming a depleted complex zone. In a suitable corrosion solution, a "carbonized complex "cathode"" "depleted complex zone "anode" battery is formed, causing corrosion in the depleted complex zone at the grain boundary. 3. What are the methods to prevent intergranular corrosion of austenitic stainless steel? 1) Heat treatment method (also called solid solution treatment), the material is heated to 1100°C and then hydrated, because the carbonized complex is dissolved at 1100°C, and uniform alloy steel can be obtained. 2) Add elements with stronger affinity to carbon than to complex, such as titanium and nickel. 3) Reduce the carbon content to less than 0.03% so that the amount of carbonized complex produced is small and intergranular corrosion will not be caused. What is stress corrosion? Under what circumstances does stress corrosion occur? How to prevent stress corrosion? The corrosion of metals and alloys caused by the simultaneous action of corrosion and stress is called stress corrosion. Stress corrosion only occurs in some specific "material-environment" systems. For example, in systems such as "austenitic stainless steel-green chloride ions", "carbon steel-nitrogen trioxide" and other systems. Of course, there must also be stress (residual stress caused by external force or welding, cold working, etc.). There are generally two types of stress corrosion cracks. One develops along grain boundaries, which is called intergranular cracks. ； The other type passes through the grain and is called transgranular rupture. There are also mixed types such as the main seam being intergranular and the branch seams being transgranular. The main methods of prevention include: Stress is generally eliminated or reduced through heat treatment ； Take the value below the critical stress corrosion cracking strength in the design ； Improve design structure to avoid stress concentration ； Compressive stress applied to the surface ； Use electrochemical protection, coatings or corrosion inhibitors, etc. What is stress corrosion cracking? Which "environment-material" systems cause stress corrosion cracking? Under certain temperature conditions, the cracking of metal caused by the combined action of stress and corrosion is called stress corrosion cracking. Because the rupture is brittle and has no obvious warning, it can easily cause catastrophic accidents. The "material-environment" that can be caused include: 1) The material is carbon steel or low alloy steel, and the environment is alkali liquid. For example, nitrate solution, anhydrous liquid ammonia, hydrogen sulfide, acetic acid, etc. 2) The material is austenitic stainless steel, and the environment is chloride ions, chloride, water vapor, wet hydrogen sulfide, alkali liquid, etc. 3) The environment of austenitic stainless steel containing molybdenum is alkali solution, chloride aqueous solution, sulfuric acid plus copper sulfate aqueous solution, etc. ； 4) The material is brass, and the environment is ammonia gas and solution, ferric chloride, wet sulfur dioxide, etc. 5) The material is titanium, and the environment is methanol, ethanol, molten sodium chloride, etc. containing hydrochloric acid. 6) The material is aluminum, and the environment is hydrogen sulfide, seawater, etc. Introduction to several commonly used materials for compensators: commonly used austenitic 300 series: SUS316L consists of 00Cr17Ni14Mo2, has a temperature resistance of 550°C and good acid and alkali resistance. Contains a large amount of MO2, which is beneficial to welding and improves welding quality. Strong resistance to stress corrosion ； SUS316, whose main component is 0Cr17NI12MO2, has a temperature resistance of about 500°C, good acid and alkali resistance, and good welding performance. SUS304L is composed of 00Cr19Ni9 and has a temperature resistance of 500°C. 304 is mainly composed of 0Cr18Ni9 and has a temperature resistance of 450°C. SUS310L is mainly composed of 0Cr25Ni20 and has a temperature resistance of about 900°C.

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