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Introduce the advantages and structure mechanism of polyurethane insulation pipe
Release time:2022-06-23   Browse:653 Return

Polyurethane thermal insulation pipe is a direct buried prefabricated thermal insulation pipe with good thermal insulation performance, safety and reliability, and low engineering cost. It effectively solves the problems of heat preservation, sliding lubrication and waterproofing of exposed pipe ends for prefabricated thermal insulation pipe fittings for high temperature heat transfer at 130℃-600℃ in urban central heating. Prefabricated directly buried thermal insulation pipes/prefabricated thermal insulation pipe fittings not only have the technical and practical performance that traditional trenches and overhead laying pipelines are incomparable to, but also have significant social and economic benefits, and are also a powerful measure for heating and energy saving. The prefabricated thermal insulation pipe fittings adopt directly buried heating pipeline technology, which indicates that the development of heating pipeline technology in China has entered a new starting point.

Application of prefabricated direct buried insulation pipe/prefabricated insulation pipe fittings:

Prefabricated thermal insulation pipe fittings are widely used in liquid and gas transportation pipeline network, chemical pipeline thermal insulation engineering, petroleum, chemical industry, central heating network, central air conditioning ventilation pipeline, municipal engineering, etc.

Features of prefabricated direct buried insulation pipe:

The prefabricated thermal insulation pipe fitting is composed of a steel pipe, a glass fiber reinforced plastic inner sheath, and a glass fiber reinforced plastic outer shell, and is characterized in that it also includes a high temperature resistant thermal insulation layer, a lubricating layer, and an elastic seal. The prefabricated thermal insulation pipe fitting of the utility model effectively solves the problems of heat preservation, sliding lubrication and waterproofing of exposed pipe ends for prefabricated directly buried thermal insulation pipes/prefabricated thermal insulation pipe fittings for high temperature heat transfer at 130°C-600°C in urban central heating.

The polyurethane insulation pipe is divided into three layers from the inside to the outside: the working steel pipe layer is generally selected according to the design and customer requirements. (GB3092-93). After the surface of the steel pipe is treated by shot blasting and rust removal, the rust removal grade of the steel pipe can reach Sa2 level in the GB8923-1988 standard, and the surface roughness can reach R=12.5 microns in the GB6060.5-88 standard. The second layer: Polyurethane insulation layer It is formed by injecting rigid polyurethane foam stock solution at one time into the cavity formed between the steel pipe and the outer sheath with a high-pressure foaming machine. The so-called "tube-in-tube foaming process". Its functions are firstly waterproof, secondly heat preservation, and thirdly support the self-weight of the heat network. When the temperature of the conveying medium is: -50℃-120℃, the rigid polyurethane foam is selected as the thermal insulation layer. The third layer: high-density polyethylene protective layer is prefabricated into a black (color) plastic pipe with a certain wall thickness, its function is to protect the polyurethane insulation layer from mechanical hard objects damage, and the second is to prevent corrosion and waterproof.

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What material is the electrode made of, the type and use of the electrode

What material is the electrode made of, the type and use of the electrode

What material is the electrode made of? There are many types of welding rods. The more common ones on the market are silver welding rods, stainless steel welding rods, cast iron welding rods, carbon steel welding rods, aluminum welding rods, low alloy steel welding rods, cobalt-based welding rods, etc. Welding electrodes are divided into wear-resistant electrodes, universal electrodes and other categories. The electrode type has a lot to do with its usage and usefulness, so let's learn about the electrode type and use together!1. What material is the electrode made of?The electrode is to apply the coating (coating) evenly and centripetally on the welding core outside the metal welding core. The welding core is the metal core of the electrode. In order to ensure the quality and performance of the weld, there are strict regulations on the content of each metal element in the welding core, especially the content of harmful impurities (such as sulfur, phosphorus, etc.), which should be strictly controlled. The limit is better than that of the base metal. The electrode is composed of two parts: the welding core and the coating. Different types have different solder cores. Here are some common electrodes:1. Silver electrodeSilver electrode is a kind of electrode with silver or silver-based solid body, which has excellent process performance, low melting point, good wettability and ability to fill gaps, and has high strength, good plasticity, and electrical conductivity. It has excellent corrosion resistance and can be used to braze all black and non-ferrous metals except aluminum, magnesium and other low melting point metals. This product is widely used in refrigeration, lighting, hardware and electrical appliances, instrumentation, chemical industry, aerospace and other industrial manufacturing field.2. Stainless steel electrodeStainless steel electrode refers to a type of electrode coated with stainless steel as raw material. It can be divided into chrome stainless steel electrode and chrome nickel stainless steel electrode, which are widely used in chemical, fertilizer, petroleum, medical machinery manufacturing and other industries. In addition to meeting the general welding process performance and the mechanical properties of the welded joint, the stainless steel electrode must also ensure that the welded joint can meet certain corrosion resistance requirements.3. Cast iron electrodeCast iron electrode is an electrode used for cast iron, which is characterized by high strength and good plasticity. Suitable for gray cast iron and ductile iron, and can be machined. Cast iron is an iron-carbon alloy with a carbon content greater than 2%. There are more than 10 kinds of cast iron electrodes available in China, which can be selected according to different cast iron materials, different machining requirements and the importance of welding repair parts.Due to the high carbon content, uneven structure and low plasticity of cast iron, it is a material with poor weldability. In the welding process, defects such as white mouth, cracks and pores are easily generated. Therefore, cast iron welding repairs also require higher technical proficiency for welders. Cast iron welding repairs can be roughly divided into two types: preheating welding and cold welding.4. Carbon steel electrodeCarbon steel electrodes (the tensile strength of the deposited metal is less than or equal to 500MPa or 50kgf/mm2) are suitable for carbon steel and low-strength low-alloy steel welding.For low-hydrogen type and iron powder type electrodes, the electrode must be baked at 350°C or higher before welding, and it should be done as much as possible. cracks, deterioration of process performance, etc.). For cellulose-type electrodes, the baking temperature should be strictly followed. If the temperature is too high, the cellulose in the coating will be burned off and the inherent process performance of the electrode will be destroyed.2. Types and uses of welding rods1. SH.J422It is used for welding more important low carbon steel structures and low alloy steels with low strength grades such as Q235.Description: J422 is a carbon steel electrode with titanium calcium type coating. It has excellent welding process performance, stable arc, beautiful weld bead, small spatter, both AC and DC, and can be used for all-position welding.Uses: Used for welding important low carbon steel structures and low alloy steels with low strength grades, such as Q235.2. SH.J426For welding important low carbon steel and low alloy structures. Has good mechanical properties and crack resistance. It needs to be baked at 350°C xlh before use.Description: J426 is a carbon steel electrode with low hydrogen potassium type coating. Has good mechanical properties and crack resistance. AC and DC dual-use, can perform all-position welding.Application: Used for welding important low carbon and low alloy steel structures.3. SH.J427For welding important low carbon steel and low alloy structures. It has good plasticity, toughness and crack resistance. It needs to be baked at 350°C xlh before use.Description: J427 is a carbon steel electrode with low hydrogen sodium type coating. With DC reverse connection, all-position welding can be performed, and it has excellent plasticity, toughness and crack resistance.Application: Used for welding important low carbon steel and low alloy steel structures.4. SH.J506For welding of mild and medium carbon steels. Has good mechanical properties and crack resistance. It needs to be baked at 350°C xlh before use.Description: J506 is a carbon steel electrode with low hydrogen potassium type coating. Has good mechanical properties and crack resistance. AC and DC dual-use, can perform all-position welding.Application: Used for welding medium carbon steel and low carbon steel.5. SH.J507Can weld medium carbon steel and some low alloy steels. It adopts DC arc welding current reverse connection, which has good plasticity, toughness and crack resistance. It needs to be baked at 350°C xlh before use.Description: 507 is a carbon steel electrode with low hydrogen sodium type coating. With DC reverse connection, all-position welding can be performed. The weld metal has good plasticity, toughness and crack resistance.Application: It can weld medium carbon steel and some low alloy steel.5. A402 (E310-16)Description: A402 is a pure austenitic stainless steel electrode with titanium calcium type coating. The deposited metal has excellent oxidation resistance under the high temperature condition of 900℃-1000℃. AC and DC dual-use, with good operating performance.Uses: It is used for welding of the same type of heat-resistant stainless steel working under high temperature conditions, and can also be used for welding of chromium steels with high hardening (such as chromium, molybdenum, chromium, molybdenum, chromium 13, chromium 28, etc.) and dissimilar steels.