Alloy elbow

Alloy elbow bend pipe is the function of the connection, is connected to two of the same nominal diameter tube, and make the line do turn 90 ° or other angles.

Alloy elbow to connect two of the same nominal diameter tube, and make the line do turn 90 ° or other angles. It has a variety of materials and has a wide range of USES. The ordinary bronze bend of bronze is more common in the general tap water pipe, but with the improvement of living standard, many tap water pipes are converted to stainless steel elbow. Manganese steel alloy material elbow as manganese steel can withstand shock, extrusion, material wear of excellent properties, such as is commonly used in the conveying pipe, mud pipeline etc wear consumption more serious in the pipeline. However, the bending of high manganese steel alloy is used in the pipeline with stronger fluid flow and stronger impact. Nickel alloy steel quality bend are usually used in high concentration of oxidizing acid (nitric acid, sulfuric acid) at room temperature in the pipeline, but in reducing acid (hydrochloric acid, thin sulfuric acid, etc.) of severe corrosion in the pipeline will be, unless the hydrochloric acid concentration is very low; Martensitic alloy bend under 650 ℃ high temperature strength, oxidation resistance and water vapor corrosion resistant ability, but poor weldability.

Production method of alloy elbow:

Push hot forming

Hot push bend forming technology is to use special elbow push system core machine, mold and heating device, to set on the mould of billet in pushing forward movement, under the impetus of the machine in motion is heated and hole enlargement and forming process. Hot push bend deformation characteristics are based on volume before and after plastic deformation rule of metal materials determine the pipe diameter, pipe diameter bend diameter, through the core module and control the deformation of the process, make the inner arc compressed metal flow, the compensation to other parts of the thinned by hole diameter, wall thickness uniform Angle is obtained.

Hot push bend forming technology has a good appearance, uniform wall thickness and continuous operation, suitable for the characteristics of mass production, thus become the main forming methods of carbon steel, alloy steel elbow, and also the application in some of the specifications of the stainless steel elbow forming.

Forming process of the heating mode with intermediate frequency or high frequency induction heating (heating can be multiple times or lap), flame heating and reverberatory furnace heating, adopt what kind of heating mode according to the condition of forming product requirements and energy.

stamping

Stamping elbow is first applied to the forming process of the mass production of seamless elbow, the commonly used in the production of the specifications of the elbow has been replaced by a hot method or other forming process, but in some of the specifications of the elbow because of less production quantity and wall thickness too thick or too thin.

The product is still in use when it has special requirements. The punching forming of the elbow adopts the pipe blank equal to the outer diameter of the elbow, and the pressure machine is used to directly suppress the forming in the mould.

Before stamping, the tube billet is placed on the top of the mould, and the inner core and the end mould are put into the tube billet. The upper mold downward movement starts to suppress, and the bending is formed through the constraint of the external mould and the support of the inner mould.

Compared with the heat push process, the appearance quality of the stamping forming is inferior to the former. In the shape of the punching elbow, the outer arc is stretched and there is no extra metal to compensate for it, so the wall thickness of the outer arc is about 10% less. However, due to the characteristics of single-piece production and low cost, the process of punching elbow is used in the manufacture of small batch and thick wall elbow.

The stamping elbow is divided into cold stamping and hot stamping, which usually chooses cold stamping or hot stamping according to material properties and equipment ability.

Cold extrusion of bend forming process is the use of dedicated elbow forming machine, pipe to be included in the external formwork, upper and lower mould clamping, under the impetus of the push rod, tube billet model along the internal model and reserved clearance sports and forming process.

Using die cold extrusion process inside and outside the elbow and good appearance, uniform wall thickness, size deviation is small, so for the stainless steel elbow especially thin wall stainless steel elbow forming more made by this technology. The internal and external mode precision of this process is high; The wall thickness deviation of the tube is also more demanding.

Make alloy elbow need some special raw material for production of materials, the material selection and control, must carry on the strict raw material to choose appropriate, otherwise the production of stamping welding elbow there will be no quality assurance. Stamping welding elbow materials used in a broad categories with special electrical, acoustic, thermal, mechanical, chemical and biological function of new materials, high-tech areas like biotechnology, energy technology and an important foundation for national defense construction materials, but also to reform some traditional industries, such as agriculture, chemical industry, building materials play an important role. The selection of the material must be paid attention to when choosing the alloy elbow. After all, the alloy elbow has yp09066 to a certain extent. JPG determines the quality of the entire pipeline. The overall strength of pipe and elbow is also considered. In electric power, mining, metallurgical and other industries, material conveying, output, are using at close range, high pressure conveying, pipeline under considerable pressure, and sustained serious wear and tear, single material pipeline is very difficult to meet the requirements of this condition, especially the elbow, by considering its use of security, and service life, focus on improving pipe lined with toughness, impact resistance, and abrasion resistance. Due to the user's popularity, the wall wear-resisting elbow is more widely used, and the cost is more and more affordable.

As the bending time increases, the inner surface of the curve will slowly corrode, but because of the unintuitive observation, it is impossible to get the curved head to corrode the correct data and the corrosion site. In the case of corrosion, it is usually found that the wall of the elbow is thinning, and the local depressions and pitting. There are two kinds of widely used detection in China: leakage flux and ultrasonic testing.

In this paper, ultrasonic detection method is used to detect the thickness of tube wall after corrosion. Detection will launch ultrasonic pulse probe perpendicular to the elbow wall, probe first received by the inner surface of tube wall reflection pulse, then probe will receive from the reflection of the surface outside wall pulse, the pulse and the distance between the internal surface reflection pulse spacing reflects the thickness of tube wall. Second magnetic flux leakage method to detect the basic tableland principle is based on the high permeability of the properties of ferromagnetic materials, elbow corrosion defect of permeability is far less than the permeability of elbow, elbow in the applied magnetic field under the action of magnetized, when no defects in elbow, most of the lines of magnetic force by steel tube, the lines of magnetic force uniform distribution; When there is a defect inside the elbow, the magnetic force line bends and a part of the magnetic force line leaks out the surface of the steel pipe. Detect the leakage flux of the magnetized bend surface and determine whether the defect exists.