Concrete Pump Elbow Its curvature radius
(1) butt welding elbow according to its radius of curvature, can be divided into long radius butt welding elbow and short radius butt welding elbow. The radius of curvature of the long radius butt is equal to 1.5 times the outer diameter of the pipe, ie R = 1.5D. The radius of curvature of the short radius butt is equal to the outer diameter of the tube, ie R = 1D. Where D is the diameter of the butt weld and R is the radius of curvature. If there is no special instructions, the general choice is 1.5D elbow.
(2) According to the pressure level, there are about 17 species, and the American pipe standard is the same, there are: Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS; Sch80 , Sch100, Sch120, Sch140, Sch160, XXS, the most commonly used are STD and XS two.
(3) According to the angle of the elbow, there are 45 degrees butt welding elbow, 90 degrees butt welding elbow and 180 degree butt welding elbow and other different angle elbow.
(4) Materials are: carbon steel, alloy steel and stainless steel. The specific production method is: hot pressing elbow is the tube after heating with professional equipment processing and molding, and then cut to the critical temperature above the insulation, insulation for some time soon after the quenching agent, so that the temperature suddenly reduced to greater than the critical cooling Speed rapid cooling method made of elbow. Quenching is to heat the elbow above the critical temperature for a period of time, and then quickly into the quenching agent, so that the temperature suddenly reduced to more than the critical cooling rate of rapid cooling, and to obtain the main martensite Balance the heat treatment of the organization. Quenching can increase the strength and hardness of steel, but to reduce its plasticity. Quenching commonly used in the quenching agents are: water, oil, alkaline water and salt solution. The use of galvanized elbow now gas, heating with the kind of iron pipe connection is galvanized elbow, galvanized elbow as a pipe connection, use a few years later, the tube produces a lot of rust, the outflow of yellow water not only pollution sanitary ware , And mixed with non-smooth inner wall of bacteria, rust caused by heavy metal content in water is too high, seriously endangering the health of the human body. The sixties and seventies, the international developed countries began to develop new pipe, and one after another ban galvanized pipe and galvanized elbow. China Construction Department and other four ministries also issued a document from 2000 to ban galvanized elbow, the new district of cold water pipes have been rarely used galvanized elbow connecting pipe, and some of the district's hot water pipe is used galvanized bending Head connection. Because of the relationship between the material, stainless steel shaped tube is generally more than 304 material for more than 200,201 material hardness, forming more difficult.
Stainless steel profiled tubes are widely used in various structural parts, tools and mechanical parts. Compared with the tube, stainless steel shaped tube generally have a larger moment of inertia and cross-section modulus, a greater bending and torsional ability, can greatly reduce the weight of the structure, saving steel.