Performance index analysis of square pipe ground

　　1. Welded steel pipes for low pressure fluid transportation (GB/T3092-1993) are also called general welded pipes (square pipe type), commonly known as black pipes. It is used for conveying water, gas, air, oil and heating steam and other general low pressure fluid and other uses of welded steel pipe. The wall thickness of steel pipe is divided into ordinary steel pipe and thickened steel pipe, and the pipe end is divided into non-threaded steel pipe (bare pipe) and threaded steel pipe. The size of the steel pipe is specified by the nominal diameter (mm), and the nominal diameter is the approximate value of the inner diameter. Commonly used in inches, such as 11/2 and so on. Welded steel pipes for low pressure fluid conveying are not only directly used for fluid conveying, but also widely used for galvanized welded steel pipes for low pressure fluid conveying.

　　2. the straight seam welded steel pipe (YB242-63) is a steel pipe longitudinally parallel to the pipe. They are usually divided into metric welded pipe, welded thin-walled tube, transformer cooling oil pipe and so on.

　　The square tube is divided into seamless and welded joints, and seamless square tubes are formed by extruding seamless circular tubes.

　　Performance index analysis and plasticity of 1. square tubes

　　Plasticity refers to the ability of metal materials to produce plastic deformation (permanent deformation) without damage under load.

　　Performance index analysis of 2. square tubes - hardness

　　Hardness is a pointer to measure the hardness and hardness of metallic materials. Pressing hardness method is the most commonly used method to determine the hardness in production. It uses a certain geometry of the head under a certain load into the surface of the metal material to be tested, according to the degree of being pressed to determine its hardness value.

　　The usual methods are Brinell hardness (HB), Rockwell hardness (HRA, HRB, HRC) and Vivtorinox hardness (HV).

　　Performance index analysis of 3. square tubes fatigue

　　The strength, plasticity and hardness discussed above are the mechanical properties of metal under static loading. In fact, many machine parts work under cyclic loads, under which fatigue occurs.

　　Performance index analysis of 4. square tubes - impact toughness

　　The loads acting on the parts at very high speeds are called impact loads, and the ability of metals to resist damage under impact loads is called impact toughness.

　　Performance index analysis of 5. square tubes - strength

　　Strength refers to the performance of metal materials under static loading to resist breakage (excessive plastic deformation or fracture). Because the load action way has the tensile, compressive, bending, shear and so on form, therefore the strength also divides into the tensile strength, the compressive strength, the bending strength, the shear strength and so on. Tensile strength is often used as the basic strength indicator.