Steel pipe straightness

Straightness measurement is an important indicator for testing the quality of steel pipes. The straightness required for steel pipes used in different industries is also different. Some are strict and loose, although for the current production technology, the steel pipe can be well controlled. Straightness, but in the practical process, the straightness of the steel pipe is actually measured, so that the optimal construction scheme can be implemented according to the degree of bending.

For the straightness of steel pipe, the standard is not high in the pipeline for general fluid transportation. This pipe mainly requires the concentricity of the nozzle to facilitate the welding of the pipe. However, if the steel pipe is used on processing machinery, especially rubber rollers, central shafts, etc., their requirements for straightness or bending are high, and this is also a very important indicator for them. Because it involves a problem of processing volume, the amount of processing directly affects the size of production costs. If the processing does not come out, this steel pipe is directly waste. Therefore, manufacturers like the production of roller equipment pay special attention to the straightness detection of steel pipes when purchasing seamless steel pipes or straight seam steel pipes.

For the seamless steel pipe, straight seam steel pipe and forged steel pipe, the straightness is preferably a number of forged steel pipes. Since the outer diameter is the little out of the processing equipment, the straightness is generally no problem. Secondly, the seamless steel pipe has a three-roll straightening process in the production process of the steel pipe, which can basically meet the requirements of the customer for straightness. The worst is the linear steel pipe. Although the basic process also has this process, it is all made of steel or coiled steel. If the internal stress of the steel is not released very well, it will cause deformation of the steel pipe after processing. .

There are two general calculations for straightness or curvature:
First, the local bending of seamless steel pipe or straight seam steel pipe: that is, the ruler with a length of one meter depends on the maximum bending of the steel pipe, and the chord height (mm) is measured, which is the local bending value, and its unit is mm. /m, indicating a method such as 2.5mm/m. This method is also applicable to tube end bending.

Second, the total bending length of the steel pipe: use a string, pull from the two ends of the pipe, measure the maximum chord height (mm) of the bending of the steel pipe, and then convert into the length (in meters) percentage, which is the length of the steel pipe The full length curvature of the direction.