Knowledge of Residual Elasticity of Welded Steel Pipe

The residual stress caused by the partial bending moment (referred to as residual bending moment or residual bending moment) remaining on the welded pipe has a significant effect on the service performance of the welded steel pipe. Therefore, The recognition and research of the residual bomb recovery problem is becoming more and more important. At present, the purchaser in the order of the steel pipe, in order to ensure that the pipeline (especially some important oil and gas pipeline) is safe and reliable operation, the residual pipe debris control is usually a clear quantitative limit and attached to the more stringent requirements of the steel pipe Supplementary technical conditions. This practice has become a common practice. In the manufacture of welded steel pipe in the process of strip along a certain angle and direction was sent to the roll forming device, after three-roll bending machine bending deformation, outer roller or inner roller forming, internal and external welding device of the welding process, the remainder of the finished tube will remain part of the elastic moment. This part of the elastic moment is balanced with the moment required to keep the tube blank, and the tube itself is in a state of elasticity. If the tube is cut in its axial direction and its circumferential direction is removed, the residual elastic moment of the part will be released freely, resulting in the occurrence of elasticity of the tube. This is the so-called welding steel pipe residual bomb problem. After the welding of welded steel pipe is not cold after the expansion process, making the welding after the end of the residual performance of the pipe should be complex and diverse types, such as uneven distribution, the higher the peak, and the manufacturers of Longitudinal Welded Pipe residual stress difference. There is a large residual tensile stress inside the welded steel pipe is the main reason to limit the use of welded steel pipe.
The residual tensile stress on the one hand and the delivery pressure are superimposed together to become the driving force of the crack instability expansion. On the other hand, due to the inhomogeneity of the residual stress distribution, there is a high residual tensile stress in the welded steel pipe high stress and work pressure after the stack, in the presence of corrosive media, prone to stress corrosion damage or corrosion fatigue damage, resulting in early failure of the pipeline: This is also believed that the reliability of welded steel pipe than UOE pipe low reason two. And with the increase in conveying pressure and the improvement of the pipe grade, the problem is even more prominent. However, for the outer sizing implement, the bending curvature 1 / R2 formed when the strip is bent and deformed in the three-roll bending machine of the former is larger than the bending curvature 1 / R of the finished tube. , It is still possible to make the tube of α2 (Ro) in a small diameter state by welding with a damping device (which requires special design) in the helical direction of the tube output, Before the expansion to the specified diameter RO and to achieve the purpose of the outer roller on the tube diameter. As shown in Figure 633, the resulting tube will have a circumferential negative elasticity.
That is, the outer sizing implement is used as an auxiliary control means when it is provided by means of a specially designed damping device. It is also possible to produce a tube having a circumferential negative elasticity. Although this damping device is not yet really applied, but this type of art assurance measures to the rationality and feasibility can not be denied, the above is the introduction of welded steel pipe elastic characteristics.

Hunan Great Steel Pipe Co.,Ltd: http://www.great-pipe.com/
Address: Hunan Steel Industrial Zone,No.9 Xiangfu Road, Yuhua District, Changsha, Hunan, China
Postcode:410116                     
Tel:0086-731-88678502             
Fax:0086-731-88678508
E-mail: info@great-pipe.com
welded steel pipe: http://www.great-pipe.com/product.html
Hunan Great Steel Pipe Co.,Ltd is a world-class production and service provider of submerged arc straight seam welded pipe as the first subsidiary of Shinestar Group. Hunan Great Steel Pipe Co.,Ltd pays more attention to in the pipeline engineering research areas as a pioneer of China Petroleum Pipeline & Gas Pipeline Science Research Institute, Such as: the use of oil and gas pipelines, pipe welding technology innovation, high-end plumbing materials research and development, as well as special tools technological innovation pipeline construction, pipeline corrosion protection science and technology research, science and technology research pipeline non-destructive testing, pipeline quality assessment, and research pipeline standards and so on. In the future, we will try to use new technology to create new business value and to contribute to research and product development for the pipeline.

Hunan Steel Industrial Zone,No.9 Xiangfu Road, Yuhua District, Changsha, Hunan, China

This release was published on openPR.