Study on Wall Thickness Eccentricity of Seamless Steel Tube

2010 ◽  
Vol 148-149 ◽  
pp. 1071-1074 ◽  
Author(s):  
Qing Gong Lv ◽  
Long Zhou Peng ◽  
Jing Qing Zhu
Keyword(s):  
Cross Section ◽  
Wall Thickness ◽  
Steel Tube ◽  
Steel Tubes ◽  
Increase Wall Thickness ◽  
Factors Influencing ◽  
Feed Angle ◽  
Seamless Steel Tube ◽  
Seamless Steel Tubes ◽  
Seamless Steel

Wall thickness is measured by a micrometer on shells after piercing, hollows after rolling and tubes after stretch reducing in an Assel production line for seamless steel tubes. The characteristics of wall thickness eccentricity are exhibited, and the heredity and origin of wall thickness eccentricity are analyzed. Finally, the factors influencing wall thickness eccentricity are discussed. The results show that: (1) Wall thickness eccentricity originates from temperature eccentricity in cross section of round billets, comes into being on shells in piercing process, and is passed down to hollows and finally to tubes; (2) Bigger feed angle of piercing, smaller plug diameter and less stability of plug bar will increase wall thickness eccentricity, while complying to the influence of temperature eccentricity on round billets.

Prediction of Mechanical Properties of Seamless Steel Tubes Using Artificial Neural Networks

2020 ◽  
Vol 19 (04) ◽  
pp. 2050028
Author(s):  
Ramon Santos Correa ◽  
Patricia Teixeira Sampaio ◽  
Rafael Utsch Braga ◽  
Victor Alberto Lambertucci ◽  
Gustavo Matheus Almeida ◽  
...  
Keyword(s):  
Neural Network ◽  
Mechanical Properties ◽  
Sampling Rate ◽  
Steel Tube ◽  
Support Vector ◽  
Neural Network Models ◽  
Steel Tubes ◽  
Inference Models ◽  
Seamless Steel Tubes ◽  
Seamless Steel

A bottleneck of laboratory analysis in process industries including steelmaking plants is the low sampling rate. Inference models using only variables measured online have then been used to made such information available in advance. This study develops predictive models for key mechanical properties of seamless steel tubes, by strength, ultimate tensile strength and hardness. A plant in Brazil was used as the case study. The sample sizes of some steel tube families given namely, yield a particular property are discrepant and sometimes very small. To overcome this sample imbalance and lack of representativeness, committees of predictive neural network models based on bagging predictors, a type of ensemble method, were adopted. As a result, all steel families for all properties have been satisfactorily described showing the correlations between targets and model estimates close to 99%. These results were compared to multiple linear regression, support vector machine and a simpler neural network. Such information available in advance favors corrective actions before complete tube production mitigating rework costs in general.

Influence of Roll Speed Schedule on Transverse Wall Thickness Evenness of Shell Elongated by Mandrel Mill

2010 ◽  
Vol 654-656 ◽  
pp. 1311-1314 ◽  
Author(s):  
Sheng Zhi Li ◽  
Zhi Chao Zhang ◽  
Hai Yan Bao ◽  
Zhi Yang Zhou
Keyword(s):  
Wall Thickness ◽  
Rolling Process ◽  
Steel Tube ◽  
Transverse Wall ◽  
Data Reliability ◽  
Continuous Rolling ◽  
Roll Speed ◽  
Seamless Steel Tube ◽  
The Relationship ◽  
Seamless Steel

The seamless steel tube continuous rolling process with 8-stand full-floating mandrel is simulated with the aid of commercial FE code MSC. SuperForm. The relationship is analyzed between the distribution of the transverse wall-thickness and the speed schedule of the rollers. The result shows that the transverse evenness of the wall thickness of the tubes can be enhanced by optimizing the speed schedule. Furthermore, by adopting meliorated method to measure the wall-thickness of the shell, the error is reduced while data reliability is increased. When using the existing equipments (mandrel mill), it is an effective way to improve the transverse wall-thickness accuracy of the shell tube by adjusting the speed schedule. Compared with present roll speed schedule, the transverse wall-thickness accuracy can be increased by 10% for the rolling of elongated shell with 152.5mm in OD and 6mm in wall thickness tube under the 3# speed schedule put forward in this paper.

scholarly journals Analysis and Control of Cracking and Wrinkling at the End of Seamless Steel Tube with Multi-Pass Large Deformation Diameter-Reducing

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1438
Author(s):  
Heng Liu ◽  
Liandong Wang ◽  
Xiaodi Wang ◽  
Qiying Tan
Keyword(s):  
Residual Stress ◽  
Tensile Stress ◽  
Wall Thickness ◽  
Geometric Model ◽  
Steel Tube ◽  
Deformation Analysis ◽  
Residual Tensile Stress ◽  
Seamless Steel Tubes ◽  
And Control ◽  
Seamless Steel

Axial cracking and circumferential wrinkling are found at the end of seamless steel tubes during multi-pass large deformations pushing diameter-reducing (PDR), which seriously affects product quality. However, the cracking and wrinkling mechanism of PDR has not been elucidated yet. In this paper, the Equation of circumferential residual stress at the end was deduced from the warping deformation and shear stress. It is revealed that the circumferential residual stress in the end warping area from the inner to outer surface is tensile, and the generation mechanism of circumferential wrinkling on the inner wall at the end was revealed through the deformation analysis of PDR. The geometric model of the tube with periodic alternating variation of wall thickness was established to reveal the generation and development of circumferential wrinkling. In addition, the four-pass PDR experiments and simulations were developed to reveal the influence of reducing pass and wall thickness deviation on the end warpage, unevenness and circumferential residual tensile stress. The pushing-pulling diameter-reducing (PPDR) method was proposed to control the wrinkling and cracking. The simulation and experimental results showed that the end warpage, unevenness and circumferential residual tensile stress are all greatly decreased, and the risk of axial cracking and circumferential wrinkling is eliminated.

Possibilities of Stereological Analysis of Grain Boundary Orientation in Longitudinal Sections of Precision Cold Drawn Seamless Steel Tubes

2017 ◽  
Vol 891 ◽  
pp. 51-54
Author(s):  
Martin Ridzoň ◽  
Maroš Martinkovič ◽  
Milan Mojžiš ◽  
Ján Turňa ◽  
Lucia Domovcová ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Cold Drawing ◽  
Steel Tube ◽  
Relative Reduction ◽  
Steel Tubes ◽  
Tube Cross Section ◽  
Boundary Orientation ◽  
Seamless Steel Tubes ◽  
Selection Of ◽  
Seamless Steel

Cold drawing of steel tubes refers to a forming operation where a precision steel tube is being formed in a die while reducing tube cross-section, altering the wall thickness and making the final tube much longer than the original hollow. The forming itself takes several drawing passes (a.k.a. draws) depending on the final tube dimension requested. The selection of relative reduction for a particular tube diameter plays an important role because an excessive reduction during drawing causes stresses that induce substantial plastic deformation, eventually leading to cracking. In this paper we evaluate the effect of selected reductions on the longitudinal grain boundary orientation in cold drawn tubes, taking tube sample measurements and making necessary calculations of grain boundary orientation in selected planes.

scholarly journals Development of the Wall Thickness Measuring System Using the Electromagnetic Acoustic Technique for Hot Seamless Steel Tubes and Pipes

1984 ◽  
Vol 70 (9) ◽  
pp. 1131-1138
Author(s):  
Hisao YAMAGUCHI ◽  
Kazuo FUJISAWA ◽  
Riichi MURAYAMA ◽  
Koichi HASHIMOTO ◽  
Renpei NAKANISHI ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Measuring System ◽  
Tubes And Pipes ◽  
Steel Tubes ◽  
Acoustic Technique ◽  
Seamless Steel Tubes ◽  
Seamless Steel
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