Rotary Piercing Process Research Articles

Technology Optimization Analysis of Three-Roll Rotary Piercing Process for Seamless Steel Pipe

Technology Optimization Analysis of Three-Roll Rotary Piercing Process for Seamless Steel Pipe

Effect of Three-High Rotary Piercing Process on Microstructure, Texture and Mechanical Properties of Magnesium Alloy Seamless Tube

Effect of Three-High Rotary Piercing Process on Microstructure, Texture and Mechanical Properties of Magnesium Alloy Seamless Tube

Enhanced mechanical properties of magnesium alloy seamless tube by three-roll rotary piercing with severe plastic deformation

Three-roll rotary piercing process (TRPP) with severe plastic deformation was conducted to fabricate magnesium alloy seamless tubes with high mechanical properties. After TRPP, the grains are refined to 12.5% of the original grain size and microstructure became more homogeneous due to accumulated strains. The tensile strength was improved due to grain refinement, a large number of spherical nanoparticles dispersed in the matrix and generation of new mixed texture. The elongation increased from 11% for the as-extruded billet to about 20% for tube. The enhanced elongation was attributed to grain boundary sliding and the easier activation of non-basal slips contributed by remarkable grain refinement.

A Useful Manufacturing Guide for Rotary Piercing Seamless Pipe by ALE Method

The development of numerical simulations is potentially useful in predicting the most suitable manufacturing processes and ultimately improving product quality. Seamless pipes are manufactured by a rotary piercing process in which round billets (workpiece) are fed between two rolls and pierced by a stationary plug. During this process, the material undergoes severe deformation which renders it impractical to be modelled and analysed with conventional finite element methods. In this paper, three-dimensional numerical simulations of the piercing process are performed with an arbitrary Lagrangian–Eulerian (ALE) formulation in LS-DYNA software. Details about the material model as well as the elements’ formulations are elaborated here, and mesh sensitivity analysis was performed. The results of the numerical simulations are in good agreement with experimental data found in the literature and the validity of the analysis method is confirmed. The effects of varying workpiece velocity, process temperature, and wall thickness on the maximum stress levels of the product material/pipes are investigated by performing simulations of sixty scenarios. Three-dimensional surface plots are generated which can be utilized to predict the maximum stress value at any given combination of the three parameters.

Study of the Tubular Billets Geometric Characteristics during Computer Simulation of the Rotary Piercing Process

The results of the computer simulation of the tubular billet rotary piercing process are presented. The research methodology of the deformation zone geometric ratios with due regard for the tubular billet change of shape at each helical curve step was developed .The changes pattern of the helical curve step length (li), quotient reduction (Δr/r0), ratio of the tubular billet radius to the contact surface width (r/b), contact surface length of the tubular billet (l0) with a roll, depending on the feed angle (β), roll rotation frequency (N) and plug nose extension at the gorge (Сg) was established.

New rotary piercing process for an AZ31 magnesium alloy seamless tube

ABSTRACTTo address the existing defects in the processing of magnesium alloy seamless tubes (MASTs), a new technology for producing AZ31 alloy tubes using a rotary piercing process was studied. Through the finite-element method and experimental analyses, the distributions of stress and strain and the temperature fields were analysed. The effects of temperature, radial reduction, plug diameter, and advance on the penetration rate, diameter, and wall thickness of the tube were studied. The results showed that temperature is the most important parameter; the penetration rate of the tube was >90% for rolling temperatures of 350–450°C. There was complete dynamic recrystallisation and a uniform distribution of equiaxed grains. This process can potentially replace the traditional extrusion process to produce MASTs.

Simulation of Rotary Piercing Process

The rotary piercing process is studied using Deform-3D software based on the finite-element method. The trajectories of points with different radial coordinates are found, and the draft is determined. The screw lead within the deformation zone is calculated. The draft, reduction, contact width, ovality, and strain are determined.

Influence of Roll Rotational Speed on inside Bore and Lamination Defects in Rotary Piercing Large Diameter Heavy Wall P92 Steel Pipe Process

To investigate the influence of different roll rotational speeds on tendency of inside bore and lamination defects of large diameter heavy wall seamless P92 (9Cr-0.5Mo-1.8WVNb) steel pipe pierced by two-high rotary piercing process, with the aid of commercial FE code MSC. SuperForm, 3D thermo-mechanical coupled simulations were presented. The damage field of the rolled piece during rotary piercing process, and the tendency of forming inside bore and lamination defects were analyzed using Oyane ductile fracture criterion. The results show that When roll rotational speed increases from 7rpm to 11rpm, the maximal damage characteristic value decreases from 0.4279 to 0.3340 in center area of rolled piece in front of the plug, but which increases from 0.3780 to 0.4858 in a certain depth zone (15~25mm) adjacent to the internal surface of the rolled piece contacting with the front end of the plug. With the increase of roll rotational speed, the tendency of forming inside bore defects of rolled piece reduces, but the tendency of forming lamination defects increases. Therefore, there exists a critical roll rotational speed to make the tendency of both inside bore and lamination defects reduce. This study provides scientific basis for formulating reasonable rotational speed schedule to prevent or reduce inner overlap and lamination defects.

Complex Numerical Analysis of the Tube Forming Process Using Diescher Mill

Abstract This paper presents the results of FEM simulations of the rotary piercing process in which disc guiding devices of the Diescher type are used. During this process the material is formed by means of two skew rolls, two guiding devices, and the piercing plug mounted on the mandrel. The aim of the analysis was to determine the effect of the plug diameter, the plug advance, the feed angle and the diameter reduction on the piercing process. Nine cases of piercing with three different plugs used were analyzed. The effects of the basic process parameters on the tube shell diameter and the tool load were analyzed. The numerical results obtained using Simufact.Forming 10.0 were verified under experimental conditions in which the tube shell made from 100Cr6 bearing steel was pierced. The results of the FEM calculations show agreement with the experimental results.

A Study of Formation Mechanism of the Spiral Mark Defect in Cone-Type Rotary Piercing Process

The spiral mark is one of the quality defects on the tube surface in cone-type rotary pericing process. In this paper, the numerical simulation study was carried out for cone-type rotary piercing process using rigid-plastic finite element method. From the simulation results, the axial load applied on piercing plug and mandrel bar were then obtained. Taking the elastic deformation of mandrel bar into consideration, the variation of plug location under axial load during pericing process and the non-homogeneous wall thickness were investigated. The formation mechanism of the spiral mark on the tube surface can be found in the obtained results.

Study on plastic deformation in cone-type rotary piercing process using model piercing mill for modeling clay

Pierce rolling is the rolling performed first in the production of seamless pipes. In both barrel-type rotary piercing and cone-type rotary piercing, the material is subjected to shearing deformation due to rotary forging. Only a few experimental studies on cone-type rotary piercing have been conducted to obtain the strain components. This paper describes the plastic deformation in the cone-type rotary piercing process using a model piercing mill with modeling clay. First, the model piercing mill is designed and fabricated, and then the effects of the cross-angle and feed angle on the strain components are clarified. It was found that, when the cross-angle is approximately 20°, the longitudinal section of the specimen before rolling becomes the longitudinal section of the specimen after rolling, irrelevant of the feed angle.

PREDICTION OF PLUG TIP POSITION IN ROTARY TUBE PIERCING MILL USING SIMULATION AND EXPERIMENT

Typical seamless tube production processes are an extrusion and a rotary tube piercing. The rotary piercing process is more competitive than the extrusion process from the viewpoint of flexibility. Main components of this equipment are twin rolling mills and a plug. Twin rolling mills are installed on a skew with proper angles in two directions. These angles are called the cross angle and the feed angle. The internal crack initiation and the growth at central area of the billet are gradually progressed due to the Mannesmann effects. The feed angle affects on the position of the crack initiation in the rotary tube piercing process. Adjustable design parameters in the equipment are the feed angle and the plug insertion depth. In this research, the rotary tube piercing equipment was developed. Finite element analyses with the plug and without the plug were carried out in order to predict the internal crack initiation position under good calculation efficiency. Ductile fracture models with the one variable equation were utilized to crack initiation criteria. The forward distance of the plug was determined to be 5 mm through the analysis. It was testified by experiments of a carbon steel billet.

Influences of Piercing Ratio, Expansion Ratio, Feed, Cross and Skew Angles on Available Piercing Size Range in Rotary Piercing Process.

A cone-type piercing mill was developed by the authors for materials with poor hot workability. This piercing mill is called "the super piercer" in Europe and America. This mill has a pair of cone-type main rolls supported at both ends with their roll axes inclined and crossed so as to enable piercing at high feed and cross angles. In order to ensure the best performance of the rotary piercing, disc rolls are adopted instead of plate guide shoes. The super piercer was put into practice at the small-diameter seamless tube plant operated in 1983. The recent progress in our research and development on the super piercer has resulted in the concept of "the new super piercer", which allows expansion piercing. Namely, the development of the skewing technology for disc roll axes and its application to the cone-type piercing technology has realized remarkable increase in the expansion ratio. The new super piercer was adopted as the core technology of the new medium-diameter seamless tube plant operated in 1997. In this paper, studied in detail were the influences of the piercing ratio, expansion ratio, feed and cross angles for main roll axes and skew angle for disc roll axes on the available piercing size range.

Influences of Feed and Cross Angle on Rotary Forging Effects and Redundant Shear Deformations in Rotary Piercing Process.

It was in 1967 that Sumitomo Metal Industries, Ltd. started its research and development efforts of an improved rotary piercing mill in full swing. In 1983, its first product was put into practice at the small-diameter seamless steel tube plant in the Wakayama Steel Works. Since then, the field operation at this plant has been successfully carried out. The rotary piercing mill employed at the above plant has the arrangement that cone-type rolls supported at both ends are used as the main rolls of which axes are inclined and crossed so that piercing may proceed at a high feed and cross (toe, cone) angle, with the disc rolls adopted instead of the plate guide shoes.Though several reports on this cone-type piercing mill have been published, they are rather fragmentary and leave something yet to be clarified. Furthermore, the recent progress in our research and development has resulted in the concept of "the new super piercer" which allows expansion piercing. This new super piercer will be employed as the core technology of a new medium-diameter seamless steel tube plant now under construction scheduled to operate in 1997. First of all, the influences of the feed and cross angle on the rotary forging effects and redundant shear deformations are summarized in this paper.

Assessment of the strain distribution in the rotary piercing process by the finite element method

The helical rolling in a rotary piercing mill is one of the modern methods of seamless tube manufacturing. On the basis of finite element simulation the distribution of strains in the deformation zone has been determined. The huge mesh deformation and an axial cavity in front of the plug as well as the highest strains gradients near the inner surface have been observed. According to the described simulation method the optimal process parameters can be determined.