Weld Neck Flange Research Articles

A methodology for the manufacturing of weld neck flanges by arc deposition additive manufacturing

A methodology for the manufacturing of weld neck flanges by arc deposition additive manufacturing

A METHOD TO REDUCE THE NUMBER OF ASSEMBLY TIGHTENING PASSES IN BOLTED FLANGE JOINTS

Abstract Bolted flange joints are extensively used in the pressure vessels and piping equipment and rotating machinery. Achieving a uniform bolt preload during the assembly process is particularly important to satisfy in bolted flange connection of oil and gas and fossil and nuclear applications. However, it is a very difficult task when tightening all bolts one by one due to elastic interaction. The risk of leakage failure under service loading is consequently increased because of the scatter of the bolt preload. This paper takes the advantage of a developed analytical model based on the theory of circular beams on linear elastic foundation that simulate the elastic interaction of bolted flange joints to reduce the number of passes while achieving bolt load uniformity. As such, a novel methodology for the optimization of the tightening sequence strategies is suggested to obtain uniform bolt tension while avoiding yield under minimum tightening passes. In this regards, based on the target preload, the load applied to each bolt in each pass is suggested. The developed approach is validated both numerically using FEM (finite element method) and experimentally on a NPS 4 class 900 welding neck flange joint using the criss-cross tightening and sequential patterns.

Modeling Structure of Portable River Bridge using Fiber – Reinforced Polymer (FRP)

Portable bridge is a device that serve to connect areas near the river to the opposite. The study of portable bridge based on marine buildings (platforms) about ballast system. This utilizes fluid from a constant river flow to meet the bridge ballast pipe with a normal flow control valve. The system was developed by installing a branch and flange on the main pipe as a regulator. A lightweight material chosen as the main material in the portable bridge is Fiber-Reinforced Polymer (FRP) based on ACI 440R-07 standard. Portable river bridge structure modeling is supported by 3D CAD software that focuses on building structures, especially in the main pipe and flange.. This model using main pipe 16”NPS Sch-STD Pipe based on ANSI/ASME B36.10M/19M 2004 standard and flange 16”NPS Weldneck Flange 300# RF Sch-STD based on ASME B16.5 Flanges standard

Study of Force and Kinematic Parameters of the Low-Waste, Zero-Draft Hot Forging of Welding Neck Flanges on the Basis of a Combined Expansion-Extrusion Deforming Procedure

This paper demonstrates the development of a technology for low-waste zero-draft hot forging of axisymmetric parts, in particular, welding neck flanges, on the basis of an expansion-extrusion deforming procedure. In this study, we carried out a process simulation by means of DEFORM 3D for a qualitative evaluation of the plastic yield. Based on the simulation results, the method was proven feasible, and we set forth the goal to prepare the process and design guidelines for further industrial application. The region of plastic deformation was determined, and a general view of the function for determining kinematic parameters was given according to A.L. Vorontsov’s procedure. The force parameters of the zero-draft hot forging process by the combined expansion-extrusion procedure were analyzed by studying the kinematic conditions of the forging. The general function for determining the force parameters was found.

Evaluation of a Pipe–Flange Connection Method Based on Cold Work

The conventional joining method of a pipe and a flange uses welding. However, welded pipe–flange joints have the drawback with the inherent distortions and residual stresses resulting from the welding process, which can affect the mechanical integrity and performance of the flange significantly. In this study, a novel pipe–flange connection method based on cold work is evaluated using the finite element method. A weld neck flange is modified by manufacturing circumferential grooves at its internal surface and the pipe is cold worked into the grooves using a hydraulic expansion tool. The finite element model incorporates a pressure dependent friction model for the contact interaction between the tool–pipe–flange and a strain-based ductile failure locus for the pipe material accounting for ductile damage initiation during the cold work process utilizing a continuum damage mechanics approach. The finite element results show that a high load carrying capacity can be achieved for the cold work pipe–flange connection and has good potential for replacing the conventional welded joint.

Roll Design Method of Single–Stage Profile Ring Rolling Based on Modified UVDET

The aim of this study is to suggest the die design method for single-profile ring rolling in the production of a large scale welding neck flange, based on the modified uniform volume distribution element technique (UVDET). UVDET is presented as the ratio of volume change of ring blanks to that of undeformed rings per unit height. A welding neck flange has only one–side contour without a symmetry plane and the highly different volume distribution. To manufacture this type of ring, the blank preforming is recommended before a single–stage profile ring rolling process. FE simulations were performed to test the validity of proposed die design method, under Forge software environment.

Study on the Portable and Integrated Type Pore Plate Flow Measureing Device for Condensate Water of 300MW Steam Turbine

In order to insure the accuracy of steam turbine thermal test in power plant, the flowrate measurement accuracy of condensate water should be insured. In this paper, the portable and integrated type flow measuring device for condensate water of 300MW steam turbine flow is designed, which is based on the condensate water parameters and the specific pipeline conditions at the exit of the No. 5 low pressure heater for 300MW unit. A integration of non standard differential pressure orifice flow meter is designed in this paper Through calibration in standard experimental system, the reason of the large error is that the flow field is disturbed by the origin plate type downward welding connecting flanges. Then the welding neck flanges is designed for the connecting flanges. The distribution of connecting flanges of flow field is weaken, and the measurement accuracy can meet the demand of steam turbine thermal test.

열간 단조 제품 A694-F70 플랜지의 항복강도 향상

A welding neck flange is widely used for an interconnection between pipes. It is produced by a hot forging process, and required high yield strength under the high pressure condition, like a deep-sea. Generally, to increase yield strength, a increasing of carbon content is used, however a carbon content of welding neck flange is limited to 0.47. So, in this study, a strengthening by grain refinement without changing carbon content is used to increase yield strength. Taguchi method and FEM are used for the optimization of forging process and the experiment for the yield strength of the prototype with the optimal forging process is performed for validity.

American Petroleum Institute welding neck flange design for subsea pipelines

Flange design has been a subject of intensive research and discussion over many decades as engineers strive to maximize the capacity of flanges in application while reducing costs and providing effective seals. Calculation frameworks such as those contained within American Society of Mechanical Engineers (ASME) VIII have been used for a considerable number of years to provide reasonably accurate models for analysing the various factors contributing to flange selection. However, they do not cover all situations and this is especially significant within the oil and gas industry where American Petroleum Institute standards can ‘confuse’ the design and selection process for flanges. Therefore, in this article the authors present a revised approach to the design of welding neck flanges used in subsea applications that is based on the existing design approaches contained within ASME VIII, Kellogg, Kuppan and PD8010. This revised approach to welding neck flange design also examines the key influences of gasket geometry and loading, as well as the matching of a particular flange to its pipe capacity. Finally, results of the authors’ calculations are compared against existing finite element-derived data contained within API 6AF.

Numerical simulation to study the effect of tack welds and root gap on welding deformations and residual stresses of a pipe-flange joint

This paper presents a three dimensional sequentially coupled non-linear transient thermo-mechanical analysis to investigate the effect of tack weld positions and root gap on welding distortions and residual stresses in a pipe-flange joint. Single-pass MIG welding for a single ‘V’ butt-weld joint geometry of a 100 mm diameter pipe with compatible weld-neck ANSI flange class # 300 of low carbon steel is simulated. Two tack welds at circumferentially opposite locations, with the crucial effect of the tack weld's orientation from the weld start position is the focus in this study. Four different angular positions of tack welds (0 and 180°, 45 and 225°, 90 and 270°, 135 and 315°) are analyzed. In addition, four cases for root gaps (0.8, 1.2, 1.6, 2.0 mm) are considered and computational results are compared. A basic FE model is also validated with experimental data for temperature distribution and deformations. From the results, the axial displacement and tilt of the flange face are found to be strongly dependent on the tack weld orientation and weakly dependent on the root gap.

Numerical simulation of the effect of constraints on welding deformations and residual stresses in a pipe–flange joint

This paper presents a detailed three-dimensional finite element (FE) study to investigate the effect of mechanical constraints on welding distortions and residual stresses in a pipe–flange joint. The FE model of a pipe–flange joint is subjected to sequentially couple nonlinear transient thermo-mechanical analysis to simulate complex welding phenomena. Single-pass gas metal arc welding for single ‘V’ butt-weld joint geometry of a 100 mm diameter pipe with compatible weld-neck ANSI flange class #300 of low carbon steel is simulated. Two tack-welds at 90° and 270° from the weld start position are modelled. Four different constraint conditions representing the welding of unassembled joints, welding of assembled joints, welding of assembled joints with reflective symmetry and welding of perfectly constrained joints are analysed. To model the constraints and boundary conditions more realistically contact pairs are used between the matching surfaces of different structural components. Basic FE models are validated with experimental data for temperature distribution and deformations. Predicted welding distortions and residual stresses are compared and discussed in detail. From the results, axial displacement and tilt of the flange face are found to be strongly dependant on the constraint conditions. Minimum axial distortion on the flange face is found for rigidly clamped flanges. However, residual stresses have a weak dependence on the constraints set.

Automated finite element analysis of circular weld neck flange assemblies

An automated Finite Element computer program to analyse bolted circular weld neck flange and gasket assemblies has been developed. The program is based on an extensive database of British, European and American flange and gasket standards. The program is ideal for identifying problem areas and conducting sensitivity studies

Automated FE analysis of flange assemblies

An automated finite element computer program to analyse bolted circular weld neck flange and gasket assemblies has been developed. The program is based on an extensive database of British, European and American flange and gasket standards. The program is ideal for identifying problem areas and conducting sensitivity studies.

Determination of the gasket load drop at large size welding neck flange joints in the case of nonlinear gasket model

This paper deals with the calculation of gasket load drop caused by internal pressure at flange joints. The method published here makes it possible to take into consideration the nonlinearity of gasket material and the stiffness effect of the integrated part of the flange ring. The equations published refer to large size welding neck flanges but the method itself can be applied at any other types of flange joint too. The preciseness of this method, as well as the convergence of trial-and-error calculations used, are proved by results of calculations carried out on a flange joint.

Simulation of ring rolling with new wax-based model materials on a flexible experimental machine

Nowadays, the practice of using model materials for the analogical simulation of most forming processes is well established: however, the practice is almost non-existent in ring rolling. Important new opportunities for ring rolling have arisen due to a remarkable development over the last five years: highly unsymmetrical thin-walled rings and weld-neck flanges are being required to an increasing extent in high-cost materials such as aluminium alloy, stainless- and maraging-steels, heat-resisting alloys, titanium-, magnesium-, nickel-alloys and such-like. The present investigation explores the applications of the analogical-simulation method in ring-rolling sequences. For these applications, a new flexible horizontal machine has been developed for the rolling of model-material rings, the outer diameters of which do not exceed 700 mm. Typical rolling examples are concerned with the prediction of rolling forces and torques, with the analysis of flow patterns, and with some operating rules for idler and edging rolls. In addition to the demonstration of good agreement between the simulated and the actual rolling parameters, it is shown that the simulation on a flexible low-cost machine is an up-to-date and quick method for developing competitive ring-rolling procedures.

Flat Face Flanges With Metal-to-Metal Contact Beyond the Bolt Circle

A method of designing flat face flanges with metal-to-metal contact beyond the bolt circle is described. The design method takes into account the interaction between shell and flange and provides for continuity at the flange-shell junction. Weld neck flanges, where the hub is of uniform thickness, and flange rings welded directly to a shell are discussed in detail, however, the same analytical approach can be extended to include tapered, hubbed flanges. Although the approach is fundamentally rigorous, sophisticated analyses have been omitted in favor of making the method useful to most engineering design offices.

Closure to “Discussions of ‘Design of High-Pressure Integral and Welding Neck Flanges With Pressure-Energized Ring Joint Gaskets’” (1964, ASME J. Eng. Ind., 86, p. 204)

Closure to “Discussions of ‘Design of High-Pressure Integral and Welding Neck Flanges With Pressure-Energized Ring Joint Gaskets’” (1964, ASME J. Eng. Ind., 86, p. 204)

Design of High-Pressure Integral and Welding Neck Flanges With Pressure-Energized Ring Joint Gaskets

This paper provides all necessary information to design high-pressure flanges with pressure-energized ring joint gaskets, for any pressure and made from any suitable material. These rules have been used to design the American Petroleum Institute Standard API—10,000 lb and 15,000 lb flanges.