Manufacture Of Pressure Vessels Research Articles

Integral Hydro-Bulge Forming of Single and Multi-Layered Spherical Pressure Vessels

The recently developed integral hydro-bulge forming (IHBF) process was utilized in the manufacturing of single and multi-layered spherical pressure and storage vessels. Single-layered spherical vessels of 1.6-mm thickness and diameters of 316.5, 634.1, and 953.2 mm were manufactured. As an alternative means of manufacturing thick-walled spherical pressure vessels, the IHBF procedure was modified and used informing double-layered composite pressure vessels with an effective thickness of 15 mm. The results showed that the modified IHBF process may successfully be applied in the manufacturing of multi-layered spherical vessels of various thicknesses and diameters. In this paper, the conventional and modified IHBF procedure will be outlined and the experimental results and analysis will be presented. Finally, areas where further work is needed are identified.

Pressure vessel manufacturing: Mechanical analysis of gas bottles with convex end-plates

The three-centre geometry design for the bottom end-plates of gas bottle cylinders is analysed using an approximate method involving Finite Element techniques. Shell elements are adopted to obtain the equivalent stress distribution along a generatrix of the bottle. The maximum stress profile in the bottom zone is plotted versus normalized geometrical parameters. The area which bounds acceptable solutions according to basic Standards Codes is outlined in the diagrams. Experimental measurements by means of electrical resistance strain gauges are compared with the numerical forecasts. The good correlation which was obtained confirms the validity of the proposed approach in dealing with industrial applications.

Production of high pressure vessels from austenitic steel for cryogenic engineering based on the electroslag casting technology

Special equipment has been created and the associated technology has been developed based on the electroslag casting (ESC) method. This development is applicable to the manufacture of thick-walled high pressure vessels from austenitic high-alloyed steels for cryogenic engineering. They permit one to melt high quality metals and to produce simultaneously castings for items of intricate shape. Complex application of different control methods at the main stages of the high pressure vessel manufacture by the ESC method permits one to provide a high level of reliability and stability of the produced items.

Manufacture of thick-walled pressure vessels in particular consideration of advanced welding processes and measures for quality assurance

The use of most advanced welding processes for the manufacture of thick-walled pressure vessels is demonstrated by reference to nuclear component production. A detailed description is given of sub-arc narrow-gap welding and TIG welding as typical joint-welding processes. Surface corrosion protection is provided by weld cladding using corrosion-resistant 18 8 steels or nickel-based alloys. The sub-arc strip process has given excellent results when used for large-area cladding; a most interesting development is the electroslag weld-cladding method. The sub-arc fine-wire process is available for hollow bodies, preferentially with a small diameter. The welding processes referred to above would be incomplete if there were no reference to the special measures taken for satisfying even extremely stringent quality requirements. Quality planning, quality inspection, and quality documentation are combined to form a comprehensive quality assurance programme for ensuring high-quality production as well as the availability of complete quality records without any gaps.

Understanding design-manufacture interaction using compromise decision support problems—III. Design for manufacture of composite pressure vessels

The decision support problem (DSP) technique is being developed to facilitate the concurrent implementation of design, manufacture, and maintenance. This involves the development of a domain-independent method (and the associated software) that can be used to process domain-dependent information and thereby provide support for human judgment. Modeling and gaining an understanding of the interaction between design and manufacture is an important step in this development. A conceptual model of a process for design (for composite material pressure vessels) and the formulation and solution of a “non-textbook” compromise DSP template for the preliminary synthesis of composite pressure vessels is reported in parts II and III, of this paper respectively. This work provides the foundation on which the current work, namely, the development and implementation of a template to help understand the interaction between design and manufacture, is based. A parametric study to demonstrate the utility of the template to a designer is also included. The focus in this paper is on the method and on understanding the subsequent ramifications; the focus is not on the designs which are obtained by solving the template.

Pressure Vessel Manufacture using the Chinese Ribbon Winding Technique

During the past 20 years a technique has been developed in the People's Republic of China for manufacturing thick-walled pressure vessels using thin steel ribbons, helically wound under tension onto a thin inner steel core. The technique is described herein and the advantages claimed are outlined, together with brief descriptions of some related areas of development.

海外に於ける機器の製作（イタリア）

海外に於ける機器の製作（イタリア）

Creep Behavior of Copper and Copper Alloys As Design Criteria in Pressure Vessel Manufacture

Abstract Six materials, copper and copper alloys, have been subjected to long-term creep tests (30 000 h) per DIN 50 118 at a range of 100 to 250°C, except for aluminum bronze which was tested from 150 to 300°C. The following annealed materials were tested: SF-Cu (DIN 1787)—equivalent to C 12200, Phosphorus Deoxidized Copper, high residual Phosphorus (Cu-DHP); CuZn39Pb0.5 (DIN 17 660)—equivalent to C 33500, low-leaded brass; CuZn20Al2 (DIN 17 660)—equivalent to C 68700, aluminum-brass, arsenical; CuZn28Sn1 (DIN 17 660)—equivalent to C 44300, Admiralty brass, arsenical; CuZn38SnAl (DIN 17 660), improved Muntz-metal, 60%, not standardized in the United States; and CuAl10Ni5Fe4 (DIN 17 665)—similar to C 62730 or C 63000, nickel-aluminum-bronze. The test conditions and the metallurgical history of the materials are described. The minimum value of the 1% creep strain and the average value of creep strength, both temperature and duration dependent, as well as the stress for minimum creep rates of 1% for a given time are also shown. The design criteria for pressure vessels are discussed.

Critical fracture stress and fracture strain models for the prediction of lower and upper shelf toughness in nuclear pressure vessel steels

Critical fracture stress and stress modified fracture strain models are utilized to describe the variation of lower and upper shelf fracture toughness with temperature and strain rate for two alloy steels used in the manufacture of nuclear pressure vessels, namely SA533B-1 (HSST Plate 02) and SA302B (Surveillance correlation heat). Both steels have been well characterized with regard to static and dynamic fracture toughness over a wide range of temperatures (−190 to 200°C), although validJIc measurements at upper shelf temperatures are still somewhat scarce. The present work utilizes simple models for the relevant fracture micromechanisms and local failure criteria to predict these variations in toughness from uniaxial tensile properties. Procedures are discussed for modelling the influence of neutron fluence on toughness in irradiated steel, and predictions are derived for the effect of increasing fluence on the variation of lower shelf fracture toughness with temperature in SA533B-1.

Steels for Seamless Hydrogen Pressure Vessels

To provide engineering data useful in the design, manufacture, and operation of seamless pressure vessels, extensive tests have been conducted in hydrogen at pressures ranging from 3000 to 14,000 psi (21 to 97 MN/m/sup 2/) with precracked specimens of steels having a wide range of mechanical properties. The critical stress-intensity level at which crack propagation spontaneously arrests (K/sub H/) was determined. The values of K/sub H/ were used in an illustrative calculation to estimate the critical flaw size at which hydrogen crack propagation would be expected in thick members loaded in bending. In general, the susceptibility of steels tested increased with yield strength. For the steels with intermediate yield strengths (85 to 113 ksi (586 to 779 MN/m/sup 2/)), K/sub H/ tended to decrease as pressure was increased from 3000 to 14,000 psi (21 to 97 MN/m/sup 2/). The crack path was analyzed, and a sequence of events is described involving the initiation, growth, and arrest of cracking induced by gaseous hydrogen.

Scope of Welding Technology in the Manufacture of Vessels for Cryogenic Services

Manufacture of Pressure Vessels for Cryogenic Services is relatively a new field in India. The word "CRYOGENIC" was inherited from the Greek word "KRYOS" which means frost or ice and "Genes" means "born". Cryogenics is the branch of physics concerned with phenomena at very low temperatures.

Steels for Seamless Hydrogen Pressure Vessels

To provide engineering data useful in the design, manufacture, and operation of seamless pressure vessels, extensive tests have been conducted in hydrogen at pressures ranging from 3000 to 14,000 psi (21–97 MN/m2) with precracked specimens of steels having a wide range of mechanical properties. The critical stress-intensity level at which crack propagation spontaneously arrests, KH, was determined. The values of KH were used in an illustrative calculation to estimate the critical flaw size at which hydrogen crack propagation would be expected in thick members loaded in bending. In general, the susceptibility of steels tested increased with yield strength. For the steels with intermediate yield strengths (85–113 ksi or 586–779 MN/m2), KH tended to decrease as pressure was increased from 3000 to 14,000 psi (21–97 MN/m2). The crack path was analyzed, and a sequence of events is described involving the initiation, growth, and arrest of cracking induced by gaseous hydrogen.

Application of Weld Forming Technique to Manufacturing of Pressure Vessel and Piping

Application of Weld Forming Technique to Manufacturing of Pressure Vessel and Piping

Metallography of explosive welds

Explosive welding is one of the industrially important techniques employing high energies derived from explosives. This technique produces sound metallurgical bonding between a wide variety of similar as well as dissimilar metals and alloys like aluminium, brass, stainless steel, invar, titanium, etc. which are not normally weldable by conventional methods. In this process a weighed amount of explosive is spread over a protecting plate placed on the cladding plate, which is spot-welded at a certain angle to the base plate. The included angle between the cladding and base plates and the amount of explosive used are critical for obtaining sound welds. These weld composites successfully withstand the normal metal-working processes. They find extensive use in bimetal industry, coinage, chemical process equipment, pressure vessel manufacture, rocket technology, etc. Collapse of the cladding plates during explosion generates a pressure wave moving ahead of the collision front and the material forming the colliding surfaces flows forward and is ejected in the form of a jet. Thus the surface jetting normally associated with this process gives rise to wavy interface as noticed in a number of weld combinations. High pressures are generated at the collision front resulting in localised severe plastic deformation. In order to develop sound explosive welds with good shear resistance, it is essential to understand the mechanism of bond formation between the two component metals and also the nature and composition of the interface regions. Techniques like optical and electron metallography, hot-stage microscopy, electron probe microanalysis, microhardness testing, etc. have been employed to investigate the metallurgical aspects of the explosive welds. Bond interface and the adjoining regions reveal many unusual microstructuralfeatures like complex pattern of plastic flow, formation of solidified melt zones, presence of shock-twins, entrapment of metal pockets, etc. Columnar grain structures, characteristic of cast metals, within the mixture zones indicate localised melting and subsequent rapid solidification starting from either side. High microhardness values of these zones could possibly be attributed to the high rates of cooling bringing in large amounts of microstresses and also possible leading to the formation of some non-equilibrium phases similar to those obtained in liquisol-quenched samples. Sets of fine recrystallized grains noticed at regions adjoining the interface indicate the presence of heat-affected zones. Hot stage microscopic examination of mild steel—stainless steel explosive welds shows features like the formation of parallel banded contours, presence of substructure within the twin bands, formation of decarburised layer in mild steel, diffusion of elements across the interface, etc. Electron probe analysis has also been used for the study of these welds by scanning the bond zones for elemental distribution and also by conducting point analysis for their composition. These studies generally indicate an alloy series midway between the two component metals. However, chance combinations of elements approximating to the composition of some intermetallic compounds could also occur. The normal diffusion does not seem to be operative in the explosive welding process, as sharp changes in concentrations have been reported in almost all the weld combinations. A number of explosive welds have also been investigated at our Defence Metallurgical Research Laboratory; some of the results of which are incorporated in this paper.

Manufacture of Large Weldless Forged-Steel Pressure Vessels

Abstract This paper describes in detail the various steps taken in the manufacture of large weldless forged-steel cylinders for high-pressure boiler drums and for various uses in the oil-refining and chemical industries. It covers the melting, casting, and heating of the ingot; cutting-off, piercing, and expanding the billet; forging, treating, and machining the cylinder; and illustrates a number of ways in which the ends of the cylinder can be closed.