CS233277B1 - Method of manufacturing large pressure vessel bodies - Google Patents

Abstract

The invention relates to a method of manufacturing bodies of large pressure vessels, for example nuclear reactors, consisting of several thick-walled cylindrical parts and a bottom. The essence of the invention is a technological process in which all weld bevels of circumferential welds are first formed, then an upper and lower system or section is formed from individual cylindrical parts or rings. After welding the rings, the individual sections are heat treated to remove stress, after which the weld bevel is machined at the last cylindrical parts of both sections for the final weld. The invention can be used primarily * in nuclear engineering, in chemical and food engineering.

Description

The invention relates to a process for the production of pressure vessel bodies, for example nuclear reactors, consisting of several thick-walled cylindrical parts and a bottom which has to be welded together.

The solutions known hitherto consist in the fact that these bodies are manufactured in such a way that the individual parts and the bottom of the pressure vessels are gradually welded together by circumferential welds. Each individual weld is then followed by a series of control, handling, heat-processing, defectoscopic and chip-reprocessing operations. This manufacturing method is unsatisfactory because it causes a strong overall thermal influence on the weld joints and the base material by heat treatment operations. Production is laborious and time consuming.

It is an object of the invention to accelerate the process of manufacturing large pressure vessel bodies by uniting several, especially welding, manufacturing operations, thereby substantially reducing the aforementioned drawbacks. The object of this invention is to provide a novel process for the production of bodyweight pressure vessels according to the invention, which is based on a process in which all weld bevels of circumferential welds at each cylindrical part and also at the bottom are already formed during machining from blanks. Thereafter, at least four cylindrical parts or three cylindrical parts and a bottom are joined by welding the theological staples to form two assemblies - the lower and the upper, the upper being usually provided with inlet necks and is therefore also referred to as the throat. The parts of each system are stacked when stacking. The assembled assemblies are then each leveled. After welding, the individual systems are heat-treated to eliminate stress, after which all the welds of each section are defectoscopically checked and then the weld bevel is machined on the last cylindrical parts of the two cylinders for the final weld of the pressure vessel body.

Advantages of the process for producing a large pressure vessel according to the invention are that it enables the welding operation and the subsequent flow operation to be combined in two large production stages, thereby significantly reducing the overall thermal influences of the weld joints and the base material of the heat treatment operation to relieve stress of the entire manufacturing process of the body of the pressure vessel, and furthermore, and such an manufacturing effort, will shorten the production cycle of the pressure vessel.

Particular applications of the method of manufacturing large pressure vessel bodies according to the invention can be used in the manufacture of a pressure vessel with a distance of 10.9 at a wall thickness of 200-300 nn of a nuclear reactor. First of all four four-walled cylindrical parts or rings. during the machining of the workpiece, all the bevels of the Perimeter Welds will exempt from the last of each of the sections the end weld. The rings ee position themselves one after another, then welded on the outside of the technological clamp the knee to the circumference of the welds. The upper section is then leveled and prepared for the welding workstation. Thereafter, the individual regions of the circumferential welds from the inside are preheated to the welding temperature by the induction heating device and are subsequently welded successively. After welding, the entire section is immediately heat-treated and stress-relieved. After the heat treatment, the section treats the excess weld of the circumferential welds and the remains of the technological staples, and then the welded area was externally and ventilated for subsequent inspection of all welds by ultrasound and radiation. Then the perlitic sleeves are welded on the upper section and the perlitic lining on the forehead is welded on. The austenitic anticorrosion liner is then welded on the lower ee. Then, both the upper and lower sections are rotated to the evielo position and the machining is performed for the final evar of the body. Upon completion of the entire ppering process, the two sections are pushed together in horizontal position and the automatic evar is carried out by the automat, the entire body of the reactor pressure vessel being finished.

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The use of this method of production of large pressure vessel bodies can be applied especially in nuclear engineering in the production of segmented and dimensional pressure vessels from low-alloy structural steels, which are subject to high demands on the resulting mechanical properties of the base metal and weld joints. and shortening the production cycle.

Claims (2)

SUBJECT OF THE INVENTION 233 277 1. A process for producing bodies of large pressure vessels _and Holy of Renli generated during rotation, at least two sets of mutually welded APOLO silnostěnnýoh rings, one of těohto * system is provided with a fixed bottom TLM ^ characterized that each ring of each set formed by first joining the weld bevels, whereupon the rings are joined into at least two assemblies, from which one bottom is thus connected to one end assembly, and each such assembly is then formed separately so that the individual rings are welded successively immediately one after the other and after welding each assembly, heat treatment to remove stress, meohanlocal treatment of the system surface and defectoscopic inspection are performed at the same time, then closing weld bevels on the canoe rings of the systems are welded to each other! 2. The method for producing large pressure vessel bodies according to claim 1, characterized in that the rings are connected to the individual systems by technological staples in a vertical position, whereas the mutual welding of the individual rings of such a system is carried out in a horizontal position.