What is the manufacturing process for large-scale equipment?
Thread Content
I study engineering, and I suddenly wondered: how are those devices that operate under high temperature and pressure and are of large size, such as reactors, manufactured? Thinner ones can be rolled into cylinders; but how are those with wall thicknesses of dozens or even hundreds of millimeters manufactured? Wondering……
Looking forward to the answer together: time:
Tubes with a wall thickness of over 50 mm are manufactured using a multi-layer wrapping method. Nanjing Dahua Machinery has extensive experience in this field and was once the leader in China’s machinery industry.
For those that are hundreds of millimeters thick, several plates can be assembled first and then rolled into tube sections. As long as the roll former meets the requirements, it’s fine – it’s not a difficult task at all!
Given the production capabilities of China’s large-scale chemical machinery manufacturers today, producing cylinders with walls hundreds of millimeters thick is by no means a problem. Moreover, by drawing on advanced foreign technologies, it is entirely possible to achieve this!
High-pressure reactors can be of the multi-layer wrapped type, or they can be fabricated from forgings or thick plates rolled into shape； The production of forgings begins with the procurement of forging materials (the purchaser is specified in the contract). Once the materials arrive at the manufacturing facility, their various properties are rechecked; only after they pass these tests does the process of machining, welding, flaw detection, pressure testing, and transportation proceed. The various steps involved in shaping thick steel plates are similar to those used for forgings ； The breakdown of detailed processes is thorough.
Additionally, thin plates can be turned into thicker plates through explosive welding; however, this approach is not very useful when the wall thickness is already low, as thin plates are more expensive than thick ones. For thick plates, explosive welding can indeed be used. I have been in coking plants and other similar facilities, as well as in steel mills for inspections – and that’s basically how it works. As long as the inspections show satisfactory results, that’s enough
Thicknesses of dozens or hundreds of units are no big deal; when the thickness is greater, hot rolling can be used, and it’s very simple. My previous workplace was able to easily roll 110mm BHW35 cylinders. It’s unclear what exactly the large structure mentioned by the poster refers to; if it cannot be transported, the parts are usually manufactured in the workshop and then welded on site
During my studies, I thank everyone for their information :)
For applications with high requirements, welding of forged parts is used; another manufacturing method involves employing the automatic electroslag casting process throughout the entire structure, with the casting head moving from bottom to top along the outer wall of the inner cylinder or on the mold, layer by layer from the inside out. This method is more suitable for the manufacturing of thick-walled container sections as a whole, and the material quality of the castings is good; common casting defects such as shrinkage cavities, cracks, inclusions, or other macroscopic imperfections can be avoided in dot- slag casting. Thermal nesting can also be used to nest cylinders of different diameters layer by layer to form thick-walled tube sections; the advantage of this method is that the inner and outer walls can be made of different materials depending on the specific requirements. These two methods are often used in the fabrication of reactors with high requirements. Another category of large-scale devices is those that are considered oversized containers – equipment that, after being manufactured, cannot be transported as a whole from the factory to the site of use using conventional methods. Such devices are usually transported in sections, pieces, or individual components. For oversized thin-walled containers, temporary deformation techniques are employed to temporarily compress the cylindrical sections or thin-walled shells, so that they can be transported to the site and then assembled there. The spherical tanks and 10,000-cubic-meter tanks that were built in our factory the year before last are of this kind. This post was last edited by bluerain76 on 2008-3-10 10:44.]
For domestic pressure vessel manufacturers at present, rolling steel sheets with a thickness of several dozen to 100 millimeters is not a problem; the key lies in whether the necessary production equipment is available.
I’ve learned about it, but I still find the principle of explosion welding incredible; I really hope to see it in person if I get the chance, :) Steel plates several hundred millimeters thick wrapped around something – what if… wouldn’t that be amazing? :funk: Rolling it up – I really want to see a machine like that… :P Last edited by Great foolishness appears as wisdom on 2008-4-15 06:43]
Thick cylinders can be wrapped using multiple layers, tied together, or fitted with heat-shrink sleeves, among other methods.
Now, some manufacturing plants in the country already possess strong production capabilities, so this issue is no longer a problem. Nanhua Machinery, Jinchong, and Hagao can all do it, so there’s no need to worry~