Conditions for substituting materials by using thinner ones in place of thicker ones, inferior ones in place of superior ones, and those that exist in place of those that do not exist
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That’s right; it’s about discussing the conditions under which materials can be substituted with thinner ones in place of thicker ones, with inferior ones in place of superior ones, and with those that are available in place of those that are not available. Not applicable to: large enterprises with substantial financial resources. Don’t let a petty profit ruin your reputation for life. Applicable to: small manufacturing plants that are struggling to survive, operating in difficult conditions, and competing fiercely over every small advantage. Simple, basic pressure vessel products with familiar materials. At the present time, the market is characterized by fierce price competition, resulting in slim profits; the slightest mistake can lead to losses in the production of a single piece of equipment. “Condition of using a thinner thickness in place of a thicker one: 1. The strength calculations must pass, and there must be sufficient margin against corrosion and processing; in other words, the original design had a considerable excess thickness. 2. The original design unit agrees to use an alternative. For example, in the case of a steam distribution cylinder whose cylinder body is made from pipes with a diameter of φ325*8, and you have pipes with a diameter of φ325*7, this usually meets the requirements for use. “Conditions of using inferior materials in place of superior ones, and existing materials in place of none: 1. The \"inferior materials\" used are capable of meeting the operating requirements of the equipment. 2. The original design unit agrees to use an alternative. For example: use 20g in place of 20R. The proper approach should be for the original design team to agree to change 20R to Q235-C, so that the manufacturing party can use 20g in place of Q235-C. In fact, Q235-C has a wide range of applicable conditions, so 20g is sufficient for most uses. HG20581 4.0.2.3 When 20R is difficult to obtain, 20g can be used. In short, to survive in such competitive conditions and maximize profits, it is necessary to study technical specifications and standards in depth, and to take advantage of any loopholes in them as much as possible. Anything that can be found in the standards, even things that were once part of those standards but are no longer included in them, as long as it is not explicitly prohibited by current standards, can be used as a basis. Of course, anything that is explicitly prohibited by current technical specifications and standards must not be done. Again, companies with substantial financial resources should not engage in such activities.
One must be cautious when dealing with such matters, whether it’s design or manufacturing; especially during the manufacturing phase, one shouldn’t get too involved in it!
It is relatively difficult to implement. Since it’s such a substitute method, it means the design and manufacturing are not handled by the same party; convincing the design team will likely be… difficult! However, since design and manufacturing are integrated, this alternative method has been in use for a long time; as long as the strength is satisfactory and it meets the standard specifications.
It said that the page couldn’t be displayed; trying to send it again resulted in the same issue, so I had no choice but to modify it. If it’s not appropriate, just delete it. This post was last edited by Wen Bing on 2008-1-13 at 18:06.]
The issue of manufacturing costs – haha, good analysis; bosses like that kind of thing.
I don’t agree with this statement. 1. If things are not done according to the standards, the person who made the changes will be held responsible when problems arise; the company will not protect you. There’s no need to take risks just to please the boss. 2. The cost savings from replacing materials are not significant; small factories should not risk damaging their company’s reputation and losing opportunities for growth just for such minor gains. 3. From a safety perspective, in the event of an accident that results in injuries or deaths, will you be able to face the consequences? You’ll regret it then. Not only wealthy companies should avoid doing such things. Small manufacturing plants should not do such things if they want to grow and thrive. It’s fine to pursue maximum profits, but never seek petty gains at the cost of safety – it’s not worth it.
At the very least, efforts should be made to meet the minimum standards; it’s too dangerous to go below that threshold!
Using a thicker layer instead of a thinner one can also lead to problems such as the range of flattening and heat treatment, which should also be taken into account
“Using thin materials in place of thicker ones, inferior materials in place of high-quality ones, and existing items in place of those that are not available – this is a very complex issue. On one hand, it may be related to the procurement of materials; for example, 20R material is indeed difficult to find in the market, which leads to many situations where substitute materials are used in place of 20R. On the other hand, it is related to the operating conditions of the equipment – when the equipment is under stress-corrosion conditions, the quality of materials used may differ from that in normal operating conditions； Once the material is ready for use, it may lead to actions such as processing, flaw detection, or even a change in equipment category. Therefore, the issues of using thinness in place of thickness, inferior quality in place of high quality, and the presence of something in place of its absence should be considered on a case-by-case basis.