Can bar stock be used instead of forgings?
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Can bar stock be used instead of forgings? Can small-diameter high-pressure reinforced pipes be machined from No. 20 steel bars instead of forgings? There is no bar stock in the strength calculation software. Not available in GB150 either. The thickness exceeds the range of thick-walled pipes and is calculated using forgings. In production, No. 20 steel bars are often used for turning, but the thickness of the reinforcing pipe is not thick, and No. 20 steel pipes are used in strength calculations. Now the pressure is high and the wall is thick. It is better to use No. 20 steel bar for turning. I am a little worried. It is better to use forgings. It needs to be outsourced for processing, which will take a long time. When it is put into production, the workshop will definitely want to use bar stock for turning. I wonder if this is possible? Please give your opinion. I have never found a theoretical basis
It stands to reason that bars cannot be used instead of forgings, because the manufacturing inspection requirements of bars are certainly lower than those of forgings, and they cannot be used under high-pressure conditions.
Yes, it is possible. In theory, there is no standard that says it is not possible. In fact, steel pipes are OK. Steel rods are also a process of dense organization. No, the diameter of ordinary steel rods is only more than 300, and larger ones can only use forgings. Therefore, many design units directly write forgings, while some design institutes will only write a 20 and will not indicate whether it is a steel pipe, steel rod or forging at the end. It is all OK and there is no problem.
That makes sense. Generally, manufacturers understand it this way. If you are not sure, you can do some physical and chemical tests against the standards.
We have used parts machined from bar stock, and their performance is worse than forgings.
Can't. 1. The mechanical properties of bars and forgings are different. 2. The poster mentioned that it is a high-pressure reinforced pipe. This is generally a third-level forging, and it cannot be replaced by a bar. ； 3. On the design drawings, the design institute should indicate the types of materials used. For some design drawings that are not standardized, for example, the flange design institute in the drawing only writes 20, which is generally understood to mean that it can be processed with steel plates or forged parts. If it is written as 20II, it is a forged part and cannot be processed with steel plates. The same goes for reinforcing tubes. This is what I did during the inspection process.
Theoretical differences: The tissue fibers of forgings are continuous ； The tissue fibers turned from bar stock are discontinuous, and their mechanical properties are relatively poor.
No, because the rods listed in GB150 are only used as fastener materials and cannot be used as pipe materials. The structure of the bar is not as uniform as the forging, and its mechanical properties and acceptance items are not as good as the forging, so the forging cannot be replaced by the bar.
The eighth floor statement is correct and cannot be substituted because the rods listed in GB150 are only used for fasteners and cannot be used as pipes. The structure of the bar is not as uniform as the forging, and its mechanical properties and acceptance items are more stringent for the forging.
Agree with what the 6th floor said, we clearly indicate 20Ⅱ in the material column on the drawing.
Category 1 and 2 can be considered, but category 3 containers should never be used!
Opposing the argument on the 3rd floor: Round steel (steel bar) is a rolled material, and the quality requirements of the tube blank are higher than that of round steel. After processes such as piercing, pushing, pulling, pulling and shaping, its deformation has far exceeded the forging ratio of ordinary forgings. In addition, there is no mechanical processing of the inner and outer walls after forming, and the internal tissue fibers of the steel pipe are continuous and dense. If we want to make a forced comparison, we can only say that the forging quality of steel pipes is similar to that of high-precision die forgings, but is far from the same level as round steel (steel rods).
Personally I don't think it can be substituted. The bar is formed by hot rolling multiple times, and its mechanical properties in the axial and cross-sectional directions are quite different. Forging is required to change this difference, making its microstructure denser and its mechanical properties uniform. If it can be substituted, it means it is not processed according to the designer's requirements. The performance and safety of the parts cannot be fully guaranteed. If you want to use it as a substitute, you also need the approval of the designer.
No, the performance of bars is much worse than that of forgings.
Learn again* Got new knowledge, :lol
No. Study seriously * You can see it by looking at the corresponding technical requirements for forgings and bars.
Take a good look at GB150. It doesn’t mean that rods can’t be used for takeovers at all. It just has restrictions.
The calculations that are definitely irreplaceable are based on forgings, which must comply with the material composition, performance, delivery status, etc. of the forging standards. Bars will definitely not meet the requirements of the forging standards.