Weld evaluation, thick and thin butt welds – ask again
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Expert, please help solve this. For example, when connecting to a PL flange, the actual flange has chamfers. Assume a butt weld exists between a 65 mm thick 16MnⅡ flange and a 5 mm thick 20# pipe (with chamfered ends). According to the definitions in 47014 and the older versions, both thin and thick evaluation categories are required. What we want to determine this time is that for the thick plate process qualification specimens we use, with a thickness of ≥32 mm (Q345R), post-weld heat treatment is required. In fact, this example does not involve post-weld heat treatment. Heat-treated test pieces cannot cover weldments that have not been heat-treated. How can the weld evaluation for such thick plates be covered? ? Regarding the discussion standards, how should this be resolved appropriately (without considering what friends in the group have said about it – that a certain thickness of weld coverage on thin plate test pieces is permitted for inspection at certain locations). ）----Just to understand the standard
You can conduct an evaluation of thick plates without heat treatment
When conducting weld evaluation, there is no need to follow the requirement of 150 – heat treatment is not required if the thickness of Q345R is greater than 32 mm; that is a requirement for manufacturing purposes. For weld evaluation, whether heat treatment is necessary depends on the needs of the evaluation as well as the welding properties of the material.
When welding to a flat-face flange, whether a groove is used or not, it should be treated as a fillet weld. I recall that the specification requires that it be a corner joint between the pipe and the cylinder, and in such cases it should be handled as a butt weld plus a fillet weld
Thank you. Hello, the example mentioned in the explanation is indeed one of takeover and the cylinder. But in terms of groove shape, it is butted. Appendix D of 47014, which deals with fillet welds, specifies that several types of joints between heat exchange tubes and tube sheets are to be evaluated based on fillet welds. In other places, I might not have found it. An example of vents being provided for the tube sheet thickness in actual industrial products is more appropriate to be discussed here
This post was last edited by wanlirn on 2018-7-5 at 14:15. To determine whether full penetration is required, one needs to consider more than just the type of groove; a flat-welded flange clearly does not require full penetration, nor do the tube sheet and heat exchange tubes. Additionally, when working with welding, it is also necessary to have an understanding of container design. In your example, when welding a 56-flange to a 20-size component using a flat weld, and following the structure specified in 20592 along with the use of fillet welds, there is no problem. However, if you have a shell with a thickness of 56 and a fitting of size 20, the designer must ensure that the structure resembles that of a flange – full penetration is definitely required in such cases. It depends on where it is being used
The owner should distinguish between: 1. the difference between joints and welds； 2. The evaluation is conducted to verify the welding process, based on NB47014.
Thank you! I am preparing a 40mm specimen that will not undergo heat treatment. Hello, I have another question: does the production of specimen 47014 need to be carried out within the welding procedures specified for 47015? If so, in this case, preheating is required for welded joints of low-alloy steel with a thickness of over 25 mm. If that is the case, the important factor of (preheating) for this test piece contradicts to some extent the fact that such joints are not preheated in practice (resulting in a smaller weld thickness).
This post was last edited by han*nruoshui on 2018-7-5 17:13. There are indeed differing opinions on this; some think it’s necessary to preheat, while others believe it’s not required. I personally still prefer not to use preheating, as in 47014 a reduction of the preheating temperature by more than 50 degrees is considered an important factor. However, since welding inspections do not require preheating, applying preheating in actual construction should not be regarded as a significant change in requirements; therefore, I think preheating is unnecessary. But if you don’t preheat it, it won’t meet the standards and there’s nothing you can do. No basis has ever been found for this issue.
For the assessment without preheating, the actual welded part can be preheated. I saw a post like this in a bar before. I have a question here: must we conduct weld evaluations within the framework of standard 47015? If so, this thick specimen needs to be preheated. As for the previous heat treatment, I understand your explanation. Thank you
Hello. This example is a corner joint, a combined weld of butt welding and corner welding. Our assessment is mainly focused on this butt weld. Friend, can you elaborate a bit here?