Why is ultrasonic testing required for steel, and why should magnetic particle or penetrant testing be performed on its welding grooves?
Thread Content
This post was last edited by ztr1118 on 2012-9-22 09:50. Why is ultrasonic testing required for steel, and why should magnetic particle or penetrant testing be carried out on its welding grooves? …… Clause 11.1.3 of HG20584-2011: Pressured components and their alloys shall be subjected to magnetic particle or penetrant testing in accordance with GB150 \"Steel Pressure Vessels\" and the provisions of Clause 7.1.1 of this standard, ……………. 1 For all steel materials that are to undergo ultrasonic testing, magnetic particle or penetrant testing shall be conducted on both the weld groove and the backside of the weld root after cleaning. (Note: The provisions do not specify the types of steel (steel plates, steel pipes, forgings) or the material categories (low-alloy high-strength steel, Cr-Mo steel, ordinary low-alloy steel, …). Does this refer to all types of steel?) ) 2 Austenitic stainless steels with a thickness greater than 20 mm, …… This post mainly discusses the surface inspection of welding grooves and the understanding of the standard provisions – does the term \"steel\" in these provisions refer to all types of steel? GB150 provides clear specifications for the inspection of welded grooves: According to clause 6.3(b), for low-alloy steels and Cr-Mo low-alloy steels with a minimum standard tensile strength of Rm ≥ 540 MPa, the surface of the grooves obtained through thermal cutting must be subjected to magnetic particle testing in accordance with JB/T4730.4 after processing, and it shall meet Grade I requirements. We understand that paragraph 1 of clause 11.1.3 in HG20584-2011 refers primarily to the welding groove of steel plates. Forgings of CrMo steel and high-strength steel, as well as steel pipes, should also be considered. I invite experts to share their opinions and engage in discussion. Thank you!
This seems to be some kind of non-destructive testing method used to check the welding quality of weld joints; I’m not sure if that’s correct Continue downstairs.
According to the original intent of HG/T20584, does this also apply to surface inspection of grooves on parts made of fittings or forgings?
As I understand it, when machining grooves in such high-strength low-alloy steels, internal defects in the steel can easily occur or be induced, such as delamination and cracks; therefore, it is necessary to inspect the weld grooves
In my opinion, ultrasonic testing is used to detect internal defects, while magnetic particle and penetrant testing are used for detecting surface defects; combining these two methods ensures high safety levels
Radiographic and ultrasonic testing are primarily used to detect internal defects, while magnetic particle testing is used to detect surface or near-surface defects; penetrant testing is used only to detect surface-opening defects
This is briefly described in some reference books; as far as I remember, high-strength steel and chromium-molybdenum steel require surface testing because flame cutting acts as a form of surface quenching. The situation where the second half cannot be detected applies to electroslag welding. Specifically, you can look at some training tutorials or books on technical Q&A. My standards list these sentences, but I forgot the source
UT is mainly used to detect defects such as delamination in sheets
Paragraph b) of Article 6.3: The effects of thermal cutting on high-strength steel and Cr-Mo steel are similar to those in welding; it easily leads to cold brittleness, therefore groove inspection is necessary.
The requirement for ultrasonic testing of steel indicates high standards for this material; issues such as delamination in steel plates, as well as internal defects in pipes and forgings, are of concern. This also shows that high requirements are placed on welding processes. To ensure welding quality, surface inspection of the weld joints is a means of guaranteeing good welding results.
I agree with what was said on floor 10: the requirement to conduct ultrasonic testing on steel materials indicates high standards for container manufacturing. Moreover, cracks resulting from flame cutting are prone to defects, and this clearly does not meet the requirements; testing is necessary as per the regulations. The cracks that are removed from the back side of the weld are actually similar to those produced by flame cutting, and they also need to be inspected.