Beware! Pressure equipment welded using flux-cored wires are all defective

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For welding flux-cored wires, there are **standards such as GB/T10045-2001 for carbon steel flux-cored wires, GB/T 17493-2008 for low-alloy steel flux-cored wires, and GB/T17853-1999 for stainless steel flux-cored wires**. NB/T47018.1-2017 \"Technical requirements for ordering welding materials used in pressure vessels\" also specifies the requirements regarding flux-cored wires to be used in pressure vessels. Recently, I came across an article titled “To reiterate the truth in detail: Beware!” written by Professor Ge Zhaowen, a member of the editorial board for the NB/T47018.1-2017 standard \"All pressure-bearing equipment welded using flux-cored wires are defective products,\" and I would like to share this information with you all. From 1998 to 2018, our country used **standards for flux-cored wires formulated according to the American AWS standards. In 2011, China issued NB/T 47018-2011 \"Technical Requirements for Ordering Welding Materials for Pressure Equipment,\" which established principle guidelines for the use of flux-cored wires. Six years later, NB/T 47018-2017 specified the detailed requirements for flux-cored wires: alkaline slag systems, the composition of the flux core as well as the uniformity of its distribution, and methods to ensure control of diffused hydrogen levels. To date, no official reports have been seen regarding flux-cored wire manufacturers that meet the requirements of NB/T 47018.1. It is reported that the European company××× can supply flux-cored wires based on basic slag systems, but at a high price. According to various sources of information, over the years many companies in the pressure equipment industry have misused, altered, or used for personal purposes welding rods that do not meet the requirements of NB/T 47018.1; in other words, they have used ordinary welding rods to manufacture pressure equipment. Recently, someone on the internet admitted that between 2007 and 2015 he used ordinary welding rods to construct a total of 8 pressure vessels in three different locations. In 2023, he went to City X to conduct an “inspection,” and found that “everything was normal,” thereby proving that it was correct to use ordinary welding rods in the first place. I was shocked after seeing it! From the perspective of standards and supervision/management of pressure equipment ； All eight of these pressure vessels are substandard products! The problems that arise from this deserve attention. (1) The correct understanding of clause 3.5 C) in NB/T 47018.1-2017 is as follows: ① Flux-cored wires shall, in accordance with the technical requirements specified in NB/T 47018.2, also include batch identification, grouping rules, quality certificates, and re-inspection. ② Flux-cored wires used for carbon steel and low-alloy steel shall all have an alkaline slag system. ③The order contract must include specific details and inspection methods regarding the flux core composition, as well as the uniformity of flux core filling for carbon steel, low-alloy steel, and stainless steel. ④Measures to ensure that the hydrogen content in the deposited metal is within acceptable limits after opening the vacuum-packed welding wire. (2) The criteria for determining whether the quality of pressure equipment meets requirements are stipulated in relevant laws and standards. These eight pressure vessels were constructed during the period when GB/T 10045-2001 \"Carbon Steel Flux-Cored Welding Electrodes\" and GB/T 17493-2008 \"Low-Alloy Steel Flux-Cored Welding Electrodes\" were in effect. Both standards contain warnings advising readers to pay close attention to the \"uniformity of flux composition and distribution\" as well as the \"unstable mechanical properties of the deposited metal.\" Anyone with basic knowledge of welding knows that such electrodes cannot be used for welding pressure-bearing equipment! “The “warriors” who dared to challenge ASME ignored the standards; within eight years, they welded 8 pressure vessels that were defective and violated basic regulations. They treated pressure vessels with explosion risks as test pieces, thereby creating landmines the size of spherical tanks ranging from 1000 M3 to 4000 M3. Clause 4.4.2 of NB/T 47018.1-2011 stipulates: \"For welding materials of corresponding types that are not specified in this standard, their technical requirements shall be determined with reference to the provisions of this standard, and evidence from welding performance tests and practical engineering applications shall be available.\" Without studying the relevant standards in advance, conducting any analytical assessments, or performing verification tests, 4 units were welded in 2007, and another 4 units were welded on two occasions in 2015. (3) The person who disclosed the information, XXX, conducted an on-site “inspection” of the first four units in 2023, and found that “everything was normal.” The question is: was it necessary to open the containers for inspection? Are there official documents such as test reports from inspection agencies to confirm this? Or it’s a lie told to comfort oneself after an “inspection”. The so-called “everything is normal” only indicates that the four pressure vessels are still in use despite being faulty; it says nothing about the actual condition of these vessels, their usage and maintenance history, or the distribution of corrosion defects on their inner and outer surfaces. It cannot be used as a basis to justify continued use, let alone as a reason to use ordinary flux-cored wires in pressure-bearing equipment! (4) Is it a personal act to have \"done it\", \"completed it\", or \"used it\" by welding 8 pressure vessels with ordinary cored wire? Is it still a “unit” behavior? Has it undergone verification, review, and approval by the internal and external quality assurance management systems? (5) Both individual actions and those carried out by \"units\" are illegal and improper behaviors; they must be reported to the owner and the safety supervision agency, so as to enhance supervision and management, improve routine maintenance, increase the frequency of inspections, and reduce the service level to prevent unexpected incidents. (6) Standards must comply with regulations. Standards are products of coordination; regardless of whether one is involved in their development, different opinions can exist regarding existing standards, and people have the right to express them or file complaints. However, before the standards are revised, it is necessary to abide by them – this is a principle that those involved in standard development must follow. The individual in question has been involved in the development of NB/T 47018 for 12 years; they have always agreed with the provisions of clause 3.5(c) in NB/T 47018.1. However, in practice, they insisted on using ordinary flux-cored welding wires to weld 8 pressure vessels, refusing to comply with NB/T 47018.1 – this is a hypocritical attitude that has extremely negative consequences. Conclusion: The American ASME BPVC II C:2023 \"Welding Materials\" cites the American AWS SFA-5.29/SFA-5.29M:2022 \"Specifications for Low-Alloy Steels for Flux-Cored Wire Arc Welding.\" The provisions regarding the composition of the flux core and the uniformity of the filler material are governed by AWS A 5.02/A 5.02M:2007 \"Standard Specifications, Packaging, and Physical Properties for Filler Metals.\" Clause 4.2.3 states that \"the composition of the flux core and the filler metal core should be sufficiently uniform throughout the length of the wire, so as not to adversely affect the usability of the wire or the properties of the weld metal or deposited metal.\" ”It is evident that the flux-cored wire standard formulated by AWS in the United States still pays attention to uniformity. Since 2018, China has begun to formulate flux-cored wire standards in accordance with ISO standards. Although no warning statements are included in these standards any longer, it should not be assumed that flux-cored wire manufacturers, both domestic and foreign, can meet the requirements specified in clause 3.5C of NB/T 47018.1. When purchasing flux-cored wire for use in pressure-bearing equipment, it is crucial to specify in the order contract that the wire must comply with the requirements of clause 3.5C of NB/T 47018.1.