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U.S. Parallel Welding Quality Inspection And Its Implications

U.S. Parallel Welding Quality Inspection And Its Implications

Oct 24, 2014

This article describes the case of the United States parallel inspection of welding quality, standardized basis, and some suggestions combined with our situation. If improperly, please correct me. 

An American National Standards advocates parallel testing in the United States, steel fabrication / installation industry generally implement two kinds of quality inspection, that the contractor (construction units) of supervision test. 

Both tests are separate, parallel. Supervision Inspection. Supervision Inspection not be construed as contractor detected, the owner sent next to the station supervision, but should be understood as the owners to hire a qualified professional testing organizations independently tested. American laws and standards, and our country, we see contractors (construction units) take full responsibility for their products (works) quality. But the United States Steel summarizing numerous painful lesson after the accident said: contractor accountability alone is not enough and too vague. Must take effective measures, and that is to give power to the owners supervision inspection, it is necessary to manufacture / installation and supervision of these two tests. These two parallel test appears to be repetitive, but it is necessary. Because the purpose is to strive for quality inspection contractor characterize his product is in line with the prescribed requirements, he can hand over the quality control in the range; while the owners aim is to verify the quality inspection of product quality if indeed guaranteed. In this sense, the contractor's activities are quality control and quality assurance activities are the owners. Based on the above considerations, the American National Standard ANSI / AWS D1.1-98 "Steel Welding Code" explicitly welding quality inspection is divided into two categories, namely, inspection and supervision of manufacturing contractor / installation testing and the owners, said they has two different functions, and pointed out that the former is the responsibility of the contractor, which is the power of the owners. The former is necessary to implement the whole construction process, the depth of the latter, the breadth is determined by the owners. 

Actual operation, there are also a test case separately. Less important for the performance of such steel, or contractors, inspection personnel qualifications, inspection equipment, tools, owners are trustworthy, the owners can give up power supervision inspection, carried out only manufacture construction / installation testing, but to create the owners management charge (project director of Quasi) to supervise the inspection is essential. In another case, namely through the parallel test, confirmed test useless or intentionally cheating manufacture / installation side, the owners have the right to cancel the inspection of manufacturing / installation side, with the depth, breadth, covering the whole process of inspection supervision instead of two tests. These cases, specifications are allowed, of course, check with supervision instead of manufacturing / installation testing, the corresponding inspection fee shall be determined from the contractor deducted. In the United States, owners and contractors in order to save the cost of duplicate testing, in terms of the contract altogether clear manufacture / installation inspection carried out by the owners hired a professional testing organization. Supervision Inspection such owners are not necessary. Professional testing organization. Supervision Inspection such owners are not necessary. Professional testing organizations in the U.S. steel fabrication / installation industry is very popular. It is also known as first party inspection test. 

Parallel to the US welding quality inspection, standardized basis, and some suggestions combined with our situation. If improperly, please correct me. 

An American National Standards advocate parallel test 

In the U.S., steel manufacturing / installation industry generally implement two kinds of quality inspection, that the contractor (construction unit) manufacturing / installation inspection and owners (construction unit) of supervision test. These two tests are independent, parallel, parallel. Supervision Inspection not be construed as contractor detected, the owner sent next to the station supervision, but should be understood as the owners to hire a qualified professional testing organizations independently tested. 

American laws and standards, and our country, we see contractors (construction units to take full responsibility for their products (works) but the quality of the lessons learned from countless American steel after the tragic accident that:. Solely accountable contractors is not enough, too general must take effective measures, that is to give power to the owners supervision inspection, it is necessary to manufacture / installation and supervision of these two tests. these two parallel test appears to be repetitive, but is necessary because the purpose is to strive for quality inspection contractor characterize his product is in line with the prescribed requirements, he can hand over the quality control in the range; while the owners aim is to verify the quality inspection of product quality really reached the requirements , whether it is really safe and reliable performance is guaranteed from this sense, the contractor's activities are quality control and quality assurance activities are the owners. based on the above considerations, the American National Standard ANSI / AWS D1.1-98 "steel welding Code "explicitly welding quality inspection is divided into two categories, namely, inspection and supervision of manufacturing contractor / installation testing and the owners, said they have two different functions, and pointed out that the former is the responsibility of the contractor, the latter is the power of the owners. former should run through the whole construction process, the depth of the latter, the breadth is determined by the owners. 

The actual operation, there are a case of a single test. For example less important steel, or contractor performance, qualification testing personnel, testing equipment, tools, owners are trustworthy, the owners can give up power supervision inspection, carried out only manufacture construction / installation testing, but the owners of the construction management responsible person (project director of Quasi) to supervise the inspection is essential. In another case, namely through the parallel test, confirmed test useless or intentionally cheating manufacture / installation side, the owners have the right to cancel the inspection of manufacturing / installation side, with the depth, breadth, covering the whole process of inspection supervision instead of two tests. These cases, specifications are allowed, of course, check with supervision instead of manufacturing / installation testing, the corresponding inspection fee shall be determined from the contractor deducted. In the United States, owners and contractors in order to save the cost of duplicate testing, in terms of the contract altogether clear manufacture / installation testing, the corresponding inspection fee shall be determined from the contractor deducted. In the United States, owners and contractors in order to save the cost of duplicate testing, in terms of the contract altogether clear Manufacturing Manufacturing / installation inspection carried out by the owners hired a professional testing organization. Supervision Inspection such owners are not necessary. Professional testing organizations in the U.S. steel fabrication / installation industry is very popular. It is also known as third party inspection test. 

Personnel qualification two parallel inspection America 

In the United States, whether employed by the contractor or the owner's quality inspection personnel must certificates, which seems more than emphasize "according to their professional posts," one step further. NDT personnel, to hold the American Society for Nondestructive Testing (ASNT) certificate in the appropriate level of work. Even the appearance of weld seam quality inspection personnel must be trained, qualification assessment, the American Welding Society Certificate holders Steel Committee (AWS) or the Canadian Welding Bureau issued to posts. On behalf of the owners, that is responsible for creating a management qualification review. U.S. specification to censor a lot of power. D1.1-98 Specification Section 6.6.2 is this provision: "The Contractor shall inspector (regardless of which party is employed inspectors) requirements, the quality of materials and processing errors were corrected to conform to the contract requirements of the text. "

Respect for knowledge and professional certificates, which seems to be characteristic of the industrial countries. In the United States, you may be creating a management engineer (Quasi our supervision engineers), but if there is no censor certificate, you do not check the weld appearance quality qualifications. Early American norms but also more attention to titles qualified engineers and technicians, which is right, but later found their quality engineering, testing and actual test data, the accuracy of the operator from the welding and inspection, so they to welder qualification certificate requirements, testing personnel to accreditation, certificate of inspectors to. 

3 U.S. parallel NDT inspection 

NDT manufacturing / installation and supervision of these two parallel tests important content, means this is the most shoddy contractors frightened. A thickness of 10mm butt weld, such as the use of CO2 gas shielded arc welding (SMAW or), in the case of the outer surface of the weld width similar open groove (or back gouging) and without groove (or negative unclear root) compared to about more use of consumables nearly doubled, comprehensive ergonomics for the latter third. Supervision at the time of testing is not performed, some of the local testing site contractor beveling (detection ratio is less than 100%) of the weld, in testing sites open groove (or instead of gouging), more attention to welding, weld better quality, but without testing the site, is another matter. If there is a problem is not testing the site, the contractor will say: "I was sampling, and not able to get that part of how to do it I've got to ask me 100 percent inspection, or as agreed to expand the proportion of exploration?." That is to say, prison NDT inspection made in any part of the weld may be random, but not limited to manufacturing / installation checks over the part. This provision to improve the welding quality of the local testing is crucial. In the United States there is this situation: even if the structure does not require non-destructive weld testing, but the owners have found cheating contractor (if not open groove, welding is not drying, etc.), while the use of non-destructive testing methods proven the Contractor shall bear the costs arising therefrom all disappear. 

It should also be noted that in the United States regardless of the manufacturing / installation, or supervision, non-destructive testing methods used are not limited to this kind of ultrasonic flaw detection method, fillet welds are generally for magnetic particle examination, full penetration butt joints and T-shaped connector, although with ultrasound-based, but "when the display plane characteristics within the sensitivity range scanning, you may need to use other more detailed evaluation methods," such as rays, another ultrasound technologies. This limitation is the specification requirements. 

4 related revelation (or suggestions) 

Relatively speaking, the United States steel welds on specific eligibility criteria of quality, and in many countries compared (including China) are loose, but the United States Steel accident rate in the world is minimal. This is why, "I think the United States benefit from parallel rows of test Inspired, I made the following suggestions to the person concerned for domestic reference: 

(A) of Regulation parallel test should be vigorously promoted. U.S. parallel examination is carried out, is the United States norms advocated. Our specification is not limited to technical aspects of the requirements, there should be quality inspection management requirements. I hope as soon as possible revision of norms, early and advanced specification standards. In the case of our country has not yet revised specification, construction administrative departments should promote parallel testing, please third party sampling, quality of the project objective and fair evaluation of the steel works which is very necessary. 

(2) supervision unit should "parallel testing" as an indispensable responsibility. This year the State Council issued the "Construction Quality Management Regulations" will "parallel testing" as a form of "supervising the implementation of the construction project," the. I think that a form of "construction project supervision," the. I think supervision unit construction unit commissioned by representatives of the construction supervision unit test in parallel construction side, is a not shirk responsibility. Steel project supervisors should emphasize professional counterparts, due welding engineer. Due to the special nature of non-destructive testing, supervision should be recommended or joint qualified professional testing organizations to test