Discussion on the Problems of Welder Examination in Special Welding Projects in Welding Rules

Time:2017-09-18 12:00:00

The safety of special equipment is related to the quality of the special equipment body. It is related to the technical level of the operators. It is an important way to achieve the combination of quality and safety of special equipment and safety of personnel. Improve the level of personnel operations, which requires the use of scientific and standardized examination methods to train high-level special equipment operators. Although there are standard rules for the corresponding exams, there are still some blind spots in some details. This article will address some of the issues that are not detailed in the Rules.

Status and problems

The General Regulations of the General Administration of Quality Supervision, Inspection and Quarantine issued the "Special Equipment Welding Operators Assessment Rules (TSG Z6002-2010)", hereinafter referred to as the "Rules", implemented from February 1, 2011. The new "Rules" has been greatly improved compared with the original "Boiler and Pressure Vessel Pressure Pipe Welder Examination and Management Rules" (National Quality Inspection Pot [2002] No. 109), adding many new contents, but with social progress and The development of science and technology, the emergence of new materials and new welding techniques, the "Rules" is difficult to cover all welding projects, therefore, in the "Rules" Article 36 and "about the special equipment welding operators assessment rules" implementation comments (Quality Inspection Letter [2011] No. 9), welding methods other than those specified in the Rules (such as brazing), material types (such as medium carbon steel, tin bronze, zirconium and zirconium alloy), filling material categories and Weld joint forms (such as wear-resistant layer surfacing, terminating welds, slot welds and plug welds) and electromechanical equipment use materials that exceed the scope of the domestic design code, or use standard tensile strength lower limit values greater than 610 MPa Welding such as low alloy steel is collectively referred to as “special welding project”. In the "Rules", only the principle requirements are required for the welder examination of special welding projects. There is no project code, test method, content and test result evaluation standard for welding quality, which creates a blind spot for such examinations. In response to this situation, the author combined with many years of experience in the examination management of operators, and discussed with a number of welding experts in Shandong Province, summed up the scientific and standardized examination procedures for special welding projects in Shandong Province: the implementation of the "two" examination is a standardized examination. Premise guarantee; scientifically prepare the "examination plan", solve the test what to do; combine the actual implementation of the test to clarify the test focus.

Preparation and implementation of the test plan

The test of the straight seam high-frequency electric resistance welding steel pipe welder operator is a kind of special welding project test, but there are some problems in the detailed rules such as the specific test. For example: how to develop test method representation and code, how to judge the quality of welding. Here, the implementation plan of the "straight seam high-frequency electric resistance welding steel pipe welding machine operator" test mainly includes the examination method, procedure steps and examination procedure evaluation; the examinations of other special welding items are similar and so on.

1. Test item representation method and code. In conjunction with the General Rules of the "Exclusions" test item number, and consulting with experts from Shandong University professors, corporate technology leaders and the main drafters of the "Rules", after inquiring about the US standards and EU standards, the straight-slit high-frequency resistors were finally determined. The welding pipe welding machine operator test item representation method and code name is: HFRW (high frequency welding welding high-frequency resistance welding English first letter abbreviation), and electric resistance welding in English is: electric resistance welding, abbreviated as ERW. HFRW can express the meaning of high-frequency resistance welding more accurately than ERW; the welding position is flat welding test piece, code is 1G, the welding material country does not require it; the welding process factor is: visual observation, control, code 19; no automatic Tracking system, codenamed 07; single pass weld, codenamed 08. Namely: the straight seam high-frequency electric resistance welding steel pipe welding machine operator test items and certification project code is expressed as: HFRW-1G-07/08/19.

At present, the society often uses the straight seam in the high-frequency electric resistance welding steel pipe welding machine operator test item code (HFRW-1G-07/08/19) and the "welded steel pipe for low-pressure fluid transmission GB/T 3091-2008". High frequency resistance welded steel pipe product standard (ERW) confusion. The "welded steel pipe for low-pressure fluid transmission GB/T 3091-2008" stipulates: (1) straight seam high-frequency electric resistance welded steel pipe code is ERW, (2) straight seam submerged arc welded steel pipe code is SAWL, (3) spiral seam Submerged arc welded steel pipe code is SAWH, which is the marking code of the steel pipe products welded by the three welding methods, not the project code of the welder test for operating these three welding equipments.

2. Implement the "two-in-one" test method. According to the requirements of the "Rules", the straight seam high-frequency resistance welding steel pipe welding machine operator test is divided into two parts: the basic knowledge test and the operation skill test. First of all, the Provincial Quality Supervision Bureau will designate the examination institution that implements the examination to meet the conditions of the examination in the Rules, so that the subject of the examination is legal. Secondly, the implementation of the "two" examination, that is, the examination of the theoretical examination machine, the actual operation of the examination materialization or simulation, the theoretical knowledge examination using the computer answer method, in 2011, Shandong independently developed the "Shandong Province special equipment operator examination system" The province's unified "theoretical test question bank" was compiled, and the test bank was updated and improved every year. The test system covered all the test items of the operators; the province's unified "real test standards" and "real test" were prepared. The question bank has solved the theoretical examination and practical examination of special welding projects.

3. Test procedure method. After passing the basic knowledge test, you can take the operation skill test, and the welding operation skill test uses the method of welding the test piece and performing the test evaluation. The state stipulates that this test allows the use of the company's existing operating equipment for practical examinations, and allows the actual operational skills of the project to operate the teacher's qualifications exempt from forensics. The examination plan shall be formulated and implemented according to the product design and manufacturing technical conditions, but the experts shall be organized to review the method, content and evaluation criteria of the examination. The examination plan for the examination shall be reviewed and approved by the technical person in charge of the examination organization. Go to the on-site exam.

4. The equipment used in the practical examination. The actual test equipment adopts the existing Φ76mm high-frequency electric resistance welded pipe unit of the enterprise. Each tester performs a separate operation test according to the welding process card of the Φ76mm straight seam high-frequency welded pipe unit which has been prepared by the enterprise and verified by the technical person in charge of the examination organization. The number and length of the test pieces shall meet the requirements of testing and inspection, and the test pieces of each candidate shall be marked.

5. Test the test piece. The test piece is: the material steel number is Q235B, the plate thickness is 3mm, and the straight seam welded pipe with the specification of Φ60.3×3mm×6000mm is welded, and the welding position is the straight seam flat welding position.

6. Test items, test methods and evaluation criteria. The inspection items have visual inspection, process performance inspection (bending test, flattening test), and non-destructive testing.

6.1 Visual inspection: Refer to the pipe weld requirements in the Rules.

6.2 Process performance check: The process performance inspection of straight seam high-frequency electric resistance welded steel pipe is divided into bending test and flattening test.

6.2.1 Bending test: According to the provisions of GB/T3091-2008 "welded steel pipe for low-pressure fluid transport", the electric resistance welded steel pipe with outer diameter not more than Φ60.3mm shall be subjected to bending test. During the test, the sample shall be free of filler. The bending radius is 6 times the outer diameter of the steel pipe, the bending angle is 90°, and the weld bead is located on the outer side in the bending direction. After the test, cracks were not allowed on the specimen.

6.2.2 Flattening test: According to the provisions of GB/T3091-2008 "welded steel pipe for low-pressure fluid transport", the electric resistance welded steel pipe with outer diameter greater than Φ60.3mm shall be flattened. The length of the flattened specimen shall be not less than 64mm. The welds of the two specimens shall be located at 90° and 0° respectively to the direction of application. During the test, when the distance between the two plates is 2/3 of the outer diameter of the steel pipe, no cracks or cracks shall be allowed at the weld. When the distance between the two plates is 1/3 of the outer diameter of the steel pipe, cracks or cracks are not allowed in other parts beside the weld; continue to flatten until it fits against the pipe wall, and it is not allowed to appear during the entire flattening process. Layering or metal over-burning.

6.3 Non-destructive testing: Ultrasonic flaw detection of electric resistance welded steel pipes shall comply with the acceptance level L3 (C10) in SY/T 6423.2. The inspection and test methods and evaluation standards of the test pieces shall be carried out by the enterprise in accordance with the product design and manufacturing technical conditions and the corresponding technical specifications and technical requirements. The inspection results shall be reported to the examination organization for review and filing.

7. The test scores, the results of the test results, the re-examination rules and precautions refer to the uniform requirements of the Rules.

Conclusion

The "Rules" is the basis of the welder's examination. For the blind spots in some special welding projects, this article discusses how to develop the test procedures for special welding projects without specific implementation rules, based on the "Rules", supplemented by other standards, and Verification in practice and exploring a reasonable test plan. The implementation and promotion of such programs is a useful supplement to the "Rules" and provides a necessary reference and basis for the future improvement of the "Rules".

(Author: Shandong Special Equipment Inspection and Research Institute)