Selection of Liquefied Gas Storage Tanks - Zhongjie Equipment - Sales and Manufacturing of Liquefied Gas Storage Tanks and Pressure Vessels

Description :

　　Common Problems in Liquefied Gas Storage Tank Inspection (Part 2)

　　(1) Material management: ① The storage management of materials is chaotic, with no distinction between furnace batch numbers or grades, no distinction between those awaiting inspection and those already inspected, and no distinction between qualified and unqualified materials, all piled up together. ② The symbols of materials, some of which cannot distinguish the furnace batch number, are not transplanted, and many cut leftover boards are sent to the workshop without material symbols or return procedures. Material re inspection, some materials do not have the original certificate of raw materials, and the copies do not have the signature of the distributor's legal representative and the special seal for inspection. ③ The use of welding materials, some units do not have strict guidelines for the use and recycling of welding rods, some use welding rods with different batch numbers from the welding rod furnace, and some use them by one person while others use them.

　　(2) In terms of non-destructive testing: ① The content of the non-destructive testing trust letter is incomplete, and some of the parts inspected during testing are unclear, resulting in missed detections and a lack of testing shares. The layout diagram in the testing statement cannot clearly reflect the testing location. ② Lack of RT testing share: What is a certain cylinder? 273, RT testing. But there are only four 300mm negatives in the non-destructive testing statement. According to JB4730 regulations, Heze Boiler Factory Co., Ltd. has a useful length of 110mm for its film, and there should be 10 missed 110mm films during RT testing. The support of a certain vertical container is made of angle steel directly welded to the cylinder and head, but there are gaps on both ends of the angle steel at the weld seam between the simplified body and the head. The two ends of the angle steel do not touch the weld seam, but the angle steel covers the weld seam here. RT testing should also be conducted here.

　　(3) Product welding test plate: The non-destructive testing film of the product welding test plate is not identified. If there are defects, sampling cannot be avoided from the defective parts. For those with heat treatment requirements, the test panel will not be subjected to heat treatment in the same furnace as the product.

　　(4) In terms of production equipment: Some units have poor equipment condition, and voltage meters, current meters, and pressure meters are not calibrated.

　　(5) Welder problem: ① A container factory has not produced for more than 10 months, and the welders did not take the exam when they resumed production. ② A certain container is a composite plate of 16MnR and 1Cr18Ni9Ti. Welders holding the welding items of 16MnR and 1Cr18Ni9Ti cannot weld the composite plate of 16MnR and 1Cr18Ni9Ti. According to the "Examination and Management Rules for Welders of Boiler and Pressure Vessel Pipelines", the welding of composite plates should obtain welding qualification.

　　(6) In terms of water pressure testing: ① There is a lack of requirements for the water pressure testing process and related procedures, and there are no rules for the pressure testing medium and safety protection. There is no laboratory statement for the analysis of chloride ion content. ② The water pressure test of the reaction kettle resulted in the welding of a jacket without conducting a water pressure test on the inner cylinder, which caused defects that cannot be repaired.

　　(7) Outsourcing issues: ① Outsourcing does not evaluate subcontractors and does not file with the issuing organization; ② There are no standardized experimental methods in the physical and chemical entrustment letter; ③ When purchasing materials, only steel grades or grades are given without specific requirements such as rules for sulfur and phosphorus content. Forming some harmful elements exceeding the standard; ④ The thickness of the head does not comply with the rules. According to JB4746, the small thickness of the head should be greater than the nominal thickness minus the additional wall thickness. What is a liquefied gas storage tank? 1000. The planned thickness is 12mm. The head is limited by 16MnR steel plate, and the wall thickness reduction is about 1mm, which is greater than the negative error of the steel plate. 14mm 16MnR steel plate should be used for restriction, and its small wall thickness meets the planning requirements.

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