Liquefied LNG tank manufacturer supplies 150 cubic meters of low-temperature storage tanks to the ceramic industry

Description :

　　Requirements for Repair of Welded Joints in Natural Gas Storage Tanks

　　1. We should analyze the causes of the shortcomings and propose corresponding repair plans.

　　2. A detailed repair process should be developed and approved by the welding engineer before implementation. The repair process should at least include the reasons for the occurrence of defects; Skill measures to prevent the recurrence of defects; Determination of welding process parameters; Repair welders; Trademark and standards of welding materials; Signature of the person in charge of preparing the repair process and the person approving it.

　　3. The number of repairs for the same part (referring to the area where the filler metal for welding overlaps) should not exceed 2 times. Repairs exceeding 2 times shall be approved by the technical director of the production unit, and the number of repairs, location, non-destructive testing results after repairs, and the approval of the technical director shall be recorded in the product production change statement of the liquefied gas storage tank quality certificate.

　　4. The on-site record of the repair should be detailed, including at least the groove type, size, repair length, welding process parameters (welding current, arc voltage, welding speed, preheating temperature, interlayer temperature, post heating temperature and insulation time, welding material trademark and standard, welding direction, and the welder and their steel seal).

　　5. Liquefied gas storage tanks that require post weld heat treatment should be welded and repaired before heat treatment; If welding repair is carried out after heat treatment, heat treatment should be carried out again after repair.

　　6. Austenitic stainless steel liquefied gas storage tanks with intergranular corrosion resistance requirements must still maintain their original intergranular corrosion resistance at the repair site.

　　7. For those that need to be repaired after pressure testing, the repaired parts shall pass non-destructive testing according to the original requirements. For liquefied gas storage tanks that require repair due to welding joints or pipe leaks, or for repair depths greater than 1/2 of the wall thickness, a new pressure test should be conducted.

AfterSalesService :

• Liquefied LNG tank manufacturer