この溶接継手の製造方法は、温液化ガスタンクの使用温度において、溶接金属の線膨張係数と母材の線膨張係数との差に起因して溶接継手に生じる熱応力を求める熱応力算出工程と、溶接継手に欠陥を想定し、熱応力の影響を加味して、低温液化ガスタンクの運用中に低温液化ガスタンクが脆性破壊しないための必要CTOD値を求める必要CTOD値算出工程と、低温液化ガスタンクの使用温度における溶接継手の熱影響部のCTOD値を測定するCTOD値測定工程と、熱影響部のCTOD値が必要CTOD値以上であることが確認された厚鋼板を前記母材として使用して母材を溶接する溶接工程と、を含む。
This welded joint manufacturing method includes: a thermal stress calculating step for obtaining a thermal stress generated in a welded joint as a result of a difference between a linear expansion coefficient of welded metal and the linear expansion coefficient of a base material at a usage temperature of a low-temperature liquefied gas tank; a required CTOD value calculating step for obtaining a required CTOD value for preventing brittle fracture of the low-temperature liquefied gas tank during operation of the low-temperature liquefied gas tank, taking into account the effects of thermal stress, assuming a defect in the welded joint; a CTOD value measuring step for measuring the CTOD value of a heat affected zone of the welded joint at the usage temperature of the low-temperature liquefied gas tank; and a welding step for welding the base material, using, as the base material, a thick steel plate for which it has been confirmed that the CTOD value of the heat affected zone is equal to or greater than the required CTOD value.
溶接継手の製造方法、溶接継手、低温液化ガスタンクの設計方法、及び低温液化ガスタンク
2024-04-10
Patent
Electronic Resource
Japanese