- 期刊
石油工業用球形儲槽破裂問題與防範
Precautions for Avoidance of Fracture of Spherical LPG Storage Tanks in the Oil Refinery
摘要
目前造船工業、煉鋼工業、建築工業、交通工具如橋樑、車輛及機械工業，特別是近晚各種壓力容器之建造都需借重熔銲技術來完成工作，但在銲接施工中常會發生許多問題，因此技術上有待作進一步探討。尤其是球形儲槽之銲建多用高強力鋼材料來代替軟鋼，於是問題更多。事實上依據許多文獻報導，歐美及日本各工業先進國家每年建造球槽有數以千計之多，其中LPG儲槽多在耐壓試驗過程中發生脆性破壞，每在轟然巨響之下瞬息間釀成槽毀人傷的慘重災害。有關球槽破裂真正原因和如何加強防範來以策安全的問題，著實是困難，只能藉事後之檢討與改進。譬如材料之挑選、設計、施工和確立檢查標準都非常重要，然而最被重視的應首推銲接技術，如銲接龜裂和母材，銲口之遲緩破壞（Delayed Fracture）、銲口強度和特性以及銲接輸入熱量、疲勞特性、材料抗拉強度與切口韌性（Notch Toughness）等觀念均益形重要，非常值得研究。筆者直到現在因多年從事球槽興建工作，故略具些許心得，有鑑於球槽施工困難且係高壓容器，為了減輕發生破裂漏氣爆炸之災害，不揣學淺，針對球槽之設計、構造、熔接、檢查和作業上安全等之措施作較有系統之介紹，力避高深理論，提供工程界讀者參考，冀其稍有助益。
並列摘要
In many cases, brittle fracture in the actual welded steel structure should be assumed to be originated from the local defects, which located at the welded joints with discontinuous shaped parts, having high stress field. Practically, local defects of the structure include weld cracks, lack penetrations, and other welded defects such as fatigue cracks, stress corrosion cracks, segregation of steel, under cutting, poor fusion, porosity, slag inclusions, and flame cutting notch etc.In recent years, a larger number of spherical pressure vessels made by high strength steels, have been used for storing combustible high pressure gas and liquid gas so that their fabrication and service safety must be of the utmost importance. However there were two fractures occurred in the spherical tank during water pressure tests in 1968. At an annual inspection of the interior of LPG tanks, many micro cracks were detected on the inner surface of the shell plates, in Japan.In this paper, some important points have been made such as main welding defects, and some problems in fabricating, design, welding, manufacturing, and inspection techniques, of spherical tanks, base on my experience and may reference to many technical papers.The weldability, workability, residual stress, and deformation, especially welding cracking during fabrication seems to be the most important factors, if the fracture of spherical tanks is to be avoided.To avoid such brittle failures of pressure vessels, it is necessary precaution taken during design, manufacture, and maintenance.