【摘要】：全焊接球閥應用于大型石油天然氣管線,其質(zhì)量直接關(guān)系到國家能源運輸安全。由于應用條件限制,焊后不能進行熱處理,因此對焊縫有較高的強度要求。同時,長輸管線惡劣的應用環(huán)境對管線球閥的抗外載荷能力提出了嚴格的技術(shù)要求。合理控制焊接殘余應力的分布以及確定管線球閥的極限承載能力對優(yōu)化工藝參數(shù)和節(jié)省材料具有重要的意義。 在彈塑性理論的基礎上,在ABAQUS軟件中建立了全焊接球閥的有限元模型,根據(jù)實測殘余應力值,使用生死單元技術(shù)預制了多層焊下全焊接球閥的殘余應力。在此基礎上,通過對管線球閥施加內(nèi)壓和彎曲載荷,得到了管線失效時球閥的應力分布,結(jié)果表明,材料發(fā)生失效的位置出現(xiàn)在閥門和管道相接處。然后,根據(jù)ASMEⅧ-2中的相關(guān)規(guī)定,在球閥關(guān)鍵位置繪制等效應力線,對應力進行分類和強度評定,論證了全焊接球閥的應力在管道失效時處于安全水平。 為進一步研究閥門的承載能力,通過改變載荷條件,確定了現(xiàn)有壁厚下管線球閥所能承受的極限內(nèi)壓。在進一步的閥體壁厚校核中發(fā)現(xiàn),實際閥門的厚度遠遠大于壓力設計厚度,因此,通過對不同厚度的閥門進行試算,最終確定了工作內(nèi)壓下的最小閥門壁厚。
[Abstract]:The quality of fully welded ball valve used in large oil and gas pipeline is directly related to the national energy transportation safety. Due to the limitation of application condition, heat treatment can not be carried out after welding, so the strength of weld seam is very high. At the same time, the harsh application environment of long distance pipeline puts forward strict technical requirements for the ability of pipeline ball valve to resist external load. It is important to control the distribution of welding residual stress and determine the ultimate bearing capacity of pipeline ball valve for optimizing process parameters and saving materials. On the basis of elastic-plastic theory, the finite element model of fully welded ball valve is established in ABAQUS software. According to the measured residual stress value, the residual stress of fully welded ball valve under multilayer welding is prefabricated by using the birth and death element technique. On this basis, by applying internal pressure and bending load to the pipeline ball valve, the stress distribution of the ball valve is obtained when the pipeline fails. The results show that the material failure occurs at the junction of the valve and the pipeline. Then, according to the relevant provisions of ASME 鈪，

本文編號：2235959