【摘要】：全焊接球閥應(yīng)用于大型石油天然氣管線,其質(zhì)量直接關(guān)系到國(guó)家能源運(yùn)輸安全。由于應(yīng)用條件限制,焊后不能進(jìn)行熱處理,因此對(duì)焊縫有較高的強(qiáng)度要求。同時(shí),長(zhǎng)輸管線惡劣的應(yīng)用環(huán)境對(duì)管線球閥的抗外載荷能力提出了嚴(yán)格的技術(shù)要求。合理控制焊接殘余應(yīng)力的分布以及確定管線球閥的極限承載能力對(duì)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(chǔ)上,在ABAQUS軟件中建立了全焊接球閥的有限元模型,根據(jù)實(shí)測(cè)殘余應(yīng)力值,使用生死單元技術(shù)預(yù)制了多層焊下全焊接球閥的殘余應(yīng)力。在此基礎(chǔ)上,通過(guò)對(duì)管線球閥施加內(nèi)壓和彎曲載荷,得到了管線失效時(shí)球閥的應(yīng)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(yīng)力線,對(duì)應(yīng)力進(jìn)行分類和強(qiáng)度評(píng)定,論證了全焊接球閥的應(yīng)力在管道失效時(shí)處于安全水平。 為進(jìn)一步研究閥門的承載能力,通過(guò)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(jìn)一步的閥體壁厚校核中發(fā)現(xiàn),實(shí)際閥門的厚度遠(yuǎn)遠(yuǎn)大于壓力設(shè)計(jì)厚度,因此,通過(guò)對(duì)不同厚度的閥門進(jìn)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(hào)：2235959