【摘要】：隨著火電機(jī)組參數(shù)和容量的增大,機(jī)組的安全運(yùn)行問題愈來愈突出,而管道在高溫高壓下的蠕變是設(shè)備發(fā)生故障的一個(gè)主要因素。彎頭在電廠管路中起著至關(guān)重要的作用,同時(shí)也是較易出現(xiàn)失效的環(huán)節(jié),因此對在高溫條件下工作的處于多軸應(yīng)力狀態(tài)下的管道彎頭的蠕變行為進(jìn)行研究,對電站管道設(shè)計(jì)、壽命管理、建立高溫結(jié)構(gòu)完整性評點(diǎn)規(guī)范具有重大意義。本文設(shè)計(jì)并進(jìn)行了全尺寸管道彎頭的蠕變試驗(yàn),實(shí)現(xiàn)管道彎頭在650℃彎矩載荷作用下的持續(xù)實(shí)驗(yàn),并設(shè)計(jì)了測點(diǎn)的采集方案觀察不同時(shí)效時(shí)的變形情況和微觀組織形貌,研究多軸應(yīng)力下P92鋼的蠕變行為以及硬度、應(yīng)力的影響。同時(shí)選取蠕變本構(gòu)模型進(jìn)行有限元分析,對ANSYS軟件二次開發(fā)加入損傷的影響以模擬蠕變的整個(gè)階段,探究彎頭的應(yīng)力分布、損傷發(fā)展與蠕變的關(guān)系,結(jié)果表明損傷會(huì)改變應(yīng)力的分布情況,但對彎頭蠕變的分布影響較小,并分析了彎頭的主要失效位置及壽命。且考慮到彎頭制造工藝工程中壁厚的改變,模擬分析不等壁厚時(shí)彎頭的蠕變與等壁厚時(shí)的區(qū)別,研究實(shí)際情況下壁厚的變化對彎頭蠕變的影響,發(fā)現(xiàn)壁厚會(huì)改變應(yīng)力的分布梯度,但不會(huì)造成損傷發(fā)展速度的變化。通過實(shí)驗(yàn)結(jié)果與模擬結(jié)果的對比,驗(yàn)證由缺口試驗(yàn)得到的多軸應(yīng)力狀態(tài)對蠕變影響的結(jié)論和蠕變模型的有效性,以及本文的模擬分析具有一定的可靠性和參考性。
[Abstract]:With the increase of thermal power unit parameters and capacity, the problem of unit safe operation becomes more and more serious, and the creep of pipeline under high temperature and high pressure is one of the main factors of equipment failure. The bend plays an important role in the pipeline of the power plant, and it is also the link which is prone to failure. Therefore, the creep behavior of the pipe bend working under the condition of high temperature under multiaxial stress is studied, and the pipeline design of the power station is made. Life management, the establishment of high-temperature structural integrity evaluation code has great significance. In this paper, creep tests of full-scale pipe bends are designed and carried out to realize the continuous experiment of pipe elbows under the action of 650 鈩，

本文編號：2320061