本文選題：304不銹鋼粉末　切入點：粉末燒結　出處：《華東理工大學》2017年碩士論文　論文類型：學位論文

【摘要】：304不銹鋼管由于具有優(yōu)良的耐腐蝕性能而被廣泛應用于沸騰傳熱設備中,其換熱效率對熱交換器的工作效率有著很大影響。表面沸騰強化管能夠有效提高沸騰傳熱系數(shù)、降低沸騰所需過熱度,這為沸騰傳熱設備的性能升級帶來巨大潛力;碳鋼管以及銅合金表面沸騰強化管工在業(yè)上較為常見,而不銹鋼材質的表面多孔管卻很少見到,因而對不銹鋼表面多孔管進行研究開發(fā)具有十分重要的科研以及工程價值。本文將從以下兩個方面展開:(1)提出制備不銹鋼表面多孔換熱管并制定其燒結方案,通過試驗優(yōu)化不銹鋼內(nèi)表面多孔燒結結構以確定最佳制備工藝:為確定不銹鋼表面多孔層燒結工藝參數(shù),通過改變粉末類型、粒徑、以及燒結氣氛等因素,在不同燒結溫度下分別進行了燒結試驗,實驗結果表明:燒結氣氛是決定燒結結構以及母材性能的關鍵因素,真空燒結可以保證燒結過程的順利進行;隨著燒結溫度的升高,燒結時間的延長,燒結結構的結合強度升高,而孔隙率呈現(xiàn)急劇下降趨勢;粉末粒徑不是影響孔隙率的主要因素,但是孔隙的當量直徑隨著粒徑的增大有變大的趨勢,而混合粒徑的粉末得到的燒結結構能夠得到孔隙當量直徑分布較寬的燒結結構;確定了不銹鋼表面多孔管最佳燒結工藝:采用真空燒結,在燒結溫度1000℃～1020℃下保溫15min左右,得到的燒結結構孔隙率約在30%～60%,剪切結合強度不低于1.5 KN/mm;(2)制備工業(yè)用不銹鋼表面多孔換熱管并對其傳熱性能進行分析:自主搭建了沸騰傳熱試驗試驗設備,采用表面張力較小的甲醇水溶液作為管內(nèi)沸騰工質對在最佳燒結工藝下得到的燒結多孔管進行了沸騰試驗,試驗結果表明:在相同的沸騰溫差下,燒結強化管的沸騰傳熱系數(shù)可達光管的1.6～2倍左右;相同的總溫差下,燒結強化管的熱流密度是光管的1.4～1.6倍;相同溫差下,燒結強化管的總傳熱系數(shù)為光管的1.4～1.6倍,這說明燒結多孔管能夠有效提高換熱性能。
[Abstract]:304 stainless steel tube is widely used in boiling heat transfer equipment because of its excellent corrosion resistance. The heat transfer efficiency of 304 stainless steel tube has great influence on the working efficiency of heat exchanger. Reducing the superheat required for boiling has great potential for upgrading the performance of boiling heat transfer equipment. Surface boiling enhancement of carbon steel pipes and copper alloys is more common in industry, but porous tubes with stainless steel surfaces are rarely seen. Therefore, the research and development of the porous tube on the surface of stainless steel has very important scientific research and engineering value. In order to determine the sintering parameters of the porous layer on the stainless steel surface, the powder type, particle size and sintering atmosphere were changed to determine the optimum preparation process by optimizing the porous sintering structure of the inner surface of the stainless steel. The sintering experiments were carried out at different sintering temperatures. The results show that the sintering atmosphere is the key factor to determine the sintering structure and properties of the base metal, and vacuum sintering can ensure the smooth sintering process with the increase of sintering temperature. With the prolongation of sintering time, the bonding strength of sintered structure increases, while the porosity decreases sharply, the particle size of powder is not the main factor affecting porosity, but the equivalent diameter of pore increases with the increase of particle size. The sintered structure of the powder with mixed particle size can obtain the sintered structure with wide pore equivalent diameter distribution, and the optimum sintering process of the porous tube on the surface of stainless steel is determined as follows: vacuum sintering is adopted, and the sintering temperature is 1000 鈩，

本文編號：1617711