本文選題：304不銹鋼粉末　切入點(diǎn)：粉末燒結(jié)　出處：《華東理工大學(xué)》2017年碩士論文　論文類型：學(xué)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(yīng)用于沸騰傳熱設(shè)備中,其換熱效率對(duì)熱交換器的工作效率有著很大影響。表面沸騰強(qiáng)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(shè)備的性能升級(jí)帶來巨大潛力;碳鋼管以及銅合金表面沸騰強(qiáng)化管工在業(yè)上較為常見,而不銹鋼材質(zhì)的表面多孔管卻很少見到,因而對(duì)不銹鋼表面多孔管進(jìn)行研究開發(fā)具有十分重要的科研以及工程價(jià)值。本文將從以下兩個(gè)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(jié)方案,通過試驗(yàn)優(yōu)化不銹鋼內(nèi)表面多孔燒結(jié)結(jié)構(gòu)以確定最佳制備工藝:為確定不銹鋼表面多孔層燒結(jié)工藝參數(shù),通過改變粉末類型、粒徑、以及燒結(jié)氣氛等因素,在不同燒結(jié)溫度下分別進(jìn)行了燒結(jié)試驗(yàn),實(shí)驗(yàn)結(jié)果表明:燒結(jié)氣氛是決定燒結(jié)結(jié)構(gòu)以及母材性能的關(guān)鍵因素,真空燒結(jié)可以保證燒結(jié)過程的順利進(jìn)行;隨著燒結(jié)溫度的升高,燒結(jié)時(shí)間的延長(zhǎng),燒結(jié)結(jié)構(gòu)的結(jié)合強(qiáng)度升高,而孔隙率呈現(xiàn)急劇下降趨勢(shì);粉末粒徑不是影響孔隙率的主要因素,但是孔隙的當(dāng)量直徑隨著粒徑的增大有變大的趨勢(shì),而混合粒徑的粉末得到的燒結(jié)結(jié)構(gòu)能夠得到孔隙當(dāng)量直徑分布較寬的燒結(jié)結(jié)構(gòu);確定了不銹鋼表面多孔管最佳燒結(jié)工藝:采用真空燒結(jié),在燒結(jié)溫度1000℃～1020℃下保溫15min左右,得到的燒結(jié)結(jié)構(gòu)孔隙率約在30%～60%,剪切結(jié)合強(qiáng)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(duì)其傳熱性能進(jìn)行分析:自主搭建了沸騰傳熱試驗(yàn)試驗(yàn)設(shè)備,采用表面張力較小的甲醇水溶液作為管內(nèi)沸騰工質(zhì)對(duì)在最佳燒結(jié)工藝下得到的燒結(jié)多孔管進(jìn)行了沸騰試驗(yàn),試驗(yàn)結(jié)果表明:在相同的沸騰溫差下,燒結(jié)強(qiáng)化管的沸騰傳熱系數(shù)可達(dá)光管的1.6～2倍左右;相同的總溫差下,燒結(jié)強(qiáng)化管的熱流密度是光管的1.4～1.6倍;相同溫差下,燒結(jié)強(qiáng)化管的總傳熱系數(shù)為光管的1.4～1.6倍,這說明燒結(jié)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(hào)：1617711