【摘要】：隨著對(duì)火電機(jī)組運(yùn)行參數(shù)要求的不斷提升,鍋爐再熱器與過(guò)熱器管的服役條件也越發(fā)苛刻。制造這些部件的材料需具備良好的抗高溫氧化及煤煙氣氧化腐蝕性能。深入研究過(guò)熱器管材料Inconel740H的抗高溫氧化及煤煙氣氧化腐蝕的性能具有重要意義。本文對(duì)Inconel740H合金進(jìn)行高溫空氣氧化實(shí)驗(yàn),用自行設(shè)計(jì)設(shè)備進(jìn)行空氣-水蒸汽混合氣高溫氧化實(shí)驗(yàn)和高溫煤煙氣氧化腐蝕實(shí)驗(yàn)。使用不連續(xù)增重法稱(chēng)量高溫實(shí)驗(yàn)后的試樣增重并繪制增重曲線。對(duì)高溫實(shí)驗(yàn)后試樣使用掃描電鏡(SEM)觀察表面與截面氧化膜形貌與基體組織,通過(guò)能譜儀(EDS)分析氧化層成分。利用X射線衍射儀(XRD)分析表面氧化層相組成。研究分析了Inconel740H在不同環(huán)境下的氧化腐蝕的動(dòng)力學(xué)規(guī)律及氧化腐蝕產(chǎn)物與氧化腐蝕溫度、時(shí)間的關(guān)系。實(shí)驗(yàn)結(jié)果表明,Inconel740H在不同氣氛環(huán)境下的氧化增重隨溫度提高、時(shí)間延長(zhǎng)而增加,但具體氧化腐蝕動(dòng)力學(xué)規(guī)律各異。在700℃和800℃的水蒸氣氧化中的氧化動(dòng)力學(xué)曲線近似遵循拋物線規(guī)律,在900℃水蒸氣中的氧化動(dòng)力學(xué)曲線遵循線性規(guī)律。對(duì)于空氣氧化,在700℃100h內(nèi)遵循線性規(guī)律,而800℃和900℃的則遵循拋物線規(guī)律。煤煙氣腐蝕在700℃和900℃都近似遵循拋物線規(guī)律。水蒸氣對(duì)氧化具有加速作用,相同溫度下,水蒸氣環(huán)境氧化增重空氣環(huán)境的氧化增重。研究發(fā)現(xiàn),短時(shí)間氧化后,表面氧化膜主要由Cr_2O_3構(gòu)成。延長(zhǎng)氧化時(shí)間,氧化膜物相轉(zhuǎn)變成由尖晶石NiCr_2O_4以及鉻鈦氧化物為主。長(zhǎng)時(shí)間氧化后生成由Al_2O_3與TiO_2組成的內(nèi)氧化物。分別在700℃和800℃進(jìn)行高溫煤煙氣腐蝕后的生成物以氧化物為主,由Cr_2O_3、SiO_2組成,另含部分NiC與S;長(zhǎng)時(shí)間腐蝕后同樣出現(xiàn)Al_2O_3為主的內(nèi)氧化物;800℃300h煤煙氣氧化腐蝕產(chǎn)物層出現(xiàn)疏松多孔現(xiàn)象。900℃煤煙氣腐蝕后的生成物包括Cr_2O_3、Al_2O_3、NiC、SiO_2以及鉻鈦的混合氧化物。Inconel740H經(jīng)過(guò)900℃長(zhǎng)時(shí)間空氣氧化后會(huì)發(fā)生表層氧化膜剝落現(xiàn)象。900℃水蒸氣氧化120h后試樣表層氧化膜破碎。Inconel740H在900℃長(zhǎng)時(shí)間的空氣氧化和空氣-水蒸氣氧化期間觀察到不同程度的氧化膜剝落現(xiàn)象,該材料不能滿足在900℃下長(zhǎng)期服役的要求。
[Abstract]:With the continuous improvement of the operation parameters of the thermal power unit, the service conditions of the boiler reheater and the superheater tube are becoming more and more severe. The materials for making these components shall have good resistance to high temperature oxidation and oxidation of soot. It is of great significance to study the high temperature oxidation of Inconel 740H and the oxidation corrosion of soot. In this paper, the high-temperature air oxidation experiment of Inconel 740H alloy is carried out, and a self-designed equipment is used for the high-temperature oxidation experiment of air-water vapor mixed gas and the oxidation corrosion experiment of high-temperature soot. The weight gain of the sample after the high temperature experiment was weighed using a discontinuous weight gain method and the weight gain curve was plotted. The morphology of the surface and the cross-sectional oxide film was observed by scanning electron microscope (SEM) and the composition of the oxide layer was analyzed by the energy dispersive spectrometer (EDS). The surface oxidation layer was analyzed by X-ray diffractometer (XRD). The kinetics of the oxidation corrosion of Inconel 740H in different environments and the relationship between the oxidation corrosion product and the oxidation corrosion temperature and time are analyzed. The experimental results show that the oxidation weight gain of Inconel 740H in different atmosphere is increased with the temperature, and the time is prolonged, but the specific oxidation corrosion dynamics are different. The kinetics of the oxidation in water vapor oxidation at 700 鈩，

本文編號(hào)：2493838