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1、摘要摘要隨著國(guó)民經(jīng)濟(jì)快速發(fā)展的需要,至U2020年全國(guó)裝機(jī)容量將達(dá)N9.5億千瓦,其中火電裝機(jī)容量仍然占70%以上,為了提高火力發(fā)電機(jī)組效率,要求繼續(xù)提高運(yùn)行溫度和壓力。為此,改善鍋爐用鋼及其焊接接頭的耐熱腐蝕性能成為大型電站鍋爐制造業(yè)的關(guān)鍵技術(shù)之一。針對(duì)高參數(shù)、大容量電站鍋爐的使用要求而最新開(kāi)發(fā)的奧氏體不銹鋼SUPER304H、TP347H和HR3C,模擬鍋爐的實(shí)際工作環(huán)境,選用Na2S04/NaCl作為熱腐蝕介質(zhì),通過(guò)涂鹽試樣的熱腐蝕性試驗(yàn),研究腐蝕介質(zhì)成分、腐蝕溫度以及表面噴丸處理對(duì)不銹鋼母材、焊接接頭
2、及接頭各區(qū)抗熱腐蝕性能的影響規(guī)律,并利用SEM、)碌D等技術(shù)觀察腐蝕形貌,分析腐蝕產(chǎn)物及成份。結(jié)果表明:奧氏體不銹鋼的熱腐蝕程度隨著溫度的升高而增加。當(dāng)腐蝕溫度相同時(shí),在Na2S04/NaCl熱腐蝕介質(zhì)中NaCl組分的熱腐蝕起主要作用。通過(guò)表面噴丸處理后的TP347H奧氏體不銹鋼,其耐熱腐蝕性能存在一個(gè)最佳的噴丸參數(shù),即當(dāng)噴丸時(shí)間為120min時(shí),在腐蝕溫度650℃、腐蝕劑成分Na。S04:NaCI=2:1條件下的耐熱腐蝕性能最好。焊接接頭、焊縫、母材及熱影響區(qū)(HAZ)的熱腐蝕性試驗(yàn)表明,在相同的熱腐蝕條件
3、下,HAZ耐熱腐蝕性能最差,焊縫次之,而母材的耐腐蝕性最好,腐蝕產(chǎn)物主要為Fe203、Cr203和NaFe02。關(guān)鍵詞:新型奧氏體不銹鋼;焊接接頭;熱腐蝕大連交通大學(xué)工學(xué)碩士學(xué)位論文AbstractIn2020theinstalledcapacitywillreach950millionkilowatts,Thermalpowerinstalledcapacityofwhichstillaccountedformorethan70%,inordertoimprovetheefficiencyofthermal
4、powergeneratingunits,itiSnecessarytoincreasethepressureandtemperature.therefore,theboilersteelandweldedjointsoftheheat.resistantsteelcorrosioniStoincreasethepressureandtemperatureiSoneofthekeytechnologies.Themaintestfortheuseofexistingpowerstationboilersreq
5、uirethelatestdevelopmentoftheausteniticstainlesssteelSusper304H、TP347HFGandHR3C,boilersimulationoftheactualuseoftheenvironment,useNa2SOdNaClastllecorrosive,toconductedonsamplesofsalt,studytheregionalsituationwhichcorrosiveonthebasemetal,corrosionofweldedioi
6、ntsoncorrosivecomposition,corrosivetemperatureandsurfacehotpeening;thoughtXRDandSEMtoanalysistheMorphologyofcorrosionandingredientsofcorrosion.Throughthetestdatawecansee:tllatthedegreeoftheausteniticstainlesssteelhotcorrosionincreaseasthetemperatureriseshig
7、her,whencorrosiontemperatureiSthesame,inNa2SOdNaClhotcorrosionmedium,NaClofbasemetalcorrosionplaysamajorrole;ThrougnsurfacerotoblastausteniticstainlesssteelTP347H,heat.resistantcorrosionhaveabestrotoblastnumber,whenthetimeofrotoblastiS120min,corrosiontempre
8、tureiS650℃corrosioncompositionNa2S04:NaCI=2:1,theheat-resistantcorrosionofTP347HiSthebest.Comparetheregionalweldedjoints,weld,basemetal,heat-affectedareas,wecanknownthat:underthesanlecorrosioncondition