發(fā)布時(shí)間：2018-01-18 12:32

  本文關(guān)鍵詞：GH3625合金中的夾雜物及純凈化研究　出處：《蘭州理工大學(xué)》2016年碩士論文　論文類(lèi)型：學(xué)位論文

  更多相關(guān)文章： GH3625合金 真空感應(yīng)熔煉 電渣重熔 非金屬夾雜物 純凈化

【摘要】：高溫合金通常作為各類(lèi)發(fā)動(dòng)機(jī)和燃?xì)廨啓C(jī)中的關(guān)鍵服役材料,要求其具有優(yōu)異的冶金質(zhì)量,尤其要最大限度的控制材料中的微量有害雜質(zhì)元素(O、N、S)含量以及這些雜質(zhì)元素形成的非金屬夾雜物。因此,本文針對(duì)鑄態(tài)GH3625合金中的夾雜物和純凈化工藝進(jìn)行了一系列研究:利用JMat Pro軟件計(jì)算GH3625合金的平衡相圖表明,當(dāng)合金中含有氣體雜質(zhì)元素O、N時(shí),在液相線溫度以上會(huì)形成以Al為主要元素的氧化物夾雜M2O3(Al2O3),在固液兩相區(qū)生成以Ti為主要元素的氮化物夾雜MN(Ti N),且非金屬夾雜物M2O3、MN的含量分別由O、N含量控制;其中非金屬夾雜物及一次碳化物的析出過(guò)程為:L+M2O3→L+M2O3+γ→L+M2O3+γ+MN→L+M2O3+γ+MN+MC(Nb C)。討論雙聯(lián)工藝熔煉GH3625合金各工藝階段合金錠合金成分、雜質(zhì)元素含量、鑄態(tài)組織發(fā)現(xiàn),電渣重熔后合金成分更加均勻,合金錠頭尾及橫截面合金元素偏差小于±0.1%;S、O含量分別降低至10、7ppm,脫除率分別為58%,59%;二次枝晶間距增大,Nb C由顆粒狀變?yōu)闈h字體狀。各階段鑄錠中最主要的偏析元素為Nb,尤其是鑄錠心部枝晶間偏聚大量的Nb C、Laves相。非金屬夾雜物金相原位觀察和電解提取夾雜物分析共同表明,GH3625合金中的夾雜物主要為氮化物(Ti,Nb)N和復(fù)合型氧化物Mg O·Al2O3尖晶石,尺寸在2~3μm之間;合金中的氮主要來(lái)源于冶煉原材料Cr、Mo;真空感應(yīng)熔煉時(shí)氧化物夾雜主要來(lái)源于Mg O爐襯材料,而電渣重熔時(shí)氧化物夾雜是由渣系組元進(jìn)入合金基體而形成。選用高真空感應(yīng)重熔精煉工藝在GH3625母合金的基礎(chǔ)上做進(jìn)一步凈化處理表明,高真空感應(yīng)重熔時(shí)元素?fù)]發(fā)燒損和富化均控制在標(biāo)準(zhǔn)成分范圍;單純高真空感應(yīng)重熔時(shí),合金中的氧通過(guò)C-O反應(yīng)脫除,可脫氧至10ppm,氮分壓降低使氮含量脫至70ppm,但在去硫方面無(wú)明顯作用;高真空加0.5%鈣作凈化劑重熔時(shí),Ca-O反應(yīng)以及Ca與Al2O3坩堝內(nèi)壁反應(yīng)可實(shí)現(xiàn)深度脫氧,通過(guò)Ca-S反應(yīng)使合金中硫含量顯著降低,然而氮含量降低程度有限,其含量遠(yuǎn)高于氮在GH3625合金中的溶解度。采用Al2O3坩堝,選擇高真空熔煉工藝及適量鈣的加入,可使氧、氮、硫含量分別降低到6、60、9ppm。
[Abstract]:High temperature alloy usually as a key engine and gas turbine in service materials, with its excellent metallurgical quality, especially to trace impurity elements control the material maximum in (O, N, S) and the content of non-metallic inclusions of these impurities formed. Therefore, in this paper, a series of studies for inclusion casting state GH3625 alloy and purification process were: indicates that the equilibrium phase diagram calculation of GH3625 alloy by using JMat Pro software, when the alloy contains gas impurity elements O, N, Al as the main element of the formation of oxide inclusions in M2O3 above the liquidus temperature (Al2O3), produced by Ti as the main element of the nitride the MN inclusion in the solid-liquid zone (Ti N), and M2O3 non metallic inclusions, the content of MN by O, the content of N control; the precipitation process of non metallic inclusions and primary carbides are: L+M2O3, L+M2O3+, L+M2O3 gamma +MN - L+M2O3+ + gamma gamma +MN+MC (Nb C). To discuss the process by double melting GH3625 alloy process stages alloy ingot alloy composition, impurity content, microstructure, ESR after the alloy composition is more uniform and the alloy ingot ends and cross section of alloy element deviation is less than 0.1% S, the content of O were decreased; to 10,7ppm, the removal rate were 58%, 59% and two; the dendrite spacing is increased, Nb C by granular body shape into Chinese characters. The main elements of each stage in the ingot segregation of Nb, especially the heart of ingot interdendritic segregation of Nb C, Laves phase. Non metallic inclusion analysis metallographic in situ observation and electrolytic extraction of inclusions shows that the inclusions in GH3625 alloy mainly nitrides (Ti, Nb) N and Mg O - Al2O3 composite oxide spinel size between 2~3 m alloy; the nitrogen comes mainly from smelting raw materials Cr, Mo; vacuum induction melting of oxide inclusions Mainly from lining material Mg O, and ESR process is composed of oxide inclusion slag component into the alloy matrix formed. Using high vacuum induction remelting refining process based on GH3625 master alloy for further purification showed that high vacuum induction remelting when volatile elements have a fever loss and rich control in standard components simple range; high vacuum induction remelting, alloy oxygen removal by C-O reaction, can be deoxidized to 10ppm, nitrogen partial pressure reduced nitrogen removal to 70ppm, but no significant effect on desulphurization; high vacuum plus 0.5% calcium as a purifying agent of remelting, Ca-O reaction and Ca reaction and Al2O3 crucible wall can be realized deoxidation, through Ca-S reaction to the sulfur content in the alloy is significantly reduced, but the nitrogen content decreased, the content is much higher than that of nitrogen solubility in the GH3625 alloy. Using Al2O3 crucible, high vacuum melting process and the amount of The addition of calcium can reduce the oxygen, nitrogen and sulfur content to 6,60,9ppm., respectively.

【學(xué)位授予單位】：蘭州理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類(lèi)號(hào)】：TG132.3

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相關(guān)碩士學(xué)位論文 前1條

1 王偉;GH3625合金中的夾雜物及純凈化研究[D];蘭州理工大學(xué);2016年

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本文編號(hào)：1440990