本文選題：TIG熔覆 + 激光熔覆��； 參考：《蘭州理工大學(xué)》2017年碩士論文

【摘要】：硫酸生產(chǎn)及化工行業(yè)對耐高溫濃硫酸閥門有大量需求。傳統(tǒng)耐高溫濃硫酸閥門大多由耐腐蝕合金鑄造而成。由于高溫濃硫酸具有較強(qiáng)的腐蝕性,使得符合性能要求的金屬材料價格高昂,從而造成耐硫酸閥門的制造成本居高不下。為了得到符合技術(shù)要求同時價格低廉的閥門產(chǎn)品,應(yīng)相關(guān)企業(yè)要求,本課題組提出分別使用TIG熱源、激光熱源和激光-電弧復(fù)合熱源在價格相對較低的金屬基體上熔覆一層耐腐蝕合金,在保持其原有性能的同時,降低耐腐蝕閥門的成本。相關(guān)企業(yè)對耐硫酸腐蝕設(shè)備的技術(shù)要求為:硬度HRC40,腐蝕速率0.1a/mm,耐腐蝕等級達(dá)到5級。首先,建立了熱源系統(tǒng)試驗平臺,根據(jù)浙江宣達(dá)特種合金流程裝備股份公司XDB-6耐腐蝕鑄造合金的成分配方,研制出適合進(jìn)行熔覆的耐腐蝕合金粉末。以304不銹鋼為基體材料,分別使用TIG熱源、激光熱源和激光-電弧復(fù)合熱源在基體表面熔覆耐腐蝕合金。分析了不同工藝參數(shù)對單層單道及單層多道熔覆層熔覆層成形特征的影響;其次,通過掃描電鏡、EDS、XRD分析TIG熔覆層、激光熔覆層和激光-電弧復(fù)合熱源熔覆層的顯微組織結(jié)構(gòu)及物相組成。分析不同組織成分及物相組成對熔覆層性能的影響;最后,通過顯微硬度儀及洛氏硬度儀對熔覆層的顯微硬度和洛氏硬度進(jìn)行測試分析;通過均勻腐蝕法測量熔覆層在高溫濃硫酸中的腐蝕速率;通過掃描電鏡、EDS等檢測手段對熔覆層腐蝕后的形貌及元素成分進(jìn)行檢測并對其腐蝕機(jī)理進(jìn)行闡述分析;通過電化學(xué)工作站對熔覆層的電化學(xué)腐蝕性進(jìn)行檢測。試驗結(jié)果表明:單層單道熔覆時,三種熱源熔覆層都與基體都實現(xiàn)了良好的冶金結(jié)合。激光熔覆層宏觀形貌最好、稀釋率最低。其次為激光-電弧復(fù)合熱源熔覆層。而TIG熔覆層成形較差、稀釋率最高。激光-電弧復(fù)合熱源可以通過更小的激光功率達(dá)到與激光熔覆層相近的宏觀形貌。熔覆層內(nèi)的物相主要有Ni2.9Cr0.7Fe0.36、Fe Ni3、Fe0.64Ni0.35、γ-(Fe,Ni)等,與XDB-6鑄造合金差異較大。激光熔覆層的組織較細(xì)小、TIG熔覆層組織粗大、激光-電弧復(fù)合熱源熔覆層組織介于兩者之間。TIG熔覆層的顯微硬度約為HV0.2500~HV0.2700,激光熔覆層的顯微硬度約為HV0.2600~HV0.21000,激光-電弧復(fù)合熱源熔覆層的顯微硬度約為HV0.2500~HV0.2900,XDB-6鑄造合金的顯微硬度為HV0.2550。TIG熔覆層的洛氏硬度約為HRC52,激光熔覆層約為HRC63,激光-電弧復(fù)合熱源熔覆層約為HRC60,XDB-6合金約為HRC53。在120℃,98%濃硫酸中,TIG熔覆層的腐蝕速率為0.0298 mm/a激光熔覆層的腐蝕速率為0.0205 mm/a、激光-電弧復(fù)合熱源熔覆層的腐蝕速率為0.0224 mm/a,XDB-6鑄造合金的腐蝕速率為0.02mm/a。熔覆層及XDB-6合金的腐蝕等級均為4級。激光熔覆層與激光-電弧復(fù)合熱源熔覆層的耐腐蝕性與XDB-6相近,同時兩者的硬度遠(yuǎn)高于XDB-6。以上研究表明,熔覆層的顯微結(jié)構(gòu)及物相組成均與XDB-6鑄造合金有較大差異,但熔覆層的洛氏硬度和耐腐蝕性均符合企業(yè)技術(shù)要求。所以使用熔覆的方法在廉價基體材料上制備耐高溫濃硫酸熔覆層可以代替全鑄造耐腐蝕合金閥門,從而達(dá)到降低成本的目的。
[Abstract]:The sulphuric acid production and chemical industry have a great deal of demand for high temperature resistant concentrated sulfuric acid valves. The traditional high temperature concentrated sulfuric acid valves are mostly made of corrosion resistant alloys. Because of the strong corrosiveness of high temperature concentrated sulfuric acid, the price of metal materials which meet the requirements of performance is high and the manufacturing cost of the sulphuric acid valve is high. To meet the technical requirements and low price valve products, according to the requirements of relevant enterprises, our team proposed to use TIG heat source, laser heat source and laser arc composite heat source to cover a layer of corrosion resistant alloy on relatively low price metal matrix, and reduce the cost of corrosion resistant valve while maintaining its original property. The technical requirements for the sulfuric acid corrosion resistant equipment are: hardness HRC40, corrosion rate 0.1a/mm and corrosion resistance grade to 5. First, a test platform of heat source system was established. According to the composition of the XDB-6 corrosion resistant cast alloy in Zhejiang special alloy process equipment Co., Ltd., the corrosion resistant alloy powder suitable for cladding was developed. 304 Stainless steel is the matrix material, using TIG heat source, laser heat source and laser arc composite heat source to melt corrosion resistant alloy on the surface of the matrix. The influence of different process parameters on the forming characteristics of single layer and single layer multichannel cladding layer is analyzed. Secondly, the TIG cladding layer, laser cladding layer and laser coating are analyzed by scanning electron microscope, EDS and XRD. The microstructure and phase composition of the cladding layer of the arc compound heat source. The effects of different composition and phase composition on the properties of the cladding layer were analyzed. Finally, the microhardness and Rockwell hardness of the cladding layer were measured and analyzed by the microhardness tester and the Rockwell hardness tester, and the cladding layer was measured in the high temperature concentrated sulfuric acid by homogeneous corrosion method. The corrosion rate was detected by scanning electron microscope (SEM) and EDS. The corrosion mechanism of the cladding layer was examined and the corrosion mechanism was analyzed. The electrochemical corrosion of the cladding layer was detected by electrochemical workstation. The results showed that the three kinds of heat source cladding layers were all solid with the matrix when single channel cladding. The laser cladding layer has the best macroscopic morphology and the lowest dilution rate. The second is the laser arc composite heat source cladding layer, and the TIG cladding layer is poor in forming and the dilution rate is the highest. The laser arc composite heat source can reach the macroscopic morphology near the laser cladding layer through the smaller laser power. The main phase in the cladding layer is the main phase. Ni2.9Cr0.7Fe0.36, Fe Ni3, Fe0.64Ni0.35, gamma (Fe, Ni) are different from that of XDB-6 casting alloy. The microstructure of the laser cladding layer is smaller, the microstructure of the cladding layer of TIG is coarse, and the microstructure of the cladding layer of the laser arc composite heat source is about HV0.2500~HV0.2700, and the microhardness of the laser cladding layer is about HV0.260. 0~HV0.21000, the microhardness of the laser arc composite heat source cladding layer is about HV0.2500~HV0.2900. The microhardness of the XDB-6 casting alloy is about HRC52, the laser cladding layer is about HRC63, the laser arc composite heat source cladding is about HRC60, and XDB-6 alloy is about HRC53. at 120, 98% concentrated sulfuric acid, and TIG cladding. The corrosion rate of the layer is 0.0298 mm/a laser cladding layer and the corrosion rate is 0.0205 mm/a, the corrosion rate of laser arc composite heat source cladding layer is 0.0224 mm/a, the corrosion rate of XDB-6 cast alloy is 4 grade for 0.02mm/a. cladding layer and XDB-6 alloy. The corrosion resistance of laser cladding layer and laser arc composite heat source cladding layer It is similar to XDB-6, and the hardness of the two is much higher than that of more than XDB-6.. The results show that the microstructure and phase composition of the cladding layer are all different from that of the XDB-6 cast alloy, but the Rockwell hardness and corrosion resistance of the cladding layer are all in accordance with the technical requirements of the enterprise. So the high temperature and concentrated sulfuric acid melt is prepared on the cheap matrix material by the method of cladding. The coating can replace the fully cast corrosion-resistant alloy valve, so as to achieve the goal of reducing cost.
【學(xué)位授予單位】：蘭州理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TG174.44

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 李正秋;石s，

本文編號：1906293