發(fā)布時間：2018-05-23 18:50

  本文選題：304不銹鋼 + 夾雜物　； 參考：《北京科技大學》2017年博士論文

【摘要】：非金屬夾雜物對不銹鋼的強度、硬度、疲勞和表面質(zhì)量等影響很大。同時,夾雜物還可能引起很多不銹鋼產(chǎn)品的缺陷。夾雜物的控制已經(jīng)成為不銹鋼生產(chǎn)關鍵任務之一。一些高端304不銹鋼產(chǎn)品被應用于手機殼和手表鏈的生產(chǎn),因此對不銹鋼對產(chǎn)品的表面質(zhì)量具有很高的要求。目前我國自主生產(chǎn)的高端304不銹鋼產(chǎn)品很難滿足用戶的需求,夾雜物引起的產(chǎn)品缺陷是最主要原因之一。因此,關于304不銹鋼中的夾雜物控制的基礎研究對我國企業(yè)實現(xiàn)高端304不銹鋼的自主生產(chǎn)具有重大意義。本課題首先通過文獻調(diào)研和產(chǎn)品調(diào)研等方法,確定了304不銹鋼夾雜物的控制目標。研究發(fā)現(xiàn)夾雜物中MgO-Al2O3和Al2O3含量很高會引起304不銹鋼產(chǎn)品的缺陷,某一樣品的分析結(jié)果表明不銹鋼現(xiàn)場冶煉過程夾雜物中Al2O3含量逐漸升高。確定304不銹鋼中夾雜物的控制目標為：減少夾雜物中的Al2O3含量,將鋼中夾雜物成分控制在Al2O3-SiO2-CaO系和Al2O3-SiO2-MnO系夾雜物相圖的低熔點區(qū)域。其次,研究了精煉過程精煉渣成分對304不銹鋼中夾雜物的影響。研究發(fā)現(xiàn)低堿度精煉渣有利于降低304不銹鋼夾雜物中Al2O3含量；初始渣中的Al2O3含量增加,夾雜物中Al2O3含量明顯增加；初始精煉渣中MgO增大對夾雜物中Al2O3含量影響不大,但有利于減小耐材的侵蝕。結(jié)合實驗結(jié)果,應用FactSage熱力學計算軟件建立了渣-鋼-夾雜物平衡反應熱力學模型,通過模型研究了不同精煉渣成分對鋼液成分、脫硫、夾雜物成分、夾雜物熔點、耐火材料侵蝕等的影響。最后確定精煉渣堿度小十1.75、MgO含量為10%-15%且不含Al2O3的精煉渣有利于降低304不銹鋼夾雜物中Al2O3含量。再次,研究了精確鈣處理的控制對304不銹鋼中夾雜物改性的可行性,建立了304不銹鋼中夾雜物的精確鈣處理模型,可實現(xiàn)根據(jù)304不銹鋼中不同鋼液成分對最優(yōu)喂鈣線量進行精確計算。同時,通過現(xiàn)場實驗驗證了鈣處理變性夾雜物的效果,從而實現(xiàn)304不銹鋼中夾雜物鈣處理改性的精確控制。接著,研究了中間包二次氧化對304不銹鋼中夾雜物的影響。研究發(fā)現(xiàn)在硅錳脫氧304不銹鋼發(fā)生二次氧化后,鋼中吸氧區(qū)域的[Al]和[Ca]元素迅速被氧化并且降低到極低的含量。鋼中過量的氧會氧化鋼中含量較高的[Mn],瞬態(tài)生成大量的MnO含量很高的1-2μm的小尺寸夾雜物。從開澆到穩(wěn)定澆鑄過程中,夾雜物中瞬態(tài)生成的MnO含量逐漸減小并降低至正常水平。熱力學計算結(jié)果表明：硅錳脫氧304不銹鋼二次氧化會引起夾雜物中MnO含量上升,鋁脫氧的304不銹鋼二次氧化會引起夾雜物中Al2O3含量上升。然后,研究了熱處理對304不銹鋼中夾雜物的影響。研究發(fā)現(xiàn)在1373 K下的氬氣保護氣氛的熱處理過程中,304不銹鋼夾雜物的演變機理為：在熱處理之前,鋼中的夾雜物主要為球形液態(tài)MnO-SiO2夾雜物。熱處理過程中,鋼中的[Cr]元素逐漸向鋼/MnO-SiO2夾雜物界面?zhèn)髻|(zhì),隨后[Cr]還原MnO-SiO2夾雜物中的SiO2和MnO,在MnO-SiO2夾雜物表面生成MnO·Cr2O3尖晶石夾雜物,同時生成的[Si]和[Mn]從反應界面?zhèn)髻|(zhì)回鋼中。最終,MnO-SiO2夾雜物被完全變性為純MnO·Cr2O3尖晶石夾雜物。將熱處理溫度從1273 K增加至1473 K可以有效地加快夾雜物的轉(zhuǎn)變速率。此外,建立了一個熱處理過程夾雜物轉(zhuǎn)變動力學模型,可以有效預測不同溫度下的熱處理過程中夾雜物的轉(zhuǎn)變率。本文通過304不銹鋼的工藝的調(diào)研、試樣產(chǎn)品的檢測、精煉過程渣改性和鈣處理改性、連鑄過程二次氧化影響、熱處理對夾雜物的影響等研究,確定了304不銹鋼中冶煉過程各類夾雜物的生成機理和影響因素。可根據(jù)304不銹鋼的不同用途和不同的夾雜物控制需求,確定最優(yōu)的冶煉工藝,實現(xiàn)對304不銹鋼的各類夾雜物的控制。
[Abstract]:Non-metallic inclusions have great influence on the strength, hardness, fatigue and surface quality of stainless steel. At the same time, inclusions may also cause defects in many stainless steel products. Inclusion control has become one of the key tasks of stainless steel production. Some high-end 304 stainless steel products are used in the production of cell phone shells and watch chains. The steel has a high requirement for the surface quality of the products. At present, the high-end 304 stainless steel products produced by our country are difficult to meet the needs of the users. The product defects caused by inclusions are one of the main reasons. Therefore, the basic research about the inclusion control in 304 stainless steel is the independent production of the high end 304 stainless steel in our country. It is of great significance to determine the control target of 304 stainless steel inclusions by means of literature investigation and product investigation. It is found that the high content of MgO-Al2O3 and Al2O3 in inclusions will cause defects of 304 stainless steel products. The analysis results of a sample show that the content of Al2O3 in the inclusions of stainless steel in the process of smelting process is the same. The control goal of inclusion in 304 stainless steel is to be determined: to reduce the Al2O3 content in the inclusions, to control the inclusions in the steel in the low melting point area of the Al2O3-SiO2-CaO and Al2O3-SiO2-MnO inclusions. Secondly, the influence of the refining slag composition on the inclusions in the 304 stainless steel is studied. The refining slag can reduce the content of Al2O3 in the inclusions of 304 stainless steel, the content of Al2O3 in the initial slag increases, the content of Al2O3 in the inclusion increases obviously, and the increase of MgO in the initial refining slag has little effect on the Al2O3 content in the inclusions, but it is beneficial to reduce the corrosion of the refractory. The slag is used to establish the slag by the thermodynamic calculation software of FactSage. - the influence of the composition of different refining slag on the composition of molten steel, desulphurization, inclusion composition, inclusion melting point and corrosion resistance of refractory material. Finally, it is determined that the alkalinity of the refining slag is ten 1.75, the content of MgO is 10%-15% and the refining slag without Al2O3 is beneficial to the reduction of Al2O3 in the inclusions of 304 stainless steel. Again, the feasibility of controlling the inclusion of inclusions in 304 stainless steel by the control of precise calcium treatment was studied. A precise calcium treatment model for inclusion in 304 stainless steel was established. The exact calculation of the optimal calcium feeding line was achieved according to the composition of different steel liquid in 304 stainless steel. In order to achieve the accurate control of the calcium treatment modification in 304 stainless steel, the effect of the two oxidation of the tundish on the inclusions in 304 stainless steel was studied. The study found that after two oxidation of the 304 stainless steel, the [Al] and [Ca] elements in the oxygen absorption region of the steel were rapidly oxidized and reduced to a very low content. Excessive oxygen in the medium will oxidize the high content of [Mn] in the steel and produce a large number of small size inclusions with a large number of MnO content of 1-2 m. The transient MnO content in the inclusions gradually decreases and decreases to the normal level from the open cast to the stable casting process. The thermodynamic calculation shows that the two oxidation of silicon manganese deoxidization 304 stainless steel will cause the process. The content of MnO in the inclusions increases and the two oxidation of 304 stainless steel with aluminum deoxidization causes the increase of Al2O3 content in the inclusions. Then, the effect of heat treatment on inclusions in 304 stainless steel is studied. It is found that the evolution mechanism of the 304 stainless steel inclusion in the argon gas protection atmosphere under 1373 K is that before heat treatment, the steel is in the steel. The inclusions are mainly spherical liquid MnO-SiO2 inclusions. During the process of heat treatment, the [Cr] elements in the steel gradually transfer to the interface of the steel /MnO-SiO2 inclusions, then [Cr] reduction of SiO2 and MnO in the MnO-SiO2 inclusions and the formation of MnO Cr2O3 spinel inclusions on the surface of the inclusions on MnO-SiO2, and the [Si] and [Mn] from the reaction interface from the reaction interface are mass transfer back to the steel. Finally, MnO-SiO2 inclusions are completely denatured into pure MnO Cr2O3 spinel inclusions. The increase of heat treatment temperature from 1273 K to 1473 K can effectively speed up the transition rate of inclusions. In addition, a kinetic model of inclusion transition in heat treatment process is established, which can effectively predict inclusions in the heat treatment process at different temperatures. In this paper, through the investigation of the technology of 304 stainless steel, the testing of the sample products, the modification of the slag in the refining process, the modification of the calcium treatment, the influence of the two oxidation of the continuous casting process and the influence of the heat treatment on the inclusions, the formation mechanism and influence factors of all kinds of inclusions in the smelting process of 304 stainless steel are determined. It can be based on the difference of the 304 stainless steel. Use and different control requirements of inclusions, determine the best smelting process, and achieve the control of all kinds of inclusions in 304 stainless steel.
【學位授予單位】：北京科技大學
【學位級別】：博士
【學位授予年份】：2017
【分類號】：TF764.1

【參考文獻】

相關期刊論文 前10條

1 任英;張立峰;楊文;;不銹鋼中夾雜物控制綜述[J];煉鋼;2014年01期

2 張立峰;李燕龍;任英;;鋼中非金屬夾雜物的相關基礎研究(Ⅱ)——夾雜物檢測方法及脫氧熱力學基礎[J];鋼鐵;2013年12期

3 張立峰;李燕龍;任英;;鋼中非金屬夾雜物的相關基礎研究(Ι)——非穩(wěn)態(tài)澆鑄中的大顆粒夾雜物及夾雜物的形核、長大、運動、去除和捕捉[J];鋼鐵;2013年11期

4 袁綱;李光強;李永軍;陳兆平;;鈦穩(wěn)定超純鐵素體不銹鋼硅鋁復合脫氧的試驗研究[J];鋼鐵研究學報;2013年02期

5 CHEN Shu-hao;WANG Xin-hua;HE Xiao-fei;WANG Wan-jun;JIANG Min;;Industrial Application of Desulfurization Using Low Basicity Refining Slag in Tire Cord Steel[J];Journal of Iron and Steel Research(International);2013年01期

6 ;Top slag refining for inclusion composition transform control in tire cord steel[J];International Journal of Minerals Metallurgy and Materials;2012年06期

7 季文華;;不銹鋼的分類與選擇[J];科技信息;2012年04期

8 茅衛(wèi)東;;SUS304不銹鋼表面拋光缺陷原因分析及改進措施[J];上海金屬;2011年02期

9 李雙江;姜周華;黃宗澤;李陽;李明;;精煉渣堿度對304不銹鋼夾雜物的影響[J];鋼鐵;2010年12期

10 莊迎;姜周華;李陽;;精煉渣堿度對304不銹鋼中夾雜物的影響[J];東北大學學報(自然科學版);2010年10期

，

本文編號：1925911