1473 K熱處理過程夾雜物與鋼基體界面固相反應機理
發(fā)布時間：2018-11-29 11:09
【摘要】：經(jīng)熱處理和軋制工序后在鋼基體中最終所形成的非金屬夾雜物的種類、數(shù)量、尺寸、形貌特征以及物化特性,直接影響著鋼鐵產(chǎn)品的質(zhì)量和性能,而此類非金屬夾雜物與鋼液凝固前其內(nèi)部初始存在的夾雜物往往差異較大,其中一個主要原因在于,鋼基體經(jīng)歷的后續(xù)熱處理工藝不僅能夠改變金屬材料的組織結(jié)構(gòu)與性能,同時也會對其內(nèi)部非金屬夾雜物造成影響,固態(tài)金屬材料與夾雜物之間能夠發(fā)生固相反應,從而造成鋼基體成分偏析、原有夾雜物的變性以及新夾雜物的析出。通過合適的熱處理工藝實現(xiàn)對合金基體內(nèi)非金屬夾雜物物化特性的控制是可行的。本研究結(jié)合熱力學平衡計算和管式爐高溫平衡實驗,構(gòu)建和驗證了1873 K溫度下MnO-SiO2-FeO非金屬氧化夾雜物與Fe-Mn-Si合金以及Al2O3-CaO-FeO系非金屬氧化夾雜物與Fe-Al-Ca合金之間平衡關(guān)系,繼而利用高溫共聚焦激光顯微鏡和石英管真空密封等設(shè)備,研究了1473 K下保溫熱處理、硫元素、氧元素等分別對上述兩類擴散偶樣品中合金基體與夾雜物之間界面固相反應以及二者物化特性的影響規(guī)律,探討和揭示了鋼基體與夾雜物之間固相反應和擴散機理,并最終結(jié)合實驗結(jié)果,開發(fā)和構(gòu)建了控制和預測兩類固相反應和夾雜物變性的有效動力學理論模型。研究結(jié)果表明：1)熱力學平衡計算和高溫平衡實驗表明,1873 K下與Fe-Mn-Si合金和Fe-Al-Ca合金相平衡的脫氧產(chǎn)物分別為三元MnO-SiO2-FeO和Al2O3-CaO-FeO氧化物；2)原1873 K下Fe-Mn-Si合金和MnO-SiO2-FeO氧化物以及Fe-Al-Ca合金與Al2O3-CaO-FeO氧化物的平衡體系在1473 K熱處理過程中不再保持平衡,合金與氧化物會發(fā)生高溫固相反應和元素相互擴散作用；3)隨熱處理時間的延長,兩類擴散偶體系中PPZ、MCZ以及ACZ等區(qū)域的寬度均呈逐漸增大趨勢。對于Fe-Mn-Si合金和MnO-SiO2-FeO氧化物體系,PPZ和MCZ寬度分別由熱處理前的15μm、15μm,增加至熱處理10h后的79μm、120μm以及熱處理50h后的138μm、180 μm；對于Fe-Al-Ca合金與Al2O3-CaO-FeO氧化物體系,PPZ和ACZ寬度分別由熱處理前的7μm、20μm,增加至熱處理10 h后的31μm、90μm以及熱處理50 h后的87μm、170μm；另外,由于FeO分解作用,兩類氧化物中均出現(xiàn)單質(zhì)Fe顆粒物質(zhì),且顆粒尺寸和數(shù)量均呈增大趨勢：4)對于兩類擴散偶體系,氧化物中FeO含量的升高能夠提高過剩O氧含量,促進合金與氧化物的界面固相反應,增大PPZ、MCZ以及ACZ等區(qū)域；5)硫元素對熱處理過程中MnO-SiO2-FeO氧化物和Fe-Mn-Si合金之間元素相互擴散和界面固相反應起抑制作用,但對Fe-Al-Ca合金與Al2O3-CaO-FeO氧化物體系基本無影響。6)對于Fe-Mn-Si合金與MnO-SiO2-FeO氧化物體系,當氧化物中FeO含量或S含量較高時,為保持氧化物中整體電中性,Mn2+和Si4+等陽離子由氧化物中擴散至合金基體,造成靠近交界面處的合金內(nèi)Mn、Si元素含量下降到一定程度后出現(xiàn)再次升高的現(xiàn)象,而當氧化物的FeO和S含量較低時,該種現(xiàn)象受到抑制；7)靠近交界面Fe-Al-Ca合金內(nèi)析出樹枝狀Al2O3-CaO類夾雜物的數(shù)量和尺寸與氧化物中FeO含量呈負相關(guān)關(guān)系,而與熱處理時間呈正相關(guān)關(guān)系。8)基于Wagner內(nèi)部氧化模型,構(gòu)建了不同F(xiàn)eO含量及熱處理時間下Fe-Mn-Si合金與MnO-SiO2-FeO氧化物、Fe-Al-Ca合金與Al2O3-CaO-FeO氧化物之間界面固相反應的動力學擴散模型,模型結(jié)果能夠較好地反映熱處理過程中兩類合金與氧化物體系之間的固相反應現(xiàn)象。
[Abstract]:The type, the quantity, the size, the appearance characteristic and the physical and chemical properties of the non-metal inclusion formed in the steel matrix after the heat treatment and the rolling process directly influence the quality and the performance of the steel product, and one of the main reasons is that the subsequent heat treatment process experienced by the steel matrix can not only change the structure and the performance of the metal material, in addition, that effect of solid phase reaction between the solid metal material and the inclusion can be caused by the influence of the non-metal inclusion in the solid metal material, so that the segregation of the component of the steel matrix, the modification of the original inclusion and the precipitation of the new inclusion are caused. It is feasible to control the physical and chemical properties of the non-metallic inclusions in the alloy matrix by a suitable heat treatment process. In this study, the equilibrium relationship between the non-metallic oxide inclusions of MnO-SiO2-FeO and the Fe-Mn-Si alloy and the non-metallic oxide inclusions of the Al2O3-CaO-FeO system and the Fe-Al-Ca alloy was constructed and verified in combination with the thermodynamic equilibrium calculation and the high-temperature equilibrium experiment of the tube furnace. in turn, a high-temperature co-focusing laser microscope and a quartz tube vacuum seal are used to study that effect of heat treatment, sulfur element, oxygen element and the like on the interface solid phase reaction and the physical and chemical properties of the alloy matrix and the inclusion in the two types of diffusion couple samples under the condition of 1473K, The solid-phase reaction and diffusion mechanism between the steel matrix and the inclusion are discussed and revealed, and the experimental results are combined to develop and construct an effective kinetic theory model for controlling and predicting the two types of solid-phase reaction and inclusion modification. The results show that: 1) The thermodynamic equilibrium calculation and the high-temperature equilibrium experiment show that the deoxidized products of the phase equilibrium with the Fe-Mn-Si alloy and the Fe-Al-Ca alloy under the 1873K are ternary MnO-SiO2-FeO and Al2O3-CaO-FeO oxide, respectively; 2) The balance system of the Fe-Mn-Si alloy and the MnO-SiO2-FeO oxide and the Fe-Al-Ca alloy and the Al2O3-CaO-FeO oxide in the original 1873K is no longer balanced in the 1473K heat treatment process, The widths of PPZ, MCZ and ACZ in the two types of diffusion-coupling systems are gradually increasing. For the Fe-Mn-Si alloy and the MnO-SiO2-FeO oxide system, the PPZ and MCZ widths are respectively 15. m u.m, 15. m The PPZ and ACZ widths are respectively 7. m u.m, 20. m u.m before the heat treatment, 31. m u.m, 90. m u.m after the heat treatment for 10 h, and 87. m and the content of FeO in the oxide can be increased, the interfacial solid phase reaction of the alloy and the oxide can be promoted, and the areas such as PPZ, MCZ and ACZ can be increased; 5) The elements of the Fe-Al-Ca alloy and the Al2O3-CaO-FeO oxide system have no effect on the mutual diffusion and the interfacial solid phase reaction of the elements between the MnO-SiO2-FeO oxide and the Fe-Mn-Si alloy in the heat treatment process, but the Fe-Al-Ca alloy and the Al2O3-CaO-FeO oxide system have no influence on the Fe-Mn-Si alloy and the MnO-SiO2-FeO oxide system, and when the content of FeO or the content of the S in the oxide is high, in ord to maintain that total electrical neutrality in the oxide, cations such as Mn2 + and Si4 + are diffused into the alloy matrix from the oxide, resulting in an increase in the content of Mn and Si in the alloy near the interface, the phenomenon is inhibited; 7) the number and the size of the dendritic Al2O3-CaO-like inclusions in the Fe-Al-Ca alloy close to the interface are inversely related to the FeO content in the oxide, and a positive correlation with the heat treatment time (8) is based on the Wagner internal oxidation model, The dynamic diffusion model of the interface solid phase reaction between the Fe-Mn-Si alloy and the MnO-SiO2-FeO oxide, the Fe-Al-Ca alloy and the Al2O3-CaO-FeO oxide under different FeO content and heat treatment time is constructed, and the model results can better reflect the solid-phase reaction phenomenon between the two kinds of alloy and the oxide system during the heat treatment process.
【學位授予單位】：北京科技大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：TG161;TG142
本文編號：2364828
[Abstract]:The type, the quantity, the size, the appearance characteristic and the physical and chemical properties of the non-metal inclusion formed in the steel matrix after the heat treatment and the rolling process directly influence the quality and the performance of the steel product, and one of the main reasons is that the subsequent heat treatment process experienced by the steel matrix can not only change the structure and the performance of the metal material, in addition, that effect of solid phase reaction between the solid metal material and the inclusion can be caused by the influence of the non-metal inclusion in the solid metal material, so that the segregation of the component of the steel matrix, the modification of the original inclusion and the precipitation of the new inclusion are caused. It is feasible to control the physical and chemical properties of the non-metallic inclusions in the alloy matrix by a suitable heat treatment process. In this study, the equilibrium relationship between the non-metallic oxide inclusions of MnO-SiO2-FeO and the Fe-Mn-Si alloy and the non-metallic oxide inclusions of the Al2O3-CaO-FeO system and the Fe-Al-Ca alloy was constructed and verified in combination with the thermodynamic equilibrium calculation and the high-temperature equilibrium experiment of the tube furnace. in turn, a high-temperature co-focusing laser microscope and a quartz tube vacuum seal are used to study that effect of heat treatment, sulfur element, oxygen element and the like on the interface solid phase reaction and the physical and chemical properties of the alloy matrix and the inclusion in the two types of diffusion couple samples under the condition of 1473K, The solid-phase reaction and diffusion mechanism between the steel matrix and the inclusion are discussed and revealed, and the experimental results are combined to develop and construct an effective kinetic theory model for controlling and predicting the two types of solid-phase reaction and inclusion modification. The results show that: 1) The thermodynamic equilibrium calculation and the high-temperature equilibrium experiment show that the deoxidized products of the phase equilibrium with the Fe-Mn-Si alloy and the Fe-Al-Ca alloy under the 1873K are ternary MnO-SiO2-FeO and Al2O3-CaO-FeO oxide, respectively; 2) The balance system of the Fe-Mn-Si alloy and the MnO-SiO2-FeO oxide and the Fe-Al-Ca alloy and the Al2O3-CaO-FeO oxide in the original 1873K is no longer balanced in the 1473K heat treatment process, The widths of PPZ, MCZ and ACZ in the two types of diffusion-coupling systems are gradually increasing. For the Fe-Mn-Si alloy and the MnO-SiO2-FeO oxide system, the PPZ and MCZ widths are respectively 15. m u.m, 15. m The PPZ and ACZ widths are respectively 7. m u.m, 20. m u.m before the heat treatment, 31. m u.m, 90. m u.m after the heat treatment for 10 h, and 87. m and the content of FeO in the oxide can be increased, the interfacial solid phase reaction of the alloy and the oxide can be promoted, and the areas such as PPZ, MCZ and ACZ can be increased; 5) The elements of the Fe-Al-Ca alloy and the Al2O3-CaO-FeO oxide system have no effect on the mutual diffusion and the interfacial solid phase reaction of the elements between the MnO-SiO2-FeO oxide and the Fe-Mn-Si alloy in the heat treatment process, but the Fe-Al-Ca alloy and the Al2O3-CaO-FeO oxide system have no influence on the Fe-Mn-Si alloy and the MnO-SiO2-FeO oxide system, and when the content of FeO or the content of the S in the oxide is high, in ord to maintain that total electrical neutrality in the oxide, cations such as Mn2 + and Si4 + are diffused into the alloy matrix from the oxide, resulting in an increase in the content of Mn and Si in the alloy near the interface, the phenomenon is inhibited; 7) the number and the size of the dendritic Al2O3-CaO-like inclusions in the Fe-Al-Ca alloy close to the interface are inversely related to the FeO content in the oxide, and a positive correlation with the heat treatment time (8) is based on the Wagner internal oxidation model, The dynamic diffusion model of the interface solid phase reaction between the Fe-Mn-Si alloy and the MnO-SiO2-FeO oxide, the Fe-Al-Ca alloy and the Al2O3-CaO-FeO oxide under different FeO content and heat treatment time is constructed, and the model results can better reflect the solid-phase reaction phenomenon between the two kinds of alloy and the oxide system during the heat treatment process.
【學位授予單位】：北京科技大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：TG161;TG142
【參考文獻】
相關(guān)期刊論文 前1條
1 幸偉;倪紅衛(wèi);張華;何環(huán)宇;;鋼液脫氧工藝的發(fā)展狀況分析[J];過程工程學報;2009年S1期
，本文編號：2364828
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