1473 K热处理过程夹杂物与钢基体界面固相反应机理
发布时间：2018-11-29 11:09
【摘要】：经热处理和轧制工序后在钢基体中最终所形成的非金属夹杂物的种类、数量、尺寸、形貌特征以及物化特性,直接影响着钢铁产品的质量和性能,而此类非金属夹杂物与钢液凝固前其内部初始存在的夹杂物往往差异较大,其中一个主要原因在于,钢基体经历的后续热处理工艺不仅能够改变金属材料的组织结构与性能,同时也会对其内部非金属夹杂物造成影响,固态金属材料与夹杂物之间能够发生固相反应,从而造成钢基体成分偏析、原有夹杂物的变性以及新夹杂物的析出。通过合适的热处理工艺实现对合金基体内非金属夹杂物物化特性的控制是可行的。本研究结合热力学平衡计算和管式炉高温平衡实验,构建和验证了1873 K温度下MnO-SiO2-FeO非金属氧化夹杂物与Fe-Mn-Si合金以及Al2O3-CaO-FeO系非金属氧化夹杂物与Fe-Al-Ca合金之间平衡关系,继而利用高温共聚焦激光显微镜和石英管真空密封等设备,研究了1473 K下保温热处理、硫元素、氧元素等分别对上述两类扩散偶样品中合金基体与夹杂物之间界面固相反应以及二者物化特性的影响规律,探讨和揭示了钢基体与夹杂物之间固相反应和扩散机理,并最终结合实验结果,开发和构建了控制和预测两类固相反应和夹杂物变性的有效动力学理论模型。研究结果表明：1)热力学平衡计算和高温平衡实验表明,1873 K下与Fe-Mn-Si合金和Fe-Al-Ca合金相平衡的脱氧产物分别为三元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合金与Al2O3-CaO-FeO氧化物的平衡体系在1473 K热处理过程中不再保持平衡,合金与氧化物会发生高温固相反应和元素相互扩散作用；3)随热处理时间的延长,两类扩散偶体系中PPZ、MCZ以及ACZ等区域的宽度均呈逐渐增大趋势。对于Fe-Mn-Si合金和MnO-SiO2-FeO氧化物体系,PPZ和MCZ宽度分别由热处理前的15μm、15μm,增加至热处理10h后的79μm、120μm以及热处理50h后的138μm、180 μm；对于Fe-Al-Ca合金与Al2O3-CaO-FeO氧化物体系,PPZ和ACZ宽度分别由热处理前的7μm、20μm,增加至热处理10 h后的31μm、90μm以及热处理50 h后的87μm、170μm；另外,由于FeO分解作用,两类氧化物中均出现单质Fe颗粒物质,且颗粒尺寸和数量均呈增大趋势：4)对于两类扩散偶体系,氧化物中FeO含量的升高能够提高过剩O氧含量,促进合金与氧化物的界面固相反应,增大PPZ、MCZ以及ACZ等区域；5)硫元素对热处理过程中MnO-SiO2-FeO氧化物和Fe-Mn-Si合金之间元素相互扩散和界面固相反应起抑制作用,但对Fe-Al-Ca合金与Al2O3-CaO-FeO氧化物体系基本无影响。6)对于Fe-Mn-Si合金与MnO-SiO2-FeO氧化物体系,当氧化物中FeO含量或S含量较高时,为保持氧化物中整体电中性,Mn2+和Si4+等阳离子由氧化物中扩散至合金基体,造成靠近交界面处的合金内Mn、Si元素含量下降到一定程度后出现再次升高的现象,而当氧化物的FeO和S含量较低时,该种现象受到抑制；7)靠近交界面Fe-Al-Ca合金内析出树枝状Al2O3-CaO类夹杂物的数量和尺寸与氧化物中FeO含量呈负相关关系,而与热处理时间呈正相关关系。8)基于Wagner内部氧化模型,构建了不同FeO含量及热处理时间下Fe-Mn-Si合金与MnO-SiO2-FeO氧化物、Fe-Al-Ca合金与Al2O3-CaO-FeO氧化物之间界面固相反应的动力学扩散模型,模型结果能够较好地反映热处理过程中两类合金与氧化物体系之间的固相反应现象。
[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.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TG161;TG142
本文编号：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.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TG161;TG142
【参考文献】
相关期刊论文 前1条
1 幸伟;倪红卫;张华;何环宇;;钢液脱氧工艺的发展状况分析[J];过程工程学报;2009年S1期
，本文编号：2364828
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