高氮奥氏体不锈钢机械纳米化表面层及其热稳定性研究

发布时间：2018-03-29 09:09

  本文选题：高氮奥氏体不锈钢　切入点：表面机械压磨　出处：《长春工业大学》2015年硕士论文

【摘要】：高氮奥氏体不锈钢具备高强度、高韧性、高塑性以及高蠕变抗性、强耐蚀性和无磁特性等诸多优异的物理化学性能,因而在军工行业、海洋工程以及石油化工等领域内具备十分良好的应用前景。尤其是高氮钢的无磁特性,不论是在无磁钻铤还是在军工设备制造等领域内都具备独特的优势。另外,以氮代镍的不锈钢制备技术能大大降低不锈钢生产领域对金属镍的依赖作用,对稀缺镍资源的战略储备具有十分积极的意义。同时,相对于稀缺镍元素来说,氮元素低廉的价格也使得不锈钢的价格优势十分明显。随着高氮钢常压冶炼技术日趋成熟和完善,不锈钢的生产成本也能得到有效的控制,企业化、规模化的生产已经成为可能。优异的性能和低廉的价格将会促进高氮钢在各个领域的应用和快速推广近年来,人们发现利用塑性变形技术能够制备金属纳米材料,实现对材料表面性能的改进并拓展其应用领域。通过对材料表面的强塑性变形处理能制备梯度纳米结构。梯度纳米结构的多级构筑类型不仅能将纳米结构材料的优异性能发挥出来,还能克服纳米材料的性能缺陷,是纳米材料制备及应用的新出路。本论文以热成形Fe-21 Cr-17Mn-2.43Mo-Nb-0.83N为研究对象,首先对其进行1150℃,10h的扩散退火、水淬；然后利用自行设计的内嵌滚珠的摩擦头在铣床上对打磨光滑的板材进行时间分别为240min、360min、480min的表面机械压磨处理,并对处理后试样进行不同温度和时间的真空保温处理。采用X-RAY、显微硬度计、透射电镜等实验设备,对表面机械压磨前后以及真空保温处理前后的试样进行了系统表征,探究了高氮奥氏体不锈钢梯度纳米结构制备的机理及热稳定性,对高氮钢应用领域的拓展具有一定的参考意义。本文主要研究结果如下：1)本研究提供了一种制备表面纳米结构层的新工艺一表面机械压磨法,并能通过此种方法制备梯度纳米结构金属材料。2)高氮奥氏体不锈钢0Cr21Mn17Mo2NbN0.83经过240min、360min、480min机械压磨处理后,其表面纳米细化层与过渡层的总厚度超过700μm,且硬度值提高一倍以上；3)高氮奥氏体不锈钢0Cr21Mn17Mo2NbN0.83在表面机械压磨以及后续的热处理过程中,未生成新相、始终为单一的奥氏体组织；4)热处理温度对机械压磨的高氮奥氏体不锈钢0Cr21Mn17Mo2NbN0.83的梯度纳米结构影响较大,温度升高到923K后,表面纳米层厚度会减小且过渡区会发生回复再结晶现象；5)在873K以内,保温时间对高氮奥氏体不锈钢0Cr21Mn17Mo2NbN0.83的梯度纳米结构稳定性影响较小,金相组织无明显变化,显微硬度值变化也不明显,但在873K长时间(300min)保温的过程中,过渡区部分高应变率的组织会发生回复再结晶现象,梯度纳米结构的稳定性也会受到影响。
[Abstract]:High nitrogen austenitic stainless steel has many excellent physical and chemical properties, such as high strength, high toughness, high plasticity, high creep resistance, strong corrosion resistance and non-magnetic properties. Ocean engineering, petrochemical and other fields have a very good application prospects. In particular, the non-magnetic characteristics of high-nitrogen steel, whether in the field of non-magnetic drill collar or military equipment manufacturing and other fields have unique advantages. In addition, The technology of preparing stainless steel with nitrogen instead of nickel can greatly reduce the dependence on metal nickel in the field of stainless steel production, and has a very positive significance for the strategic reserve of scarce nickel resources. The low price of nitrogen also makes the price advantage of stainless steel very obvious. With the maturation and perfection of atmospheric pressure smelting technology of high nitrogen steel, the production cost of stainless steel can also be effectively controlled and commercialized. Large scale production has become possible. Excellent performance and low price will promote the application and rapid promotion of high nitrogen steel in various fields. In recent years, it has been found that metal nanomaterials can be prepared by plastic deformation technology. To improve the surface properties of materials and expand their application fields. Gradient nanostructures can be prepared by means of strong plastic deformation treatment on the surface of materials. The multilevel construction types of gradient nanostructures can not only change the properties of nanostructured materials. The excellent performance is brought into play, It is also a new way for the preparation and application of nanomaterials. In this thesis, hot forming Fe-21 Cr-17Mn-2.43Mo-Nb-0.83N was studied by diffusion annealing at 1150 鈩，

本文编号：1680464