邹勇,王秋林,门正兴,等.激光熔化沉积SUS 316不锈钢的组织与性能[J].精密成形工程,2024,16(12):209-217.
ZOU Yong,WANG Qiulin,MEN Zhengxing,et al.Microstructure and Properties of SUS 316 Stainless Steel Deposited by Laser Melting[J].Journal of Netshape Forming Engineering,2024,16(12):209-217. |
| 激光熔化沉积SUS 316不锈钢的组织与性能 |
| Microstructure and Properties of SUS 316 Stainless Steel Deposited by Laser Melting |
| 投稿时间：2024-04-20 |
| DOI：10.3969/j.issn.1674-6457.2024.12.019 |
| 中文关键词: 激光熔化沉积过程 缺陷产生 显微组织 性能 机理 |
| 英文关键词: laser melting deposition process defect generation microstructure property mechanism |
| 基金项目:国家自然科学基金(12272245);成都航空职业技术学院重点自然科研项目(ZZX0624091) |
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| 中文摘要: |
| 目的 探索激光熔化沉积SUS 316不锈钢的组织变化、缺陷产生过程及其对性能影响机理。方法 采用激光熔化沉积技术在316不锈钢薄壁管上制造了同一化学成分的316薄片，用扫描电镜(SEM)和光学金相显微镜(OM)观察微观结构，用X-射线衍射仪(XRD)进行物相分析，并测试了力学、物理和化学性能。结果 316薄片与薄壁管结合良好，结合处无元素偏析、裂纹等缺陷，热影响区小，但316薄片中含有孔洞、未熔化颗粒等缺陷。沉积态316的晶粒细小，主要有等轴状和枝晶状或柱状2种形态。主要物相为奥氏体γ，同时含有少量的铁素体δ。相对于挤压态的316管，沉积态316的抗拉强度和伸长率分别下降了8.18%、34.10%，密度下降了1.01%，硬度提高了13.2%，电阻率和腐蚀失重率分别增大了32.56%和5.66%。结论 熔化沉积316的凝固模式为F-A型，少量的铁素体δ对强硬度的贡献较少;孔洞类缺陷和残余应力主要产生在凝固结晶和再次沉积2个阶段，对降低材料性能影响很大;细晶强化机制只有在受到局部载荷时表现明显;大量原子排列不规则和不可避免的孔隙阻碍了自由电子移动，导致电阻率增大;偏离平衡的原子具有较高的动能和层间凹陷地方易于形成原电池这2个因素，使耐腐蚀性下降，腐蚀失效机制为晶间腐蚀。 |
| 英文摘要: |
| The work aims to study the changes in microstructure, the process of defect generation, and the mechanism of impact on performance in SUS 316 stainless steel by laser melting deposition (LMD) technology. The laser melting deposition technology was used to manufacture 316 sheets with the same chemical composition on 316 stainless steel thin-walled tubes. The microstructure of 316 tubes and sheets was observed with a scanning electron microscope (SEM) and a metallographic optical microscope (OM), and phase analysis was performed using X-ray diffraction (XRD), together with the tests for properties such as mechanical, physical, and chemical. The result showed that the 316 sheet had a good bonding with the thin-walled tube, with no defects such as element segregation and cracks at the bonding area, the heat affected zone was small, but the 316 sheet contained defects such as pores and unmelted particles. The grain size of sedimentary state 316 was small, mainly in two forms:equiaxed and dendritic or columnar. The main phase was austenite γ, Simultaneously, it contained a small amount of ferrite δ. Compared with extruded 316 tubes, the tensile strength and plasticity of deposited 316 decreased by 8.18% and 34.10% respectively, density decreased by 1.01%, hardness increased by 13.2%, electrical resistivity and corrosion weight loss rate increased by 32.56% and 5.66%, respectively. In conclusion, the solidification mode of melt deposited 316 is F-A type. A small amount of ferrite δ has less contribution to strong hardness. Pore defects and residual stresses mainly occur in two stages:solidification crystallization and re-deposition, which have a significant impact on reducing material properties. The mechanism of fine grain strengthening is only evident when subject to local loads. A large number of irregularly arranged atoms and inevitable gaps hinder the movement of free electrons, leading to an increase in electrical resistivity. Atoms that deviate from equilibrium have higher kinetic energy and are prone to forming primary cells in interlayer depressions, which leads to a decrease in corrosion resistance. The corrosion failure mechanism is intergranular corrosion. |
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