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1.
45 钢表面激光合金化组织分析及硬度测试   总被引:1,自引:1,他引:0       下载免费PDF全文
目的为了提高45钢表面性能,采用CO2激光器对其表面进行合金化处理。方法利用带有能谱的扫描电子显微镜(SEM/EDS)、金相显微镜、X射线衍射仪、显微/维氏硬度计、扫描电镜等,对合金化层组织及性能进行了观察和分析。结果激光合金化层由合金化区、结合区和热影响区3部分组成,涂层与基体呈冶金结合;涂层主要含Cr3C2,Fe Ni3,Cr23C6,Fe3C相;激光合金化层的显微硬度达1032 HV,约为基体的3.5倍。结论 45钢经激光合金化处理,可改善其表面性能,显著提高其硬度。  相似文献   

2.
本文采用2kWCO_2激光器对20Cr_(2)Ni_(4)W钢进行了激光表面钴合金化的试验研究。用光学显微镜、扫描电镜、电子探针、X射线衍射、透射电镜、显微硬度计等手段分析了合金化区域的成分、组织和性能。结果表明,激光表面钴合金化可获得含钴均匀的合金化层,合金化层的高温硬度和热疲劳性能均有提高,在热作工具钢表面性能优化领域有着良好的应用前景。  相似文献   

3.
利用消失模铸造工艺,通过正交实验合金化工艺,重点研究了表面合金化的形成机理,建立了消失模铸件表面合金化模型,分析了合金化过程的动力。在不同真空度、金属粒度、温度为780℃的条件下进行浇注,发现在镁合金基体表面形成均匀的合金化层,通过扫描电镜(SEM)分析表层组织变化,对生成的新相进行微区成分和表层线成分分析。研究表明,在表层生成的新相主要是Mg17Al12,并且表层显微硬度明显高于基体。分析了合金化机理和影响形成均匀合金化层的主要因素,得出了合金化颗粒粒度和铸渗动力在合金化过程中起关键作用,随着合金化颗粒粒度和真空度增大,表面合金化效果明显得到了提高。  相似文献   

4.
为改善20钢件的表面性能,利用强流脉冲电子束(HCPEB)技术与预置涂层相结合的技术在20钢表面合金化Cr元素以获得高性能的合金复合改性层。利用X射线衍射、金相显微镜、扫描电子显微镜、透射电子显微镜、维氏硬度计以及多功能微机电化学分析仪对合金化层的显微组织以及性能进行研究。结果表明:20钢经过HCPEB辐照合金化后,形成了厚度约为4~6μm的合金化改性层,Cr元素在样品表层发生了固溶和扩散。部分渗碳体在辐照诱发的应力作用下出现弯折、粒化等现象,并在基体溶解与Cr结合析出颗粒细小弥散的Cr_(23)C_6增强相。HCPEB辐照合金化后材料表层显微硬度提高了35%,腐蚀电流密度降低了1个数量级。  相似文献   

5.
轧辊的失效及其修复技术   总被引:1,自引:1,他引:1  
轧辊是轧机的主要变形工具,由于自身材质及其所处的恶劣工作条件,经常发生失效乃至报废,通过修复技术可以延长其使用寿命.综述了冷、热轧辊的工作条件、用材和失效形式,介绍了几种常用的轧辊修复表面技术,并对激光表面合金化技术修复轧辊的发展前景进行了展望.  相似文献   

6.
2Cr13钢激光表面合金化的组织和性能分析   总被引:1,自引:0,他引:1  
2Cr13钢通过激光表面合金化达到表面改性的目的。利用扫描电镜观察了在不同工艺参数下,激光表面合金化的强化效果及显微组织。用显微硬度计检测了激光合金化组织的显微硬度。结果表明,2Gr13钢激光表面合金化能大大提高其表面的硬度和耐磨性,使它的应用更为广泛。  相似文献   

7.
表面缺陷对于汽车外用热镀锌钢板的成材率具有很大影响,以钢板表面的典型缺陷分析方法为例,通过显微组织观察和微区成分分析,判断了缺陷的成因,总结了理化检验技术在汽车外用热镀锌合金化钢板生产中的应用方法。结果表明:缺陷发生的位置在镀锌工位之后、平整工位之前,设备材料属于有机组成;通过现场调研发现缺陷设备为一组挤干辊,通过替换完好的挤干辊保证了生产的顺利进行。  相似文献   

8.
为了扩大等离子合金化的应用范围,研究了Cr,Ni合金化成分和工艺参数对45钢等离子合金化层显微硬度和耐蚀性的影响。结果表明:合金粉末成分和等离子工艺参数对合金化层显微硬度影响不大,但对耐蚀性能影响较大;等离子合金化过程中由于Cr有较大烧损需用较快扫描速度;等离子合金化可以在45钢表面获得较高的耐蚀性能,具有广阔的应用前景。  相似文献   

9.
针对再制造大型热轧支承辊堆焊层的服役早期开裂现象,通过检测分析堆焊层硬度、显微组织和断口形貌,确定堆焊层开裂失效机制是低周接触疲劳破坏。由于堆焊层内残余奥氏体含量过多,马氏体相含量相对不足,堆焊金属低硬度、低强度,降低了再制造热轧支承辊面堆焊层的抗接触疲劳性能。通过高温回火热处理促使堆焊层残余奥氏体向马氏体转变,调控辊面堆焊层亚稳相残余奥氏体和马氏体含量,提高再制造支承辊面硬度、强度,可有效避免服役期内再制造热轧支承辊面堆焊层开裂现象,从而提高再制造大型热轧支承辊的质量稳定性和使用寿命。  相似文献   

10.
纯镁强流脉冲电子束表面改性及合金化研究   总被引:2,自引:0,他引:2  
强流脉冲电子束是一门新兴的表面处理技术。本文利用强流脉冲电子束对纯镁进行表面改性,并尝试表面合金化铝处理。利用光学显微镜、扫描电镜和透射电镜对表面处理层形貌和组织结构进行了分析,同时也进行了摩擦腐蚀性能测试。纯镁强流脉冲电子束表面改性后,显微硬度得到明显提高;纯镁表面合金化铝后,样品抗5%NaCl溶液腐蚀性能得到显著提高,维钝电流密度降低2个数量级以上,同时也对相关改性机理进行了初步分析。  相似文献   

11.
为提高马氏体不锈钢的耐蚀和耐磨性能,选择40Cr13不锈钢为基材、纯铌板为靶材,采用双辉等离子表面冶金技术在不锈钢表面制备合金化层.用SEM、GDOES、XRD等方法分析渗铌温度对铌合金层组织、成分、相组成、表面形貌及硬度的影响,并对渗层形成机制及表面硬化机理进行了研究.结果表明:在900~1 000℃形成的铌合金层组织均匀致密,合金层主要由Nb2C、Nb C、Fe2Nb、Cr2Nb及铌组成;合金层表面粗糙度随渗铌温度的提高而增加;合金层厚度随渗铌温度改变发生不同变化规律,950℃渗铌形成的渗层约13μm,900和1 000℃渗铌后合金层厚度均为7μm左右;不同温度渗铌后试样的表面硬度与基体相比均有较大幅度的提高,1 000℃渗铌后试样表面硬度高达约985 HV0.025,900℃渗铌后约758 HV0.025,而950℃渗铌后表面硬度最低,约698 HV0.025.  相似文献   

12.
Laser surface alloying (LSA) is increasingly recognised as a powerful surface modification tool to enhance the wear and corrosion resistance of engineering components. The present work deals with laser alloying of medium carbon steel with silicon carbide using a high-power CO2 laser. A processing regime, identifying an appropriate laser power-scan speed combination for achieving defect-free alloyed layers, has been established during the study. The influence of repetitive scans on the alloyed layer properties was also subsequently investigated in a comprehensive manner. Repetitive scanning was found to affect substantially the laser-alloyed zone (LAZ) and heat-affected zone dimensions, as well as the phase constitution of the laser-alloyed layers. The microstructure in the LSA layers was also observed to vary significantly with the number of scans, besides changing quite distinctly with depth in the LAZ. Tribological tests revealed considerable improvement in abrasive wear performance by laser surface alloying, and the results also emphasise the need to control the number of repetitive scans to achieve optimum performance.  相似文献   

13.
Laser surface alloying (LSA) was used to formin situ Fe-Cr-C alloys on AISI 1018 steel substrates. Chromium powders of different particle sizes were mixed together to obtain optimum packing density of the powder deposited on the substrate. The surface was then melted using a 2kW CW carbon dioxide laser. The processing conditions were related to solute (chromium) content, microstructural refinement of the laser alloyed zone and the heat affected zone (HAZ). The microstructure of the laser surface alloyed region was investigated by optical, scanning and transmission electron microscopy, and X-ray microanalysis techniques. Microstructural study showed a high degree of grain refinement and an increase in solid solubility of alloying element. This process produced a fine distribution of complex type of carbide precipitate in the martensite-ferrite matrix because of the high cooling rate. An alloy of this composition does not show any retained phase. The nature of alloying and chemical diffusion profile as a function of intertrack separation distance affects the final content of alloying element in the surface layer.  相似文献   

14.
钛合金表面加弧辉光离子渗镍铬及其性能研究   总被引:3,自引:0,他引:3  
采用加弧辉光离子渗金属新技术处理钛合金Ti5Al2.5Sn表面,研究了渗层的相组成特点,成分分布情况,评价了改性层的磨擦摩损性能,及与钛合金基体间的接触腐蚀相容性等。结果表明加弧辉光离子渗技术可以快速地在钛合金表面获得NiCr镀渗复合层。渗层由Ni3Ti等金属间化合物组成,其硬度、耐磨性能均高于离子注氮层,具有较高的抗含Cl^-1水溶液腐蚀性能,在含Cl^-1腐蚀环境中与钛合金基体接触相容。  相似文献   

15.
In this research, microstructure and wear behavior of Ni-based alloy is discussed in detail. Using tungsten inert gas welding process, coating of nearly 1–2 mm thickness was deposited on ductile iron. Optical and scanning electron microscopy, as well as X-ray diffraction analysis and electron probe microanalysis were used to characterize the microstructure of the surface alloyed layer. Micro-hardness and wear resistance of the alloyed layer was also studied. Results showed that the microstructure of the alloyed layer consisted of M23C6 carbides embedded in Ni-rich solid solution dendrites. The partial melted zone (PMZ) had eutectic ledeburit plus martensite microstructure, while the heat affected zone (HAZ) had only a martensite structure. It was also noticed that hardness and wear resistance of the alloyed layer was considerably higher than that of the substrate. Improvement of wear resistance is attributed to the solution strengthening effect of alloying elements and also the presence of hard carbides such as M23C6. Based on worn surface analysis, the dominant wear mechanisms of alloyed layer were found to be oxidation and delamination.  相似文献   

16.
本文采用5KWTEACO_2激光器,对 Ti—6Al—4V 钛合金进行表面合金化处理,实验结果表明,经激光辐照后,材料表层及次表层组织结构产生变化,与基体组织大不相同,其硬度有很大提高,由 Hv250提高到 Hv800~900。磨损试验表明,经激光处理的试件,其耐磨性提高2~3倍。扫描电镜分析表明:处理区域由精细枝晶区,等轴细晶区和马氏体区组成,表层硬度的提高及耐磨性的改善与表层组织形态、晶粒细化及硬质点的弥散分布有关。  相似文献   

17.
铸钢件表面铸渗合金化试验研究及应用   总被引:1,自引:0,他引:1  
通过对各组成比例不同的合金涂料进行试验,研究各种涂料对铸件表面质量和合金化层组织的影响,从中选择合理的配比,并应用于破碎机机锤。生产试验结果表明,经表现合金化的破碎机机锤磨耗明显低于未经表现合金化的破碎机锤;合金涂料的配比是铸件表面合金人技术的关键。  相似文献   

18.
Commercial flake graphite cast iron substrate was coated with titanium powder by low pressure plasma spraying and was irradiated with a CO2 laser to produce the wear resistant composite layer. The macro and microstructural changes of an alloyed layer with the traveling speeds of laser beam, the precipitate morphology of TiC particulate and the hardness profile of the alloyed layer was examined. From the results, it was possible to composite TiC particulate on the surface layer by direct reaction between carbon existed in the cast iron matrix and titanium with thermal sprayed coating by remelting and alloying them using laser irradiation. The cooling rate of the laser remelted cast iron substrate without a titanium coating was about 1 × 104 K/s to 1 × 105 K/s in the order under the condition of this study. The microstructure of the alloyed layer consisted of three zones; the TiC particulate precipitate zone (MHV 400–500), the mixed zone of TiC particulate + ledeburite (MHV 650–900) and the ledeburite zone (MHV 500–700). TiC particulates were precipitated as a typical dendritic morphology. The secondary TiC dendrite arms were grown to a polygonized shape and were necking. Then the separated arms became cubic crystal of TiC at the slowly solidified zone. In the rapidly solidified zone near the fusion boundary, however the fine granular TiC particulates were grouped like grapes.  相似文献   

19.
介绍了一种在Q235钢表面进行等离子合金化及热处理工艺,获得表面高性能强化层的技术方法.通过该技术方法的处理,使Q235钢表面含有Mo,Cr,C合金元素,成分达到或接近冶金高速钢.该工艺技术的基本原理是在真空容器中,利用辉光放电的溅射现象,首先在Q235钢表面渗入合金元素Mo,Cr,表面含量分别达到12%(质量分数,下同)和4%左右,随后进行超饱和渗碳,使表面含碳量达到2.0%以上,合金化层成分接近钼系高速钢.合金层中的碳化物细小、均匀、弥散,无粗大的共晶莱氏体组织.Q235钢表面合金化后分别采用淬火 低温回火,淬火 2h深冷处理 低温回火两种工艺.结果发现,经深冷处理的试样表面硬度达到1600HV,明显高于未经过深冷处理试样的表面硬度.摩擦磨损实验表明,经深冷处理试样的滑动摩擦系数较未经深冷处理试样的要小,经深冷处理试样的耐磨性是未经深冷处理的1.6倍.  相似文献   

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