硼含量对NiCrB堆焊合金高温氧化性能的影响  

Effect of Boron Content on High-temperature Oxidation Resistance of NiCrB Surfacing Alloy

作　　者：王旭[1] 贺定勇[1,2] 邵蔚 周正 吴旭[1] 张铁军[3] WANG Xu;HE Ding-yong;SHAO Wei;ZHOU Zheng;WU Xu;ZHANG Tie-jun(Faculty of Materials and Manufacturing,Beijing University of Technology,Beijing 100124,China;Beijing Engineering Research Center of Eco-Materials and LCA,Beijing 100124,China;Pipe Technology Service Center,Sinopec Shengli Petroleum Engineering Co.,Ltd.,Shandong Dongying 257000,China)

机构地区：[1]北京工业大学材料与制造学部,北京100124 [2]北京市生态环境材料及其评价工程技术研究中心,北京100124 [3]中石化胜利石油工程有限公司管具技术服务中心,山东东营257000

出　　处：《表面技术》2023年第8期247-254,300,共9页Surface Technology

摘　　要：目的探究硼含量对NiCrB堆焊合金高温氧化性能的影响。方法以粉芯丝材为原材料,利用氩弧焊工艺制备5种不同硼含量的NiCrB(B的质量分数为0~3.5%)堆焊合金,在800℃的温度下进行氧化试验,总氧化时间为200 h。通过XRD和SEM检测样品的物相组成和微观形貌,并用EDS分析化学成分。堆焊合金氧化前后的硬度通过维氏硬度计测量。结果随着硼含量的提高,堆焊合金中硼化物的含量逐渐增加,因此堆焊合金的硬度也逐渐升高。氧化后,硼含量为0的NiCr堆焊合金表面生成致密的Cr_(2)O_(3)氧化膜,抗氧化性能为最佳。硼的质量分数≥0.8%的堆焊合金表面形成含有Cr_(2)O_(3)和CrBO_(3)的氧化膜,其抗氧化性能因CrBO_(3)含量的升高而降低。硼的质量分数为0.8%时,NiCrB堆焊合金的抗氧化能力接近NiCr合金,当硼的质量分数≥1.6%后,氧化膜逐渐变为疏松,硼含量越高,氧化膜剥落面积越大。硼的质量分数为3.5%时,堆焊合金与氧化膜界面处的CrB和Cr_(5)B_(3)优于铬发生氧化,成为氧向内部扩散的通道。氧化后合金的硬度变化很小。结论硼的质量分数为0.8%的NiCrB堆焊合金的硬度有明显提高,并有较好的抗氧化性,硼的质量分数≥1.6%后,CrBO_(3)的大量产生降低了氧化膜的保护性。Ni-based surfacing alloys have the reliable oxidation resistance in protecting the steel tubes of coal-fired boilers operating in power plant.However,these conventional surfacing alloys are not hard enough to bear the wear from the sand particles in circulating fluidized bed boiler.Therefore,the protective surfacing alloys should possess both good oxidation resistance and high hardness.Researchers have shown that chromium(Cr)can enhance the oxidation resistance of Ni-based surfacing alloys while boron(B)can improve the hardness of the surfacing alloys.Thus,NiCrB surfacing alloys with different boron contents were designed in this work for tube protection.The oxidation resistance and hardness of the surfacing alloys were investigated.Five NiCrB(Cr:24.0%,B:0~3.5%in mass)cored wires with different boron contents were produced,and then these cored wires were used to manufacture surfacing alloys by TIG process.The high-temperature oxidation behavior of the surfacing alloys was investigated after 200 hours of oxidation at 800℃.An electronic scale with an accuracy of 0.01 mg was used to measure the mass of the samples during the high-temperature oxidation tests.The high-temperature oxidation kinetic curves were plotted based on the per unit area mass gain of the samples and the oxidation time.The hardness,phase compositions and microstructures of the surfacing alloys were analyzed by Vickers hardness tester,XRD and SEM-EDS,respectively.Compared to NiCr surfacing alloy,the hardness of NiCrB surfacing alloys was significantly increased.The rise in boron content increased the boride content in the alloy,and thus the hardness was improved.In addition,the hardness of the alloys before and after oxidation changed slightly.The NiCrB surfacing alloys possessed NiCr solid solution and borides,which were was mainly CrB and Cr_(5)B_(3).After oxidation tests,NiCr surfacing alloys showed the best oxidation resistance due to the formation of dense Cr_(2)O_(3)oxide scale.The oxidation products of NiCrB surfacing alloys were composed

关 键 词：NiCrB合金 粉芯丝材 堆焊 高温氧化 CrBO_(3) 硬度 

分 类 号：TG174.2[金属学及工艺—金属表面处理]