摘要
以电熔氧化镁稳定氧化锆和单斜氧化锆为主要原料,碳酸镁为稳定剂,采用热压铸工艺,石蜡加入量分别为9.5%、10%和10.5%,制备了大尺寸氧化锆导流管坯体,经脱脂后分别在1650、1700和1750℃下保温7 h烧成,研究了石蜡加入量和烧成温度对大尺寸氧化锆导流管性能的影响,并与进口大尺寸氧化锆导流管进行对比。结果表明:随着烧成温度的提高,试样的致密度和常温抗折强度提高;随着石蜡加入量的增加,试样的致密度和常温抗折强度降低,热膨胀系数降低。进口导流管的致密度低于本实验导流管的致密度,热膨胀系数略低于自制导流管,1100℃抗热震性能与石蜡加入量10%、1700℃烧成的导流管相当。1700℃保温7 h、石蜡加入量10%的导流管综合性能最佳,满足一次上线服役要求。提高导流管的抗急冷冲击性能有利于导流管的重复再使用。
Ceramic delivery tube was the key functional component of vacuum induction melting gas atomization method(VIGA).With the enlargement of equipment,the size of ceramic delivery tube was also gradually larger.The BN delivery tube had good thermal shock resistance,but it was prone to oxidation and erosion in practical application.It was one of the main factors affecting the production and alloy powder quality.ZrO_(2)had high temperature resistance,wear resistance,chemical resistance,low specific heat and thermal conductivity,so it was the ideal material to replace the BN delivery tube.The thermal shock resistance of ZrO_(2)became worse with its larger size and more complex structure.Large size delivery tube with complex structure and heavy wall(20 mm thickest)required higher fluidity of hot injection moulding.The effects of paraffin addition amount and sintering temperature on the performance of large-size ZrO_(2)delivery tube were studied.On account of phase transition,the thermal shock resistance of m-ZrO_(2)was poor.Stabilizers were usually introduced to make m-ZrO_(2)become partially stabilized ZrO_(2).MgO,CaO and Y_(2)O_(3) were the commonly used stabilizers.MgO stabilized ZrO_(2)had the best thermal shock re‐sistance.The Large-size ZrO_(2)delivery tube was prepared by hot injection moulding with MgO stabilized ZrO_(2)and monoclinic ZrO_(2)as the main materials,MgCO_(3) as the stabilizer,the paraffin wax addition amount of 9.5%,10%and 10.5%respectively.After degreasing,the bodies were sintered at 1650,1700 and 1750℃for 7 h,respectively.The results shows that the density and room temperature flexural strength of the samples are gradually increased with the increase of sintering temperature.The density,room temperature flexural strength and thermal expansion coefficient of the samples are decreased with the increase of paraffin wax addition amount.The density and thermal expansion coefficient of imported large-size ZrO_(2)delivery tube are lower than that of the experimental samples,and the thermal shock resistance at 1100℃is equivalent to that of the experimental samples sintered at 1700℃with the paraffin wax addition content of 10%.Through this study,the technical bottleneck that hot injection moulding cannot prepare thick-wall products has been broken,and the technical parameter for preparing thickwalled products by hot injection moulding is determined.The delivery tube sintered at 1700℃with the paraffin wax addition content of 10%has the best comprehensive performance and meets the requirements of one-time on-line service.Improving the cold shock resistance of delivery tube is beneficial to its reuse.
作者
王来稳
于建宾
税国彦
郭新力
王刚
杜鹏辉
WANG Laiwen;YU Jianbin;SHUI Guoyan;GUO Xinli;WANG Gang;DU Penghui(Sinosteel Luoyang institute of Refractories Research CO.,Ltd,State Key Laboratory of Advanced Refractories,Luoyang 471039,China;Shenyang Research Institute of Foundry,Shenyang 110022,China)
出处
《粉末冶金工业》
CAS
北大核心
2022年第4期25-30,共6页
Powder Metallurgy Industry
基金
科技部重点研发计划资助项目(2021YFB3701400)。
关键词
真空感应熔炼气雾化
大尺寸
氧化锆
导流管
热压铸工艺
vacuum induction melting gas atomization
large-size
ZrO_(2)
delivery tube
hot injection moulding
