不锈钢管道的比放气率研究
Research on the Outgassing Rate of Stainless Steel Pipes
范永山 1杜畅通 1张化一 1郑曙昕 1邢庆子 1王学武 1闫逸花 2王敏文 2王忠明2
作者信息
- 1. 清华大学粒子技术与辐射成像教育部重点实验室 北京 100084;清华大学先进辐射源及应用实验室 北京 100084;清华大学工程物理系 北京 100084
- 2. 强脉冲辐射环境模拟与效应国家重点实验室 西安 710024
- 折叠
摘要
不锈钢管道的比放气率是超高真空系统设计的关键参数,降低比放气率是提高真空度的有效方法之一.在西安200 MeV质子应用装置(XiPAF)的重离子升级工程中,重离子同步环真空管道内要求达到超高真空度(10-10 Pa量级),要求不锈钢管道的比放气率不超过 1.5×10-13 Pa·m3/(s·cm2).文章通过研究降低不锈钢管道比放气率的方法,得到一套不锈钢管道处理方案,使得不锈钢管道的比放气率不大于此数值.降低比放气率的方案包括三个关键问题,即不锈钢材料的选取、真空炉高温烘烤方案选择和加热带烘烤方案选择.论文设计了实验方案,定制加工了四根相同尺寸的不锈钢实验管道,304和 316L两种材料各两根,四根管道分为两组分别进行真空炉500℃和950℃烘烤,每根管道做四次加热带烘烤实验,烘烤温度依次设定为 150℃、200℃、250℃和 300℃,并测量每根管道最终的比放气率.为测量不锈钢实验管道的比放气率,搭建了一套比放气率测试平台.测量结果表明,加工厂家提供的 304和 316L两种不锈钢材料的初始管道比放气率的大小与材料种类无特定规律;实验中真空炉或者加热带的烘烤均能使比放气率降低 1～2个数量级;管道依次进行真空炉 950℃烘烤和加热带 300℃烘烤之后,比放气率可以达到5×10-14 Pa·m3/(s·cm2)以下,满足XiPAF重离子升级工程要求.
Abstract
Outgassing rate of the stainless steel pipe is a key parameter for the design of the ultra-high vacuum system,and reducing the outgassing rate is one of the efficient ways to raise the vacuum level.An ultra-high vacuum level(～10-10 Pa)inside the vacuum pipes of the synchrotron ring is required for the heavy-ion upgrade project of the Xi'an 200 MeV proton application facility(XiPAF).It is further demanded that the outgassing rates of stainless steel pipes must not exceed 1.5×10-13 Pa·m3/(s·cm2).To guarantee that the outgassing rate of the stainless steel pipe is not higher than this value,the method to lower the rate is researched and a treatment proposal is presented in this paper.Three major concerns are involved in the proposal to lower the outgassing rate:the selection of stainless steel material,the choice of high-temperature vacuum furnace baking scheme,and the choice of heating band baking scheme.An experimental process is designed.Four stainless steel pipes are customized with the same size,with two pipes made of 304 and another two 316L.The four pipes are divided into two groups,and each group is baked inside a vacuum furnace at 500℃and 950℃,respectively.Four heating-band baking tests are conducted for each pipe with the temperatures progressively set at 150℃,200℃,250℃,and 300℃.Ultimately,the final outgassing rate of each pipe is measured.A dedicated platform is constructed to measure the outgassing rates of the stainless steel experimental pipes.The measurement results indicate that,for the two types of stainless steel material—304 and 316L—there is no particular pattern regarding the relationship between the type of material with the initial outgassing rate of the pipes provided by the processing manufacturer.The outgassing rate can be reduced by one or two orders of magnitude after baking in a vacuum furnace or with heating bands.After undergoing successive baking at 950℃in the vacuum furnace and 300℃with heating bands,the outgassing rate can reach below 5×10-14 Pa·m3/(s·cm2),satisfying the requirement of the XiPAF heavy-ion upgrade project.
关键词
比放气率/超高真空/不锈钢管道/烘烤温度Key words
Outgassing rate/Ultra-high vacuum system/Stainless steel pipe/Baking temperature引用本文复制引用
出版年
2024
NETL
NSTL
万方数据