上海光源储存环不锈钢真空室

Stainless Steel Vacuum Chamber for Storage Ring of Shanghai Synchrotron Radiation Facility

铝合金和不锈钢都适合制造上海光源储存环的真空室,但各有特色,从而导致不同的加工和成本问题。实质上,不锈钢真空室可以看作是铝合金真空室的一个"内核"。上海光源最终采用了不锈钢真空室,其主要理由是加工铝合金真空室时要用数控床切削掉约一半的材料,而加工壁薄不锈钢真空室几乎没有材料的损失。因此,经费大量节省和加工周期大大缩短。但结构复杂的薄壁不锈钢真空室的尺寸精度要做到和机加工铝合金真空室相当,难度极大。在研制了多个样机后,终于解决了成形片尺寸公差和焊接变形等难题,定型了工艺和工装,真空室的尺寸公差得到了控制。长度约3m的每段真空室的平面度和直线度的公差都小于1mm。真空室经900℃真空退火后,焊缝处的导磁率从2.5下降到1.02。真空预调试后真空室内达到5×10-9Pa的极限真空。400m真空室现场安装后的位置公差都小于2mm。

The ultra large, dedicated vacuum chamber for the storage ring of Shanghai Synchrotron Radiation Facility （SSRF） has been successfully developed using stainless steel as an aherative material to replace the nearly-finished one made of aluminum alloy in 2005 for the purpose of saving long fabrication time and high cost. The total solutions have been provided to solve a number of major technical problems, such as high machining precision of complicated stuctures, deformation of large vacuum chambers, the less than 1 mm tolerance of flatness and straigtness for 3 meter long chambers, and welding without sophisticated welder, etc. For example, the annealing chamber at 900℃ reduced the magnetic permeability from 2.5 to 1.02. The pressure in all chambers approached 5 × 10^- 9pa in the preliminary test. The positioning toltionn of all vacuum chambers.erance was controlled to be less than 2mm in the final installationn of all vacuum chambers.