| 摘要 |
PURPOSE:To produce a heat resistant cast steel pipe having strength to rupture by hihg temp. creep by using a heat resistant centrifugal casting pipe as a blank material and subjecting the same to elongation and reduction plastic working to a desired pipe diameter with a pilger mill. CONSTITUTION:The melt of the Cr-Ni-Nb heat resistant cast steel contg. 0.05- 0.25% C, <2.0% Si, <2.0% Mn, 19-27% Cr, 30-40% Ni, 0.3-2.0% Nb, <0.15% N is centrifugally cast to a hollow blank pipe. The inside and outside casting surfaces of the blank pipe are suitably machined, whereafter the blank pipe is subjected to elongation and reduction plastic working to an intended pipe diameter. The pipe is finally subjected to a solutions heat-treatment at 1,050- 1,150 deg.C in order to relieve the strain hardening induced by the working. The seamless heat resistant cast steel pipe for a heat exchanger is easily produced. |
