SOME RESULTS ON THE TUBES CONTROL AT A CRACKING REACTOR FOR METHANE GAS

摘要

The estimation of the lifetime for equipments and installations working at high temperatures represent an actual problem. Last years, there have been proposed a lot of methods in order to evaluate the lifetime for the equipments working under creep conditions. In the frameworks of the paper, some results regarding the manufacturing quality of pipes from the INCOLLOY alloys belonging to a methane gas cracking reactor are presented. Pipes worked on about 160.000 hours under a pressure of 14 atm and a temperature of 800°C. Some results for welded and non-welded pipes are presented after the control process has been performed. The behavior of the material under a static traction test has been analyzed for six temperatures and the dependence "σ-ε" has been plotted. On the basis of these results, the variation of the mechanical characteristics at different temperatures as well as some microstructure aspects have been followed. In order to praise the influence of the corrosion process about the walls of the pipes, some tests for plate specimens, cut both from working on and new pipes, have been performed. These studies have been putted together with creep tests and, on the basis of the analysis, some predictions about the lifetime at different temperatures have been done.