Process Test Study Of Ultra-supercritical Boiler Steel T/P92

T/P92 on the basis of T/P91 is further studied and developed, higher strength grade ferrite steel. This steel has good high temperature oxidation resistance and corrosion resistance. It can make the main steam parameters to reach 610℃and reheat steam temperature increased to 625℃. This paper makes further research of T/P92 process test in the Ultra-supercritical boil. Accordingly we have a more comprehensive understanding of T/P92 steel and put forward optimization of process parameters. It provided technical support in the aspect of instructing an appropriate welding process, heat treatment process and machining process during the manufacturing in the Shanghai Boiler Works Ltd, moreover, it has an important significance in enhancing the capacity of thermal power generating units, improving power generation efficiency, reducing the cost of power generation, better solving power shortage for our country and promoting development of China’s national economy.This paper mainly studies T/P92 steel and its welded joints. T/P92 Overall properties can be evaluated through different welding methods, different interpass temperature and different post-welding heat treatment, finally determined the optimum process parameters and post-weld heat treatment specification under different welding methods. We make T92 tubes’cold-formed, necking and have a squash test & microstructure and grain size measure & specimen hardness in order to determine what is the conditions of normalizing plus tempering for the different ratio R/D And that determine optimum heat treatment specification. We have short-term and lasting high temperature tests for T92 steel weld joints Under 625℃and extrapolate stress value under 105 hours according to running time under six stress point (160 MPa, 150MPa, 140MPa, 130MPa, 120MPa, 110MPa) . At last the broken sample of 110MPa is made microanalysis in order to determine whether or not T92 tubes’lasting strength can meet the application requirements under 625℃.The results show that: SA213-T92 Post-weld heat treatment specification is determined 750-780℃×2h no matter what the same steel butt welding or different steel butt welding. Besides lasting strength of T92 tubes’butt joints can meet the application requirements under 625℃.T92 tubes’ovality and reduction will be guaranteed when tube cold bending radius R≥1.5D. After T92 tubes’cold bending, normalizing plus tempering should be preformed when the ratio R/D is less than 2 and annealing with welded attachments when the ratio R/D is not less than 2. There is little extension for T92 steel, so the material is not required necking. For P92 weld joints, the interpass temperature should be strictly controlled under 300℃in order to get better weld properties. In addition, the weld joint should be immediately de-hydrogenation after welding in order to prevent from reducing cold crack. The P92 optimum temperature of post–weld heat treatment is 770℃and holding time selected from 6 to 10 hours.