蒸汽过热炉炉管的性能测试和安全评估

THE MECHANICAL PROPERTIE DETERMINATION AND SAFETY EVALUATION OF STEAM SUPERHEATING FURNACE TUBES

某蒸汽过热炉在烘炉时一组炉管因过热导致表面严重氧化,炉管全部弯曲失稳。对炉管能否继续安全使用进行了试验和评估。取与炉管同材料、同直径的12Cr1MoVG低合金钢管材在模拟的过热温度和持续时间下加热,测定过热炉管在设计温度和常温下的力学性能。结果表明,750℃过热36h后的炉管,其σ0.2和σb分别降低18%和30%,伸长率(δ5)和断面收缩率(ψ)变化不大,炉管在设计应力下的持久断裂时间也是足够的,故该过热炉炉管在设计工况下工作是安全的。

A set of furnace tubes were superheated and their surfaces were severely oxidized during drying out. In order to assess the safety of the tubes for use, the tubes of 12Cr1MoVG were heated, which are identical in material and radius with ones in the furnace, under the condition of simulated temperature and hold time. The tensile test is taken at the room temperature and designed temperature and the mechanical properties were analyzed. Finally the results show that the yield strength σ_(0.2) and the tensible strength σ_b of material of heated tubes at 750℃ for 36h were decreased by 18% and 30% respectively, however the flexibilities δ_5 and ψ have no variation. Moreover the creep rupture time of tubes under the designed pressure is enough. So these tubes can be operated in safety under designed pressure.