A kind of manufacturing method of heat-resistant alloy and alloy pipe for pressure steam pipeline

Abstract

The invention relates to a heat-resisting alloy used for a pressure steam pipeline and a method for manufacturing an alloy pipe by adopting the heat-resisting alloy. The heat-resisting alloy used for the pressure steam pipeline comprises the following chemical components: 24-26% of Cr, 19-21% of Co, 1.3-1.5% of Nb, 0.3-0.5% of Mo, 1.1-1.4% of Ti, 1.4-1.8% of Al, 0.01-0.03% of C, 0.04-0.06% of Zr, 0.0005-0.004% of Mg, 0.003-0.012% of P, more than 0% and less than or equal to 0.015% of B, more than 0% and less than or equal to 0.003% of S, and more than 0% and less than or equal to 0.15% of Si, wherein the contents of Al and Ti account for more than or equal to 2.6%, the ratio of Ti to Al is 0.7-0.85, and the ratio of Mg to S is 1.3-1.8. The method for manufacturing the alloy pipe by adopting the heat-resisting alloy comprises the following steps: smelting to form the alloy; carrying out hot forging, wherein an initial forging temperature of 1180-1200 DEG C and a final forging temperature of 900-950 DEG C; carrying out hot extrusion at the temperature of 1160-1200 DEG C, wherein extrusion ratio is less than or equal to 8, deformation of each pass during cold deformation is less than or equal to 45%, and an annealing temperature is 1100 + / - 10 DEG C; carrying out solution heat treatment on a seamless pipe at the temperature of 1150 + / - 10 DEG C, and performing heat preservation for 30 + / - 2 minutes; carrying out ageing thermal treatment at the temperature of 800 + / - 10 DEG C, and performing heat preservation for 8 + / - 1 hours. The heat-resisting alloy pipe manufactured by adopting the method provided by the invention is safe at working temperature and high in endurance strength.

Description

Technical field [0001] The invention relates to a heat-resistant alloy for pressure steam pipelines and a method for manufacturing the alloy pipes. Background technique [0002] Heat-resistant alloys are widely used in many industries, such as garbage incinerators, continuous caster guide rollers, combustion nozzles, thermal power boiler tubes, and so on. Its use on pressurized steam pipelines directly affects the safe operation of equipment, especially for the pipes used in thermal power generation boilers, the direct loss of a pipe burst reaches tens of millions. [0003] For superheater pipes for thermal power boilers with a steam temperature of 700 ℃, the service temperature of the inner wall of the pipe is 700 ℃, and the actual service temperature of the outer wall of the pipe facing the fire can reach up to 750-770 ℃. In the process of detailed research on a Ni-Cr-Co nickel-based heat-resistant alloy (prototype alloy), the inventor found that the alloy still produces η phase...

AI Technical Summary

Problems solved by technology

During the careful study of a Ni-Cr-Co nickel-based heat-resistant alloy (prototype alloy), the inventors found that during the long-term aging process at 770°C, the alloy still produces η phase, and it is found for the first time that it is found in some grain boundaries Abnormal growth of large carbides, these two factors seriously reduce the toughness and durability of the alloy