Nickel-chromium-cobalt-molybdenum heat resisting alloy and pipe manufacturing process thereof

Abstract

The invention provides a nickel-chromium-cobalt-molybdenum heat resisting alloy and a pipe manufacturing process thereof and belongs to the technical field of the heat-resisting alloys. The alloy comprises the following chemical components in percentage by weight: 21-23% of Cr, 0.05%-0.07% of C, less than or equal to 0.3% of Mn, 11-13% of Co, 6.0-9.0% of Mo, 0.3-0.5% of Ti, 0.8-1.3% of Al, 0.1-1.0% of W, 0.002-0.005% of B, 0.03-0.15% of Zr, 0.2-0.6% of Nb+V and 0.01-0.05% of Nb, less than or equal to 0.15% of Cu, less than 0.008% of P, less than 0.002% of S, less than or equal to 0.015% of N, 0.005-0.02% of Mg, less than or equal to 0.01% of Ca, less than or equal to 0.01% of As, less than or equal to 0.07% of Pb, less than or equal to 0.001% of Bi and the balance of nickel and inevitable impurity elements. The nickel-chromium-cobalt-molybdenum heat resisting alloy has the advantages that the room-temperature mechanical properties, the high-temperature mechanical properties, the low cycle fatigue properties and the durability of a large-diameter thick-wall boiler pipe produced from the nickel-chromium-cobalt-molybdenum heat resisting alloy are all over ASME standard requirements and the technical requirements of CCA617 alloys; the formulation of HAZ liquation cracks and stress relaxation cracks is greatly reduced, and the HAZ long term rupture strength and the tenacity after long term aging both are excellent.

Description

technical field [0001] The invention belongs to the technical field of nickel-based heat-resistant alloys, and in particular provides a nickel-chromium-cobalt-molybdenum heat-resistant alloy (C-HRA-3) and its pipe manufacturing process, which can be used for advanced ultra-supercritical thermal power units with 700°C steam parameters The use of large-diameter thick-walled boiler tubes and related piping. Background technique [0002] According to statistics from the China Electricity Council, in 2013, the total installed capacity of electric power in the country reached 1,247.38 million kwh, of which thermal power installed capacity reached 862.38 million kwh, accounting for about 70% of the total installed capacity. On the one hand, China has abundant coal reserves. Compared with other energy sources, coal-fired power generation is cheap and economical; on the other hand, traditional coal-fired power generation technology brings more CO 2 emissions of polluting gases. In ...

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Problems solved by technology

[0011] In addition, the toughness of aging-type heat-resistant alloys with high strength will be greatly reduced after long-term use, so at present, large-diameter boiler tubes use solid-solution-strengthened heat-r

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