Welding material for ni-based heat-resistant alloys, and welded metal and melded joint each using same

Abstract

A welding material for Ni-based heat-resistant alloys, which has a chemical composition containing 0.06-0.18% of C, 0.5% or less of Si, 1.5% or less of Mn, 45-55% of Ni, 25-35% of Cr, 7.0-13.0% of W, more than 0.2% but 1.5% or less of Ti, less than 0.1% of Al, 0.002-0.20% of N, and if necessary, 1.0% or less of Nb, with the balance made up of Fe and impurities that include 0.02% or less of O, 0.008% or less of P and 0.005% or less of S. This welding material for Ni-based heat-resistant alloys exhibits excellent welding workability and high-temperature cracking resistance during welding.

Description

technical field [0001] The present invention relates to a welding material for a Ni-based heat-resistant alloy, a welding metal and a welding joint using the same. Specifically, it relates to a welding material suitable for welding a Ni-based heat-resistant alloy used in equipment used at high temperatures, such as a boiler for power generation, and a weld metal and a welded joint obtained by using the same. Background technique [0002] In recent years, from the viewpoint of reducing the environmental load, the operating conditions of boilers for power generation and the like have been increased to high temperature and high pressure globally, and materials used therein have been required to have more excellent high temperature strength. [0003] As a material satisfying such a requirement, there is, for example, a Ni-based heat-resistant alloy specified in UNS N06617. In addition, Patent Documents 1 to 5 disclose various Ni-based alloys. For these Ni-based alloys, various...

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Problems solved by technology

[0017] In addition, the above-mentioned Patent Document 6 and Patent Document 7 do not consider stress relaxation cracking at all.

Therefore, the weld metal obtained by using the welding materials proposed in the above-mentioned Patent Document 6 and Patent Document 7 also has a problem of remaining stress relaxation cracks.

In addition, when the welding materials proposed in the above-mentioned Patent Document 6 and Patent Document 7 contain a large amount of Ti and / or Al, there is also a problem of poor workability during welding.

[0018] On the other hand, in the welding material proposed by the present inventors in Patent Document 8, since the Ti content is small, there is room for improvement in securing better creep strength.

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