A large-diameter nickel-based composite pipe x groove welding method without argon back filling

Abstract

The invention provides a large-caliber nickel base composite pipe X groove no-back surface argon filling welding method. A base layer of a nickel base alloy composite pipe is Q245R; a composite layeris Incoloy825; and the pipe diameter is not smaller than 500 mm. The method firstly adopts carbon steel welding wires and welding strips to weld the base layer, and then, uses welding wires and welding strips of nickel base alloys for welding a transition layer and the composite layer. The argon back surface protection is not used in the whole welding process, so that a lot of argon is saved, andwelding steps are simplified; and the base layer is welded by common carbon steel, so that the welding material cost is low, and the welding layer number is low. The method shortens the construction period, saves the energy, reduces the emission, and achieves excellent economical benefit and social benefit.

Description

technical field [0001] The invention belongs to the technical field of pipeline welding, and in particular relates to a method for welding a large-diameter nickel-based composite pipe X groove without argon filling on the back side. Background technique [0002] Incoloy 825 is a titanium-stabilized fully austenitic nickel-iron-chromium alloy with additions of copper and molybdenum. It is resistant to acid and alkali metal corrosion in both oxidizing and reducing environments. It is a typical heat-resistant alloy and can be used at high temperatures. high pressure medium. Q245R is a rigid carbon steel that provides better mechanical properties. Q245R and Incoloy825 composite pipes use Q245R as the base layer and Incoloy825 as the clad layer, which combines the excellent properties of the two materials, so they are more and more widely used in the petrochemical industry. [0003] For the welding of Q245R and Incoloy825 clad pipe, in the traditional method, the annular weld o...

AI Technical Summary

Problems solved by technology

Otherwise, using nickel-based alloy welding consumables first and then carbon steel welding consumables will inevitably cause the interlayer temperature of the iron-nickel-based alloy Incoloy825 to exceed 100°C, which will affect the integrity and plasticity of the welded joints

Nickel-based alloy welding consumables are expensive, and a large amount of welding consumables is required for welding large-diameter composite pipes; and for large-diameter pipes, the amount of argon gas required for argon back protection is also increased, which further increases the cost

Argon back protection requires multiple steps to check the quality, the steps are cumbersome, and the welding time is long

Images