Novel Ni-Cr corrosion-resistance alloy heat exchange tube plate and welding process thereof

Abstract

The invention discloses a novel Ni-Cr corrosion-resistance alloy heat exchange tube plate and a welding process thereof. A heat exchange tube adopts ferrite stainless steel XDS-I with a chromium massfraction of 25-30%; the tube plate and a welding wire both adopt austenite stainless steel XDS-II with a chromium mass fraction of 24-26% and a nickel mass fraction of 19-22%; the total content of C+Nelements in the ferrite stainless steel XDS-I material adopted by the heat exchange tube is not higher than 0.025%; a special welding process is cooperated to achieve excellent welding effect, smoothand uniform welding lines and excellent metallographic structure distribution; macroscopic and microscopic structures of welding lines of the tube and the tube plate are free of obvious defects, excellent in morphology and free of such defects as cracks, incomplete fusion and incomplete penetration; and the welding lines are qualified. Heat affected zones and melting areas of microscopic metallographic structures of the sections of the welding lines are excellently transited, and are free of burnt structures, hardened martensitic structures, netty precipitates and netty structures.

Description

Technical field [0001] The invention specifically relates to the technical field of heat exchangers, in particular to a new type of Ni-Cr corrosion-resistant alloy heat exchanger tube sheet and its welding process. Background technique [0002] At present, heat exchangers are heat exchange equipment widely used in petroleum, chemical, metallurgical and other industrial fields. In the heat exchanger production process, the welding of the tube sheet and the heat exchange tube is an extremely important part. The welding quality of the tube joint directly determines whether the heat exchanger can work normally. Most of the heat exchangers are damaged and damaged. All failures are due to problems with the welded joints. Firstly, welding defects such as pipe wall penetration and unfusion of weld seams are prone to occur during welding; secondly, a large number and densely distributed weld seams will cause serious uneven heat input distribution in different areas of the tube plate duri...

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Problems solved by technology

First of all, welding defects such as tube wall penetration and weld infusion are prone to occur during welding; secondly, the large number and densely distributed welds will cause serious uneven heat input distribution in different areas of the tube plate during welding, These two problems will lead to a decline in the welding quality of the pipe joints and a relatively serious deformation of the tube sheet, which poses a threat to the sealing of the heat exchanger. Again, the heat exchanger is more used in various acid corrosion environments, and even Some equipment also have strict requirements on the resistance to acid corrosion, intergranular corrosion and stress corrosion of welded joints. The quality of the welded joints is directly related to the safe and stable operation of the heat exchanger, which may cause direct economic losses

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