Surface coating for tuyeres of blast furnace and method for preparing the same

Abstract

The invention provides a composite surface coating for blast furnace tuyere and a preparation method thereof. The composite surface coating for blast furnace tuyere is composed of a bottom layer, a transition layer and a surface layer; wherein the bottom layer is made by Ni-based alloy material by plasma surfacing technique; the transition layer is made by NiCrAl alloy material by supersonic speed flame plating technique; the surface layer is made by mixture of ZrO2Y2O3 and Al2O3 by plasma spraying technique. As the composite surface coating is adopted for surface treatment of the blast furnace tuyere, the gradient change of linear expansibility between the coating and copper parent metal is realized; and the wearing resistance and thermal shock resistance of the blast furnace tuyere are ensured; pitting resistance is improved, the service life of the blast furnace tuyere is prolonged, the requirement of optimizing maintaining model of the blast furnace is met, stable and smooth production of the blast furnace is ensured, and equipment maintenance cost is greatly reduced.

Description

technical field [0001] The invention relates to surface treatment engineering, in particular, the invention relates to a composite coating used on the surface of blast furnace tuyeres and a preparation method thereof. Background technique [0002] The existing blast furnace tuyere bodies are all made of pure copper higher than 99.5%, and the surface wear-resistant treatment methods are mainly surfacing and spraying. [0003] The blast furnace tuyere adopts surfacing welding process for surface treatment. The surfacing layer has high hardness and good wear resistance. At the same time, a metallurgical bond is formed between the surfacing layer and the tuyere body. The bonding strength is high, and its thermal shock resistance has been improved. Greater improvement and improvement. Since the current tuyere surfacing process is argon arc welding with nickel-based electrodes, although the characteristics of good wettability and easy surfacing of nickel-based materials and coppe...

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Problems solved by technology

Such as: Chinese Patent Publication CN1075339 discloses a "blast furnace tuyere surface composite alloy infiltration treatment method", which is to improve the service life of the tuyere by using a high-strength ceramic alloy metal layer formed by the tuyere surface composite alloy infiltration treatment method. Complicated; the "blast furnace tuyere surface protection layer" disclosed in Chinese patent publication CN1224764 is to use powder metallurgy process to mix MCrAlY series alloy powder and high hardness ceramic powder and sinter them into cermet prefabricated parts, and then connect the prefabricated parts to the inner wall or outer wall of the tuyere To improve the thermal shock resistance, erosion resistance, and thermal corrosion resistance of the tuyere, since the cermet prefabricated parts need to be sintered under the protection of vacuum or inert gas, or adopt liquid phase sintering, the process is complicated, and it is not mentioned in the article Data such as thermal shock resistance of this surface protective layer; US patent application US4189130 describes a blast furnace tuyere treatment method, which is to improve its wear resistance and thermal shock resistance by spraying cermet materials on the tuyere surface; Japanese patent application JP54158336 It improves the heat resistance and wear resistance of the tuyere by spraying a hard alloy layer after surfacing CuNiMoTi alloy or similar alloy on the surface of the tuyere; Japanese patent application JP56003608A improves its wear resistance by spraying aluminum or aluminum alloy on the surface of the tuyere Performance and corrosion resistance; Japanese Patent Publication No. 53-138905 discloses a thermal spray coating formulation on the wall surface of blast furnace tuyere, using thermal spraying method to sequentially spray Ni-based self-fluxing alloy layer, Co-Ni-Mo- W-Si or Co-Ni alloy plus Al 2 o 3 -ZrO 2 Cermet coating, Al 2 o 3 -ZrO 2 Ceramic surface layer, because the inner wall coating is easy to peel off from the substrate, so the thickness of the coating is difficult to exceed 0.5mm, and the anti-erosion protection effect of the coating is limited under the long-term working conditions of the tuyere

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