CN1844452A

CN1844452A - Method for spreading wearable anti-corrosion coating on surface of carbon steel

Info

Publication number: CN1844452A
Application number: CN 200610011815
Authority: CN
Inventors: 郭志猛; 高峰; 林涛; 隋延安
Original assignee: University of Science and Technology Beijing USTB
Current assignee: University of Science and Technology Beijing USTB
Priority date: 2006-04-28
Filing date: 2006-04-28
Publication date: 2006-10-11

Abstract

This invention relates to a method that coating wear-resisting and corroding-resisting coat on the carbon steel surface. In this invention spread reaction Fe2O3+2Al=2Fe+Al2O3 discharges great heat, the product is in molten state, under the centrifugal force, the liquid Fe and Al203 are separate, adding excessive aluminum in reaction material, then Al and Fe can be made into iron aluminum metal compound; and the heat produced form spread reaction can make steel surface smelt, which makes iron aluminum metal compound is easy to join with steel base, after the reaction is over, removing the alumina layer on the surface to obtain metal compound coat. The advantage in this invention is that the technology is simple, the coat and base forms into metallurgy joining, the joining intension is high. The coat thickness can be controlled. The coat rigidity is uniform, the stiffness HVO.3 can get to 4.66GPa.

Description

Method for coating wear-resistant and corrosion-resistant coating on surface of carbon steel

Technical Field

The present invention belongs to a method for preparing an intermetallic compound coating by a self-propagating high-temperature synthesis technology. In particular to a method for coating a wear-resistant and corrosion-resistant coating on the surface of carbon steel, which is a method for coating an Fe (Ni) -Al intermetallic compound coating on the surface of the steel by utilizing a self-propagating fusion casting technology.

Technical Field

The wear resistance and corrosion resistance of common carbon steel are poor, the performance of the common carbon steel is generally improved by surface strengthening or forming a wear-resistant coating, the PVD, the CVD, the surface chemical heat treatment, the laser surface cladding, the thermal spraying and other technologies are generally adopted, and the methods have the defects of long production period, complex process, high cost or high requirement on equipment and the like

The iron-aluminum intermetallic compound has low cost, lower density, obvious high temperature vulcanization resistance and oxidation resistance, high hardness and excellent corrosion resistance. The current production methods of iron-aluminum intermetallic compounds mainly comprise a fusion casting method and a powder metallurgy method.

Self-propagating High-temperature Synthesis (abbreviated as SHS) is a new technology for preparing materials by utilizing Self-heat releaseof chemical reaction. The high temperature generated by the self-propagating reaction mixture during the combustion synthesis process exceeds the melting point of the product to form a melt, and the melt is treated by a metallurgical process to obtain a casting and a coating or complete welding, wherein the method is called SHS metallurgy. Self-propagating fusion casting is a form of self-propagating metallurgy. In a self-propagating reaction And excessive Al is added to generate the Fe-Al intermetallic compound.

Chinese patent CN94104459.9 provides a method for producing a heat-resistant and corrosion-resistant steel-lined composite steel pipe, which is characterized in that an aluminothermic centrifugal method is adopted, oxides of chromium, nickel, tungsten, titanium and the like are added into a mixture of iron oxide and aluminum powder, the reduced metals of iron, chromium, nickel and the like and a byproduct of aluminum oxide are melted by utilizing the high temperature emitted by aluminothermic reaction, the molten products form different types of stainless steel and heat-resistant steel, and under the action of centrifugal force, the stainless steel or the heat-resistant steel is combined with an outer layer mother steel pipe to form a composite steel pipe, thus forming metallurgical combination.

Disclosure of Invention

The invention aims to provide a method for coating a wear-resistant corrosion-resistant coating on the surface of carbon steel, which adopts a self-propagating centrifugal casting method to prepare an Fe (Ni) -Al intermetallic compound coating and forms the wear-resistant corrosion-resistant intermetallic compound coating on the surface of the carbon steel, thereby realizing simpler process and low cost.

Self-propagating reactionin the invention The huge heat is released, the product is molten, and under the action of centrifugal force, liquid Fe and Al are generated₂O₃Separating, adding excessive aluminum into the reaction raw material, and generating iron-aluminum intermetallic compounds by Al and Fe. Simultaneous self-propagating reaction The heat evolved melts the steel surface, allowing the iron-aluminum intermetallic to readily form a metallurgical bond with the steel substrate. And removing the aluminum oxide layer on the surface after the reaction is finished to obtain the intermetallic compound coating. The specific process comprises the following steps:

1. mixing Fe₂O₃And mixing the powder with aluminum powder, and performing ball milling for 2-3 hours, wherein the aluminum powder accounts for 31-40% of the total mass of the mixed powder.

2. Can use Ni₂O₃Powder instead of Fe₂O₃Powdering to form a Ni-Al intermetallic coating.

3. Piling the mixed powder after ball milling on the surface of a steel matrix, and controlling the centrifugal acceleration of the reaction raw material to be 500-5000 m/s²。

And removing the aluminum oxide layer on the surface after the reaction is finished to obtain the intermetallic compound coating. And observing and analyzing to form an intermetallic compound coating with the thickness of 1-5 mm on the surface of the steel substrate.

The invention has the advantages of simple process, metallurgical bonding between the coating and the substrate, and high bonding strength. The thickness of the coating is controllable. Uniform coating hardness, Vickers hardness HV_0.3Can reach 4.66 GPa.

Drawings

FIG. 1 is a schematic diagram of the present invention before the reaction of applying the wear-resistant coating to the steel pipe by the axial centrifugation method. The steel-based composite material comprises a steel matrix 1, a mixture 2 of iron oxide powder and aluminum powder, and a tungsten wire 3 for ignition.

FIG. 2 is a schematic diagram of the invention after the reaction of applying the wear-resistant coating to the steel pipe by the axial centrifugation method is finished. The intermetallic compound coating layer 4 and the alumina layer 5 are formed.

FIG. 3 is a schematic representation of the steel sheet of the present invention before reaction to apply the wear-resistant coating thereto

FIG. 4 is a schematic representation of the steel plate of the present invention after the completion of the reaction for applying the wear-resistant coating.

FIG. 5 is a scanning electron micrograph of the junction of the coating and the substrate taken back from the microscope. White for the steel substrate and grey for the iron-aluminium intermetallic coating.

Detailed Description

Example 1: 320g of iron oxide powder and 144g of aluminum powder serving as reaction raw materials are uniformly mixed and then are filled into a steel pipe to be coated, wherein the size of the steel pipe is phi 74mm, the wall thickness is 4mm, and the length is 200 mm. The round tube is clamped on a centrifuge, the centrifuge is started, the rotating speed is 1110 r/min (the centrifugal acceleration of the reaction raw material is 500 m/s)²) Ignitingthe material with tungsten filament, burning under centrifugal force to release great heat, cooling and eliminating the alumina layer to obtain Fe₃An intermetallic compound coating layer containing Al as a main phase.

Example 2: 32g of iron oxide powder and 21.6g of aluminum powder serving as reaction raw materials are uniformly mixed. The steel plate has a length of 40mm, a width of 40mm and a thickness of 5mm, and is placed in a graphite cavity, the graphite cavity is clamped on a centrifugal machine, the bottom of the cavity is 20cm away from the center of the core machine, the centrifugal machine is started, and the rotating speed is 1000 r/min (the centrifugal acceleration of reaction raw materials is 2240 m/s)²) The tungsten wire is used to ignite the material, the combustion reaction is carried out under the centrifugal force, the huge heat is discharged, and the aluminum oxide layer on the surface is removed after cooling, thus obtaining the intermetallic compound coating taking FeAl as the main phase.

Example 3 the reaction raw materials iron oxide powder 320g and aluminum powder 180g were mixed uniformly and charged into a steel pipe to be coated, the steel pipe having a size of phi 74mm, a wall thickness of 4mm and a length of 200 mm. Round tube clamping in centrifugationOn the machine, the centrifugal machine is started, the rotating speed is 3600 r/min (the centrifugal acceleration of the reaction raw material is 4975 m/s)²) Igniting the material with tungsten filament, burning under centrifugal force to release great heat, cooling and eliminating the alumina layer to obtain Fe₃An intermetallic compound coating layer containing Al and FeAl as main phases.

Claims

1. The present invention is self-propagating reaction process of coating antiwear and anticorrosive coating on carbon steel surface The huge heat is released, the product is molten, and under the action of centrifugal force, liquid Fe and Al are generated₂O₃Separating, adding excessive aluminum into the reaction raw materials, and generating an iron-aluminum intermetallic compound by Al and Fe; simultaneous self-propagating reaction The discharged heat can melt the surface of the steel, so that the iron-aluminum intermetallic compound can easily form metallurgical bonding with a steel substrate, and an aluminum oxide layer on the surface is removed after the reaction is finished to obtain an intermetallic compound coating; the process comprises the following steps:

a. mixing Fe₂O₃Mixing the powder and aluminum powder, and performing ball milling for 2-3 hours, wherein the aluminum powder accounts for 31-40% of the total mass of the mixed powder;

b. piling the mixed powder after ball milling on the surface of a steel matrix, and controlling the centrifugal acceleration of the reaction raw material to be 500-5000 m/s²。

2. The method of claim 1, wherein: with Ni₂O₃Powder instead of Fe₂O₃Powdering to form a Ni-Al intermetallic coating.