CN202366947U

CN202366947U - Hot roll with composite lubricating abrasion-proof coating

Info

Publication number: CN202366947U
Application number: CN2011204530884U
Authority: CN
Inventors: 赵运才
Original assignee: Jingdezhen Ceramic Institute
Current assignee: Jingdezhen Ceramic Institute
Priority date: 2011-11-16
Filing date: 2011-11-16
Publication date: 2012-08-08
Anticipated expiration: 2021-11-16

Abstract

The utility model relates to a hot roll with a composite lubricating abrasion-proof coating. The hot roll comprises a hot roll substrate (4) and a metal ceramic composite coating, wherein the hot roll substrate (4) is made from alloy structure steel 40Cr; and the metal ceramic composite coating is sprayed on the surface of the hot roll substrate (4), and consists of an adhesive layer (1), a transition layer (2) and a working layer (3), which form gradient transition from inside to outside. The problem that a surface layer of a metallurgical hot roll is abraded and eroded by high-temperature metal melt is solved, the service life of the hot roll can be greatly prolonged, the product quality and stability of a hot rolled part can be improved, and production cost can be lowered.

Description

A kind of hot roll that has composite lubricated wear-resistant coating

Technical field

The utility model belongs to metallurgical hot rolling equipment technology field, is specifically related to a kind of hot roll that has composite lubricated wear-resistant coating.

Background technology

Roll is the strength member on steel rolling mill's rolling mill, and the pressure that produces when utilizing a pair of or one group of roll rolling rolls the stone roller steel.Hot roll adopted overall structure in the past, and material commonly used is: 55Mn2, and 55Cr, 60CrMnMo, 60SiMnMo etc., whole normalizing or quenching are adopted in heat treatment, and case hardness requires HB190-270.Roll exists serious roll wear in the mill milling process.Roll wear has not only increased the roller consumption, and has changed original roller type, directly influences the accurate control of rolled piece plate shape, strip crown, is seriously restricting the raising of product quality.Roll wear also can aggravate the edge thinning phenomenon of thin plate rolling, and the flat shape bad phenomenon of aggravation Medium and Heavy Plate Rolling, reduces lumber recovery.The reason that produces the problems referred to above mainly is field failure form and the operating mode characteristics that do not take into full account roll when hot roll is designed, and causes the decline of rolled piece quality and the initial failure of roll for hot-rolling.

Summary of the invention

The purpose of the utility model is to solve the top layer wearing and tearing of metallurgical hot roll and receive high-temperature metal melt etch problem, and a kind of hot roll that has composite lubricated wear-resistant coating is provided.

The purpose of the utility model is achieved in that a kind of hot roll that has composite lubricated wear-resistant coating; Comprise that material is the hot roll matrix of structural alloy steel 40Cr; It is characterized in that being coated with cermet composite coating at described hot roll matrix surface, described cermet composite coating is made up of adhesive linkage, gradient transitional lay and working lining.

Cermet composite coating adopts gradient-structure, and as tack coat, 12Co-WC cermet powder+Ni wraps WS with the NiCrA1 alloy powder ₂+ La ₂O ₃As working lining.The chemical composition of coating is by the mild surface that carries out the transition to coating in gradient of matrix; Reduce matrix and the composition gap that is coated with interlayer; Cause the tissue and the physical and chemical performance of coating also to be continuous transition, avoided matrix, alleviated stress at the interface and concentrated to the tissue of coating, the sudden change of performance; Improved the bonding state of coating interface, comprised between NiCrA1 and the 40Cr matrix, NiCrA1 and 12Co-WC cermet powder+WS ₂+ La ₂O ₃Between, not only make the hardness of coating obtain mild transition, and Bond Strength of Coating is improved greatly, effectively improved the performance of coating.

The utility model when rolling working roll be with between the steel and and support roller between be in contact with one another friction; The wearing and tearing of roll have been caused; Analyzing its wear form mainly contains: (1) abrasive wear: the iron scale of high temperature billet steel (more than 850 ℃) surface regeneration is broken under the draught pressure effect; Its fragment forms abrasive wear as the continuous grinding roller roll surface of abrasive particle; (2) fatigue wear: roll is bearing contact fatigue and heat fatigue in periodic carrying, unloading, heating, cooling procedure; When pulsating stress surpasses the fatigue strength of roll material; Superficial layer will cause crackle and expansion gradually; The material fracture of cracked zone is peeled off, fatigue wear promptly takes place; (3) adhesive wear: the plastic deformation of steel billet makes iron scale can not intactly surround roller surface, and when high temperate zone steel closely contacted under pressure with roll surface, the band steel produced adhesive wear to roll surface; (4) oxidative wear: contact with high temperate zone steel and rub and make the work roll surface temperature raise, impel the roll surface oxidation to accelerate, under the load effect, the oxide layer generation oxidative wear that breaks.Thereby the residing hot environment of roll is the principal element that influences its wear out failure.On the other hand, lubrication in heat-rolling process has and improves plate surface quality significantly, reduces roll wear, reduces the roll amount of refacing, and reduces power consumption, effect such as boost productivity.But after lubricating oil was supplied with roller surface, temperature height, wetting oil viscosity significantly descended in rolling deformation the district in, even the part of attaching oil will produce the influence of factors such as burning, gasification and metal lateral flow, caused lubricant effect undesirable.Through having changed traditional hot roll design concept, field failure form and the operating mode characteristics above-mentioned according to roll adopt coating form to be designed to multilayer materials, and can improve the hardness and the high temperature corrosion resistance of coating; Give full play to solid lubricant WS ₂Under hot environment, have material characteristics separately such as stable frictional behaviour, avoided satisfying the working condition requirement of roll for hot-rolling owing to hot roll unfavorable situation of lubricant effect under hot environment.The utility model can significantly improve the service life of hot roll, improves service life more than 1 times; Improve the product quality and the stability of hot rolling product, reduce production costs, production cost descends more than 50%.

Description of drawings

Fig. 1 is the utility model hot roll cross-sectional view.

The specific embodiment

One, coat system design

The material selection structural alloy steel 40Cr of the utility model matrix 4; Coating material select for use have high fusing point, the 12Co-WC cermet powder of hardness, elastic modelling quantity and good wearability, add Ni bag WS simultaneously ₂High-temperature lubricant and the rare earth La that adds ability crystal grain thinning and raising coating compactness ₂O ₃Through proportioning and test repeatedly, the mass ratio of selecting composite coating material for use is 12Co-WC: Ni bag WS ₂: rare earth La ₂O ₃=72: 26: 2.

Coating adopts gradient-structure, and as tack coat 1,12Co-WC cermet powder+Ni wraps WS with the NiCrA1 alloy powder ₂+ La ₂O ₃As working lining 3, the structural design of coating is seen table 1, and the 1st layer is that adhesive linkage 1, the layer 2-3 is that gradient transitional lay is a functional layer for 2, the 4 layers, also is working lining 3.

The design of table 1 coating structure

Annotate: C is the coating components of working layer; N is NiCrA1

Two, adopt supersonic speed plasma spraying equipment spraying and adhesive bonding layer, gradient transitional lay and working lining

Adopt the powder mixing machine mode that selected alloy powder is evenly mixed with lubricant, spraying equipment adopts HEPJet type supersonic speed plasma spray system.Earlier use the acetone roller surface before the spraying, use brown corundum sandblast then.After the spraying, sprayed coating is carried out grinding reach the roller surface quality requirement.

Preparation technology of coating is as shown in table 2:

Table 2 spraying parameter

The flying speed of supersonic speed plasma spraying equipment spraying particle high (about 400-600 m/s), it is fine and close to form the coated foil layer structure, sheet interlayer bond strength (cohesive strength) and coated substrate interface bond strength (macroscopical bond strength) height.The porosity of coating reduces greatly, generally is lower than 1%, and particularly the lamellar structure distortion is abundant, fine and close, has overcome the appearance of open hole (or through hole), has effectively slowed down the oxidation of alloying component in the coating.

Three, laser remolten supersonic speed plasma spraying coating

The laser remolten test is not have helium crossing current CO in the HL-1500 type ₂Carry out on the laser instrument, through experiment screening optimization, laser power is decided to be 1200W, sweep speed 4mm/s, spot diameter 5mm.

Last century late nineteen eighties, win along with ceramic coating is good can represent, plasma spray technology particularly plasma spraying technology in the face coat technology, obtain extensively, overall application.But still there are some intrinsic defectives in the supersonic speed plasma spraying ceramic coat, as: have typical layer structure, in coating, produce in more crackle, the coating and have hole etc. inevitably.Laser remolten provides new approach for the solution of this technical barrier; Can eliminate the layer structure of sprayed coating, most of hole and oxide inclusions; Tissue can obtain tangible refinement, forms the ceramic coating of even compact, and the crackle of existence is eliminated basically; Guarantee the performance of coating, improved the service life of roll.

Composite coating and matrix do not form metallurgical binding yet simultaneously.Laser remolten makes the roll coating experience the process of heat fused-cooled and solidified, and in cooling procedure fast, along with solid liquid interface is passed forward, the speed of growth is more and more faster, and it is tiny more that the size of crystal grain also becomes, and promoted the formation of equiax crystal.The umbrella organisations of coating is tiny equiax crystal, and the bottom is thick column crystal.Column crystal is " herring-bone form " from the upwards growth of combination interface of coating and matrix, and the dendrite axle is vertical with substrate, and its direction of growth is consistent with the thermograde direction, has typical oriented rapid solidification characteristic.In the bottom of column crystal, coating material and matrix material have formed the transition zone of metallurgical binding.This is under the high energy laser effect, and through the convection current stirring of melt in the molten bath and the short-range diffusion of alloying element, together alloying layer dissolves each other.The existence of alloying layer makes combining firmly and closely between coating and matrix.

Claims

1. hot roll that has composite lubricated wear-resistant coating; Comprise that material is the hot roll matrix (4) of structural alloy steel 40Cr; It is characterized in that being coated with cermet composite coating at described hot roll matrix surface, described cermet composite coating is made up of adhesive linkage (1), gradient transitional lay (2) and working lining (3) from inside to outside successively.

2. the hot roll that has composite lubricated wear-resistant coating as claimed in claim 1 is characterized in that the thickness of adhesive linkage (1), gradient transitional lay (2) and working lining (3) is respectively 200 μ m, 400 μ m and 400 μ m.