JP2002538016A - Method for forming a wear-resistant surface on a steel part and an apparatus comprising at least one such part - Google Patents

Abstract

According to the invention, components consisting of steel are provided with a protective coat (6) with an intermediate layer which is harder than steel and a still harder outer layer by successively melting superposed layers (8, 9) consisting of aluminium-bronze onto the steel base material (7).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD OF THE INVENTION

The invention relates, according to a first aspect of the invention, to a method for providing a wear-resistant surface on a steel part, and according to a further inventive concept, to provide an at least partially wear-resistant surface. Device comprising at least one steel member provided.

[0002]

[Prior art]

It is well known to harden the surface side of a steel member to form a hard surface, but hardening the surface requires a lengthy heat treatment, which requires skill. Moreover, the hardness achievable by such a treatment is hardly sufficient. A further disadvantage is that when hardening the front side, hardening can only be achieved at a relatively small depth, there is a high risk of delamination and therefore a relatively short life.

[0003]

[Problems to be solved by the invention]

In view of the above, the object of the present invention is to improve methods and apparatuses of the kind described above by means of easy and inexpensive means, to increase the hardness and thickness of the wear-resistant area, and to firmly secure them, It should be easy to manufacture.

[0004]

[Means for Solving the Problems]

According to the method of the present invention, a plurality of layer forming bodies made of aluminum bronze are sequentially stacked on the steel base material such that an intermediate layer harder than steel and an outer layer harder than the steel are formed by the method according to the present invention. And by means of the device according to the invention that a protective coating is provided in order to form a wear-resistant surface. This protective coating is formed by welding a plurality of, preferably two, layer formers of aluminum bronze onto a steel base material, one above the other.

[0005] Aluminum bronze is successfully welded, and it has surprisingly been found that the outer layer former of the deposited aluminum bronze is harder than the inner layer former. . In an experiment performed using two layer-formed bodies welded so as to overlap one another, a hardness of 300 to 400 HV was obtained with the inner layer-formed body, whereas a hardness of 500 HV was obtained with the outer layer-formed body. A much higher hardness of ~ 600 HV was obtained. From these results, a relatively hard outer layer and an intermediate layer that is softer than the outer layer but still harder than the steel are formed successfully on a steel base material having a hardness of 100 to 200 HV. become. Therefore, it is ensured that the difference in hardness between the base material and the outer layer having abrasion resistance is eliminated not at once but through several stages, and the shear force acting parallel to the surface and acting perpendicular to the surface Lateral force is
Properly and reliably transmitted to the base material. As a result, the reliability with respect to the prevention of peeling is increased, and the long life assured by the high hardness of the outer layer is fully utilized. In other words, the measures according to the invention ensure a favorable overall economic efficiency.

[0006] Preferred embodiments and further developments suitable for the purpose of the measures recited in the dependent claims are described in the dependent claims. A particularly preferred embodiment is to preheat the material to be welded in the furnace each time before depositing the layer former made of aluminum bronze. Preheating increases the hardness of the lower or upper layer former. In this way, a simple method for individually adapting the desired hardness to the conditions of the individual case is possible.

[0007] Particularly preferred was the case where the preheating temperature was 350 ° C. In this case, optimum hardness can be obtained without changing the structure of the base material.

A further way of adapting the achievable hardness to the requirements of the individual case is to suitably change the composition of the aluminum bronze used. When a particularly large hardness has to be realized, 13% to 16% of Al, 4% to 5% of Fe, 0.2% to
Aluminum bronze containing 0.8% Si, 1% to 2% Mn, up to 0.2% C, and Cu as the remaining component is preferably used. 8% to 11% Al, 4% to 6% Ni,
Using aluminum bronze containing 3% to 5% Fe, 1% to 2% Mn, and Cu as the remaining component results in lower hardness. In this way, the hardness of the outer layer former and / or the lower layer former can be adapted to the individual requirements.

[0009] In most cases, it is desirable that all layer formers forming the protective coating consist of the same aluminum bronze. When formed in this manner, manufacturing becomes easy, and uniform bonding between layer-formed bodies provided one above the other is obtained.

As a further preferred measure, in order to obtain good running-in properties, the outer, wear-resistant layer-former made of aluminum bronze is provided with a rapidly wearable coating, such as MoS _2. It may be provided. Such a running-in layer is one that disappears by itself during the running-in phase, thereby ensuring that the outer hard durable layer made of aluminum bronze is exposed after a certain running-in time and is effective. This has an advantageous effect in achieving a long life.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

Further advantageous embodiments and expedient developments of the measures described in the dependent claims are set out in the remaining dependent claims and in the embodiments described below in detail with reference to the drawings.

The present invention is directed to any location where a component made of steel requires a protective coating on its surface that has a hardness greater than that of steel having a hardness of 100 to 200 HV. Can also be applied. Examples of such components include various components of an engine having a running surface that receives a large load, such as a piston ring and a crosshead guide. By using a protective coating that is harder than the parent material, there is a need to reduce the rate of wear and increase life. Therefore, it is required that the hardness of the surface receiving the load be as large as possible and that the adhesion with the base material be performed as well as possible.

FIG. 1 is a partial view of a frame of a two-cycle large diesel engine, showing two support walls 2 provided on a side surface of a crosshead 1. Crosshead 1
A guide shoe 3 is provided on a side of the guide shoe 3, and guide plates 4 having support surfaces that are opposed to each other are provided on both ends of the guide shoe 3. The guide plate 4 is provided on the frame side and moves on a guide rail 5 having running surfaces facing each other.

The guide plate 4 and the guide rail 5 are made of normal steel as a base material, and a protective coating 6 is provided in the region of the running surface of these members opposed to each other. Since the protective coating has a higher hardness than steel, the service life is definitely longer. Of course, other steel components, such as bearing bushings and piston rings, which are always subjected to similar loads, can also be provided with such a protective coating.

The protective coating 6 is made of aluminum bronze, and FIG.
It is formed by two layer formers 8, 9 which are successively welded, preferably by welding, to a base material 7 made of steel and which are provided one above the other. Steel hardness is usually 100-200H
V, and the hardness of aluminum bronze usually takes a value of 200 HV. The lower layer former 8, which is first welded to the steel matrix 7, is surprisingly already approximately 30
It has a hardness of 0 to 400 HV. The second outer layer former 9 surprisingly achieves a much higher hardness of 500-600 HV. For this reason, the outer layer forming body 9 is particularly suitable as a durable layer having abrasion resistance, and such a durable layer surely achieves a long life even under severe operating conditions.

It is very advantageous if a very hard, durable layer is only effective after a certain running-in phase. In such a case, the outer layer former 9 can be provided with a run-in layer 10 made of a material such as MoS _{2 which} wears relatively quickly. Since the running-in layer naturally disappears during the running-in phase, as shown on the right in FIG. 2, an outer layer former 9 made of aluminum bronze and having a high hardness is subsequently ready for use.

The lower layer former 8 having the lower hardness is in fact a medium hardness bond connecting the very hard outer layer former 9 to the relatively soft matrix 7. It works as a layer. As a result, the hardness between the outer layer-forming body 9 and the base material 7 is adjusted stepwise, and the inner layer-forming body 8 has a lower hardness, so that the toughness and the impact strength are higher. The shear forces acting parallel to the surface and the lateral forces acting perpendicular to the surface, as indicated by arrows 11 and 12, are successfully received and transmitted to the base material 7. In the embodiment shown in the figures, the thicknesses of the layer formers 8, 9 which are welded one above the other are equal. The thickness of these layered bodies can be about 1.5 mm. Naturally, it is also possible to make the thickness different from this, or to make the thickness of the layer forming bodies 8 and 9 different. Although it is apparent that the configuration having two layer forming bodies 8 and 9 welded one above the other according to the present embodiment is particularly suitable, two or more layer forming bodies are welded one above the other. You can also think about

For the production of the layer formers 8, 9, 8% to 25% of Al and Sb, Co, Be, Cr, Sn
, Mn, Si, Cd, Zn, Fe, Ni, Pb and aluminum bronze containing 0.2% to 10% each of C and Cu as the remaining component are preferably used. If it is desired that one and / or the other layer formers 8, 9 have a particularly high hardness, 13% to 16% Al, 4% to 5% Fe, 0.2% to
Aluminum bronze containing 0.8% Si, 1% to 2% Mn, at most 0.2% C, and the remaining component Cu is preferably used. When it is desired that one and / or the other layer forming bodies 8 and 9 have a slightly lower hardness, 8% to 11% of Al,
% Bronze containing 6% Ni, 3% to 5% Fe, 1% to 2% Mn, and Cu as the remaining component. Depending on the individual case, a suitable aluminum bronze may be used for each of the layer formers 8, 9, but usually the same aluminum bronze is used for the two layer formers 8, 9. Is preferred.

As described above, the layer forming bodies 8 and 9 can be provided on the base material through the welding process. Arc welding, laser beam, or gas flame is used for welding.

In order to increase the achievable hardness, the current workpiece may be preheated before each application of the aluminum layer. That is, the base material 7 may be preheated before the lower layer forming body 8 is provided, and the intermediate product thus coated may be preheated before the second layer forming body 9 is provided. The preheating is preferably carried out in a furnace, a preheating temperature of around 350 ° C. has proven to be particularly suitable.

[Brief description of the drawings]

FIG. 1 is a view showing a part of a crosshead guide of a two-cycle large diesel engine.

FIG. 2 is an enlarged view showing a portion provided with a protective coating of FIG. 1;

[Explanation of symbols]

 6 Protective coating 7 Base material 8 Layer-forming body (layer-forming body forming intermediate layer) 9 Layer-forming body (layer-forming body forming outer layer) 10 Break-in operation layer

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Claims (12)

[Claims] 1. A method for providing a wear-resistant surface on a component made of steel, comprising a base material (7) made of steel having an intermediate layer harder than steel and an outer layer harder than the steel. A method of forming (6), wherein a plurality of layer forming bodies (8, 9) made of aluminum bronze are sequentially welded one above the other. 2. The method as claimed in claim 1, wherein two layer formers made of aluminum bronze are deposited. 3. A layer former (8, 9) forming said protective coating (6).
3. The method according to claim 1, wherein the welding is performed. 4. The method as claimed in claim 1, wherein the material to be welded is preheated in each case before the application of the layer formations (8 or 9) of the protective coating (6). Item 2. The method according to item 1. 5. The method according to claim 4, wherein the preheating is performed at about 350 ° C. 6. A layer forming body (8, 9) forming said protective coating (6).
6. The method according to any one of claims 1 to 5, wherein have the same composition. 7. Layer-forming bodies (8, 9) forming said protective coating (6).
Contains 8% to 25% of Al and at least one component of Sb, Co, Be, Cr, Sn, Mn, Si, Cd, Zn, Fe, Ni, Pb and C respectively in 0.2% to 10%. A method according to any one of the preceding claims, comprising aluminum bronze containing, and the remaining component Cu. 8. The at least one layer former (6) of said protective coating (6).
8, 9) is 13% to 16% Al, 4% to 5% Fe, 0.2% to 0.8% Si,
8. The method according to claim 7, comprising aluminum bronze containing 1% to 2% Mn, at most 0.2% C and the balance Cu. 9. At least one layered body of said protective coating (6).
8, 9) 8% to 11% Al, 4% to 6% Ni, 3% to 5% Fe, 1% to 2%
The method according to claim 6, comprising aluminum bronze containing Mn and Cu as a remaining component. 10. A device comprising at least one member made of steel, said member provided with an at least partially wear-resistant surface, said device forming said wear-resistant surface. A protective coating (6) is provided, such that a plurality of, especially two, layer-forming bodies (8, 9) of aluminum bronze are superimposed on a base material (7) of steel. An apparatus characterized by being welded. 11. The hardness of the layer forming body (8) provided near the base material is 300.
The apparatus according to claim 10, wherein the hardness is set to 500 to 600 HV, and the hardness of the layer forming body (9) provided on the front surface side is set to 500 to 600 HV. 12. In a new condition, said outer layer former (9) made of aluminum bronze is provided with a running-in layer (10) made of a material that wears quickly. 12. The apparatus according to 10 or 11.