MXPA98010629A - Procedure for the manufacture of a body of cochilla and product obtained from the mi - Google Patents

Abstract

A shell body (1) made of a hardenable copper alloy with a wear protection layer (7) made of chrome, whose hardness decreases from the surface (8) on the rope side towards the body of the body, is presented. shell (1). The wear protection layer (7) consists of two sheets or chrome sublayers (9, 10). For this the shell body in a state of red solution, is chrome and then hardens, which softens the hardness of the chromium layer (9) which was very high. The hardness of the chromium layer (9) is then 650. Then the second chrome sheet (10) is applied to increase the protection against wear. Here it is a chrome layer of conventional hardness with a hardness between 850 and 1050

Description

PROCEDURE FOR THE MANUFACTURE OF A BUCKET AND OBTAINED PRODUCT FROM THE MISND DESCRIPTION OF THE INVENTION The invention concerns on the one hand a method for manufacturing a shell body according to the characteristics of the main idea in the claim and on the other hand a shell body according to the features in the main idea of claim 5. The shell is one of the most important parts of the injection casting apparatus. In it begins the solidification of the melt. The main structure consists, as a rule, of an external steel construction and of the actual shape-giving part of the mold, that is to say the body of the shell. The body of the shell consists currently almost exclusively of copper or a copper alloy. The copper jacket has the task of properly positioning the shell body and ensuring the course of the water circuit necessary for cooling. The wear resistance of copper alloy is relatively low. Especially at the base of the shell body there is the danger of a high friction between the steel cord and the shell body wall due to the difference between the geometry of the shell body and the shrinkage behavior of the steel or due to the not enough driving of the rope under the chill mold. With REF. 28974 this can present a strong wear by friction with a corresponding variation of the shell body. For reasons of wear protection the shell is provided with an internal coating, such as nickel or chrome. Such a shell body with a protective layer against wear is shown, for example, in DE 31 42 196 C2. With this, an improvement of the friction behavior can be achieved and with this an increase in the residence time of the shell body. A chromium coating is characterized in its composition by its longer life compared to nickel and with this a related protection against improved wear. A galvanic coating of the internal surface with hard chrome therefore offers effective protection against wear. However, due to the difference in the coefficients of thermal expansion of the materials of the shell body and of the coating against wear, high stresses are reached in the wear protection layer. With this the adhesion capacity suffers and the danger of peel-off or cracking is present. Starting from the currently established technique, the present invention proposes a method for the manufacture of shell bodies from a hardenable copper alloy and a wear protection layer made of chromium with an improved adhesion between the body of the shell and the layer of protection against wear. Furthermore, the invention seeks to make possible a better quality of the shell body, to obtain a longer dwell time or duration. The solution of the part according to the process of this object consists, according to the invention, of a shell body according to claim 1. Correspondingly, the shell body consisting of a hardenable copper alloy after the red or melted solution is provided with an internal chromium coating and finally hardens. By means of this thermal treatment, the initial very high hardness of the wear protection layer is reduced, with the consequence of an increase in ductility. The difference in the properties of the materials of the copper alloy of the shell body and the wear protection layer made of chromium are thus smaller, with which the danger of a damage of the chromium layer by the properties essentially decreases different In the body of the shell, it can be basically a shell tube of a part or also of a casting mold of multiple parts, for example a plate mold.

According to the features of claim 2, hardening is carried out under a protective gas in a reducing atmosphere. Here the body of the shell is brought to its final mechanical strength. The hardening temperature is determined by the hardness of the wear protection layer, in order to avoid a strong softening of the chromium layer. Preferably, the hardening is carried out at a temperature between 400 ° and 550 ° (claim 3). Very good results were obtained in the practical tests with a temperature of 460 ° C under a protective gas, where the duration of the heat treatment was 10 hours. Here a hardness of the wear protection layer from 650 HV to 700 HV (Vickers hardness) was pursued. The wear protection layer then consists of a sufficiently high hardness, but due to the high ductility there is a suitable adhesion resistance and a low inclination to form cracks. An advantageous embodiment of the method according to the invention is presented in claim 4. Accordingly, a two-layer wear protection layer is formed. Where after hardening of the internal surface additionally chrome hardening. The chromium layer is preferably electrolytically applied. In this way, multi-layer chrome plating with a gradual hardening step is achieved. The danger of cracking formations becomes clearly smaller. In addition, it is possible, by this measurement, to make thicker layers of the layer of protection against wear made of chromium. A shell body according to the invention is characterized by the features of claim 5. The key point is the extent to which the hardness of the wear protection layer decreases from the surface of the side of the rope in the direction of the body of the shell. With this, the material loads resulting from the different qualities of the materials in the transition passage of the shell body layer and the wear protection layer can be reduced. The hardness can start from the copper alloy rising by steps. Here an increase occurs from the soft copper alloy of the shell body through the chrome layer on the side of the tube with the highest hardness to the highest hardness of the chrome layer on the rope side (claim 6) . According to the features of claim 7, the chromium layer has a hardness between 500HV and 850HV on the pipe side, where instead the chromium layer has a hardness between 850-1050 HV. The thicknesses of the layer of the chrome layer on the side of the tube and on the side of the rope are preferably between 100 microns and 150 microns, where a thickness of the overall layer of approximately 250 microns is considered especially good for the preparation. practice The wear protection layer can have a constant thickness u in the direction of the casting. Basically it is also possible that the thickness of the wear protection layer increases in the direction of the casting. In this way, an effective estimation of the cooling section of the shell that has to be available for solidification can be made, in relation to the shrinkage behavior of the rope. The variation of the coating thickness can be done linearly or stepwise. The invention is described below by means of an embodiment shown in FIG. 1. Figure 1 shows a chill tube for ep rope casting or steel extrusion. The mold tube 1 has a hollow mold space 2, whose transverse transfer at the front end 3 on the inlet side of the laundry is greater than the leg end 4 on the outlet side of the laundry. The base body 5 of the shell tube 1 consists of a copper alloy preferably based on copper / chromium / zirconium (CuCrZr). On the inside 6 is provided the shell tube 1 with a wear protection layer 7 made of chromium. The wear protection layer 7 has two sheets or layers where the hardness of the layer 7 of - protection against wear decreases from the surface 8 on the side of casting in chord in the direction of the chill tube io or the inner side 6 of the chill tube 1. For this the protective layer 7 against wear consists of two layers of chrome 9 and 10 of different hardness. The chromium layer on the side of the tube 9 has a hardness of preferably 650HV. The chrome layer 10 on the rope side has a hardness of 1000 to 1050 HV. To produce or generally the first chrome layer 9, the chill tube or its base body 5 is chromated in a red state of the solution and then hardened in a heat treatment. This gives the shell body its final mechanical strength. After application of the layers, the chrome layer 9 has a hardness of 650V. To increase the protection against wear, second layer of chromium 10 is applied in another coating process, layer 10 having a hardness of 1050 HV. In its entirety, the protective layer 7 of the wear layer has a thickness of 250 microns, where the protective layer of the chromium layer 9 is 100 microns and the protective layer of the chromium layer 10 is 150 microns. The advantage of the wear protection layer 7 on two sheets is based on the small difference between the hardness and the ductility in the transition ~ the base body 5 to the chrome 9 layer under the guarantee of a high surface hardness 8 on the rope side due to the chrome layer .

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following: REFERENCE LIST 1.- Cushion tube 2. - Hollow molding space 3. - Front end of 1. 4. - Leg end of 1. 5. -Base base of l. 6. - Internal side 7. - Protective layer against wear 8. - Surface on the rope side 9. - Chrome coating on the tube side . - Chrome layer on the rope side

Claims (7)

1. CLAIMS l. - Process for manufacturing the shell body of a shell for a rope casting installation consisting of a hardenable copper alloy, wherein the shell body is provided with an internal protection layer against wear made of chromium, characterized because, in the red-hot mold body, the wear protection layer is applied to the mold body and then the mold body hardens.
2. 2. Process according to claim 1, characterized in that the hardening takes place in a protective atmosphere.
3. 3. Method according to claim 1 or 2, characterized in that the hardening is carried out at a temperature between 400 ° C and 550 ° C.
4. 4. - Procedure according to the claims 1 to 3, characterized in that a layer of protection against the wear of two sheets is formed, where after the hardening the internal surface is further chrome-plated.
5. 5. - Casting body made from a hardenable copper alloy for the shell of a casting installation ep. rope, which has a layer of protection against wear made of chrome, characterized in that the hardness of the protective layer against wear decreases from the surface of the rope side towards the shell body.
6. 6. -Cold body according to the claim 5, characterized in that, the wear protection layer consists of two layers or sheets of chrome of different hardness, where the chrome layer on the side of the rope is harder than the chrome layer on the side of the tube.
7. 7. - Chill body according to the claim 6, characterized in that, the chrome layer on the tube side has a hardness between 500 HV and 850 HV and the chrome layer on the string side has a hardness between 850HV and 1050 HV.