JPS6362289B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a powder-filled inner liner made of Cupro Ni, Cu, Cu alloy, Fe, etc., which fits into the inner diameter of a container for a hot extruder and has excellent high-temperature abrasion resistance. It is. [Prior Art] Martensitic die steel has conventionally been used for inner liners for hot extruders. but,
When extruding copper alloys, etc., where the temperature of the extruded material exceeds 600℃, the inner surface of the inner liner comes into contact with the high-temperature extruded material during use and is subjected to high extrusion pressure. Inner surface wear and wear are severe, and strength decreases due to high-temperature tempering, and in some cases,
Cracking occurred in the extrusion direction of the inner liner, resulting in the end of its life in a short period of time. For this reason, so-called super heat-resistant alloys have recently been used, such as when the temperature of the extruded material exceeds 1000℃, such as in the extrusion of Cupro Ni, or when the temperature of the formed material exceeds 750-850℃, such as copper alloy. When extruding tubes at ℃ and with a relatively short extrusion time, the inner liner is 1.5
-It has become possible to improve tool life by about three times, but it is expensive, so this does not necessarily lead to savings in tool costs.
Also, like pure copper, the temperature of the extruded material is 800-900℃.
However, in extruded materials with high thermal conductivity, the temperature of the inner liner increases rapidly and the temperature difference in the radial direction of the inner liner becomes large, resulting in large thermal stress and shortening the life of even super heat-resistant alloys. It's short. Particularly in the case of extrusion of pure copper bars, which requires a long extrusion time, the life expectancy is significantly reduced, and the extrusion does not contribute to any reduction in tool costs. On the other hand, it has been proposed to apply weld build-up to the inner peripheral portion of the inner liner using a welding rod. The present inventors have developed an inner liner using the austenitic hot work tool steel disclosed in JP-A-59-104214 as a base material and overlaying and welding a super heat-resistant alloy, etc. on the working surface, and have achieved results. . This method is
MIG welding is applied to the inner surface of the inner liner.
It is made of Ni-based super heat-resistant alloy, etc.
However, (1) In the case of MIG welding, the amount of penetration is large and it is difficult to adjust the build-up thickness, so after applying 2-3 layers of build-up, the inner peripheral surface is processed to the specified dimensions. This causes variations in the thickness of the built-up layer. In addition, (2) adjustments such as build-up specifications are difficult, so hot cracking and cooling cracking are likely to occur, and repairs must be performed using TIG welding. Therefore, due to the above two reasons, wear and deformation occur locally, which is still unsatisfactory in that the life span of the inner liner varies widely. Furthermore, in the case of the MIG welding method, there is a limitation in that only the overlay materials that can be used to manufacture wire rods can be used. [Problems to be solved by the invention] As explained above, conventional inner liners have insufficient high-temperature strength,
Due to the lack of wear resistance, even inner liners made of super heat-resistant alloys are expensive but do not save tooling costs. The present invention has excellent high temperature strength and wear resistance, and
The aim is to provide an inexpensive inner liner. [Means for Solving the Problems] The present invention uses hot work tool steel, super heat resistant alloy, etc. as a base material, and uses powder overlay welding on the working surface of the base material.
WC, TiC, TiN, TiB ₂ ,
The above object is achieved by providing a built-up layer in which hard material particles such as VC and SiO ₂ are dispersed and held. Note that when an austenitic alloy is selected as the base material, it is also useful to perform appropriate heat treatment such as aging treatment after powder build-up welding to improve the strength of the build-up layer. [Function] The inner liner of the present invention has a powder build-up layer on its use surface. Since this built-up layer is made of a melt obtained by melting each component and powder whose blending ratio can be arbitrarily selected, high-temperature strength and wear resistance can be made sufficiently high. In addition, in powder overlay welding, the penetration rate is very small at less than 5%.
It is possible to make subtle adjustments to the thickness of the build-up layer,
Experiments revealed that there was almost no risk of hot cracking that occurred during MIG welding. In addition, if an austenitic alloy is used as the base material,
It was found that since the base material has a large coefficient of thermal expansion, the shrinkage during cooling after build-up is large, and as a result, the generation of tensile stress due to cooling shrinkage of the build-up layer is small. This shows that the overlay material can be made into a material with higher strength, and on the other hand, when combined with the powder overlay method, which allows the material to be selected regardless of the manufacturability of the welding rod, higher performance can be achieved. This makes it possible to manufacture inner liners of Furthermore, since the austenitic alloy has high high temperature strength, the retention of the built-up layer is high. In addition, in the plasma powder build-up welding method, it is easy to control heat input, and the amount of penetration, build-up thickness, etc. can be controlled more precisely. [Example] Table 1 shows examples of combinations of inner liner base material and overlay material in examples of implementing the present invention, as well as practical results. It is expressed as an index when the value is set to 100. Table 2 also shows the composition of each alloy used.

【table】

【table】

〔Effect of the invention〕

As described above, the inner liner for a hot extruder of the present invention is welded on its use surface by powder build-up welding, and has particular properties such as high-temperature strength, high-temperature abrasion resistance, and high-temperature softening resistance. It has a much higher quality. In addition, because of its composite structure, it can be supplied at a relatively low cost, and in addition to improving tool life, its industrial value is extremely large. Additionally, in the case of an inner liner for hot extrusion, what is required is high deformation resistance during hot heating, and as a build-up material,
Among Fe-based, Ni-based, and Co-based super heat-resistant alloy steels, materials with strong high-temperature strength are desirable. The present invention is not limited to the composition of these super heat resistant alloys, but may be any conventional super heat resistant alloy.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a container having a container with a powder overlay liner. 1...Tire (outer cylinder), 2...Outer liner (intermediate cylinder), 3...Inner liner (inner cylinder), 4...
Powder overlay welding part.

Claims (1)

[Claims] 1. In an inner liner for a hot extruder, the surface to be used is coated with Fe-based alloy,
An inner liner for a hot extruder, characterized in that it is composed of a base made of a Ni-based alloy, a Co-based alloy, or an alloy thereof, and an overlay layer of an alloy in which hard particles are dispersed and retained. 2 Base material is austenitic die steel, Fe base,
The inner liner for a hot extruder according to claim 1, characterized in that a Ni-based super heat-resistant alloy is used and powder build-up welding is performed by a plasma method.