JPS60170587A - Production of zirconium clad steel material - Google Patents

Abstract

PURPOSE:To obtain easily a zirconium clad steel material by constituting an intermediate metallic layer of an independent layer of an alloy contg. a specific amt. of chromium or two layers; a layer of said alloy and a nickel layer and subjecting the clad steel material to hot rolling at a specific temp. CONSTITUTION:A zirconium material 1 is preliminarily joined by, for example, explosive welding, to a steel plate 2 via a Cr steel layer 3 contg. >=10wt% Cr to form a blank material for cladding and assembling. Two pieces of such blank material for cladding and assembling are prepd. and are adhered to each other via a release material 4 which is, for example, zirconium oxide powder, interposed therebetween while the zirconium material sides are positioned to face each other. A weld zone 5 is provided by utilizing a backing plate 6 provided in the entire circumferential edge of the plate 2 and after the inside of the internal gap is evacuated through the weld zone 5, the clad material is heated to 650- 1,000 deg.C and is rolled. The edges of the entire circumferential part are cut away after allowing the rolled material to cool by which the rolled material is separated to two sheets of the steel plates clad with titanium on one side.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improved method for manufacturing zirconium-clad steel comprising a steel material as a base material and a zirconium material as a mating material.

(Prior art) So-called clad materials, which are made by laminating and integrating dissimilar metals in layers, have properties that cannot be obtained from individual metals, combine the excellent characteristics of each material, compensate for the shortcomings of each, and are inexpensive. It is widely used for several reasons. Zirconium-clad steel is technically and economically important from the standpoints of being able to take advantage of the excellent corrosion resistance of zirconium, and of reducing manufacturing costs by reducing the amount of zirconium material used by cladding.

Among the various methods for manufacturing zirconium-steel clad materials, zirconium clad steel materials, especially zirconium clad steel sheets, the so-called rolling method or explosion rolling method utilizes various metal intermediate layers. Although this method has been proposed, in addition to the problem that brittle intermetallic compounds are formed in the metal intermediate layer interposed between the zirconium material and the steel material, resulting in material deterioration, hydrogen from the surrounding environment, There was a problem in that oxygen reacted with the zirconium material, causing material deterioration.

(Objective of the Invention) An object of the present invention is to provide a method that solves the problems of the conventional method described above and allows easier production of zirconium clad steel+A, particularly steel plates.

(Summary of the Invention) Here, the gist of the present invention is to sandwich and join a metal intermediate layer between steel 'fA as a base material and a zirconium material as a composite material to form a clad assembly material. The clad assembly materials are put together with the zirconium material sides facing each other with a release agent interposed, and the entire periphery of both outer steel materials is sealed to form a sand-isolated clad assembly, and then the internal void of the assembly is sealed. A method for producing a cladding material, which comprises subjecting the obtained evacuated assembly to hot rolling after subjecting it to an evacuation treatment, wherein the metal intermediate layer contains 10% by weight or more of chromium. A method for producing a zirconium-clad steel material, comprising a single layer of an alloy or two layers of a layer of the alloy and a nickel layer, and the hot rolling is performed at a temperature range of 650 to 1000°C. .

In the present invention, it is also preferable to use explosive bonding when sandwiching and joining the metal intermediate layer between the base material and the laminate material. However, it can also be carried out by partial brazing or by spot welding.

In one embodiment of the present invention, chromium is contained in an amount of 10% or more.
This method uses a high chromium-containing alloy, preferably an alloy steel, as the metal intermediate layer, but when joining steel and zirconium, the use of a high chromium-containing alloy as the metal intermediate layer eliminates the brittle properties of Fe- This is based on the new finding that the formation of Zr intermetallic compounds is suppressed. The chromium content of this alloy as a metal interlayer is
When the amount of ffi is less than 10%, the formation of Fe-Zr intermetallic compounds is not sufficiently suppressed, so that the good physical properties of the zirconium clad material as a product cannot be maintained.

In the case of such alloys, such as alloy steel, the C contained therein
Alloying elements other than r include Mn, Mo, ■, Ti, N
b. Zr does not have an adverse effect on bonding, but adding a large amount has no industrial advantage. Unavoidable impurity elements such as P and S may be contained at normal levels, but N1, C,
Si and AQ are not preferable because they have an adverse effect on bonding.

The alloy steel used in the present invention is not particularly limited as long as it contains 10% or more of chromium, but typical chemical compositions are shown in Table 1.

In the present invention, when a nickel layer is interposed together with the above alloy layer, the nickel layer is placed on the base metal side to improve the wettability of the metal intermediate layer to the base metal, thereby achieving strong bonding and preventing carbon diffusion. It can act as a barrier layer to prevent the formation of chromium carbide and zirconium carbide at the interface. Here, the nickel layer includes not only pure nickel but also general nickel alloys as long as they are effective in improving wettability and preventing carbide formation. Therefore, it is not necessary to provide such a nickel layer if there is no need to improve wettability or if there is no risk of carbide formation.

Note that the metal intermediate layer may be in the form of a thin plate, a foil, or a film, and is preferably as thin as possible.

In the present invention, the steel material as the base material and the zirconium material as the composite material are not particularly limited in their composition and shape (for example, they may be those used in conventional zirconium clad & ZkA. Any conventional hot rolling may be used, and the present invention is not particularly limited by this.

As described above, in the present invention, the clad assembly consisting of the base material, the metal intermediate layer, and the laminate is brought together by facing the zirconium material (that is, the zirconium material, generally with a release agent interposed). In addition, by sealing the entire periphery of the steel materials on both outsides of the assembly materials described in Section 2 and exhausting air from the internal voids, zirconium nitrides and oxides are formed on the joint surface of the zirconium and steel during heating and rolling. This prevents the formation of zirconium, and also prevents zirconium from absorbing gas from the surrounding atmosphere.Furthermore, since there is no need to consider the deterioration of zirconium material, the upper limit of the temperature of the rolling process can be reduced. This has the advantage that the rolling temperature can be increased to 1000'C.
Since the temperature can be raised up to 000°C, the amount of reduction can be increased, and thereby the material quality can be homogenized and the bonding strength can be further increased. In addition,
Sufficient rolling cannot be performed unless the rolling temperature is 650°C or higher.

Preferably it is 750°C or higher.

(Aspects of the Invention) Next, the present invention will be further described in conjunction with the accompanying drawings, but the illustrated examples are merely shown for explanation, and the present invention is not particularly limited to them. . In addition, in FIG. 1 and FIG. 2, the same signal phase is indicated by the same reference numeral.

In the figure, the code 1 is zirconium as a composite layer + 4.2 is a steel plate as a base material, and 3 is 10% Cr as an intermediate alloy layer.
4 is a release agent, 5 is a welded part for sealing the entire periphery of the base metal, 6 is a patch plate, and 7 is an intermediate metal layer made of nickel.

That is, the example shown in FIG. 1 shows the case where Cr steel is used as the intermediate metal layer, and the steel plate 2 is made of C'r steel W.
Zirconium+AI is preliminarily bonded via I3, for example by explosive bonding, to form a crut assembly.

Prepare two clad assembly cumulative months obtained in this way,
As shown in the figure, the zirconium material sides are placed opposite each other, and a release agent 4, for example, zirconium oxide powder, is interposed between the zirconium materials and the material is pasted, and a patch plate 6 provided on the entire periphery of the steel plate 2 is used. to provide a welded portion 5, and then the welded portion 5
After the internal voids are evacuated, the material is heated to 650 to 1000°C and rolled. After cooling, the ears on the entire periphery are cut off and separated into two single-sided zirconium-clad steel plates.

FIG. 2 shows an example of a two-layer structure using a nickel layer and a high chromium-containing alloy layer as the intermediate metal layer. In this example, the nickel layer 7 is placed on the side of the steel material 2. This is substantially the same as in FIG. 1, except for the following.

Next, the present invention will be further explained by examples.

EXAMPLE 1 The method according to the present invention was carried out according to the embodiment shown in FIG. The compositions of the steel plate as the base material, the zirconium plate as the bonding material, and the Cr alloy steel as the intermediate metal layer are summarized in Table 2. Clat assembly stage steel plate (thickness 120m)
m), consisting of a chromium alloy steel layer (2 mm thick) and a zirconium plate (30 mm thick), two of which were combined to form a cladding assembly. This will be explained later in F;'! The thicknesses were 12 mm, 0.21 mm, and 3 mm, respectively, by rolling. After configuring the cladding assembly, the internal cavity is 10-2T.
After evacuation to 1,000° C., it was heated to 1000° C. and rolled. When an ultrasonic flaw detection test was performed on the zirconium-clad steel sheet that had been rolled after rolling, there was no peeling at all at the joint of the zirconium-clad steel sheet produced by the method according to the present invention. Note that their mechanical properties are summarized in Table 3. The example of test number 3.4 is shown as a comparative example, and the alloy steel containing 8.22% Cr shown in Table 2 was used as the intermediate metal layer.

Actual image 1 The method according to the present invention was carried out according to the embodiment shown in FIG. Table 4 summarizes the compositions of the steel plate as the base material, the zirconium plate as the bonding material, and the Cr alloy steel and nickel as the intermediate metal layer. The cladding is made of steel plate (thickness 120 am), chromium alloy M layer (thickness L)
, nickel N (thickness 0,,l++s) and zirconium plate (thickness 30 mm), and these were made into a two-piece cladding assembly. This was hot rolled to a thickness of 12 mm, 0.2 as, and 0.2 as, respectively, as described below. ．． 01m1
and 3 dragons. After constructing the cladding assembly and evacuating the internal cavity to 10-' Torr,
After rolling, the obtained zirconium clamp steel plate was subjected to an ultrasonic flaw detection test.
There was no peeling at the joints of the zirconium-clad steel sheets produced by the method according to the present invention. Note that their mechanical properties are summarized in Table 5.

The example of test number 7.8 is shown as a comparative example, and an alloy steel containing 8.22 Cr shown in Table 4 and two steels were used as the intermediate metal layer.

As shown in the above test results, the zirconium clad material produced by the method of the present invention exhibits good physical properties including high bonding strength.

[Brief explanation of the drawing]

Figure 1 is a schematic cross-sectional view of the zirconium cladding assembly:
and FIG. 2 is a schematic cross-sectional view of a modified example of the zirconium gland assembly. 1: Laminating material 2; Matrix 3.7: Intermediate metal layer 4: Release agent Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Akira Hirose - 7/M Trap 2 Diagram

Claims (1)

[Scope of Claims] (]) A metal intermediate layer is sandwiched and joined between a steel material as a base material and a zirconium material as a mating material to form a clad assembly material, and the two clad assembly materials are arranged so that the zirconium materials face each other. A sandwich-like cladding assembly is obtained by combining the above with a release agent and sealing the entire periphery of the steel material on the outside of the circle, and then performing exhaust treatment on the internal cavity of the assembly. A method for producing clad steel comprising hot rolling the evacuated assembly, wherein the metal intermediate layer is a single layer of an alloy containing 10% by weight or more of chromium or a layer of the alloy and nickel. 1. A method for manufacturing a zirconium-clad steel material, characterized in that the hot rolling is performed at a temperature range of 650 to 1000°C. (2) The method for producing a zirconium-clad steel material according to claim 1, in which the metal intermediate layer is sandwiched and joined between the base material and the laminate material by explosive bonding.