JPS6064786A - Production of titanium clad steel - Google Patents

Abstract

PURPOSE:To obtain efficiently a Ti clad steel having high joint strength and good plastic workability with a method of providing an insert material between a Ti plate and a steel plate by providing Ni and copper as the insert material. CONSTITUTION:A thin layer consisting of Ni is provided as the 1st insert material on the cladding surface side of a Ti plate and a thin layer consisting of copper or copper and Ni is provided as the 2nd insert material on the cladding surface side of the steel plate. These plates are superposed on each other at the mating surfaces and are heated to 700-1,000 deg.C. The heated plates are rolled and joined at >=70% draft and are then reduced in thickness by rolling at >=400 deg.C if necessary. The rolled plates are subjected to softening annealing at 650-750 deg.C in succession to the rolling. The decrease in strength owing to the brittle intermetallic compd. formed between the Ti and the steel, the embrittlement arising from absorption of hydrogen by Ti and the decrease in the strength arising from the diffusion of C in the steel plate to the Ti plate and the precipitation of brittle TiC are prevented according to the above-mentioned method.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The present invention relates to a method for manufacturing titanium clad steel.

(b) Prior Art Conventional methods for manufacturing titanium crund steel used as material for chemical equipment, etc. include roll crimping, diffusion bonding, and explosion bonding. Both the roll pressure bonding method and the diffusion bonding method require about 1-degree heating and pressure bonding. However, in these methods, since intermetallic compounds are generated at the joint between the titanium plate and the steel plate, a good joint cannot be obtained. In order to prevent the formation of intermetallic compounds, there is a method of providing an insert material between the titanium plate and the steel plate. For example, Special Publication No. 56-1286, Special Publication No. 56-1287,
and Japanese Patent Publication No. 71590/1983 disclose a method of using chromium, molybdenum, henanium, or a composite material of these metals and chromium, nickel, and 1-1 as insert materials. However, titanium clad steel manufactured by such a method has a low bonding strength, which causes problems such as delamination between the titanium plate and the steel plate when plastic working such as spinning is applied. Furthermore, the diffusion bonding method has to be carried out in a high vacuum or in an inert gas, which has the problem of poor productivity. Since the roll crimping method and the diffusion bonding method have the above-mentioned problems, the explosion bonding method is mainly put into practical use. However, the explosive bonding method also has the following problems. That is,
The firecracker method is not suitable for mass production, and the base material must be strong enough to withstand the explosion pressure, so the thickness of titanium crand steel that can be manufactured using this method is limited to 20 mm or more. . In addition, plastic workability is also unfavorable in the explosively bonded state. In order to improve the plastic workability of titanium Clara I steel, it is necessary to anneal it at a temperature higher than 650°C, which is the temperature at which titanium sufficiently softens, but annealing at such a temperature significantly reduces the joint strength. Do a low C. In order to solve these problems, titanium clad steel manufactured by the explosion bonding method is thinned by hot rolling or softened by annealing. Similarly, a problem arises in that intermetallic compounds are formed between the titanium plate and the steel plate. Bokosho 53
-No. 10347 and Seisen 11? (No. 53-133458 shows a method of providing nickel as an insert material between a titanium plate and a steel plate in order to solve the problems mentioned above. However, even with this method, 1. The bonding strength is not equal to IJJ, and the maximum plate thickness that can be manufactured is about 10 mm.

(c) Purpose of the Invention The present invention solves the above-mentioned problems in the conventional titanium clad steel manufacturing method, and makes it possible to efficiently produce titanium clad steel with high joint strength and good plastic workability. The purpose is to obtain a manufacturing method for titanium clara) and steel.

(D) Structure of the Invention The present inventors have discovered that the bonding strength of titanium clamp steel manufactured by the conventional titanium clamp steel manufacturing method is reduced due to the following three factors. Namely, (1) Deterioration of strength due to weak intermetallic compounds formed between titanium and steel.

(2) Carbonization due to hydrogen absorption of titanium.

(3) Carbon in the steel plate diffuses into the titanium side and weak titanium carbide precipitates, resulting in a decrease in strength.

There are three factors. In order to prevent the joint strength from decreasing due to the three factors mentioned above, it is necessary to provide a two-layer insert material of nickel and copper, or a three-layer insert material of nickel and copper. The inventor of wood discovered this. That is, in the method for manufacturing titanium clad steel according to the present invention, the first inserter i.
A dollar layer of nickel is provided as a material, an oil layer of copper or copper alloy nickel is provided as a second insert material on the mating surface side of the steel plate, and these are overlapped on the mating surface of the steel plate.
Heating to 1000°C, rolling and joining at a reduction rate of 70% or more,
Next, the process consists of softening and annealing at 650 to 750°C. In addition to each of the above steps, it is also possible to perform rolling at a temperature of 400° C. or higher before softening annealing after I (E rolling and joining).

Note that the thin layer of the insert material herein refers to "plating" or "ha〈", and preferably has a thickness of 5 microns or more after rolling. The plating shall be applied to the steel plate or the insert I material, and the titanium plate shall not be directly plated. This is because plating titanium lowers the bonding strength.

By the method of the present invention having the configuration as described above, it is possible to eliminate the three factors that reduce the bonding strength described above.

First, according to the method of the present invention, the above-mentioned factor (1) can be eliminated. That is, even if annealing is performed at a high temperature of 650 to 750°C, no fragile inter-Ir compound is generated at the joint between the titanium plate and the steel plate. An intermetallic compound is formed between titanium and nickel, and this intermetallic compound exhibits a certain degree of ductility. Therefore, it is also possible to reduce the thickness by rolling. In addition, this intermetallic compound is very easy to double harden in the -sugar crystal, but 40
00C! There is no problem if the rolling pressure is applied at the temperature specified in 1- below. Furthermore, nickel and copper and copper and steel plate form a complete solid solution, and no intermetallic compounds are generated. In addition, if the steel plate is an alloy containing many components other than iron, what happens? A weak intermetallic compound is formed between the steel sheet and the steel sheet (although it has surface properties,
In this case, this can be prevented by further providing nickel as an insert material between the copper and the steel plate.

Further, according to the method of the present invention, the above-mentioned factor (2) can also be eliminated. That is, it is possible to prevent embrittlement caused by hydrogen absorption of titanium. This is because the intermetallic compound formed between titanium and nickel prevents hydrogen from entering. However, this intermetallic compound is formed because titanium can absorb hydrogen during heating before bonding.

Combination of titanium plate and 11 & ↓ 1 after welding II; 9
It is necessary to perform hydrogen treatment.

Furthermore, according to the method of the present invention, the above-mentioned factor (3) can also be eliminated. That is, it is possible to prevent carbon in the steel sheet from diffusing toward the titanium side. This is a result of using copper as the insert material. The carburization prevention effect of copper is several times that of nickel, for example, 750
Even when annealing is performed at °C, a thickness of about 5 microns is sufficient.

(E) Example Next, the effects of the present invention will be explained based on specific test results.

Table 1 shows the mechanical properties of titanium clad steel produced by the method of the present invention and titanium clad steel produced by the conventional method. Samples A-F were obtained by the method of the present invention,
Samples G-J were prepared using conventional methods.

IT: Light 6) Samples A to C in Table 1 used a steel plate of 60t x 100ow x 2000mm and a titanium plate of 950w x 1950flc7). The steel plate is coated with a first layer of 100 micron thick plating, and then this copper plating is further coated with a layer of 100 microns thick.
Nickel plated to a micron thickness. This steel plate and a titanium plate were stacked together, and the periphery was brought into contact with each other once a month to form a clad package. This club, do package tio~15
At 0°C, the pressure was reduced to 10-2 Torr by blowing 4 Jl,
600~900 after argon gas 1″1°″l
It was hot-rolled in a range of 'C' and reduced to a plate thickness of 6 mm. 〉'Pull A was obtained by softening annealing at 650°C for 30 minutes, and sample B was obtained by softening annealing at 750°C for 30 minutes. In addition, sample C was titanium chloride;
Warm) JE extension to I'+' 3 mm, then 75
It was softened and baked at 0°C for 30 minutes. These samples A-Ci;I exhibit good mechanical properties as shown in FIG.

Samples D-F used a steel plate of 50t x 1000w x 2000mm and a titanium plate of 950w x 1950mm. As the insert material, a copper plate having a thickness of 0.8 mm and nickel plating of 100 microns on both sides was used. These were hot rolled in the same manner as Samples A to C to reduce the thickness to 12 mm. Sample D is obtained by softening annealing at 650°C for 30 minutes, and sample E is obtained by softening annealing at 750°C for 30 minutes.

In addition, sample F is made of the titanium clad steel of 600 to 4
Warm rolling to a plate thickness of 3 mm in the range of 00°C, then 7
It was softened and annealed at 50°C for 30 minutes. As shown in FIG. 1, good mechanical properties were also obtained for these samples D-F.

Samples G and H produced by the conventional method used steel plates plated with nickel. That is, samples A to C were manufactured by the same method except that copper plating was not applied. Sample G is as-rolled, and sample H is annealed at 650°C for 30 minutes. Sample G has good joint strength but lacks ductility.

Moreover, although sample H has good ductility, the bonding strength is significantly reduced. As a result of EPMA analysis of the joint boundary of this sample H5, it was found that titanium carbide was precipitated at the titanium side interface.

Samples I and J are without any insert material. That is, it was manufactured using the same process as Samples A-C except that Inser 1-kA was not used.

Sample E is as-rolled, and sample J is 6
It was annealed at 50°C for 30 minutes. The mechanical properties of Samples I and J were also insufficient due to low bonding strength.

Below 1. As is clear from the test results, titanium crush steel manufactured by the method of the present invention has 1-
It can be seen that the bonding strength is sufficient.

According to the present invention, a thin layer of nickel is provided as the first insert on the mating surface side of the titanium plate, and a second insert material is provided on the mating surface side of the steel plate. A thin layer of copper or copper is placed on top of the mating surfaces, heated to 700 to 1000°C, rolled and bonded at a reduction of 170% or more, and then 650°C.
Since the softening annealing was carried out at ~750°C, a thin layer of 200 nm was added as a material on the mating surface of the titanium plate (first insert at 1111), and copper was added as the second insert material on the mating surface of the steel plate. Alternatively, a thin layer of copper and nickel is provided, and these are superimposed on the mating surface side of II: l,), and 700
Heating to ~1000°C, rolling and joining at a rolling ratio of 70% or more, and then 1. %, the thickness is reduced by rolling at a temperature of 400°C or higher, and then softened and annealed at 650 to 750°C. Therefore, it is possible to make a titanium clamped steel with sufficient bonding strength to J1r. Becomes Ding Noh.

Special feature 1: '1 Applicant: 1 stock company, Wood and Steel Company Agent, Patent Attorney, Toshiyuki Miyauchi

Claims (1)

[Claims] 1. A thin layer of Kel is provided as a first insert material on the mating surface of the titanium plates, and a thin layer of copper or copper/nickel is provided as a tiS2 insert material on the mating surface of the steel plate. 700~1000
A method for manufacturing titanium clad steel, which is heated to 10°C, rolled and joined at a rolling ratio of 70% or more, and then softened and annealed at 650 to 750°C. 2. First insert on the mating surface side of the titanium plate; ・A thin layer of nickel is provided as the material, and a thin layer of copper or copper/nickel is provided as the second insert on the mating surface side of the steel plate, and these are placed on the mating surface side. The nails were pressed together, heated to 700 to 1,000°C, rolled and joined at a reduction rate of 70% or more, and then 400°
C or higher, reduced thickness by rolling at a temperature of 1-, then 650-750
A method for producing titanium clad steel by softening annealing at °C.