JPS62227586A - Titanium metal clad steel and its production - Google Patents

Abstract

PURPOSE:To improve joint strength by disposing a low carbon alloy steel plate contg. specific weight % of Ti, V, etc. to a cladding metal side and Ni plate to a base metal steel plate side to form a clad stock, then subjecting the stock to rolling and press welding at a specific temp. CONSTITUTION:The clad stock is formed by disposing the low carbon steel plate 3 contg. 1 or >=2 kinds among 0.01-5.0% Ti, 0.05-10% Nb, 0.01-20% V, and 0.05-10% Mo and contg. <=0.05% C to the cladding metal 4 side and disposing the Ni plate 2 to the base metal 1 side at the time of forming a clad steel by hot rolling a Ti plate 4 and the base metal steel plate 1. The cladding metal 4 and the low carbon steel plate 3 are maintained in a non- oxidative atmosphere and is subjected to rolling and press welding at 700-870 deg.C. The diffusion and intrusion of carbon from the base metal are prevented and the formation of an intermetallic compd. at the boundary face is prevented by the above-mentioned method and therefore, the joint strength of the clad is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for preparing rolled clad steel plates made of Ti and Ti alloys with excellent bondability.

(Prior Art) Conventionally, titanium clad steel sheets have been mainly manufactured by the explosion bonding method, which is subject to significant restrictions in terms of product dimensions, dimensional accuracy, productivity, and manufacturing costs. Recently, an explosion rolling method has been proposed in which the material is rolled after explosion bonding, and the manufacturing range and dimensional accuracy are being improved, but difficulties remain in terms of productivity and manufacturing cost. As a method for improving this, it is desired to establish a so-called rolled cladding method using rolling pressure welding, and several methods have already been proposed.

Here, the rolling cladding method involves the following steps: (formation of clean surface) - (assembly of cladding material) = (sealing by vacuum suction or sealing after inert gas injection) = (heating) = (rolling) However, the problems with this rolled cladding method are (
1) selection of the insert material to be interposed between the base material and composite material, (2) assembly of the clad material by welding and sealing by evacuation or injection of inert gas, and (3) rolling heating temperature.

Titanium easily forms intermetallic compounds with other elements, and the elements that form a complete solid solution with titanium are MO%Nb, V
There are limitations such as being limited to a few elements such as , Zr, etc., that these elements are expensive, and that workability is poor, making it impossible to obtain a plate-shaped insert material. The role of the insert material is to have good bonding properties between both titanium and titanium alloys and the base metal, and to prevent the formation of brittle intermetallic compounds, and to prevent carbon in the base metal from diffusing and bonding with the titanium in the titanium or titanium alloy. The purpose is to avoid deteriorating bonding properties by reacting to produce titanium carbide. Research has now revealed that considerable bonding properties can be obtained by minimizing the formation of intermetallic compounds by adjusting the rolling heating temperature.

However, the formation of titanium carbide due to the diffusion of carbon from the base metal particularly deteriorates the bonding strength and must be avoided at all costs. To achieve this purpose, an insert material is interposed between the base material and the composite material, and there are methods using Ni, pure iron, and ultra-low carbon steel (Japanese Patent Application Laid-Open No. (Sho 56-122681)
, a method of decarburizing the mating material side of the base material (Japanese Patent Application Laid-Open No. 59-22
0292), a method using Ni plating (Japanese Patent Application Laid-open No. 1983
-10347) etc. have been proposed. Ni diffuses quickly in Ti, and during rolling heating and rolling, Ni transforms from α phase (hcp crystal structure) to β phase (bee crystal structure), and Ni diffuses into Ti. Since Ni
Insert materials are disadvantageous compared to iron-based insert materials.

(Problem to be solved by the invention) When using an iron-based insert material, carbon diffusion is significantly faster than in Ni, so it is difficult to prevent this by using pure iron or by decarburizing the surface of the base material. It has become clear from various research results that this is not possible. Also, JP-A-56-
No. 122681, carbon fixing elements (Ti, Nb) are used to fix carbon in the base material and insert material.
, Mo), the base material is carbon steel that contains excessive carbon or alloy steel that cannot exist as stable carbide even during rolling heating, and in rad steel, titanium carbide is formed at the interface. cannot be sufficiently prevented from forming.

In particular, when the SR treatment (post-heat treatment) is performed after the thickness of the clad steel is reduced by hot rolling, the diffusion becomes easy. Since the TiC produced in this way is very hard and brittle, the strength of the clad steel obtained in this way is inevitably deteriorated.

(Means for Solving the Problems) Based on the results of such research and examination, the present inventors have developed ultra-low carbon alloy steel that contains sufficient carbon fixing elements in low carbon steel on the titanium (including titanium alloy) side. Used as insert material for
Furthermore, by using Ni as an insert material on the base metal side to prevent the diffusion and intrusion of carbon from the base metal, we can suppress the formation of intermetallic compounds at the interface and completely prevent the formation of titanium carbide at the interface. After learning that it was possible to manufacture rolled titanium clad steel with excellent bondability, he completed the present invention.

Furthermore, in the present invention, by using Ni as the insert material on the base metal side, the plate thickness of the ultra-low carbon alloy steel used as the insert material on the titanium side can be made thinner, thereby reducing costs. , the profit is large.

Here, the gist of the present invention is that a titanium-based metal laminate and a carbon content bonded to the laminate have a carbon content of 0.05
% or less, and furthermore, as a carbon fixing element, Ti: 0.01
~5.0%, Nb: 0.05~10%, V: 0.01
~20% and Mo: 0.05 to 10%, a low carbon alloy steel plate containing one or more types, a nickel plate bonded to the low carbon steel plate, and a base material bonded to the nickel plate. It is a titanium-based metal clad steel made of steel plate.

From another aspect, the present invention provides a method for manufacturing clad steel by laminating a titanium-based metal cladding material and a base steel plate and hot rolling, in which a carbon content is added to the cladding material side between the two members. 0.05 wt.
V: 0.01-20%, and Mo: 0.05-1O
A low carbon alloy steel sheet containing one or more of the following:
Furthermore, a nickel plate is interposed on the base steel plate side to form a cladding material, and after seal welding is performed on the cladding material so that oxygen is not supplied to the joint surface between these members,
This is a method for producing titanium-based metal clad steel, characterized in that at least the joint surface of the titanium-based metal laminate and the low carbon steel plate is heated to 700 to 870° C. in a non-oxidizing atmosphere, and then rolled and crimped.

Here, "titanium-based metal" includes pure titanium and titanium-based alloys.

(Function) Next, the reason why the alloy composition and processing conditions are limited as follows in the present invention will be described. In this specification, "%" means "%j" unless otherwise specified.

The reason why C is set to 0.05% or less is to make the carbon fixing elements shown below work effectively, and although it is desirable that this amount is low, it is set to 0.05% or less from the viewpoint of steel manufacturing cost. To fix the carbon in the insert material, it is sufficient to add an amount corresponding to the chemical equivalent of the carbon contained as an impurity. In order to capture the carbon spreading from the base material and completely avoid the formation of titanium carbide at the interface between the insert material and titanium, Ti should be 0.0
1% or more, preferably 0.5% or more, Nb5V, Mo
are 0°05% or more, 0.01% or more, and 0, respectively.
．． 0.5% or more, preferably 0.3% or more of each of Nb, V, and Mo. Additionally, the larger the amount of these carbon-fixing elements, the more advantageous it is in terms of capturing and fixing carbon, but if too much is present, the material becomes brittle, making it impossible to manufacture the plate or foil body itself as an insert material. Intermetallic compounds with iron (Tide, NbFez)
, VFe) and cannot maintain the strength as an insert material. Therefore, in the present invention, Ti, Nb
, V.

The upper limits of MO are 5.0%, 10%, 20%, and 10, respectively.
%.

Si and Mn are added as deoxidizing agents to obtain good killed steel, and are usually 0°01% and 0.01%, respectively.
The content is about 0.3%, and is not particularly limited in the present invention, but excessive addition impairs the ductility of the insert material, so if necessary, the upper limit of each content is 0.5%,
and 2.0%.

The thickness of the Ni insert material is not particularly limited in the present invention, and if the diffusion of C into Ni is taken into consideration, a thickness of about 30 μm is sufficient, but local bonding defects due to cutting of the insert foil during rolling processing should be avoided. For this reason, it is preferable that the thickness be 50 μm or more.

If the insert material thickness of ultra-low carbon alloy steel is 50 μm thick Ni insert material, the formation of titanium carbide at the interface can be avoided even if the thickness is less than 30 μm, but local bonding due to cutting during rolling process may be avoided. To avoid defects, 5
0 μm or more is required.

Although there is no need to set an upper limit on the thickness of both insert materials, it will probably be 511II11 or less in terms of productivity and cost.

The present invention will now be described in more detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a Cla-nod material seen in the manufacturing process of a titanium-based metal clad steel plate according to the present invention. The cladding structure itself is the same even in the final cladding steel, so to explain with reference to Fig. 1, a nickel plate 2, which is the material of the insert 1, is provided on the base steel plate l. Furthermore, an ultra-low carbon steel plate 3, which is another insert material, is provided. A titanium plate, which is a cladding material, is then clamped through this ultra-low carbon steel plate 3.

As mentioned above, there is no particular restriction on the thickness of each plate material, but preferably the total thickness of the insert material as the final material is about 0.1 to 10% of the total thickness of the combined steel plates, usually 0.5 to 3%. .0
It is best to set it to about %.

Next, a method for manufacturing clad steel according to the present invention will be described. First, a base steel plate, a titanium material as a mating material, a nickel plate as an insert material, and an ultra-low carbon steel plate are prepared. It is best to make each surface to be joined as clean as possible by degreasing or other treatment. (1) M-stand: As shown in Figure 1, each material is made of 121 temporary 1, nickel plate 2. , the ultra-low carbon steel plate 3 and the titanium plate 4 are laminated, and by making the size of each insert material and titanium plate slightly smaller than the base steel plate, each material on the base material is made into a different ultra-low carbon steel plate. It is covered with a cover 5 made of carbon steel plate, and each seam 6 is welded and sealed to form a cladding material 7. As for the insert materials, the laminate material (titanium or titanium alloy) side is made of ultra-carbon steel, and the base material steel plate side is made of Ni plate.

(2) Degassing: After obtaining the cladding material 7, the interior is degassed using a rotary pump or the like through the suction port 8 to create a degree of vacuum of 10-'Torr or less. At this time, the vacuum degassing treatment is performed at least on the joint surfaces of the insert materials. In the degassing process, high vacuum can be achieved more easily by degassing while heating. When a predetermined amount of degassing is completed, the suction port 8 is shut off by appropriate means such as cutting it by melting.

(3) Rolling: Excellent bonding strength cannot be maintained unless the rolling heating temperature is 700° C. or higher from the viewpoint of rolling. Furthermore, if the temperature exceeds 870°C, Ti will transform into the β phase and the corrosivity of titanium will deteriorate, and the diffusion of iron, which is the main component of the insert material, into Ti will be promoted, leading to the formation of a bond between the metals of iron and Ti. The formation of compounds is promoted and the bonding strength deteriorates.

Thus, in the clad steel manufactured according to the present invention, substantially no TIC formation was observed, and no decrease in strength was observed even after post-heat treatment.

After rolling is completed, the target titanium-based metal clad steel is obtained by peeling off the steel plate serving as the cover.

Next, the present invention will be explained by examples.

Example 1 50kg class low alloy high tensile strength tIA (SS
41 equivalent) as the base material, industrial grade pure titanium (JISI+ 46001 type equivalent) with a plate thickness of 10+++m as the mating material, an ultra-low carbon steel insert material with a plate thickness of 50 μm, and plate 1'
(Using a 50 μm Ni insert material, these materials were assembled as shown in Figure 1, and the air was evacuated using a rotary pump through the deaeration hole provided at the end. As standard conditions, 10-'T
After reducing the pressure to below orr, the deaeration hole was closed by welding, and the
It was heated to 0° C. for 5 hours and rolled at a rolling reduction ratio of 5, and then its bondability was evaluated by a shear test.

The results are shown in Table 1 along with the composition of the ultra-low carbon steel.

In the same table, a shear tensile strength of 15 kg/Imm'' or more is indicated as bondability (0), and it can be seen that according to the present invention, all exhibit excellent bondability.

Table 1 Example 2 Ultra-low carbon m composition (0,05%C-0,2%5i-0,3
%Mn) as a standard composition, and 0.02%Ti,
Clad steel was manufactured by repeating the operation of Example 1 using insert materials containing 0.05% Nb, 0.3% ■, and 0.06% MO, respectively. At this time, the rolling heating temperature was varied and the resulting changes in bonding strength were observed.

The results are summarized in a graph in Figure 2. It can be seen that a joint strength of 15 kg/am2 or more can be obtained at a rolling heating temperature of 700 to 870°C.

Example 3 In this example, the obtained clad steel was reheated at 750°C in the same manner as in Example 1, with and without using a 50 μm thick Ni foil insert material. The relationship between the processing time and bonding strength when strain relief annealing, that is, SR processing was performed, was evaluated. The results are summarized in a graph in Figure 3. 20 if Ni insert material is used.
It can be seen that a bonding strength of 15 kg/mm'' or more is maintained even after heating for hours.

In this case, rolling heating was performed at 800°C, and the composition of the ultra-low carbon steel insert material was 0.05%C-0.2%Si-
〇, 3% Mn-0, 25% Nb.

Example 4 This example also repeated Example 1, but in this example, the standard composition of the ultra-low carbon steel insert material was changed to 0.05%C-0.05%Si.
The effect of the amount of Ti on the bonding strength was examined when the amount of Ti added was changed with O, 3% Mn-Fe. The results are summarized in a graph in Figure 4.

Similarly, the effects of the amounts of Nb, V, and Mo added on the bonding strength were also examined. The results are summarized in a graph in FIG.

As can be seen from the results shown in FIGS. 4 and 5, according to the present invention, a bonding strength of 20 kgf/mn+" or more can be obtained by adding any C-fixing element.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the cladding material; and FIGS. 2 to 5 are graphs showing the results of each example of the present invention. 1: Base steel plate 2: Ni plate 3: Low carbon steel plate 4: Titanium plate 5: Cover 6; Seam 7: Clad material 8: Suction fitting! Concave: NI /: E-T2 printing 9 Fig. 2 Fig. 3

Claims (2)

[Claims] (1) A bonded material of titanium-based metal, the carbon content of which is bonded to the bonded material is 0.05% by weight or less, and the carbon fixing elements include Ti: 0.01-5.0% and Nb: 0.05% by weight or less. 05～
10%, V: 0.01-20%, and Mo: 0.05
A titanium-based metal cladding composed of a low carbon alloy steel plate containing ~10% of one or more types, a nickel plate bonded to the low carbon steel plate, and a base steel plate bonded to the nickel plate. steel. (2) In a method of manufacturing clad steel by laminating a titanium-based metal laminate and a base steel plate and hot rolling, the carbon content on the laminate side between both members is 0.05% by weight or less, and Ti as carbon fixing element: 0.01-5.0%
, Nb: 0.05 to 10%, V: 0.01 to 20%, and Mo: 0.05 to 10%. A nickel plate is interposed between the parts to form a cladding material, and after seal welding is performed on the cladding material so that oxygen is not supplied to the joint surface between these parts, at least the above-mentioned titanium-based metal laminate and low carbon A method for manufacturing titanium-based metal clad steel, which comprises heating the joint surface with a steel plate to 700 to 870°C in a non-oxidizing atmosphere and then rolling and crimping.