JPS6284883A - Manufacturing method of cladding material of Ti-based metal and Ni-based metal - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a cladding material of Ti-based metal and Ni-based metal, particularly a cladding material with excellent bonding strength in the boundary layer.

(Prior Art) Conventionally, as a method for processing Ti-Ni clad materials using TI as a core material, for example, a laminated bar material made by overlapping and coating a Ti-based metal core material with a Ni-based metal layer is heated at 200°C. ~600
A method has been proposed in which the extruded bar is subjected to warm extrusion at a temperature of 0.degree. C., then subjected to an annealing treatment to soften it, and then subjected to cold working (Japanese Patent Publication No. 13424/1983).

However, a problem in manufacturing and using this cladding material is that under the hot pressure welding conditions to improve the bonding strength between the two metals, TizNi is formed in the boundary layer.
One example of this is that a brittle Ni-Ti intermetallic compound such as 5TiNiSTiNi3 is generated, which is an obstacle to improving the bonding strength.

In other words, in the case of Special Publication No. 60-13424, 600℃
If it is below, we believe that there is almost no problem with the formation of Ni-Ti intermetallic compounds, and we propose softening by warm extrusion annealing at 200 to 600°C ↓ We propose processing through each step of cold working. The formation of Ni-Ti intermetallic compounds is still an obstacle to improving the bonding strength.

In order to solve the problem of the formation of intermetallic compounds, a clad material consisting of Ni and Ti in which Ni-Ti intermetallic compounds are formed in the boundary layer is strongly worked to finely form the intermetallic compounds in the boundary layer. A method for manufacturing a cladding material has been proposed, which is characterized in that after the clad material has been oxidized, heat treatment is performed at a temperature of 600 DEG C. or less (Japanese Patent Laid-Open No. 156879/1983). This is due to the brittle Ni-
By exploring a method of refining the Ti intermetallic compound by machining and then heat-treating it again at a relatively low temperature, the temperature constraints during cladding were significantly relaxed, resulting in a Ni-Ti cladding with improved overall bonding strength. This means that the material can be obtained.

In other words, in the case of JP-A No. 57-156879, in order to solve the above problem, rather than preventing the generated Ni-Ti intermetallic compounds from occurring, the generated intermetallic compounds are treated with a method that has relatively little influence. With the intention of improving the bonding strength by making Ni material exist in the clad material in a state of 1 at a temperature of 600°C or less, preferably 550 to 450°C, to refine the intermediate compounds.
A processing method has been proposed that includes the steps of heat treating for 0 minutes to 2 hours to cause diffusion at the boundary between Ni and Ti materials.

However, even in the improved method of JP-A-57-156879, a heat treatment step is always required, such as "processing→heat treatment", making the treatment complicated and expensive. Moreover, even with the clad material obtained in this manner, the bonding strength is a considerably low value of 0.18 kg/io+w''.

If the bonding strength is low in this way, the Ni material and the Ti material will separate in the next wire drawing process, resulting in a high defect rate.

In order to reduce the defective rate, judging from the wire drawing method, the bonding strength should be 20 kg/ll1m! The above is necessary. Therefore, the above manufacturing method also has a problem in bonding strength.

Here, methods for increasing bonding strength include explosive crimping and hot isostatic pressing. By hot isostatic pressing, the bonding strength is considerably improved to about 17 kg/mm2, but it must be said that the defect rate is still high in wire drawing at this level. On the other hand, by explosive crimping, the bonding strength is 20 kg/mmz, and wire drawing can be performed without any major problems with a low defect rate in the wire drawing process.

However, with the explosive crimping method, it is difficult to obtain long clad materials, and there are other problems such as high processing costs due to the use of explosives, and the need for special 'AH' for safety. be.

(Problems to be Solved by the Invention) The object of the present invention is to solve the problem of Ti-based metals, namely Ti or Ti.
Dramatically improves the bonding strength between the alloy and Ni-based metal, that is, Ni or Ni alloy, and combines the light weight and corrosion resistance of Ti, and the surface treatment properties such as workability, pressability, machinability, and brazeability of Ni. An object of the present invention is to provide a method for efficiently and inexpensively manufacturing a cladding material made of both types of metals.

That is, an object of the present invention is to make a cladding material by fitting a hollow member of a Ni-based metal into a core material of a Ti-based metal, and then hot (or By applying warm) elongation rolling, the joint strength increases to 20
An object of the present invention is to provide a method for efficiently and inexpensively manufacturing a cladding material having a weight of 2 kg/ffuw2 or more.

Another object of the present invention is to obtain the
An object of the present invention is to provide a method for producing a clad material with high bonding strength without heat treatment after processing as in the No. 1 issue.

Still another object of the present invention is that the clad material produced by the present invention can be subjected to the next cold working process without any heat treatment, and is therefore highly effective from the viewpoint of energy saving. An object of the present invention is to provide a manufacturing method.

(Means for Solving the Problems) Here, the present invention provides that the outer periphery of an extrusion billet of Ti or Ti alloy is coated and sealed with Ni or Ni alloy, and the inside of the coating is kept in a vacuum state or A cladding material for extrusion molding in which the air inside is replaced with an inert gas is heated to a temperature of 850°C or less to perform hot extrusion processing, and then heated to a temperature of 850°C or less and inclined rolled. This is a method for producing a clad material of Ti-based metal and Ni-based metal, which is characterized by subjecting it to hot or warm stretching by tilt rolling in a machine.

In the present invention, when making a cladding material, a core material of Ti or Ti alloy and a hollow material of Ni or Ni alloy are prepared, and after degreasing and cleaning both metal materials with Triclean etc., the two are fitted together, Perform vacuum or replace with inert gas,
The end faces are hermetically joined. Alternatively, by changing the processing order, the core material is inserted into the hollow material which has been evacuated or replaced with an inert gas, and then the end faces are hermetically bonded. This preparation of the cladding material is done in order to prevent the formation of an oxide film on the interface during heating in the next step.

Next, following a hot (warm) stretching process for stretching the crund material, the present invention is characterized in that this stretching process combines "hot extrusion" and "incline rolling" processing. do. This is because the bonding strength is as low as 10=14 kg/+u+'' with only hot extrusion processing, and furthermore, if you try to make it to a size that can be cold worked, there will inevitably be restrictions on the material size. This is because if you try to increase the area reduction rate by increasing the size of the material, the press machine itself will become very large.Also, due to the difference in deformation resistance between the core material and the outer layer material, hot It is not possible to obtain a very large reduction in area by extrusion, so in the present invention, tilt rolling is performed following the hot extrusion process.

On the other hand, with only inclined rolling, when the fitted clad materials are inclined rolled, a condition called flaring, which is unique to inclined rolling, occurs in which only the outer layer material is stretched, and a phenomenon occurs in which the core material and the outer layer material are separated. Therefore, the present invention employs a processing method that combines hot extrusion and inclined rolling.

In addition, in the above-mentioned stretching method, it is also possible to employ a generally used groove rolling method. That is,
Stretching process by groove rolling only, or hot extrusion,
Subsequently, a stretching process called groove rolling may be considered.

However, in the groove rolling method, a constrained surface and a free surface always exist, and a phenomenon occurs in which the boundary surface peels off at the free surface. The present inventors investigated the above-mentioned two points of stretching process using the groove rolling method, but upon microscopic observation of the interface of the finished product, it was confirmed that there were some places where the joints were defective.

Furthermore, in the drawing method of the present invention, a forging method may be considered instead of the groove rolling method discussed above, but as a result, the phenomenon of peeling of the boundary surface occurred as in the case of groove rolling.

Therefore, from the above, the hot (warm) stretching method in the present invention is "hot extrusion", preferably "
It was confirmed that it is necessary to combine "hot extrusion processing using a press" and "inclined rolling using an inclined rolling mill", preferably "inclined rolling using a cross-type inclined rolling mill".

Here, "inclined rolling" means rotating three or four rolls of the same shape at the same speed in the same direction with their axes tilted at a certain angle with respect to the material axis, and applying a feed rate to the material. This is a method of processing by giving In addition, "cross-type" refers to a case where the axes of the rolls are arranged so as to intersect with the material axis.The present inventors have proposed a cross-type inclined rolling method. Method (Unexamined Japanese Patent Publication No. 59-490
It is desirable to adopt item 2). That is, it is a cross-type inclined rolling mill, and the crossing angle (T) and inclination angle (β) of the inclined rolling mill are 0°, γ<15°, 3°<β<20
It is preferable to use a cross-type inclined rolling mill that is set to satisfy the following conditions: 1.degree.

Note that Ti-based metals include Ti and Ti alloys, but in that case, in addition to pure Ti, Ti and AJ, VSMnSFe, Cu%Mo, C
It includes an alloy with one or more of components such as r, W, etc., and the Ti content in the alloy is preferably 90% (wt%, hereinafter the same applies unless otherwise specified). This is because if it is less than 90%, the specific gravity will increase and the characteristics as a light metal will be impaired.

Ni-based metals include Ni and Ni alloys, but in that case, in addition to pure Ni, N containing Ni as the main component
i and Crs Cus Feb＾gs 5iSS ,,
PbSPt, Au, rare earth elements, Ti5Nbs A
One or two components such as J, Mo, Sns Co, etc.
This includes alloys with more than one species.

Further, in the hot (warm) stretching method, the heating temperature is set to 850° C. or lower because Ti reacts with other metals such as Ni and Cu and starts to melt at around 900° C. This is because "hot extrusion" and "incline rolling" adopted in the present invention can increase the degree of processing (area reduction rate), so processing heat is generated during processing, and the
This is because the material temperature increases by about ℃. Therefore, the heating temperature was set to 850°C or lower. The lower limit of this heating temperature is not particularly limited as long as so-called hot working (or warm working) is performed, but in general, it is preferably 500°C or higher in the case of hot extrusion processing, and 500°C or higher in the case of inclined rolling processing. In this case, the temperature is 400°C or higher. This is because, if the heating temperature is lower than this, the required capacities of the press and the inclined rolling mill will become very large, and the machines will no longer be of practical size.

The invention will now be described in more detail in connection with the accompanying drawings.

FIG. 1 is a schematic explanatory diagram showing a partial cross section to explain the manufacturing method of the cladding material 10. A cylindrical hollow material 11 made of a Ni-based metal material, for example, Monel, is first polished on its inner surface. prepare. On the other hand, Ti-based metal materials, such as pure Ti
After degreasing and cleaning, the billet 12 made of the above-mentioned hollow material 11 is
inserted within. After insertion, the inside of the hollow member 11 is evacuated or replaced with inert gas, and then one end is closed with a lid 1.
3 to close it and weld it to make a cladding material for extrusion processing.

Next, as shown in FIG. 2, the obtained cladding material 20 for extrusion processing is subjected to hot extrusion processing. Reference numeral 21 is a ram for extrusion processing, and 22 is a ram for extrusion processing. 23 indicates a die, and 24 indicates a container.

Next, as shown in FIG. 3, the extrusion molded product 30 is further subjected to inclined rolling by an inclined rolling mill 33 comprising inclined rolling rolls 31, 32, etc., and is finished into a predetermined shape and size. axial center line 31' of the inclined rolling roll;
32" is preferably perpendicular to the material axis.

Thus, it can be seen that according to the present invention, no peeling between the surface layer and the inner layer was observed even after fairly severe processing such as hot extrusion processing and inclined rolling, and sufficient bonding strength was obtained. In other words, by performing processing with such strength, the bonding strength between the Ti-based metal and the Ni-based metal is 20 kg.
/mm'' or more, and no delamination was observed even after cold wire drawing was performed.

Next, the present invention will be explained in more detail with reference to Examples.

Example: A pure Ti rod (JIS Class 2) with outer diameter 69I x length 200mm whose circumference has been polished and finished with outer diameter 78mm x thickness 4.5mm x length 220mm hollow monel material whose inner surface has been similarly polished. After degreasing and cleaning the contacting surfaces, they were inserted, evacuated, and welded to seal the end surfaces with monel plates (see Figure 1).

The components of pure Ti and Monel were as shown in Tables 1 and 2, respectively.

Tt> Table 1 (% by weight) Table 2: Nell> (% by weight) Using the above materials, hot extrusion was carried out in a press as shown in FIG.

[Extrusion processing conditions]

a) Area reduction rate: diameter 78mm = diameter 40III11
b) Heating temperature: 800°C, 700°C, 600°C The results of measuring the bonding strength of the hot extruded cladding materials obtained at this time are shown graphically in FIG. From the data shown, it can be seen that the bonding strength increases when heated at a lower temperature.

The bonding strength was measured in the same way (as shown in Figure 4, the test piece with the bonded article remaining was placed on a perforated stand, a load (P) was applied from above, and the bonding strength was measured until the bonded article broke at the joint). Measure the maximum load Pmay, and from the joint area A (Pmax
/A).

Next, the clad material (
Incline rolling was performed using a cross-type inclined rolling mill as shown in FIG.

[Incline rolling conditions]

a) Intersection angle (γ) -5°, inclination angle (β) -15° Roll diameter = 117mm b) Roll material = 58M440 C) Roll rotation speed -80rp + m d) Area reduction rate: diameter 40mm = diameter 20a + se)
Heating temperature -500℃, 600℃, 700'C1800
The bonding strength of the Monel material of the obtained clad material to the Ti material was measured in the same manner as in the case of FIG. 4.

The measurement results of this bonding strength are summarized in a graph in FIG.

It can be seen that the bonding strength increases when processed by heating at a low temperature, similar to hot extrusion.

Here, the above-mentioned hot extruded material heated at 800°C and having a diameter of 4oI1m, and then incline-rolled material heated at 700°C and having a diameter of 20
For the tilt-rolled material of mm, the intermetallic compound layer formed at the boundary using EPMA, namely Tis Ni, Cu
The thickness of the diffusion layer was measured. As a result, the diameter is 40011
The thickness of the diffusion layer of the hot extrusion material No. 1 is approximately 1.4 μm, and the diameter is 2
The thickness of the diffusion layer of the inclined rolled material of 0fflff+ is approximately 0.6
It was a μ habit. It can be seen from this that the diffusion layer of the material subjected to inclined rolling is extremely thin.

The reason why the bonding strength is high in FIG. 5 is considered to be because the diffusion layer becomes very thin, as can be seen from this observation result.

Furthermore, it was confirmed that by combining "hot extrusion" and "incline rolling" according to the present invention, a product with a bonding strength of 20 kgf/mm'' or more can be manufactured without any heat treatment.

[Brief explanation of drawings]

1 to 3 are process schematic diagrams schematically explaining the steps of the method according to the present invention; FIG. Nakaa 1. 7)-7<Figure 5 is a graph showing the relationship between the bonding strength and heating temperature after tilt rolling.

Claims (1)

[Claims] A cladding for extrusion molding in which the outer periphery of a Ti or Ti alloy extrusion billet is coated and sealed with Ni or Ni alloy, and the inside of the coating is kept in a vacuum state or the air inside the coating is replaced with an inert gas. The material is heated to a temperature of 850°C or less to perform hot extrusion processing, and then heated to 850°C.
Ti characterized by being heated to the following temperature and subjected to hot or warm stretching processing by tilt rolling in a tilt rolling mill.
A method for manufacturing a cladding material of Ni-based metal and Ni-based metal.