JPS6026648A - Manufacture of shape memory ni-ti alloy plate - Google Patents

Abstract

PURPOSE:To obtain an Ni-Ti alloy plate showing satisfactory shape memory characteristics by subjecting an Ni-Ti alloy having a specified composition to process annealing and cold rolling under specified conditions. CONSTITUTION:An Ni-Ti alloy ingot consisting of 49.0-52.0atom% Ni and the balance Ti or further contg. <=3.0atom% in total of one or more among V, Cr, Mn, Fe, Co, Cu, Zr, Nb, Mo, Pd, Ag, Ru, Ta and W is hot rolled. The hot rolled plate is subjected to final in-process annealing at 400-700 deg.C and final cold rolling at 15-60% draft. By cold rolling the Ni-Ti alloy at said draft, the shape memory characteristics are improved, and the resulting plate can be worked without causing cracking.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a Ni
The present invention relates to a method for manufacturing a Ti-based alloy plate.

Ni 49.0-52. Oat% or Ni'49.
0-52. Oat% and V, Cr, Mn, Fe, G
o, Cu, Zr, Nb, Mo, Pd, /'l
, Ru, Ta, W (iiJ tL ′I
Js 1 or 2 or more types in total 3. NiTi-based alloys containing Oat% or less and remaining &ST1 exhibit remarkable H3-like self-memory properties and superelasticity, and various uses have been investigated using these properties, and some have been put into practical use. Ru. However, this alloy undergoes significant work hardening and exhibits good shape memory and superelastic properties (limited to straight wire rods, and as plate materials it is once processed into wire rods (Ill wire IJ [+ The tape was crushed by four people or hot rolled, and cold or warm rolling was only used to modify the shape and dimensions of the plate.

In view of this, the present invention provides various IQ ii"l results, Ni
It was discovered that when a certain amount of cold halo is applied to a Ti-based alloy, its shape memory properties are improved. Based on this, the cold rolling method and annealing conditions were changed to improve the shape memory properties and good shape memory properties of Ti-based alloys. We have developed a manufacturing method for gNITj-based alloy plates that exhibit superelastic properties, with N149.0 to 52. Oa
t% or Ni 49.0-52. Oat% and ■, Or
, Mn, Fe, Co, Cu, Zr, Nl+, Mo, P
d, A(1) A NiTi-based alloy blank containing one or more of Ru, Ta, and W in a total content of 3.0 at% or less, with the remainder being Ti, is subjected to intermediate annealing and cold rolling. In the production of Ni Ti alloy plates, rolled plates are
It is characterized in that after final intermediate annealing at ~700°C, final cold rolling is performed at a processing rate of 15 to 60%.

That is, the present invention uses a blank plate obtained by melting and casting a Ni l'-i alloy having the above composition range in accordance with a conventional method and hot rolling it, and repeating cold rolling and intermediate annealing to obtain the desired plate thickness. In the finishing process, the final intermediate annealing is performed at 400 to 700℃.
After that, a final cold rolling process is performed at a working rate of 15 to 60%. Ni produced in this way
A Ti-based alloy plate exhibits good shape memory properties when subjected to shape memory treatment using a conventional method.

However, in the present invention, the reason why the composition of the Ni l''i alloy is limited as described above is to obtain good shape memory properties, and if it deviates from this range, good shape memory properties cannot be obtained. Intermediate annealing temperature 400~700'
The reason why it was limited to C was to enable rolling with a good surface condition in the final rolling process, as it is not possible to perform the processing necessary to obtain good shape memory properties by cold rolling at temperatures below 400°C. This is because if the temperature exceeds 700°C, the oxide film on the surface becomes thick, resulting in poor surface condition after cold rolling and lowering yield. The holding period for the final intermediate annealing varies depending on the plate thickness, but it does not affect the shape memory properties much, and a few minutes to several tens of minutes is sufficient. Furthermore, the processing rate in the cold rolling after the final intermediate annealing was limited to 15 to 60% in order to obtain good shape memory properties, and if the processing rate was 15%, the shape memory properties would be insufficient. This is because if it exceeds %, work hardening will be significant and the plate will not be able to be processed well, such as cracking.

The present invention will be described in detail below with reference to Examples.

Ni'li consisting of N i 49.6 at% and the remainder T+
Weigh the alloy and place it in a high frequency vacuum melting furnace (degree of vacuum 10-41-orr, frequency 10KHz) using a carbon crucible.
) and cast into a water-cooled copper mold to a thickness of 30 mm.
The ingot had a width of 100 mm and a length of 200 mm. After face-shaving this ingot, it was heated to 1000℃ and hot-rolled. As the thickness of the ingot became thinner, the temperature was lowered until it was rolled to a thickness of 2mm at 7oo℃.
It was made into a board.

After removing the surface oxidation scale of this hot rolled plate,
Cold rolling and intermediate annealing were repeated to form a plate with a thickness of 1 mm.
This was subjected to a final intermediate annealing for 10 minutes at various temperatures to examine the relationship between the annealing temperature, the thickness of the surface oxidation scale, and the maximum working rate that allows good cold working. The results are shown in Table 1.

Table 1 Annealing temperature Oxide scale thickness Maximum processing rate (℃) (
μ) (%) 200 0.01 4 300 0.01 15 400 0.01 40 500 0.5 55 eoo i, o e.

700 1 , 0 60 800 4.0 60 900 5.0 60 1000 8.0 60 As is clear from Table 1, if the annealing temperature is less than 400°C, a sufficient processing rate cannot be obtained and the work efficiency is poor. I understand. It is also seen that when the degree of quenching exceeds 700°C, the oxide scale becomes thicker, the surface condition deteriorates, and the yield also decreases.

Next, final intermediate annealing was performed at 600°C for 10 minutes, and final rolling was performed at various processing rates to give a width of 1 mm.
, cut out a strip specimen with a length of 100 m, sandwiched it between two stainless steel plates (thickness 2 mm), and heated it at 500°C.
A heat treatment (shape memory treatment) was performed for 30 minutes at a temperature of 150°C to memorize the flat plate state. As shown in Fig. 1 (a), the flat strip (1) was wound around a round rod (2) with a diameter of 15 mm and deformed by f4 degrees, and then immersed in hot water to recover its shape.
As shown in Figure 1 (b), the short Ill (1
) Measure the hearing angle φ of 7. -6 The results are shown in Table 2. The shape recovery temperature of this shape memory plate is 53° and lC.
6 Table 2 Final processing rate (%) Hearing angle φ.

513゜10 1'50 15 175 20 178 30 180 40 179 50 178 60 180 As is clear from Table 2, in the final cold rolling after the final intermediate annealing, cold rolling with a processing rate of 15% or more is performed. It can be seen that good shape memory properties can be obtained.

In addition, cold rolling with a processing rate of more than 60% resulted in significant work hardening, resulting in cracking of the plate, making it impossible to obtain a good alloy plate.

As described above, according to the present invention, the final intermediate annealing during cold rolling is performed at 400 to 700°C, and the processing rate of the final cold rolling is then set to 15 to 60%. It can be treated as an alloy, and is used in industrial temperature lenses, actuators, etc., and has a remarkable effect in improving the accuracy.

[Brief explanation of the drawing]

FIGS. 1(A) and 1(B) show an example of a method for testing shape memory properties, with (A) being an explanatory diagram showing a deformed state and ([C]) being a recovery state. Chapter 11 (a) 7-kuki≧ ≧-)

Claims (1)

[Claims] N i 49.0 to 52.0 at% or N i 49.
0-52. Oat% and V, Cr, Mn, Fe, Go, C
u, ZrSNblMo, Pd, A(1, Ru, T
A total of 3.0at of any one or two or more of a and W
% or less, with the balance T1, in the production of a NiTi base metal plate, which is subjected to intermediate annealing and cold rolling. A method for manufacturing a shape memory Ni'li alloy sheet, characterized by subjecting it to a final cold rolling process of 60%.