JPH08320280A - Method and device for flaw inspection of superelastic alloy material - Google Patents

Abstract

PURPOSE: To provide a flaw inspecting device for superelastic alloy material in which Ni-Ti superelastic alloy material can be inspected over the whole length with a simple nondestructive inspecting method, and in which a harmful flaw part, if present, can be ruptured to remove the rupture part, and an inspecting method. CONSTITUTION: This flaw inspecting device for superelastic alloy is formed of a liquid tank 1, a heating hot water 2, reels for bending distortion 3a, 3b, 3c, a superelastic wire rod 4, a wire rod winding machine 5, a wire rod feeding machine 6, a reel support member 7, a first reel 8a, and a second reel 8b. Using this device, a constant distortion is imparted to a wire rod in the heating state to increase the recovering load, and the part having a flaw can be ruptured by notch effect by collecting the stress to the flaw part, while the part having no flaw can be inspected without rupture, and the wire rod can be ensured for the whole length.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flaw inspecting apparatus for flaws, defect fractures and the like and a method for inspecting the same, which utilizes a load spontaneously generated by heating a superelastic alloy material.

[0002]

2. Description of the Related Art In recent years, Ni-Ti based superelastic alloys have been used in a wider range of fields, and in particular, the demand for wire rods thereof has been increasing.

However, the Ni-Ti superelastic alloy is an intermetallic compound and has poor workability, and it is difficult to manufacture a wire or the like which is free from flaws and defects over the entire length in the processing of fine wires and the like.

Further, the superelastic alloy is characterized in that it recovers its original shape even if it is subjected to a strain of about 10 times that of a general spring such as stainless steel or steel.

However, utilizing the property of recovering the shape even when a large strain is applied requires the feature that the shape returns to the original shape without breaking even under severe use such as repeated bending, which results in stable durability. Guarantee is needed.

In order to guarantee these characteristics, it is necessary to guarantee a wire rod free from flaws and defects over the entire length as much as possible.

As a conventional nondestructive inspection method for the entire length of a wire or the like, a method using a magnetic eddy current flaw detection method is generally used.

[0008]

However, in the magnetic eddy current flaw detection method, it may be difficult to determine an electrical signal even if there is a flaw depending on the shape and size of the flaw. There is a problem that it is difficult to set the condition for distinguishing the difference between the roughness and the flaw, and even if the condition can be set, the structure of the device becomes complicated to remove the flaw or the like.

In order to solve these problems, the present invention provides
It is possible to inspect the entire length of a wire or the like by a simple non-destructive inspection method, and if there is a harmful flaw, a flaw inspection device for a superelastic alloy material that breaks the flaw and removes the fracture, and its It provides an inspection method.

[0010]

That is, the present invention provides a Ni-
A feeder for feeding a superelastic alloy material composed of a Ti-based alloy, 30
Liquid tank that can be heated to 100 ° C. to 100 ° C., a reel support member that supports a plurality of reels, a first reel that diverts the sent superelastic alloy material downward, and a submerged liquid from the first reel. At least three or more bending strain reels which are arranged so as to continuously apply a bending strain of 2% or less, and a second reel which is interlocked with the three or more bending strain reels. And a winding machine for winding the material from the second reel, the alloy material being 30 ° C. to 100 ° C.
It is a flaw inspection device for a superelastic alloy material, which is characterized by heating to 0 ° C., giving a bending strain of 2% or less, spontaneously breaking a flaw, and inspecting a flaw.

Further, according to the present invention, a superelastic alloy material composed of a Ni--Ti alloy is continuously heated to a bending strain of 2% or less in a state of being heated between 30 ° C. and 100 ° C. This is a flaw inspection method for a superelastic alloy material, characterized in that stress is concentrated on a flaw portion due to a recovery load spontaneously generated by the elastic alloy wire material and spontaneously fractures to inspect the flaw portion.

[0012]

The Ni-Ti superelastic alloy has a characteristic of exhibiting an abnormal elongation when it is deformed at a temperature higher than the reverse transformation temperature, which is called superelasticity. Further, the generated load at a constant strain increases as the temperature rises, which means that the load increases at the same strain by raising the temperature.

FIG. 1 shows a stress elongation curve of a Ni-Ti alloy wire rod having a diameter of 0.5 mm at 30 ° C., 50 ° C., 70 ° C.
It showed temperature dependence with respect to ℃ and 100 ℃. It can be seen that even with a strain amount of 5%, the load increases as the temperature rises.

Utilizing this action, a constant strain is applied to the material in a heated state to increase the load for recovering, and if there is a flaw, the stress concentrates on the flaw portion, so that the material breaks due to the notch effect. be able to. Further, the present invention provides a flaw inspection device and its inspection method that can inspect a portion having no flaw without breaking and can guarantee the entire length of a wire or the like. However, in the portion having no flaw, since the shape of the superelastic wire is not permanently deformed and bending or the like should not occur, it is necessary that the bending strain amount is 2% or less in the heated state.

[0015]

Embodiments of the present invention will now be described with reference to the drawings.

As shown in FIG. 2, the flaw inspection apparatus for superelastic alloy material of the embodiment of the present invention comprises a liquid tank 1, hot water for heating 2, reels 3a, 3b and 3c for bending strain, and superelastic wire 4 ( Wire diameter φ
0.5 mm), a wire winding device 5, a wire feeding device 6, a reel supporting member 7, a first reel 8a, and a second reel 8b.

The flaw inspection according to this embodiment is performed as follows. First, a superelastic wire 4 made of a Ni-Ti superelastic alloy
Are continuously fed from the wire rod feeder 6 side to the liquid tank 1 containing the hot water 2 for heating via the first reel 8a. In advance
At least three bending strain reels 3 are provided in the liquid tank 1.
a, 3b, 3c are provided, and the sent wire rods are first in the liquid tank 1 below the reel 3a and then in the reel 3b.
After being subjected to bending strain in a heated state in a wave shape such as the upper side of, and then the lower side of the reel 3c, it is continuously wound by the winder 5. Here, if the wire has a flaw, the wire is broken by the notch effect, and the broken portion is removed. The first reel 8a, the second reel 8b, and the bending strain reels 3a, 3b, 3c are supported by the reel support member 7 in this embodiment.

Tables 1 and 2 show the relationship between the diameter of the reel, the temperature of the hot water, and the depth of the flaw, whether or not there is a break, and whether or not the flaw-free superelastic wire is bent (permanently deformed) after inspection. .

[0019]

[Table 1]

[0020]

[Table 2]

In this inspection, a bending strain of not more than 2% was applied at a temperature of 30 ° C. to 100 ° C., so that the depth of 0.
1mm to 0.3mm flaws are inspected and broken, and
The flaw-free portion was able to be inspected without any flaws in the superelastic wire without change in shape (permanent deformation).

Although hot water is used as the heating method in this embodiment, any heating method may be used, such as a thermostatic device or a heater heating method.

Regarding the bending strain reel, there are several methods for imparting strain to the wire material, such as a wavy shape, an S shape, and a spiral shape, and any of them can be considered as the same method.

Further, although the wire rod is used in the embodiment, it can be applied to a deformed wire rod, a plate material and the like.

[0025]

As described above, according to the present invention, it is possible to inspect for flaws over the entire length of the superelastic wire and to guarantee the total number.

[Brief description of drawings]

FIG. 1 is a diagram showing a stress elongation curve of a superelastic wire of Ni—Ti alloy. FIG. 1 (a) is a stress elongation curve of a super elastic wire,
The figure which shows the temperature dependence with respect to 30 degreeC and 50 degreeC. FIG.
(B) is a stress elongation curve of a super elastic wire at 70 ° C., 10
The figure which shows the temperature dependence with respect to 0 degreeC.

FIG. 2 is a sectional view showing a flaw inspection device according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid tank 2 Hot water for heating 3a, 3b, 3c Bending strain reel 4 Super elastic wire rod 5 (Wire rod) winder 6 Wire rod feeder 7 Reel support member 8a First reel 8b Second reel

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[Procedure amendment]

[Submission date] October 30, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Title of invention

[Correction method] Change

[Correction content]

Title: Defect inspection device for superelastic alloy material and inspection method therefor

Claims (2)

[Claims] 1. A feeder for feeding a superelastic alloy material made of a Ni—Ti alloy, a liquid tank capable of heating at 30 ° C. to 100 ° C., a reel supporting member for supporting a plurality of reels, and the fed super alloy. A first reel for redirecting the elastic alloy material downward, and at least three or more reels arranged so as to continuously apply a bending strain of 2% or less by charging the material into the liquid from the first reel. A bending strain reel, a second reel that is interlocked with the three or more bending strain reels, and a winding machine that winds the material from the second reel. The alloy material is 30 ° C. to 100 ° C. A flaw inspection apparatus for a superelastic alloy material, which is characterized in that a flaw is spontaneously ruptured by applying a bending strain of 2% or less to an inspected flaw portion. 2. A superelastic alloy wire made of a Ni—Ti alloy is continuously heated to a bending strain of 2% or less in a state of being heated at 30 ° C. to 100 ° C. A flaw inspection method for a superelastic alloy material, characterized in that stress is concentrated on a flaw portion due to a spontaneously generated recovery load to cause spontaneous breakage and the flaw portion is inspected.