JPS6037890B2 - Non-cutting toughness testing device for cutting tool materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ballability testing device that is capable of measuring the breaking strength of cutting tools made of hard materials such as ceramics and cemented carbide, or observing the progression of cracks.

Cutting tools are one of the uses of hard materials, but when cutting a workpiece, a large force is applied to the cutting edge of the tool, and if the tool does not have sufficient strength, it will break. Tensile tests, bending tests, Charpy tests, etc. are used as testing methods for fracture, but since these are methods that measure simple loads, they are difficult to measure against the fractures of tools that occur during actual cutting, where complex forces act.
In many cases, they are not necessarily connected. Therefore, the ballability of tool materials is currently evaluated through interrupted cutting tests or tests that cut work materials of different hardness.

However, these methods require a lot of time, labor, and materials, so a simple and highly accurate testing method that does not involve cutting is desired. Therefore, as a result of repeated research, the present inventor used a narrow-shaped superalloy sample with a radius angle of 900 or less modeled after the tool shape, and applied a cutting force to the tip of the sample in a direction perpendicular to the tooth surface of the tool material. We have found a method to examine the toughness of the sample by applying a load corresponding to .

In general, cutting with a cutting tool can be divided into initial failure, in which failure occurs suddenly, and fatigue failure, in which cracks gradually progress to failure, but these differ depending on the cutting environment.

The present invention can test both initial fracture and fatigue fracture, and for fatigue fracture, the load is applied repeatedly and the progress of cracks can be directly observed from the side of the sample using a microscope, etc., and the fracture mechanism of cemented carbide can be observed. It is also effective for investigating. By the way, between the work material 12 and the tool 8, there is a third
The three component forces of cutting resistance as shown in the figure, that is, the principal component force P,
, a feeding force P2, and a backing force P3 are well known.

In particular, the principal force P, which is a force acting perpendicularly to the tooth surface of the tool material, is the largest. The load imposed on the tip of the tool 8 is either a single component force or a resultant force. Furthermore, in addition to cases in which the load is concentrated only at one point on the cutting edge, a distributed load often acts on the tip of an actual cutting tool.

In this case, the apparatus of the present invention is particularly effective. That is, as shown in FIG. 1, load parts 2 and 3 having different elastic moduli are arranged parallel to the load direction at the tip of a fusuma-shaped material 1, and a load 5 is applied once to the fusuma-shaped sample through a pressure receiving plate 7. The sample 1 has a structure in which cracks can be observed from the tip of the sample 1. Now, Young's modulus of load component 2 is E2, load component 3
If the Young's modulus of is E3, sample 1 directly under load component 2
When a load of W is applied to , a load of WX is applied directly below 3, and an uneven load is applied to the tip of sample 1, so the Young's modulus of load parts 2 and 3 is adjusted accordingly. By selecting this, it is possible to provide a load distribution that corresponds to actual cutting. Young's modulus 62000k as load part 2
9/ Side 2 cemented carbide is used as load component 3 with Young's modulus of 2.
When using 1000k9/side 2 steel, a stress 21000/62000 = 0.34 times the stress directly below 3 acts on the stress 21000/62000 = 0.34 times that directly below 2, which is close to the cutting edge stress distribution during actual cutting.

Further, by using a larger number of load parts in addition to the load parts 2 and 3, it is possible to impart an arbitrary stress distribution to the sample 1 with a single load 5. When an appropriate stress distribution is applied as described above, a crack 6 occurs on the side surface of the sample 1, and a load of 5
By repeating this process, the progress of the crack 6 can be observed continuously.

In addition, in the conceptual diagram showing the cutting situation in FIG.
gradually increases, and it is necessary to consider the stress distribution 10 on the rake face of the tool and the reaction force 9 together.

In addition, 11 represents the resultant force, 12' represents the cutting generated by actual cutting, and 15 represents the stress distribution line near the tool cutting edge.
Therefore, considering the reaction force from the workpiece material as the force acting on the tool 8, a side plate 4 is provided as a support from the side of the tool sample 1 in FIG. A model for strength testing of a tool cutting edge having an arbitrary amount of tool wear shown in FIG. 2 is constructed by supporting the side plate 4 or by applying a load in a direction perpendicular to the preload on the side plate 4. At this time, the strain gauge 14 is attached to the side plate 4 and the reaction force 9
It is possible to calculate Incidentally, it is advantageous that the tip of the test material 1 is slightly rounded or trimmed to reduce the variation in data. As described above, the device of the present invention is extremely suitable for actual use as a tool cutting edge plowability testing device, and is useful as a testing device for examining the quality of tool materials without cutting.

[Brief explanation of the drawing]

FIG. 1 shows a specific configuration of the device of the present invention,
FIG. 2 is a conceptual diagram of the cutting situation, and FIG. 3 is a diagram illustrating three components of cutting resistance generated between the workpiece and the tool. Spear 1 Figure 3 Figure 2

Claims (1)

[Claims] 1. At the tip of a cutting tool material having a wedge angle of 90° or less,
A non-cutting toughness testing device characterized by testing the toughness of a tool material by applying a load perpendicularly to the tooth surface of the material. 2. A wedge-shaped cutting tool material is characterized by having a structure in which a load component made of a material having a different modulus of elasticity is placed at the tip of the material in parallel to the loading direction, and toughness is examined by applying a load to the wedge-shaped material. A non-cutting toughness testing device according to claim 1. 3. A non-cutting method according to claim 1 or 2, characterized by having a structure in which the tip of the sample is in contact with a side plate having a side surface parallel to the direction of loading on the wedge-shaped material. Toughness testing equipment.