JPH11258137A - Method and apparatus for evaluating form rolling workability of metallic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method for evaluating simply a bumpy shape of an edge part of an indentation transferred to a material to be processed in a form rolling process. SOLUTION: This evaluation method for form rolling workability of a metallic material includes process wherein a steel ball or a ball-head tool is pressed to a material to be processed with a predetermined load, a process wherein a size and a depth distribution of an indentation transferred to the material to be processed by the processing a measured, a process where in a work hardening coefficient (n) is obtained from a conversion graph or dynamic model, and a process wherein a transfer shape of an actual machine is evaluated by the conversion graph or dynamic model on the basis of the work hardening coefficient (n).

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to an evaluation test method and apparatus for estimating an uneven shape of an edge of an indentation transferred to a workpiece in a rolling process.

[0002]

2. Description of the Related Art When a thread groove or the like is formed by rolling, even in a portion where a tool does not directly contact, in the vicinity of a tool contact portion, a workpiece in a transfer portion is removed by machining and moves to the periphery. Is generated. Therefore, when the as-processed transfer portion is directly used as a product, a functional problem may occur unless the shape change of this portion is considered. But,
Since the deformation near the transfer part is affected by the chemical composition of the workpiece, heat treatment history, processing history, etc., it is common to evaluate by trial and error, such as performing a rolling test under conditions close to the actual machine. there were. Therefore, it takes much time and cost to determine the final transfer conditions, which has hindered rapid development.

[0003]

As described above, as described above,
Since there is no method or apparatus for easily predicting the shape of the rolled portion of the workpiece in the rolling process, trial and error must be performed under conditions close to the actual machine, which is a problem in development time and cost. That is, it has been desired to develop a method for easily evaluating the uneven shape of the edge of the indentation transferred to the workpiece in the rolling process.

[0004]

SUMMARY OF THE INVENTION The present invention provides a computer-assisted technology (hereinafter referred to as "C"), which has undergone many technological innovations in recent years and has made remarkable technological progress.
AE ". The purpose of the present invention is to evaluate the transfer characteristics of the workpiece from the indentation shape of the Brinell test known as a conventional hardness test.

[0005] That is, as means of the present invention for solving the problem, according to the invention of claim 1, in a method for evaluating the rolling workability of a metal material, a steel ball or a ball head tool is applied to a planar workpiece. A step of pressing with a predetermined load, a step of measuring the size and depth distribution of the indentation transferred to the workpiece by the pressing, a work hardening index n by a conversion graph or a dynamic model.
The method is characterized by a step of obtaining a value and a step of evaluating the transfer shape of the actual machine from a conversion graph or a dynamic model based on the work hardening index n value.

Further, according to the present invention, there is provided an apparatus for evaluating the formability of rolling of a metal material, wherein the steel ball or the ball-head tool is pushed into a flat workpiece by a predetermined load, and the workpiece is pushed into the workpiece. A contact or non-contact shape measuring device for measuring the size and depth distribution of the indent transferred to a processing unit for determining the size and the edge height variation of the indent based on a signal from the shape measuring device; A processing unit for estimating the work hardening index n value from the indentation size and the edge height change amount using a predetermined conversion graph or dynamic model, the transfer shape of the actual machine from the conversion graph or dynamic model based on the work hardening index n value. It is characterized by comprising a processing unit for evaluating and a processing unit for outputting the result.

The operation of the present invention will be described. FIG. 1 is a diagram showing an evaluation test system for rolling workability of a material of the present invention, and FIG. 2 is a diagram showing an evaluation test device of the present invention.

A feature of the present invention is that the optimization of the rolling conditions, which has been conventionally performed by trial and error, is automatically performed by the evaluation tests of FIGS. 1 and 2, so that the optimization can be performed quickly and inexpensively.

FIG. 3 shows the effect of the work hardening index n of the workpiece on the indentation shape of the steel ball indentation. The diameter of the steel ball is D, the diameter of the indentation is d, and the height of the indentation edge from the pressed surface is h. When the n value is large, that is, when work hardening occurs remarkably, h is small, and when the n value is small, that is, when work hardening does not occur, h is large.

FIG. 4 shows the results of examining the strain distribution near the indentation under the conditions shown in FIG. If the n value is large and work hardening occurs, the strain is concentrated in a wedge shape from the indentation in the figure,
When this portion is hardened and acts like a tool, h is small, whereas when the n value is small, the strain is widened, and the edge of the indentation rises.

In FIG. 5, the vertical axis represents a dimensionless height obtained by dividing the bulging height h of the indentation edge of the steel ball indentation by the steel ball diameter D, and the horizontal axis represents the work hardening index n of the workpiece. It is shown as a dimensionless parameter obtained by dividing the diameter d of the indentation by the steel ball diameter D. If the indentation diameter d is constant, the edge height h is a monotonically decreasing function of the n value. This corresponds to the fact that h is determined by the n value and a clear mechanical relationship through the strain distribution as shown in FIG. That is, if h is measured and a is known, c of the n value of the workpiece can be determined from b in the conversion graph shown in FIG.

FIG. 6 shows the relationship between the height H of the edge of the rolled portion of the product and the work hardening index n of the workpiece, the vertical height H of the edge on the vertical axis, and the processing of the workpiece on the horizontal axis. Hardening index n
Show the value. As in the case of FIG. 5, if p of the n value is known, that is, if the material is determined, r of the height H of the edge of the product can be estimated from q in the conversion graph of FIG.

[0013]

1 and 2 show an embodiment of the present invention.
This will be described with reference to FIG. FIG. 2 shows an apparatus for evaluating the rolling workability of the material of the present invention. The device is a measuring device 16, a control device 17,
The operation device 18 and the output device 15 are roughly classified into four devices.

The measuring device 16 comprises a gantry 8 and a device attached thereto. The steel ball 1 is a tool used to generate an indentation on the workpiece 2. The test piece 2 was cut out from a work material to be used in an actual machine for evaluating rolling workability. When the rolled surface in the actual machine was matched with the surface on which the indentation was made by the steel ball 1, the test piece 2 was cut. Chemical composition, heat treatment history,
Since the influence of the processing history and the like can be considered, the rolling workability of the actual machine can be more accurately evaluated. The load cell 3 has a structure in which a load cell is embedded in a table on which a test piece is installed in order to evaluate the load applied to the tool during rolling. The displacement meter 4 measures the pushing stroke of the steel ball 1. The compression drive device 5 generates a load to push the steel ball 1 in, and is preferably a hydraulic type with good controllability. The shape measuring device 6 is a sensor for measuring the unevenness of the indentation, and is preferably a non-contact type using a laser beam, but may be a contact type using a probe such as diamond. The test piece moving device 7 is used to move the test piece 2 having the indentation formed by the steel ball 1 to the shape measuring device 6, and the test piece 2 is grasped by the manipulator, and FIG.
Move as indicated by the arrow.

The control device 17 is roughly divided into three devices: a load control device 9, a shape measurement control device 10, and a test piece movement control device 11. Performs measurement control and test piece movement control.

The arithmetic unit 18 includes a dimension / shape processing unit 12,
It is roughly classified into three devices, a deformation resistance estimation device 13 and a transfer shape evaluation device 14.

FIG. 1 is a system for evaluating the rolling workability of a material according to the present invention. A steel ball 1 having a diameter D is pushed into a test piece 2 cut out from a workpiece by a measuring device 16 of FIG. 2, and the shape of an indentation generated on the surface of the test piece 2 is measured by a shape measuring device 6.

The result is transferred to the arithmetic unit 17, and the dimension and shape processing unit 12 first calculates the diameter d of the indentation and the height h of the edge shown in FIG. Next, the work hardening index n of the test piece is measured by the deformation resistance device 13 using the conversion graph of FIG.
The value is calculated. That is, the curve of d / D is selected in FIG. 5, and the n value is obtained in the order of a, b, and c in the figure from the value of h / D. The conversion graph is obtained with high accuracy using CAE, whose technology has been remarkably advanced in recent years. Further, if a dynamic model based on CAE is directly used instead of the conversion graph, there is versatility.
Next, the transfer shape evaluation device 14 evaluates the transfer shape of the actual machine, and determines the optimum tool shape and processing conditions. That is,
Once the boundary conditions such as the target shape and lubrication of the actual machine are known,
As shown in FIG. 6, there is a one-to-one correspondence between the transfer shape and the work hardening index n, and H is obtained in the order of p, q, and r from the n by using the conversion graph of FIG. The transfer shape can be evaluated. The conversion graph is obtained with high accuracy using CAE. If a dynamic model based on CAE is directly used instead of the conversion graph, there is versatility. Until the optimal processing conditions are found, optimization can be performed using a computer.
Time and number of tests can be reduced.

[0019]

EXAMPLES Examples are shown in Tables 1 and 2. Table 1 shows the results of actual machine measurement of the height H of the groove edge exerted by the heat treatment history of the workpiece when the ball screw is formed by rolling, and the method and apparatus of FIGS. 1 and 2 of the present invention. The obtained estimation result is shown. As a result of actual machine measurement, H of the annealed material is smaller than that of the as-rolled material. On the other hand, the estimation result is similar to the above, indicating that the method and apparatus of the present invention are useful.

Table 2 shows the number of trial-and-error times for actually forming a mold and correcting it by trial machining in order to optimize the shape of a rolling tool, that is, the number of trial machining of the optimal tool. It is a case that was examined. Conventional trial and error required multiple times, but with the technology of the present invention, it is possible to examine in advance whether it is optimal or not using an analytical model,
It can be seen that optimization can be achieved at one time.

[0021]

[Table 1]

[0022]

[Table 2]

[0023]

According to the present invention, it is possible to evaluate the rollability of a material under conditions similar to those of an actual machine by omitting a scale model tester of the actual machine, thereby greatly reducing the development period and cost. effective.

[Brief description of the drawings]

FIG. 1 is a view showing a system for evaluating rolling workability of a material according to the present invention.

FIG. 2 is a diagram showing an apparatus for evaluating the rolling workability of a material according to the present invention.

FIG. 3 is a diagram showing the relationship between the shape of an indentation of steel ball indentation and the work hardening index n value of a material.

FIG. 4 is a diagram showing the relationship between the strain distribution of steel ball indentation and the work hardening index n value.

FIG. 5 is a graph showing a relationship between an edge height and a work hardening index n value.

FIG. 6 shows the height H and the work hardening index n of the edge of the actual machine.
It is a graph which shows the relationship of a value.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 steel ball 2 test piece 3 load meter 4 displacement meter 5 compression drive device 6 shape measuring device 7 test piece moving device 8 gantry 9 load control device 10 shape measuring control device 11 test piece moving control device 12 dimension and shape processing device 13 deformation resistance Estimation device 14 Transfer shape evaluation device 15 Output device 16 Measurement device 17 Control device 18 Arithmetic device

Claims (2)

[Claims] In a method for evaluating the rolling workability of a metal material, a step of pushing a steel ball or a ball-point tool into a planar workpiece with a predetermined load, and a dimension and depth of an indentation transferred to the workpiece by the pushing. Measuring a work distribution, obtaining a work hardening index n value by a conversion graph or a dynamic model,
A method for evaluating the rolling workability of a metal material, comprising a step of evaluating a transfer shape of an actual machine by a conversion graph or a dynamic model based on a work hardening index n value. 2. An apparatus for evaluating the rolling workability of a metal material, comprising: a processing device for pushing a steel ball or a ball-point tool into a planar workpiece with a predetermined load; A contact or non-contact shape measuring device for measuring the depth distribution, a processing unit for obtaining the size of the indentation and an edge height change amount based on a signal from the shape measuring device, the size and the edge height of the indentation A processing unit for estimating the work hardening index n value from the change amount using a predetermined conversion graph or dynamic model, a processing unit for evaluating the transfer shape of the actual machine using the conversion graph or dynamic model based on the work hardening index n value, and the result An evaluation device for rolling workability of a metal material, characterized by comprising a processing section for outputting a value.