JPS5977337A - Friction testing device - Google Patents

Abstract

PURPOSE:To measure a frictional force, which can be matched at the time of actual plastic working, by contacting the surface of a plate shaped sliding material with one surface of a plate shaped material under test, contacting a pressure piece with the other surface, and performing the friction test, with the plastic deformation of the material under test being carrier out. CONSTITUTION:The surface of a sliding material 2, which has the same quality as that of the molds for a plastic working device, is contacted with the surface of a plate shaped material under test 1. A pressure piece 3 made of a super alloy is contacted with the opposite side. Then a simulated plastic working part is formed. A specified compressing force is applied to the pressure piece 3. The material under test 1 is slidden with respect to the sliding material 2. At the same time, a specified relative sliding speed corresponding to the actual working is imparted between the material under test 1 and the pressure piece 3. The simulated working part is heated to a specified temperature corresponding to the actual working. Then, the friction force, which matches the actual plastic working, is detected by a load cell 4, and the coefficient of friction performance of lubricating oil, and the like can be measured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a friction testing device, and more particularly to friction testing equipment for measuring friction force and coefficient of friction during plastic working such as hot rolling, cold rolling, and press forming, or lubricants used during plastic working. This invention relates to a friction test device for measuring the performance, etc. of

General No. 2, during plastic working (2 is friction between two materials, namely the material to be plasticized and the mold, due to relative sliding), which is a serious cause of scratches on the product surface and power loss. In addition to this, it also has a significant impact on the useful life of the mold.Therefore, lubricants are used to reduce the occurrence of such friction as much as possible. It is an extremely important issue to select a is essential.

By the way, when we observe the conditions during various plastic working processes that are actually performed, we find that, for example, in the case of a mandrel, the material to be plasticized, which is made of a blank pipe, is pressed between a mandrel bar and a roll. In addition, in a press, the plate-shaped material to be plasticized is pressed between a pair of male and female dies, so that the material to be plasticized is always pressed between the mold and the plastic processing tool. It has a pressure bag structure.

In addition, the conditions for plastic working that are actually performed range from cold working without heating to hot working under high temperature conditions.For example, looking at the hot rolling conditions in the seamless steel pipe manufacturing process, , the maximum rolling pressure is 1
00kg/■2, the maximum rolling speed is about 5m/s, the rolling time is about 7 to 8 seconds, the tube processing temperature is about 1200℃, and the relative sliding speed between the mandrel bar and the tube is 0.
It is about 1 to 2.5%, and in addition, there is surface sliding (new surface sliding) between the mandrel bar and the raw pipe due to the surface of the mandrel bar and the new surface of the raw pipe created by rolling. It's happening.

Therefore, in order to accurately understand the friction force, friction coefficient, performance of the lubricant used, etc. between two parts that cause friction phenomena with each other during such plastic working, it is necessary to A friction testing device that can create conditions close to those for machining is required.

However, when we examine conventional testing equipment of this type, we find that, for example, cylindrical pipe end face friction testing machines, such as the Meiki type and Ito type, are capable of testing with the presence of lubricant, but are set to plastic working conditions. It was not possible to do so, and also,
In the high temperature friction device of No. 1.50826, although it is possible to set high temperature conditions, it is not possible to increase the relative sliding speed by increasing the pressure; The problem is that it cannot be done.

Furthermore, as a friction test device that can satisfy the conditions of high temperature, high pressure, and high speed, for example, the high temperature friction device of Japanese Patent Publication No. 54-21274 is known. All conventional friction testing devices, including the high-temperature friction testing device disclosed in JP-A No. 56-150326, simply apply pressure between two members and make them slide against each other. As in the case of plastic working, the material to be plasticized is pressurized between the mold and the plastic processing tool, creating a new surface. This new surface causes surface sliding between the mold and a friction phenomenon due to so-called new surface sliding. However, there was a problem in that the friction phenomenon was not consistent with the friction phenomenon in actual plastic working, and it was difficult to say that the friction test device was a satisfactory friction test device. Moreover, these conventional friction test devices cannot be used under certain conditions in plastic working (
- Even if it was possible to measure friction force, coefficient of friction, degree of wear, etc. under suitable conditions, it was impossible to perform friction tests under other plastic working conditions, and there was also the problem of lack of versatility. .

In view of this point of view, the present inventors have determined that the friction force, friction coefficient, and lubricant used are consistent with the actual plastic working conditions under conditions that are consistent with the various plastic working conditions that are actually performed. As a result of intensive research on devices that can measure performance, etc., we have made a sliding material corresponding to the mold during plastic working and a test material corresponding to the material to be plasticized in two-sided contact with each other, and we have developed a plastic working tool. Place an indenter corresponding to 2 in contact with the test material C from the opposite side of the sliding material, press this test material against the sliding material,
A simulated plastic working part is constructed in which plastic working is actually performed on the surface of the test material. The inventors have discovered that it is possible to obtain results that are extremely consistent with actual plastic working, and have arrived at the present invention.

That is, the present invention includes a drive shaft that holds and rotates a flat test material so as to be able to slide in the axial direction, and a flat sliding material that is in surface contact with the test material at one end, and a drive shaft that holds and rotates a flat test material in the axial direction. a rotatable sliding holder having a torque detection mechanism equipped with a load cell, and an indenter that contacts the test material from the opposite side of the sliding material to press the test material against the sliding material; This is a friction testing device that is equipped with a heating mechanism that sets a simulated plastic working part, which is made up of the test material, sliding material, and indenter, to a predetermined temperature.

The principle of the friction testing apparatus of the present invention will be explained using a simulated plastic working portion shown in FIG. 1 as an example. In FIG. 1, the symbol (1
) is the test material formed into a flat plate (2), and this test material (
1) can be formed from the same material as the material to be plasticized. In addition, code (2) is a sliding material that is formed into a flat plate shape and makes surface contact with the test material (1), and this sliding material (2) is made of the same material as the mold of the plastic processing equipment used. be done. Furthermore, code (3) is an indenter corresponding to a plastic processing tool that applies pressure to the material to be plasticized in a plastic processing device, and is made of a superalloy with excellent heat resistance and wear resistance.
Its tip portion is approximately hemispherical.

With these settings, apply a predetermined pressing force to the indenter (8),
At the same time as the test material (1) is slid against the sliding material (2), a predetermined relative sliding speed is applied between the test material (1) and the indenter (3). For cold working, the test is carried out at room temperature, and for hot working, the test is carried out at a specified temperature (heated twice and tested for a specified time, and as shown in Figure 1, the test material (1) is subjected to plastic working, and , At this time, the test material (1)
The load cell (4) detects the force acting on the sliding material (2) when it slides in pressure contact with the sliding material (2).

The plastic working pressure at this time is the center of the tip of the indenter (8) (
0) to points (b, b') indicating the range where direct force is acting between the test material (1) and the sliding plate (2), and connect the point (b, b') where it intersects with the tip of the indenter (3). aha') and this (a,
a') It is determined as the pressure acting on the range of points. Further, the average pressure on the lubricating surface between the test material (1) and the sliding material (2) is determined as the range (two acting pressures) surrounded by the points (b, b').

The contact state between the test material (1) and the sliding material (2) was determined after the test by (b, b) of the test material (1) and the sliding material (2).
') It can be observed by the state of the traces generated between the points, and the frictional force and friction coefficient between the test material (1) and the sliding material (2) are the force detected by the load cell (4). required from.

In addition, in order to perform a lubricant performance test using the friction test device of the present invention, the materials of the test material (]) and the sliding material (2) are kept constant, and the surface of the sliding material (2) is lubricated. Apply the lubricant and perform a friction test, calculate the friction force, ゛, and friction coefficient from the force detected by the load cell (4), and compare it with the case without applying the lubricant or the case with the reference lubricant. and find its performance.

The results of the friction force, friction coefficient, lubricant performance, etc. obtained in this way can be obtained by matching the pressure, relative sliding speed, temperature, machining time, etc. of the simulated plastic working part with the actual plastic working conditions. It has extremely good consistency with actual plastic working and is highly reliable.

EMBODIMENT OF THE INVENTION Hereinafter, the friction test apparatus of this invention will be specifically explained based on the Example shown in an accompanying drawing.

In FIG. 2, the main parts of a friction test apparatus according to the second embodiment of the present invention are shown. It is a sliding plate formed in the shape of a flat disk and in surface contact with the lower surface of the test material (1), and the reference numeral (3) indicates the test material (moon) from the opposite side of the sliding material (2), that is, from above. This test material (
This is an indenter that presses the material (1) against the sliding material (2).

The test material (1) is rotatable via a bearing 00 provided on a frame (9) and slidable in the axial direction on the upper end of a vertically erected drive shaft (5). , is detachably held, and is rotated by a rotation drive mechanism (not shown) that is interlocked and connected to the lower end of the drive shaft (5).

The upper part of the drive shaft (5) is provided with a
) passes through the through hole (1) while maintaining a predetermined clearance.
1), the upper end has a flange part α to which the sliding member (2) that is in surface contact with the lower surface of the test member (1) is removably attached, and the lower end has a thrust bearing Q.
A sliding material holder (6) is rotatably supported on the frame (9) via the sliding material holder (6).
6) is provided with a torque detection mechanism (7) consisting of a load cell (4) and a torque lever (141) that transmits the load cell (4) (=torque).

Further, above the drive shaft (5), a bearing is supported by a pressurizing drive means such as a verofram cylinder (not shown) provided on the upper part of the frame (9), and a bearing provided on the frame (9). It is equipped with an outer cylinder αQ that is slidably guided in the vertical direction by αυ, and a pressurizing shaft α frame that is rotatably supported via two outer mool bearings 0 and is equipped with a rotational drive mechanism (not shown). A pressure mechanism 09) is disposed on the flange part provided at the lower end of the pressure shaft 0, and a bullet-shaped indenter (8 ) is removably attached.

Furthermore, the upper part of the drive shaft (5) and the sliding material holder (6) including the contact portion where the test material (1) and the sliding material (2) are in surface contact with each other, and the lower part of the pressurizing shaft 0 barrel. can be heated with a heating mechanism (8) such as a heating furnace,
It is now possible to create temperature conditions for plastic working such as hot rolling, cold rolling, and place forming.

In this example, a connecting part (A) having a rectangular fitting hole Qη is provided in the center of the test material (11), and a drive shaft is inserted into the fitting hole G!p of this connecting part Q. A rectangular prism-shaped connecting portion formed at the upper end of (5) is fitted to be slidable in the axial direction, and the rotation of this drive shaft (5) is transmitted to the test material (1). The sliding material (2) has a through hole (c) drilled in its center through which the connecting portion (a) of the test material (1) passes through while maintaining a predetermined clearance, and the peripheral edge thereof. An engagement hole (C) is bored in the upper end flange part of the sliding material holder (6). This sliding material (2) is attached to the sliding material holder (6) by fitting it into the sliding material holder (6).The symbol (b) in the figure is a heat insulating flange, and the symbol (c) is an oil-n-rule. be.

Next, a friction test method using the friction test apparatus of the above embodiment will be described below, taking as an example the case of hot working.

First, the heating mechanism (8) of the device is brought to a predetermined temperature.

Next, the sliding material (2) is coated at a lubricant application temperature of, for example, 200°C.
It is heated to around 10°C, sprayed with a specified lubricant, and set in the sliding material holder (6) of the device. In addition, the test material (11), which had been heated in advance to a plastic working temperature of 100 to 1200°C, was set to the drive shaft (51IX) of the device, and the drive shaft (5) was immediately rotated and the pressure shaft
Rotate the test material (11) and indenter (3) at a predetermined relative speed, then rotate the test material (11) and indenter (11) at a predetermined relative speed.
) to cause plastic deformation in the test material (1), and the frictional force at this time is measured by the load cell (4) of the torque detection mechanism (7).
Detect it with a recorder, measure it with a recorder, etc., and record it.

In addition, the relative speed between the test material (1) and the indenter (3) is
The rotation speed of the drive shaft (5) and the pressure shaft α may be adjusted respectively, but the rotation speed of either one may be kept constant (=
The other may be rotated in the same direction, stopped, or rotated in the opposite direction for adjustment. In addition, inside the heating mechanism (8) that heats the simulated plastic working part constituted by the test material (1), sliding material (2) and indenter (3),
For example, the same lubricant as that applied to the sliding material (2) may be used to control the atmosphere of the simulated plastic working part during the test to be the same as the lubricant combustion atmosphere, or if necessary, a different atmosphere other than the lubricant combustion atmosphere may be used. In order to create an atmosphere, active gas or inert gas is injected to control the atmosphere, and
This atmosphere may be changed over time.

In the above examples (-), test material (1) and sliding material (2)
) is formed in the shape of a flat-root solid plate, but the structure is not limited to this as long as the two can make surface contact with each other. For example, the sliding material (2) has a shape corresponding to the indenter (3). Form a protrusion with a flat upper end at the position, and connect the upper end surface of this protrusion with the indenter (
The test material (1) is sandwiched between the test material (1) and the sliding material (2), thereby keeping the contact pressure between the test material (1) and the sliding material (2) constant and reducing its distribution. It may also be possible to easily understand the equalized pressure.

In addition, in the above example, the indenter (3) corresponding to the plastic working tool has a hemispherical (two-shaped) bullet-shaped tip so that the test material (lli) undergoes two plastic deformations. However, the indenter (3) is not particularly limited to this, and for example, it may be composed of a thrust bearing or the like to apply only pressure between the test material (1) and the sliding material (2). Friction tests can be performed using the same method as the conventional precious wood type or Ito type cylindrical pipe end face friction tester.
Furthermore, the test material (1
), the ring is driven by the ring,
The number of rotations of the ring may be controlled (the relative speed between the two-strand indenter (8) and the test material (11) may be controlled. Also, a pressurizing axis α pull dial gauge may be attached to prevent wear. (the amount of deformation of the test material) can be measured.

Furthermore, in the above embodiment, the friction test device is configured vertically, but the posture of this friction test device is not limited to the vertical type, and can be configured horizontally depending on the test performed using this device. In addition, vertical and horizontal types can be used depending on the type of test, such as using a vertical type for a test similar to a four-ball test and a horizontal type for a test similar to a normal friction test. It can also be configured so that it can be changed.

As described above, the friction test device of the present invention brings the flat sliding material into surface contact with one side of the flat testing material, and also brings the indenter into contact with the sliding material from the opposite side of the sliding material. A simulated plastic working part is constructed by pressing the test material into plastic deformation, and the friction test is performed while the test material is actually plastically deformed. Therefore, the friction force, friction coefficient, and lubricant performance are evaluated under the same conditions as in actual plastic working. In addition to measuring the contact conditions between the test material and the sliding material in this simulated plastic working section, it is also possible to investigate the contact conditions during actual plastic working.For example, the wear resistance of a mandrel bar during hot rolling can be investigated. It can also be used to test the surface condition of seamless steel pipes.

Furthermore, by appropriately changing the shape of the indenter or configuring the indenter with a thrust bearing, it is possible to form a simulated plastically processed part that is suitable for various types of plastically forming processes and obtain measurement results that are consistent with the actual machine. In addition to being able to perform friction tests in the same manner as the precious wood type and Ito type cylindrical pipe end face friction testers, it can be used for various types of friction tests.

[Brief explanation of the drawing]

FIG. 1 is an explanatory view showing an example of a simulated plastic working part by the friction test apparatus of the present invention, and FIG. 2 is a partial sectional view showing the main part of the friction test apparatus according to the embodiment of the present invention. Code explanation (1)...Test material (2)...
・Sliding material (8)...Indenter (4)・
...Load cell (5) ...Drive shaft
(6)... Sliding material holder (7)...
・Torque detection mechanism (8) ・・Heating mechanism Patent applicant Nippon Steel Chemical Industry Co., Ltd. Nippon Steel Corporation Continued from page 1 ■ Applicant Nippon Steel Corporation Otemachi, Chiyoda-ku, Tokyo 2-6-3

Claims (1)

[Claims] A drive shaft that holds and rotates a flat test material so that it can slide in the axial direction, a flat sliding material that makes surface contact with the test material is attached to one end, and a torque detection device equipped with a load cell at the other end. a rotatable sliding material holder having a mechanism; an indenter that contacts the test material from the opposite side of the sliding material to apply pressure to the test material; 1. A friction testing device comprising: a heating mechanism that sets a simulated plastic working portion constituted by an indenter to a predetermined temperature.