JP2720621B2 - Friction test method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention simulates abrasion, friction, seizure, etc. between a tool used for rolling steel, non-ferrous metal, etc. and a workpiece in a state close to actual processing conditions. And a friction test method and apparatus for evaluating the performance of tools and lubricants.

[0002]

2. Description of the Related Art Conventionally, in this type of wear test, the surface condition and lubrication characteristics of a material in a sliding state, such as a cylinder block type wear tester and a piny disk type wear tester, are investigated by rotation or reciprocation. It was mainly performed by a testing machine. This is different from the actual tool use conditions, in that a surface pressure equivalent to the deformation resistance is hardly provided, and no wear conditions under the newly formed surface are given. for that reason,
The wear of a new machined surface at the surface pressure equivalent to the deformation resistance on the actual machine that manufactures plates and pipes could not be reproduced, and it was insufficient as a test for evaluating the performance of tools and lubricants in a rolling mill. Was.

In order to compensate for the above-mentioned deficiencies in the conventional wear test, a rolled material is rolled using a pair of rolls, and a rolled material is subjected to a friction test to apply forward tension to the rolled material. A method for testing the abrasion of a roll material in which one roll is driven and the other roll is driven to perform asymmetric rolling is disclosed in JP-A-1-2108.
No. 48 discloses this. In addition, the plate-shaped workpiece is rolled between the rotating rolling roll and the fixed plate-shaped tool, and both the acting force acting perpendicular to the rolling direction and the acting force acting on the tool parallel to the rolling direction are detected. A friction lubrication test method for evaluating friction characteristics at an interface between a tool and a workpiece in plastic working is disclosed in JP-A-63-73134.

[0004]

By the way, some of the tools of an actual mill, especially a tube rolling mill, include a plate guide shoe provided in an inclined roll type rolling mill such as a piercer, an elongator and a reeler. As in the case of tools that receive sliding friction beneath the new machining surface or mandrel bars of mandrel mills, the machining slide is constantly updated so that a new tool surface is continuously supplied with the lubricant applied on the tool surface. Tools that receive sliding friction under a new working surface, as well as rolls for pipe production (plug mill rolls, mandrel mill rolls, sizer rolls, and reducer rolls), as well as in the rolling direction, as well as in the circumferential direction. There are tools that receive sliding friction. The necessity of evaluating wear resistance and seizure resistance of these tools and lubricants has been increasing recently in order to improve quality and rationalize costs.

However, among the above-mentioned new wear test methods, according to the method disclosed in Japanese Patent Application Laid-Open No. Hei 1-210848, it is possible to obtain rolling conditions close to roll rolling of a plate. As in rolling using tools such as a rolling mill tool for manufacturing a seamless steel pipe that requires the use of a tool, in particular, a disc guide shoe that is a tool of an inclined roll type rolling mill, and a mandrel bar of a mandrel mill, It is impossible to apply sliding friction under the newly formed surface to the entire sliding surface of the tool.

On the other hand, in the case of the method disclosed in Japanese Patent Application Laid-Open No. 63-73134, it is possible to apply sliding friction under the newly formed surface to the tool sliding surface. However, for example, in the case of the mandrel bar of the mandrel mill, as the workpiece moves in the rolling direction, and the tool also moves in the rolling direction, the working sliding portion is constantly updated, and the tool slide surface is updated during rolling. A new tool surface is continuously supplied with the lubricant applied to the surface. This method was insufficient for evaluation under such frictional conditions. Further, with this, seizure or the like occurs early during the evaluation test, and it is difficult to increase the rolling time and the elongation of the pressure, so that there is a problem that the condition difference with the actual machine is further increased.

For this reason, most of the tools of a tube rolling mill have only a method of testing using an actual machine, even if a new tool material and a lubricant for a tool are prototyped. Had become.

[0008] An object of the present invention is to provide a tool which is subjected to sliding friction under a new surface to be machined, especially a tool which is continuously supplied with a new tool surface as the material to be rolled is moved. It is an object of the present invention to provide a friction test method and apparatus capable of making an evaluation close to below.

[0009]

According to the friction test method of the present invention, a rolling roll installed at a fixed position and a roll parallel to a rolling direction are provided.
Provided movably with respect to the rolling roll
The material to be rolled is rolled between a non-rotating tool and a non-rotational tool that is in surface contact with the rolled material, and the tool is determined from the force acting perpendicular to the rolling direction detected during the rolling and the force acting on the tool parallel to the rolling direction. a friction test method for evaluating the frictional properties at the interface between the material to be rolled and the rolling direction to the rolling rolls the tool
Rolling the material to be rolled while forcibly displacing or moving in the rolling direction or any direction different from the rolling direction in a plane parallel to the rolling direction, and disposing the tool on the rolling roll during rolling
The feature is to change the position .

The friction test apparatus of the present invention has at least a constant
A pair of upper and lower rolling rolls or one rolling roll installed at a position and a position facing the pair of rolling rolls or one rolling roll are pressed in a plane parallel to the rolling direction.
It is arranged movably with respect to the roll , and
; And a non-rotary type tool to surface contact, the rolling roll and Engineering
Method detected when rolling the material to be rolled between the tool
Acting perpendicular to the rolling direction and acting on the tool parallel to the rolling direction
Characteristics at the interface between the tool and the material to be rolled due to the changing force
In the friction tester to evaluate the rolling roll
To change the position of the tool, move the tool to a rolling row.
And a tool moving means for forcibly moving in a rolling direction or an arbitrary direction different from the rolling direction in a plane parallel to the rolling direction . The following theory
In clear light, the displacement and movement of the tool is in a plane parallel to the rolling direction.
Means the change in the position of the tool relative to the rolling roll
I do.

[0011]

According to the wear test method and apparatus of the present invention, when the material to be rolled is rolled between the rolling roll and the tool, the tool is displaced or moved in the rolling direction or in any direction different from the rolling direction. You. If the tool remains fixed, the surface of the tool, which becomes a frictional sliding part with the material to be rolled, and the lubricant applied to the tool surface will only progress in places where there is friction, but the tool will not move in the rolling direction. Or, by being displaced or moved in an arbitrary direction different from the rolling direction, the friction sliding portion on the tool surface is updated during rolling, so that the tool has a speed in the rolling direction such as a mandrel mill or an assell mill. Even in rolling in which the sliding surface changes and the tool surface and the lubricant application surface are constantly updated, accurate evaluation can be made in accordance with the actual machine use conditions.

[0012]

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

FIG. 1 is a schematic view showing an embodiment of the present invention, in which a mandrel mill is assumed.

A U-shaped material to be rolled 2 sandwiching a plate-shaped tool 1 made of a mandrel material is rolled by a 2-Hi test rolling mill 3. At this time, the tool 1 is moved in the rolling direction or in a direction opposite to the rolling direction to the cylinder 5 through the load cell 4.
(Tool moving means). From the output of the load cell 4, a force F acting on the tool in parallel with the rolling direction is detected, and from the rolling load P, a force 2P acting perpendicular to the rolling direction is obtained.
Is detected. The coefficient of friction μ is determined by μ = F / 2P.
The material of tool 1 is ductile cast iron, and the material of rolled material 2 is 2
The movement of the tool 1 in the case where two types of 2Cr steel and low carbon steel are used, and the lubricant interposed between the tool 1 and the material 2 to be rolled is two types of graphite-boric acid-based and iron oxide-based lubricants, The effect on the measured value of the coefficient of friction is shown in FIG. The moving speed of the tool 1 was represented by a ratio (rolling speed ratio) to the peripheral speed of the rolling roll.
Changing the rolling speed ratio changes the coefficient of friction. Also,
The tool does not rub at a certain place, and the friction and seizure are evaluated on the whole when the tool slides during rolling. These are the same as the case of the bar of the actual mandrel mill.

FIG. 2 is a schematic view showing another embodiment of the present invention, which also assumes a mandrel mill.

The lower roll of the 2-Hi test rolling mill is replaced with a block-shaped tool 6, and a plate-shaped material 8 to be drawn from the coil 7 is placed between the upper roll 9 of the test rolling mill and the tool 6. To roll. At this time, the tool 6 is moved by the cylinder 5 (tool moving means) via the load cell 4 in the rolling direction or in the direction opposite to the rolling direction as in the test of FIG. The coefficient of friction μ is measured by μ = P / F.
FIG. 4 shows the result of investigating the influence of the movement of the tool 6 on the measured value of the friction coefficient in the same manner as in the test of FIG. As in the test of FIG. 1, the friction coefficient changes depending on the rolling speed ratio. This indicates that the occurrence of seizure between the material to be rolled and the tool during rolling is less likely to occur due to the movement of the tool test piece. This makes it possible to evaluate tool materials in rolling such as a mandrel mill in which such tool movement actually occurs in an actual machine. The material to be rolled can be a cut plate, and the method is adopted in the following examples.

FIG. 5 shows the roll load P, test load F and friction coefficient μ = F / P when the present invention is carried out under the following conditions.
Is shown in comparison with the case where there is no tool movement.

(1) Rolling method: One-sided roll / cut plate method using a 2-Hi mill (2) Rolled material: 22Cr steel (10 mm × 29 mm × 250 m)
m) (3) Tool material: ductile cast iron for guide shoe (100
mm × 100mm × 20mm) (4) Lubricants: iron oxide (Fe ₂ O ₃ 60% -Na ₂ S)
iO ₃ 40%) Pre-furnace coating (5) Rolling conditions: Heating temperature 1000 ° C (nitrogen atmosphere (O ₂ = 0.6%), rolling 150 ° C or less) Rolling rate 10% (rolling load about 5 TON) Rolling speed 0.15 m / s (same as rolling direction) Tool material moving speed 0.075 m / s (same as rolling direction)

In the conventional example without tool movement, seizure occurred despite the presence of the lubricant during rolling, and the material to be rolled could not advance in the rolling direction and was stopped halfway. On the other hand, in the embodiment of the present invention in which the tool is moved, no seizure is observed, and the load and the coefficient of friction are stable except when the material to be rolled is engaged. That is, by moving the tool,
Prevention of seizure and reproduction test under stable rolling are possible, and accurate evaluation can be made.

The above is a typical embodiment of the present invention. The present invention can be applied to various friction tests by considering the following points.

(1) Rolling reduction, surface pressure The interface between the tool used in plate rolling, tube rolling and the like and the material to be rolled becomes a new surface because the material to be rolled is processed. The rolling rate of the material to be rolled is 0.5
% Or more is required. At this time, since the material to be rolled undergoes plastic deformation, the surface pressure applied to the tool surface becomes a surface pressure corresponding to the deformation resistance of the material to be rolled. For example, if the material temperature is 1273 ° K
(1000 ° C), about 80 N / mm ^{2 for} ordinary steel,
For stainless steel, it is about 120 N / mm ² .

(2) Temperature The tool material and the lubricant to be evaluated in the present invention may be either for cold working or for hot working. Therefore, the temperature of the material to be rolled is in the range of room temperature to 1573 ° K. The temperature of the tool material and the lubricant rises due to the frictional heat on the frictional sliding surface, the heat of the material to be rolled and the heat conduction from the processing heat, and is, for example, about 373 ° for rolled ordinary steel (heating temperature of 1273 ° C.). K-1273 °
It varies depending on K, rolling setup and rolling time.

(3) Movement of the Tool The tool is moved or displaced in the rolling direction or any other direction different from the rolling direction in order to update the working sliding portion.
Specifically, the tool position and the speed are controlled by tool moving means such as a hydraulic cylinder. The moving speed is set arbitrarily. For example, when a workpiece is rolled at a rolling speed of 0.5 m / s, a tool disposed between the rolls apart from the roll moves at a speed of 0.1 to 1.0 m / s in the same or opposite direction to the rolling direction. There are ways to do that. This speed may be constant, or acceleration / deceleration may be controlled in a certain pattern. Further, a method of intermittently moving the tool, that is, displacing the tool may be used.

(4) Shape and Material of Rolled Material The shape of the material to be rolled is a plate if the roll is flat, and a solid round bar or tube if the roll is a hole. The length of the material to be rolled is arbitrary depending on the evaluation criteria of the tool and the lubricant to be evaluated. For example, a cut material having a length of about 100 mm
mm coil or wire can be appropriately selected. In the case of a coil or wire, an uncoiler and a reel are installed in the heating furnace on the entrance side of the mill where the rolls are installed, and a water cooling tank, coil,
A wire tension adjustment position and a winder are installed.
The material to be rolled is a low-carbon steel, high-carbon steel, alloy steel, stainless steel, high-alloy steel, titanium, a titanium alloy, as well as non-ferrous metals such as copper and aluminum, or general metal or inorganic compounds equivalent to the rolled material of the actual machine, An organic compound can be appropriately selected.

(5) Tool Shape, Material and Lubricant The tool is installed at a position along a pair of rolls or one roll. Therefore, if the material to be rolled is a plate, the tool is a plate. In the case of a rod, a rod is used. The material of the tool is not particularly limited. For example, the material of the tool is used for SKD6 series used in a mandrel mill bar in a hot pipe production line particularly subjected to a sliding friction state, and used for a disc type piercer guide shoe. A high Cr-high Ni based alloy, and a low alloy used as a die in a Eugene press machine are appropriately used. Further, a tool which has been subjected to a surface treatment such as a Cr plating nitriding treatment on the surface of these tools may be used. The lubricant is generally applied in advance to the tool surface before the test, and solid lubricant is mainly used. For example, the above-mentioned graphite-based lubricant for a mandrel mill bar, iron oxide for guide shoe lubrication, sodium silicate-based lubricant, and the like may be used as appropriate, and oils and fats may be used.

[0026]

According to the friction test method and apparatus of the present invention, a plate guide provided in an inclined roll type rolling mill such as a piercer, an elongator, or a reeler, which has been difficult to accurately evaluate in a conventional test due to displacement or movement of a tool. Not only tools such as shoes that receive sliding friction under the new machining surface, but also the mandrel bar of the mandrel mill, the machining sliding part is constantly updated, and the new tool surface is continuously connected with the lubricant applied to the tool surface. Not only in the rolling direction but also in the circumferential direction, as in the case of tools that are subject to sliding friction below the newly formed surface, such as those supplied by pipes, and rolls for pipe production (plug mill rolls, mandrel mill rolls, sizer rolls, reducer rolls) Abrasion resistance and seizure resistance of tools that receive sliding friction beneath the new machining surface and lubricants for these tools have been reduced to actual machine rolling. It can be properly evaluated in the stomach conditions. Therefore, in particular, the precision of the friction test with respect to these tools and lubricants is improved, and the actual machine test becomes unnecessary, thereby reducing and speeding up the test cost.

[Brief description of the drawings]

FIG. 1 is a schematic view showing one embodiment of the present invention.

FIG. 2 is a schematic view showing another embodiment of the present invention.

FIG. 3 is a graph showing the effect of tool movement on measured friction coefficient.

FIG. 4 is a graph showing the effect of tool movement on measured friction coefficient.

FIG. 5 is a time chart of load and friction coefficient showing the effect of the present invention.

[Explanation of symbols]

 1,6 Tools 2,8 Rolled material 4 Load cell 5 Cylinder

Claims (2)

(57) [Claims] 1. A and rolling roller disposed in a fixed position, rolling
Provided so as to be movable with respect to the rolling roll in a plane parallel to the direction
The material to be rolled is rolled between a non-rotating tool and a non-rotating tool that is in surface contact with the material to be rolled, and a force acting on the tool perpendicular to the rolling direction and a force acting on the tool in parallel with the rolling direction detected during the rolling. And a friction test method for evaluating friction characteristics at an interface between the tool and the material to be rolled .
By rolling the material to be rolled while forcibly displaced or moved to a different arbitrary direction to the rolling direction or rolling direction in a plane parallel to the rolling direction and, for the rolling rolls during rolling
A friction test method characterized by changing a tool arrangement position . 2. At least one of upper and lower parts installed at a fixed position.
A pair of rolling rolls or one rolling roll, and a position opposing the pair of rolling rolls or one rolling roll can be moved relative to the rolling rolls in a plane parallel to the rolling direction.
And a non-rotational tool that is arranged in contact with the material to be rolled and presses the material to be rolled between the rolling rolls and the tool.
The force acting perpendicular to the rolling direction detected when extending,
From the force acting on the tool parallel to the rolling direction, the tool and the
In the friction tester that evaluates the friction characteristics at the interface with the material, the position of the tool with respect to the rolling roll is changed.
The tool parallel to the rolling direction
A friction test apparatus comprising tool moving means for forcibly moving in a rolling direction or an arbitrary direction different from the rolling direction within a plane .