JPH0347448B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tensile test method for plate materials.

"Tensile test" is a test that applies tension to a sample and tests and measures the elongation from the point at which plastic deformation begins (yield point) until work hardening and breaking along with deformation, strength at break, work hardening characteristics, etc. Say something.

In the conventional tensile testing method for plate materials, one end of the test plate is fixed and the other end is stretched in one direction at a constant speed to measure the properties of the plate, such as the relationship between stress and strain. However, with such a tensile test method, it is not possible to measure the properties of a plate material while keeping the strain rate dt/dε constant. In other words, if one end of the test plate is fixed and the other end is gripped by a chuck, and this chuck is moved at a constant speed in the pulling direction, the elongation dl for the distance l from the fixed end to the moving chuck is as follows: dl is constant. Despite this, l gradually increases, so it decreases and never becomes constant. Since this dl/l corresponds to the strain dε, the strain rate dε/dt will gradually decrease. There is a strong demand for tensile tests to be conducted at a constant strain rate, but in order to meet this demand, tension control that keeps dl/l constant is required, but this control is complex and requires limited equipment if carried out. The costs involved are almost prohibitive.

An object of the present invention is to provide a method for conducting a tensile test under conditions of a constant strain rate.

That is, according to the method of the present invention, one end of the board to be tested is fixed, at least one roll is placed on the surface of the board at a certain distance from this end, and a predetermined roll is placed in this stationary position (i.e., in a constant state). The characteristics of the plate material under test are determined by rotating the roll at the rotational speed and pulling the plate material in one direction (i.e., with constant dl/dt) and with constant strain rate (i.e., constant dl/ldt (∝dε/dt)). For example, tensile stress versus elongation strain characteristics are measured.

A single rotating roll may be placed on the top surface of the test plate resting on the sliding surface, but
Usually, the plate material to be tested is sandwiched between a pair of rolls, and these rolls are rotated at a predetermined rotational speed in opposite directions at a stationary position to pull the test plate material in one direction.

Further, in accordance with the present invention, both ends of the board to be tested are held between a pair of rolls, and these rolls are moved in opposite directions at their respective rest positions, and the rolls on the same side of the board are moved in opposite directions. By rotating at the same rotational speed and pulling the plate in opposite directions, the center of the plate remains stationary and properties of the plate, such as crystal grain deformation and slip deformation pattern, can be continuously measured under conditions where the strain rate is constant.

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

Please refer to FIG. In this figure, one end of the plate 8 to be tested is clamped with fixed chucks 4a and 4b, and a pair of rotary chucks 1 are attached to the other end of the plate 3 at a stationary position a fixed distance l away from the fixed chuck.
A and 1b are pressed in the directions of arrows a and a' to grasp the plate material 3. A guide roll 5 is arranged along this plate material 3. A pair of rotary chucks 1a and 1b are rotated in opposite directions at a predetermined rotational speed to pull the plate material 3 in the direction of arrow A. As a result, the plate material 3 is subjected to tension under the condition that the strain rate is constant. In this state, desired mechanical properties of the plate material, such as tensile stress versus elongation strain properties, are measured.

In FIG. 2, the first pair of rolls 1a and 1b are pressed against one end of the plate 3 to be tested in the directions of arrows a and a' to grip the plate 3, and similarly, the second pair of rolls 1a and 1b are pressed against the other end of the plate 3 to be tested. The rolls 2a and 2b of are pressed in the directions of arrows b and b' to grip the board 3, and each pair of rolls is moved in opposite directions at their respective rest positions, and the rolls on the same side of the board are moved in opposite directions. The plates are rotated at the same speed in both directions and pulled in opposite directions A and B.
In this state, the center position of the plate is stationary, so if you set the microscope at this position, the plastic deformation surface will change under the condition of constant strain rate, such as crystal grain deformation, sliding deformation pattern, optical roughness change, etc. can be measured continuously.

Figures 3a, b, and c show rotary chucks directly used in carrying out the tensile test method for plate materials of the present invention. In both cases, the roll surface has a means for frictionally engaging the plate material under test, so that the plate material can be stretched between the rolls without slipping.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram for explaining the tensile test method for plate materials according to the present invention. FIG. 2 is a schematic diagram for explaining another method for tensile testing of plate materials according to the present invention. FIG. 3 is a perspective view of a rotary chuck directly used in carrying out the method of tensile testing of plate materials according to the present invention. In the figure: 1a, 1b; 2a, 2b: rotary chuck, 3: test plate, 4a, 4b: clamp.

Claims (1)

[Claims] 1. One end of the board to be tested is fixed, at least one roll is placed on the surface of the board at a certain distance from this end, and the roll is rotated at a constant peripheral speed at this stationary position to move the board in one direction. A tensile test method for plate materials that measures the properties of the plate material by causing plastic deformation under tension. 2. The tensile test method for a plate material according to claim 1, wherein a pair of rolls are arranged at the stationary position to sandwich the plate material, and these rolls are rotated in opposite directions at a constant peripheral speed. 3. Roll one end of the board to be tested with the first pair of rolls.
The other end of the plate to be tested is then sandwiched between a second pair of rolls, each pair of rolls being moved in opposite directions at their rest positions, and the rolls on the same side of the plate being moved in opposite directions at the same peripheral speed. 2. A tensile test method for a plate material according to claim 1, wherein the plate material to be tested is rotated by a rotational speed and pulled in opposite directions.