CN115165530A - Novel high-temperature creep tensile extensometer - Google Patents

Abstract

The present invention relates to a measuring device. The purpose provides a novel high temperature creep tensile extensometer, but this extensometer real-time measurement tensile sample tensile creep volume under high temperature to have simple structure, simple to operate, characteristics that measurement accuracy is high. The technical scheme is that the novel high-temperature creep tensile extensometer comprises a base, a plurality of stand columns vertically fixed on the base, a cross beam horizontally fixed at the top of each stand column, a heat-insulating cylinder which can be installed on the stand columns in an opening and closing manner and can heat and insulate a tensile sample, a lower traction piece vertically fixed on the base and with the upper end extending into the heat-insulating cylinder to provide downward traction force, a lower measurement assembly for measuring the displacement deformation quantity of the lower end of the tensile sample and a controller; the method is characterized in that: the extensometer also comprises an upper positioning piece which is vertically fixed on the cross beam, the lower end of the upper positioning piece extends into the heat-insulating cylinder to fix the tensile sample, and an upper measuring assembly which is used for measuring the displacement deformation quantity of the upper end of the tensile sample.

Description

Novel high-temperature creep tensile extensometer

Technical Field

The invention relates to a measuring device, in particular to a novel high-temperature creep stretching extensometer.

Background

High temperature creep refers to the phenomenon that a metal material slowly generates plastic deformation under the long-term action of constant temperature and constant load. The process for measuring the high-temperature creep value of the metal material is the high-temperature creep test. The high-temperature creep test usually adopts a uniaxial tension test, and specifically comprises the steps of placing a dumbbell-shaped tension sample in a clamping device of a tension tester, then installing an extensometer and a thermocouple on the tension sample, buckling a heat preservation cylinder, then heating to a specified temperature and loading to a specified tension force, and starting timing to measure the creep amount of the tension sample.

The conventional extensometer comprises 4 high-temperature-resistant metal guide rods, wherein each 2 guide rods form a group which is buckled together and clamped on a boss part of a tensile sample, a left group of metal guide rods are used for measuring the displacement variation of one group of tensile sample, a right group of metal guide rods are used for measuring the displacement variation of the other group of tensile sample, and the average value of the left group of variation and the right group of variation is the high-temperature creep variation of the tensile sample. The device has the advantages of complex design, difficult installation, long installation time and higher technical level required for operators.

Disclosure of Invention

The invention aims to overcome the defects of the background technology and provide a novel high-temperature creep tensile extensometer which can measure the tensile creep deformation quantity of a tensile sample at high temperature in real time and has the characteristics of simple structure, convenient installation and high measurement precision.

The technical scheme provided by the invention is as follows:

a novel high-temperature creep tensile extensometer comprises a base, a plurality of stand columns vertically fixed on the base, a beam horizontally fixed at the top of each stand column, a heat-insulating cylinder which can be installed on the stand columns in an opening and closing manner and can heat and insulate a tensile sample, a lower traction piece vertically fixed on the base and with the upper end extending into the heat-insulating cylinder to provide downward traction force, a lower measurement assembly for measuring the displacement deformation quantity of the lower end of the tensile sample and a controller; the method is characterized in that: the extensometer also comprises an upper positioning piece which is vertically fixed on the cross beam, the lower end of the upper positioning piece extends into the heat-insulating cylinder to fix the tensile sample and an upper measuring component which measures the displacement deformation quantity of the upper end of the tensile sample; the upper positioning piece and the lower traction piece are mutually corresponding and coaxially arranged.

The upper measuring assembly comprises an upper grating displacement indicating ruler vertically fixed on the cross beam, an upper clamping claw fixedly clamped with an upper boss on the periphery of the tensile sample, an upper guide rod vertically and slidably penetrating through the top surface of the heat-insulating cylinder and an upper sleeve which is arranged on the heat-insulating cylinder and sleeved on the periphery of the upper guide rod so as to vertically guide the upper guide rod; one end of the upper guide rod is fixedly connected with the upper clamping jaw, and the other end of the upper guide rod is matched with the tip of the upper grating displacement indicating ruler in an abutting mode.

The lower measuring assembly comprises a lower grating displacement indicating ruler vertically fixed on the machine base, a lower clamping claw fixedly clamped with a lower boss on the periphery of the tensile sample, a lower guide rod vertically and slidably penetrating through the bottom surface of the heat-insulating cylinder and a lower sleeve which is arranged on the heat-insulating cylinder and sleeved on the periphery of the lower guide rod so as to vertically guide the lower guide rod; one end of the lower guide rod is fixedly connected with the lower clamping claw, and the other end of the lower guide rod is matched with the tip of the lower grating displacement indicating ruler in an abutting mode.

The upper clamping claw and the lower clamping claw have the same structure; the upper clamping jaw and the lower clamping jaw respectively comprise a connecting piece correspondingly connected with the upper guide rod or the lower guide rod, a U-shaped forked part fixed on the connecting piece and fastening bolts connected with the end parts of two sides of an opening of the U-shaped forked part; and a clamping groove for accommodating the upper boss or the lower boss of the tensile sample is formed in the inner side of the opening of the U-shaped bifurcated part.

One end of the upper guide rod, which abuts against the upper grating displacement indicating ruler, and one end of the lower guide rod, which abuts against the lower grating displacement indicating ruler, are both arranged into discs; the middle part of the lower guide rod is also provided with a limit boss which can be clamped with the inner wall of the bottom surface of the heat-insulating cylinder.

The upper grating displacement indicating ruler and the lower grating displacement indicating ruler comprise a scale grating, a grating reading head, a spring vertically fixed at the tail end of the grating reading head, and a tip fixed at the tail end of the spring to correspondingly abut against the top guide rod or the lower guide rod.

The heat preservation cylinder is composed of two semi-cylindrical cylinders which are hinged with each other.

And the upper positioning piece and the lower traction piece are correspondingly and fixedly connected with two ends of the tensile sample through the thread pair.

The wall of the heat-insulating cylinder is made of steel materials; a hard heat-insulating material layer is arranged on the inner side of the cylinder wall; and a resistance wire is arranged in the heat-insulating cylinder so as to heat the tensile sample.

The upper positioning piece, the lower traction piece, the upper grating displacement indicating ruler, the lower grating displacement indicating ruler and the resistance wire are respectively and electrically connected with the controller.

The invention has the beneficial effects that:

1) The device provides a certain constant-temperature working environment for the tensile sample through the heat-insulating cylinder, the tensile sample is subjected to tensile traction through the upper positioning piece and the lower traction piece, the displacement deformation quantities of the upper end and the lower end of the tensile sample can be measured in real time through the upper grating displacement indicating ruler and the lower grating displacement indicating ruler, and the creep deformation quantity is calculated and displayed in real time through the controller, so that the high-temperature creep test is smoothly completed.

2) The invention adopts the fixed extensometer, wherein the upper positioning piece and the lower traction piece are respectively and fixedly connected with two ends of the tensile sample through the thread pair, and the upper clamping jaw and the lower clamping jaw are clamped on the tensile sample, thereby greatly reducing the installation difficulty between the extensometer and the tensile sample in the test process.

3) The upper grating displacement indicating ruler and the lower grating displacement indicating ruler are both provided with spring type tips, and are always in contact with the upper guide rod or the lower guide rod in the tensile test process, and the grating displacement indicating ruler has high measurement precision.

4) The upper guide rod and the lower guide rod can be vertically and movably positioned on the heat-insulating cylinder through the sleeve, and repeated installation work of moving the upper guide rod and the lower guide rod up and down is not needed when tensile samples are replaced every time.

5) Thirdly, an upper clamping jaw and a lower clamping jaw are adopted to respectively clamp and position an upper boss and a lower boss of the tensile sample, and the clamping jaws are U-shaped, so that the upper boss or the lower boss can be conveniently, quickly, simply and practically fixed; meanwhile, the two clamping claws are provided with connecting pieces connected with the upper guide rod and the lower guide rod, so that the upper guide rod and the lower guide rod are very convenient to connect and position.

6) The invention has simple integral structure, convenient operation and high measurement precision, and is suitable for popularization and application.

Drawings

Fig. 1 is a schematic front view of an embodiment of the present invention.

Fig. 2 is a schematic front view of a tensile test specimen.

Fig. 3 is a front view structure diagram of the upper clamping claw or the lower clamping claw.

Fig. 4 is a schematic top view of the upper clamping jaw or the lower clamping jaw.

Fig. 5 isbase:Sub>A sectional view taken along linebase:Sub>A-base:Sub>A of fig. 4 (the fastening bolt is omitted).

Fig. 6 is a schematic diagram of the working principle of the present invention.

FIG. 7 is a schematic front view of a conventional high-temperature creep-elongation extensometer.

Fig. 8 is an enlarged structural view of a partial view in fig. 7.

Fig. 9 is a right-side view of fig. 7 (a right-side view of a conventional high-temperature creep-stretch extensometer).

Reference numerals:

1. a machine base; 2. a column; 3. a cross beam; 4. a heat-preserving cylinder; 5. an upper positioning member; 6. a lower traction member; 7. a rotating shaft bracket; 8. an upper grating displacement indicating ruler; 8-1, mounting a grating indicating ruler support; 8-2, an upper tip (spring tip); 9. an upper gripper jaw; 9-1, connecting pieces; 9-2, a U-shaped crotch; 9-3, fastening bolts; 9-4, a threaded hole; 9-5, a clamping groove; 10. an upper guide rod; 11. an upper sleeve; 12. a disc; 13. a lower grating displacement indicating ruler; 14. a lower gripper jaw; 15. a lower guide rod; 16. a lower sleeve; 17. a limiting step; 18. a data line; 19. stretching a sample; 19-1, an upper external thread; 19-2, an upper boss; 19-3, a lower boss; 19-4 and a lower external thread.

Detailed Description

The following further description is made with reference to the embodiments shown in the drawings.

The conventional high-temperature creep tensile extensometer (shown in fig. 7 to 9) comprises a machine base 1, a plurality of upright posts 2, a cross beam 3, a heat preservation cylinder 4, an upper positioning piece 5, a lower traction piece 6, a lower measurement assembly and a controller (not shown in the figure). The machine base is in a cuboid shape; each upright post is vertically fixed on the base; the cross beam is horizontally fixed at the top of each upright post, and the cross beam and the upright posts form a door-shaped frame.

The heat preservation cylinder is installed on the stand column and used for heating and preserving heat of the tensile sample. Specifically, the heat-preservation cylinder consists of two semi-cylindrical cylinders which are hinged with each other; the articulated shafts (the articulated shafts are omitted in the figure) of the two semi-cylindrical barrels are fixed on the upright posts through the rotating shaft brackets 7. The wall of the heat-insulating cylinder is made of steel materials; a hard heat-insulating material layer is arranged on the inner side of the cylinder wall; and the hard heat-insulating material layer is provided with a groove, a resistance wire (not shown in the figure) is arranged in the groove, the interior of the heat-insulating cylinder can be heated to a corresponding temperature, and meanwhile, a constant temperature environment is provided for a high-temperature creep test under the heat-insulating effect of the hard heat-insulating material layer.

The upper positioning piece is vertically fixed on the cross beam, and the lower end of the upper positioning piece extends into the heat preservation cylinder and is used for being connected with the upper end of the tensile sample to fix the tensile sample. The lower traction piece is vertically fixed on the machine base, and the upper end of the lower traction piece extends into the heat preservation cylinder and is used for connecting the lower end of the tensile sample so as to pull the tensile sample downwards. Go up setting element and pull piece mutual correspondence and coaxial setting down to guarantee tensile sample's vertical tensile, guarantee measurement accuracy. Preferably, the upper positioning piece and the upper end of the tensile sample and the lower traction piece and the lower end of the tensile sample are fixedly connected through thread pairs so as to facilitate installation of the tensile sample (the outer walls of the upper end and the lower end of the tensile sample are respectively provided with an upper external thread 19-1 and a lower external thread 19-2, and the lower part of the upper positioning piece and the upper part of the lower positioning piece are respectively clamped with matched screw holes). The power of the lower traction part can adopt an oil pressure system.

The above structures are the same as the present invention.

However, in the conventional high-temperature creep tensile extensometer, four groups of lower measuring assemblies are adopted as the measuring assemblies, and each group of lower measuring assembly comprises a guide rod 22 penetrating through the bottom surface (bottom end surface) of the heat-insulating cylinder, two limiting assemblies (a first limiting assembly 26 and a second limiting assembly 27) for limiting the horizontal movement of the lower part of the guide rod, and a lower grating displacement indicating ruler fixed on the machine base through a lower grating indicating ruler support 13-1. Wherein, a positioning head 21 at the top of the guide rod is connected with a chuck 20; one side of the chuck is provided with an inner cylindrical surface which is suitable for the peripheral surface of the tensile sample, and the inner cylindrical surface is provided with an annular groove which can be embedded with the upper lug boss 19-2 or the lower lug boss 19-3 of the tensile sample.

FIG. 8 shows a mounting arrangement in which two sets of lower measurement assemblies are provided; as can be seen from the figure: the annular grooves in the chucks at the tops of the two guide rods are simultaneously clamped and embedded with the left side and the right side of the boss on the tensile sample, and the outsides of the annular grooves are coated with hoops (omitted in the figure) for mutually closing and pressing the two chucks; thus, the tops of the two guide rods are connected with the upper lug boss of the tensile sample into a whole. The lower parts of the two guide rods sequentially penetrate through the bottom surface of the heat-insulating cylinder, the first limiting component 26 and the second limiting component 27. The left part and the right part of the second limiting component are respectively fixedly connected with the two lower grating indicating ruler supports, and the left part and the right part are mutually tensioned through a tension spring 23 to enable pulleys 24 arranged on the left part and the right part to be attached to the surface of the lower traction piece 6 to move up and down; the pressing blocks 25 fixed on the left part and the right part respectively form a gap for the guide rod to move up and down with a pulley, and limit the horizontal movement of the guide rod. The structure of the first limiting component is basically the same as that of the second limiting component, and the difference is as follows: a pressing block in the first limiting assembly is tightly pressed and fixed with the guide rod, and meanwhile, the bottom end of the first limiting assembly is matched with the lower tip 13-1 of the lower grating displacement indicating ruler; when measuring like this, first spacing subassembly can be with the corresponding downstream of extension (the guide arm is being driven by tensile sample and is extending together) of guide arm, and the change of displacement volume can be surveyed to lower grating displacement indicating ruler.

The other two groups of lower measuring components are used for measuring the displacement of the lower boss of the tensile sample (see fig. 9); the concept of the mounting structure is therefore the same, but the mounting position is rotated 90 degrees around the vertical axis of fig. 8 (four guide rods and four sets of lower measuring assemblies are all arranged symmetrically to the axis of the lower tractor); and the annular grooves in the top chucks of the two guide rods of the two groups of lower measuring assemblies are simultaneously clamped and matched with the left side and the right side of the lower boss of the tensile sample.

The structure has the defects that the heat preservation cylinder is opened firstly for each test of the tensile sample, and the four guide rods fixedly connected with the upper boss and the lower boss are fixed again after the original tensile sample is disassembled; at this time, although the heat-insulating barrel is opened, the operable space is still narrow, and the operation is very inconvenient; then, the lower parts of the four guide rods are subjected to installation, positioning and correction of the lower measuring assembly again; therefore, the workload is large, the time and the labor are consumed, and the working efficiency is low.

The invention is improved for this purpose as follows.

Firstly, changing the original four groups of lower measuring assemblies into an upper group of measuring assemblies and a lower group of measuring assemblies, wherein the upper measuring assembly is used for measuring the elongation change of a boss on a tensile sample; the number of measuring components is reduced by times;

an upper sleeve 11 in sliding fit with an upper guide rod of the upper measuring assembly and a lower sleeve 16 in sliding fit with a lower guide rod of the lower measuring assembly are embedded in the heat-insulating barrel; therefore, when the tensile sample is tested each time, the upper guide rod and the lower guide rod can be continuously left in the heat-insulating cylinder, and the upper guide rod and the lower guide rod do not need to be moved up and down for repeated installation;

thirdly, an upper boss and a lower boss of the tensile sample are clamped and positioned by an upper clamping claw and a lower clamping claw respectively, and the upper boss or the lower boss is fixed conveniently, quickly, simply and practically by the U-shaped clamping claws; meanwhile, the two clamping claws are respectively provided with a connecting piece connected with the upper guide rod and the lower guide rod, so that the upper guide rod and the lower guide rod are very convenient to connect and position;

fourthly, disks are respectively manufactured at the end parts of the upper guide rod and the lower guide rod and are used as a measuring reference matched with the tip of the grating displacement indicating ruler; the reference adjustment of the grating displacement indicating ruler is simple and convenient, and compared with the prior art, the installation and calibration workload is greatly reduced.

The following further explains the modified portion.

A novel high temperature creep tensile extensometer as shown in figure 1 was used to perform high temperature creep tests. In the use of the extensometer of the present invention, a tensile sample 19 to be stretched is vertically installed in a heat-insulating cylinder of the extensometer, wherein an upper boss 19-2 is provided on the periphery of the upper part of the tensile sample, and a lower boss 19-3 is provided on the periphery of the lower part of the tensile sample (see fig. 2).

The upper measuring assembly is used for measuring the displacement deformation quantity of the upper end of the tensile test sample. The upper measuring assembly comprises an upper grating displacement indicating ruler 8, an upper clamping jaw 9, an upper guide rod 10 and an upper sleeve 11. And the upper grating displacement indicating ruler is vertically fixed on the cross beam. The upper clamping claw is fixedly clamped with the upper boss of the tensile sample; specifically, the upper clamping jaw comprises a connecting piece 9-1, a U-shaped fork part 9-2 and a fastening bolt 9-3; wherein, the connecting piece is provided with a threaded hole 9-4 so as to be connected with the upper guide rod in a threaded way; the U-shaped crotch part is fixed on the connecting piece, and the inner side of the opening of the U-shaped crotch part is provided with a clamping groove 9-5 for accommodating the upper boss (the clamping groove penetrates through the end part of one side of the opening so that the upper boss or the lower boss can be embedded into the U-shaped crotch part from the opening along the clamping groove); the fastening bolt is used for connecting the end parts of the two sides of the opening of the U-shaped bifurcation part (the end parts of the two sides are both provided with through holes for inserting the fastening bolt), so that the upper clamping jaw and the tensile sample are prevented from being separated from each other in the test process (see fig. 3 to 5).

The upper guide rod can vertically and slidably penetrate through the top surface of the heat-insulating cylinder, wherein the lower end of the upper guide rod is provided with an external thread which can be screwed and fixed with a threaded hole of the upper clamping jaw connecting piece, so that the upper guide rod is convenient to mount; the upper end of the upper guide rod is arranged into a disc 12 and is matched with the tail end of the upper grating displacement indicating ruler in an abutting mode; when the heat-insulating cylinder works, the upper guide rod is limited by the disc, so that the upper guide rod can be prevented from falling into the heat-insulating cylinder. The upper sleeve is arranged on the top surface of the heat preservation cylinder, and the periphery of the upper guide rod is sleeved with the upper sleeve so as to guide the vertical movement of the upper guide rod.

The lower measuring assembly is used for measuring the displacement deformation quantity of the lower end of the tensile sample. The lower measuring assembly comprises a lower grating displacement indicating ruler 13, a lower clamping jaw 14, a lower guide rod 15 and a lower sleeve 16. And the lower grating displacement indicating ruler is vertically fixed on the base. The lower clamping claw is fixedly clamped with a lower boss of the tensile sample; the lower gripper jaw has the same structure as the upper gripper jaw, and is not described again. Obviously, the lower clamping jaw and the upper clamping jaw are both made of high-temperature-resistant materials.

The lower guide rod can be vertically and slidably positioned on the bottom surface of the heat-insulating cylinder; the upper end of the lower guide rod is provided with external threads which can be screwed and fixed with the threaded hole of the lower clamping jaw connecting piece, and the lower end of the lower guide rod is arranged into a disc and is matched with the tail end of the lower grating displacement indicating ruler in an abutting mode. The middle part of the lower guide rod is also provided with a limiting boss 17 which is positioned inside the heat-insulating cylinder, and the limiting boss can be mutually clamped with the inner wall of the bottom surface of the heat-insulating cylinder during working so as to prevent the lower guide rod from falling out of the heat-insulating cylinder under the action of gravity. The lower sleeve is arranged on the bottom surface of the heat-insulating cylinder and sleeved on the periphery of the lower guide rod so as to guide the vertical movement of the lower guide rod.

In this embodiment, the upper grating displacement indicating ruler and the lower grating displacement indicating ruler both include a scale grating, a grating reading head, a spring and a tip; the upper grating displacement indicating ruler and the lower grating displacement indicating ruler are both in the prior art and can be directly purchased from the outsourcing; the spring is vertically fixed at the tail end of the grating reading head, and the tip end of the spring is fixed at the tail end of the spring and is used for correspondingly abutting against the disc at the end part of the upper guide rod or the lower guide rod.

The upper positioning piece, the lower traction piece, the upper grating displacement indicating ruler, the lower grating displacement indicating ruler and the resistance wire are respectively electrically connected with the controller, the controller is provided with a display screen, the upper grating displacement indicating ruler and the lower grating displacement indicating ruler transmit measured displacement variation to the controller in real time through the data line 18, and creep deformation of the tensile sample is displayed on the display screen in real time.

The use mode of the invention is as follows:

firstly, two semi-cylindrical barrels of a heat preservation barrel are opened, a tensile sample to be stretched is fixed, wherein the upper end of the tensile sample is screwed with an upper positioning piece through threads, and the lower end of the tensile sample is screwed with a lower traction piece through threads, so that the tensile sample is fixed. And then, mutually clamping the clamping groove of the upper clamping jaw with the upper boss of the tensile sample, mutually clamping the clamping groove of the lower clamping jaw with the lower boss of the tensile sample, and screwing a fastening bolt. Then, the lower end of the upper guide rod is in threaded connection with a connecting piece of the upper clamping jaw (the external thread at the lower end of the upper guide rod is matched with the threaded hole of the connecting piece of the upper clamping jaw), and a disc at the upper end of the upper guide rod abuts against the tail end of the upper grating displacement indicating ruler; the upper end of the lower guide rod is in threaded connection with the connecting piece of the lower clamping jaw (the external thread at the upper end of the lower guide rod is matched with the threaded hole of the connecting piece of the lower clamping jaw), and the disc at the lower end of the lower guide rod is propped against the tail end of the lower grating displacement indicating ruler. At the moment, after the tensile sample is installed, the two semi-cylindrical barrels are closed, and then the high-temperature creep test can be carried out.

The working principle of the invention is as follows:

as shown in fig. 6, the test started with heating the resistance wire; when the specified temperature and tensile stress are reached, the creep change amount is zero; and then in the process of stretching at constant temperature, the lower traction piece applies downward tension P to the tensile sample, and the downward displacement delta 2 of the lower boss of the tensile sample can be read in real time through the lower grating displacement indicating ruler. The upper grating displacement indicating ruler is used for reading the downward displacement delta 1 of the boss on the tensile sample in real time. And subtracting the reading delta 1 from the reading delta 2 to obtain the creep real deformation amount of the tensile sample. Because the upper clamping claw generates deformation and elongation from the fixed end of the cross beam to the upper lug boss of the tensile sample in the processes of temperature rise and constant temperature stretching of the tensile sample, the upper grating displacement indicating ruler is mainly used for measuring the deformation delta 1 of the part. The lower grating displacement indicating ruler is used for measuring the deformation delta 2 from the fixed end of the machine base to the lower boss part of the tensile sample, the deformation delta 1 measured by the upper grating displacement indicating ruler is subtracted from the deformation delta 2, the actual deformation between the upper boss and the lower boss of the tensile sample is obtained, and the actual deformation is the tensile creep value at high temperature.

Finally, it should be noted that the above-mentioned list is only a specific embodiment of the present invention. It is obvious that the present invention is not limited to the above embodiments, but many variations are possible. All modifications which can be derived or suggested by a person skilled in the art from the disclosure of the present invention are to be considered within the scope of the invention.

Claims (10)

1. A novel high-temperature creep tensile extensometer comprises a base (1), a plurality of stand columns (2) vertically fixed on the base, a cross beam (3) horizontally fixed at the tops of the stand columns, a heat-insulating cylinder (4) which can be installed on the stand columns in an opening and closing manner and can heat and insulate a tensile sample, a lower traction piece (6) vertically fixed on the base and with the upper end extending into the heat-insulating cylinder to provide downward traction force, a lower measurement assembly for measuring the displacement deformation quantity of the lower end of the tensile sample and a controller; the method is characterized in that: the extensometer also comprises an upper positioning piece (5) which is vertically fixed on the cross beam, the lower end of the upper positioning piece extends into the heat-insulating cylinder to fix the tensile sample, and an upper measuring component which is used for measuring the displacement deformation quantity of the upper end of the tensile sample; the upper positioning piece and the lower traction piece are mutually corresponding and coaxially arranged.

2. The novel high temperature creep-stretch extensometer of claim 1 wherein: the upper measuring assembly comprises an upper grating displacement indicating ruler (8) vertically fixed on the cross beam, an upper clamping claw (9) fixedly clamped with an upper boss on the periphery of the tensile sample, an upper guide rod (10) vertically and slidably penetrating through the top surface of the heat-insulating cylinder and an upper sleeve (11) arranged on the heat-insulating cylinder and sleeved on the periphery of the upper guide rod so as to vertically guide the upper guide rod; one end of the upper guide rod is fixedly connected with the upper clamping jaw, and the other end of the upper guide rod is matched with the tip of the upper grating displacement indicating ruler in an abutting mode.

3. The novel high temperature creep tensile extensometer of claim 2 wherein: the lower measuring assembly comprises a lower grating displacement indicating ruler (13) vertically fixed on the machine base, a lower clamping claw (14) fixedly clamped with a lower boss on the periphery of the tensile sample, a lower guide rod (15) vertically and slidably penetrating through the bottom surface of the heat-insulating cylinder and a lower sleeve (16) arranged on the heat-insulating cylinder and sleeved on the periphery of the lower guide rod so as to vertically guide the lower guide rod; one end of the lower guide rod is fixedly connected with the lower clamping claw, and the other end of the lower guide rod is matched with the tip of the lower grating displacement indicating ruler in an abutting mode.

4. The novel high temperature creep tensile extensometer of claim 3 wherein: the upper clamping claw and the lower clamping claw have the same structure; the upper clamping jaw and the lower clamping jaw respectively comprise a connecting piece (9-1) correspondingly connected with the upper guide rod or the lower guide rod, a U-shaped forked part (9-2) fixed on the connecting piece and fastening bolts (9-3) connected with the end parts of two sides of an opening of the U-shaped forked part; and a clamping groove (9-5) for accommodating an upper boss or a lower boss of the tensile sample is formed in the inner side of the opening of the U-shaped fork part.

5. The novel high temperature creep tensile extensometer of claim 4 wherein: one end of the upper guide rod, which abuts against the upper grating displacement indicating ruler, and one end of the lower guide rod, which abuts against the lower grating displacement indicating ruler, are both arranged into discs (12); the middle part of the lower guide rod is also provided with a limit boss (17) which can be clamped with the inner wall of the bottom surface of the heat-insulating cylinder.

6. The novel high temperature creep tensile extensometer of claim 5 wherein: the upper grating displacement indicating ruler and the lower grating displacement indicating ruler respectively comprise a scale grating, a grating reading head, a spring (8-1) vertically fixed at the tail end of the grating reading head, and a tip fixed at the tail end of the spring to correspondingly abut against the top guide rod or the lower guide rod.

7. The novel high temperature creep tensile extensometer of claim 6 wherein: the heat preservation cylinder is composed of two semi-cylindrical cylinders which are hinged with each other.

8. The novel high temperature creep tensile extensometer of claim 7 wherein: and the upper positioning piece and the lower traction piece are correspondingly and fixedly connected with two ends of the tensile sample through thread pairs.

9. The novel high temperature creep tensile extensometer of claim 8 wherein: the wall of the heat-insulating cylinder is made of steel materials; a hard heat-insulating material layer is arranged on the inner side of the cylinder wall; and a resistance wire is arranged in the heat-insulating cylinder so as to heat the tensile sample.

10. The novel high temperature creep tensile extensometer of claim 9 wherein: the upper positioning piece, the lower traction piece, the upper grating displacement indicating ruler, the lower grating displacement indicating ruler and the resistance wire are respectively and electrically connected with the controller.

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