Tension-shear test method for metal composite pipe

Abstract

The invention discloses a metal composite pipe tension-shear test method which comprises the following steps: step 1, respectively processing threaded sections at two ends of a metal composite pipe, and then thinning base metal of a middle section of the metal composite pipe to a composite interface, thinning the multi-layer metal on one side to a composite interface after a distance is spaced from the middle section, so as to obtain a test sample; 2, measuring the sizes of the test sample and the metal composite pipe obtained in the step 1; and step 3, centering the threaded sections at the two ends of the test sample obtained in the step 1 and a stretcher tool sleeve, rotating and screwing in, carrying out a tensile test to obtain the maximum tensile force of the test sample, and carrying out shear strength calculation. According to the test method, the test sample with the base layer and the composite layer thinned to the composite interface on the two sides is manufactured, the spacing distance is reserved between the thinned sections on the two sides, then the maximum tensile force is measured, the shear strength is calculated through a sectional area conversion method, and the test method is suitable for measuring the shear strength of the metal composite pipe.

Description

Technical Field

[0001] The invention belongs to the technical field of high-temperature and high-pressure corrosion-resistant equipment, and in particular relates to a metal composite pipe tensile shear test method. Background Art

[0002] With the continuous progress of modern industry, higher and higher requirements are placed on the performance of metal materials in many fields such as aerospace, electronics, and chemical industry. A single metal is often difficult to simultaneously meet multiple complex requirements such as high strength, high corrosion resistance, good electrical conductivity and thermal conductivity. Therefore, the development of composite materials with comprehensive performance advantages has become an important research direction in the field of materials science. In high temperature, high pressure, and corrosive environments, metal composite sheets or pipes are usually made of different metal materials through a specific process. Tensile shear tests on metal composite sheets or pipes can test the bonding strength between materials, evaluate the effect of the composite process, and determine whether the interface bonding is firm and whether there are defects.

[0003] At present, relevant institutions and researchers at home and abroad have developed shear test methods for composite metal plates such as titanium steel, stainless steel, nickel-based alloy steel and chrome steel, and have made detailed provisions for test equipment, sample preparation, test steps, result calculation, etc. However, there is no clear tensile shear test method for metal composite pipes. As one of the mechanical property tests that must be done for hollow pipes, tensile shear tests can explore the mechanical behavior of metal composite pipes under tensile shear, provide a basis for improving composite processes and optimizing material structures, and improve the overall performance of metal composite pipes. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the above-mentioned prior art and provide a tensile shear test method for metal composite pipes. The tensile shear test method is to make a test sample with the base layer and the composite layer thinned to the composite interface on both sides, and to retain a spacing distance between the thinned sections on both sides, so that the separate composite interface can be exposed to the greatest extent for tensile testing, and the shear strength is calculated by the cross-sectional area conversion method through the measured maximum tensile force, thereby solving the problem that there is no tensile shear test scheme for metal composite pipes in the prior art.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a metal composite pipe tensile shear test method, characterized in that the tensile shear test method comprises the following steps:

[0006] Step 1: Processing threaded sections at both ends of the metal composite pipe, then thinning the base metal of the middle section of the metal composite pipe to the composite interface, and after being separated from the middle section by a distance B, thinning the composite metal on one side to the composite interface to obtain a test sample;

[0007] Step 2, measuring the dimensions of the test sample and the metal composite pipe obtained in step 1;

[0008] Step 3: Align the threaded sections at both ends of the test sample obtained in step 1 with the tooling sleeve of the tensile machine, rotate and screw them in, and perform a tensile test to obtain the maximum tensile force F of the test sample. Calculate the shear strength τ using the following formula:

[0009]

[0010] Where τ is the shear strength in N / mm 2 ; F is the maximum tensile force of the test sample, in kN; B is the length of the interval distance in step 1, in mm; D is the inner diameter of the metal composite pipe, in mm; T is the thickness of the composite layer of the metal composite pipe, in mm.

[0011] The present invention processes a composite interface of the metal composite pipe, which is the weakest part of the metal composite pipe. Therefore, during the tensile test, the test sample breaks at the composite interface, and the tensile force of the composite interface of the test sample can be measured, and then the shear strength is calculated according to the formula.

[0012] The above-mentioned metal composite pipe tensile shear test method is characterized in that the metal composite pipe is sheared before the base metal is removed in step one, and the length of the composite metal pipe after shearing is 45mm to 50mm.

[0013] The test sample of the present invention is relatively short in length, and a plurality of test samples can be processed on one metal composite pipe to be tested, thereby obtaining more accurate tensile shear test data and effectively reducing the test cost.

[0014] The above-mentioned metal composite pipe tensile shear test method is characterized in that the thinning in step 1 is performed by lathe processing and a coaxial clamping method is adopted.

[0015] The present invention adopts a coaxial clamping method to ensure that the rotating axis and the metal composite pipe are coaxial during lathe processing, and the base metal or the composite metal is accurately thinned.

[0016] The above-mentioned metal composite pipe tensile shear test method is characterized in that the test sample and the metal composite pipe are surface cleaned before the measurement in step 2.

[0017] The present invention improves the accuracy of dimension measurement by cleaning the surfaces of the test sample and the metal composite pipe, thereby improving the reliability of the calculation result.

[0018] The above-mentioned metal composite pipe tensile shear test method is characterized in that the measurement method described in step 2 is: measuring with an inside micrometer and recording the inner diameter of the test sample at more than 4 test points along its circumference; measuring with a caliper and recording the width of the test sample at more than 4 test points along its circumference.

[0019] The above-mentioned metal composite pipe tensile shear test method is characterized in that the width of B in step three is 1.5T, and B is less than 3 mm.

[0020] The present invention can control the width of the composite interface of the test sample by controlling the width at B, thereby improving the measurement accuracy of the tensile force of the composite interface.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. The present invention makes a test sample with the base layer and the composite layer thinned on both sides to the composite interface, and retains a spacing distance between the thinned parts on both sides, so that the separate composite interface can be exposed to the maximum extent for tensile testing. The shear strength of the composite interface is calculated by the measured maximum tensile force, and the shear strength is the minimum value of the shear strength of the metal composite pipe itself.

[0023] 2. The present invention processes threaded sections on the surfaces of both ends of the test sample so that the test sample can be threadedly connected to the stretching machine, effectively improving the coaxiality between the test sample and the stretching fixture, thereby ensuring the accuracy and effectiveness of the stretching data; at the same time, when performing thinning processing of base metal and composite metal, the threaded section is also convenient for connection with lathes and other equipment to improve coaxiality and thus improve processing accuracy.

[0024] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the test sample structure of the metal composite pipe of the present invention. DETAILED DESCRIPTION

[0026] Example 1

[0027] The tensile shear test method of this embodiment comprises the following steps:

[0028] Step 1: Shear the metal composite tube to obtain a metal composite tube with a length of 46 mm, process threaded sections at both ends of the metal composite tube, and then coaxially clamp the metal composite tube, and use a lathe to thin the base metal of the middle section to the composite interface, and thin the composite metal on one side to the composite interface after being spaced apart from the middle section by a distance B, to obtain the following: Figure 1 Test samples shown;

[0029] Step 2: Measure the dimensions of the test sample and the metal composite pipe obtained in step 1, and measure that B is 1.93 mm, D is 12.3 mm, and T is 1.29 mm; the measuring method is: measure with an inside micrometer and record the inner diameter of more than 4 test points of the test sample along its circumference, and measure with a caliper and record the remeasured width of more than 4 test points of the test sample along its circumference;

[0030] Step 3: Align the threaded sections at both ends of the test sample obtained in step 1 with the tooling sleeve of the tensile machine, rotate and screw them in, and perform a tensile test. The maximum tensile force F of the test sample is 10.87 kN, and the shear strength τ is calculated by the following formula:

[0031]

[0032] Example 2

[0033] The tensile shear test method of this embodiment comprises the following steps:

[0034] Step 1: Cut the metal composite tube to obtain a metal composite tube with a length of 50 mm, process threaded sections at both ends of the metal composite tube, and then coaxially clamp the metal composite tube, and use a lathe to thin the base metal of the middle section to the composite interface, and then thin the composite metal on one side to the composite interface after being spaced apart from the middle section by a distance B, to obtain the following: Figure 1 Test samples shown;

[0035] Step 2: Measure the dimensions of the test sample and the metal composite pipe obtained in step 1, and measure that B is 2.07 mm, D is 12.08 mm, and T is 1.38 mm; the measuring method is: measure with an inside micrometer and record the inner diameter of more than 4 test points of the test sample along its circumference, and measure with a caliper and record the remeasured width of more than 4 test points of the test sample along its circumference;

[0036] Step 3: Align the threaded sections at both ends of the test sample obtained in step 1 with the tooling sleeve of the tensile machine, rotate and screw them in, and perform a tensile test. The maximum tensile force F of the test sample is 10.40 kN, and the shear strength τ is calculated by the following formula:

[0037]

[0038] Example 3

[0039] The difference between this embodiment and embodiment 2 is that the length of the metal composite tube cut out in step 1 is 45 mm.

[0040] The measured values ​​of B are 2.06 mm, D is 12.08 mm, T is 1.37 mm, and the maximum tensile force F is 10.39 kN. The shear strength τ is calculated by the following formula:

[0041]

[0042] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural transformation made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A metal composite pipe tensile shear test method, characterized in that: The tensile shear test method comprises the following steps: Step 1: Processing threaded sections at both ends of the metal composite pipe, then thinning the base metal of the middle section of the metal composite pipe to the composite interface, and after being separated from the middle section by a distance B, thinning the composite metal on one side to the composite interface to obtain a test sample; Step 2, measuring the dimensions of the test sample and the metal composite pipe obtained in step 1; Step 3: Align the threaded sections at both ends of the test sample obtained in step 1 with the tooling sleeve of the tensile machine, rotate and screw them in, and perform a tensile test to obtain the maximum tensile force F of the test sample. Calculate the shear strength τ using the following formula: Where τ is the shear strength in N / mm 2 ; F is the maximum tensile force of the test sample, in kN; B is the length of the interval distance in step 1, in mm; D is the inner diameter of the metal composite pipe, in mm; T is the thickness of the composite layer of the metal composite pipe, in mm.

2. A metal composite pipe tensile shear test method according to claim 1, characterized in that: In step 1, the metal composite tube is sheared before the base metal is removed, and the length of the composite metal tube after shearing is 45 mm to 50 mm.

3. A metal composite pipe tensile shear test method according to claim 1, characterized in that: The thinning in step 1 is performed by lathe processing and coaxial clamping is adopted.

4. A metal composite pipe tensile shear test method according to claim 1, characterized in that: Before the measurement in step 2, the surfaces of the test sample and the metal composite pipe are cleaned.

5. A metal composite pipe tensile shear test method according to claim 1, characterized in that: The measurement method described in step 2 is: use an inside micrometer to measure and record the inner diameter of the test sample at more than 4 test points along its circumference, and use a caliper to measure and record the width of the test sample at more than 4 test points along its circumference.

6. A metal composite pipe tensile shear test method according to claim 1, characterized in that: The width of B in step 3 is 1.5T, and B is less than 3 mm.

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