A method for measuring the percentage elongation after fracture and the percentage reduction of area after fracture of a tensile sample

Abstract

The invention belongs to the technical field of detection methods, and particularly provides a method for measuring the percentage elongation after fracture and the percentage reduction of area afterfracture of a tensile sample. The method includes (1) putting two segments after fracture of the tensile sample into a rotary clamp in order; (3) achieving tensile sample clamping and rotation by utilizing a control cabinet, and photographing labeled-distance segments after fracture of the tensile sample in order by utilizing a microphotograph system; (3) joining the two segments, on different images, after fracture of the tensile sample to make fractures completely compatible; and (4) measuring the pixel lengths of the labeled-distance segments and the fracture, and performing conversion according to a relationship, obtained by calibration before measurement, between the pixel length and the actual dimension to obtain the minimum actual diameter dimensions of the labeled-distance segmentsand the fracture, thus obtaining the percentage elongation after fracture and the percentage reduction of area after fracture. Through the method, the percentage elongation after fracture and the percentage reduction of area after fracture can be measured through simple operation under the premise of not destroying the fracture, and the method is particularly suitable for measurement of toxic harmful failure tensile samples.

Description

technical field [0001] The invention belongs to the technical field of detection methods, and relates to a method for measuring the elongation after fracture and the reduction of area of ​​a tensile sample. Background technique [0002] Tensile properties are the basic mechanical properties of materials. Performance characterization parameters such as plasticity and strength of materials can be obtained through tensile tests, mainly including: elongation after fracture (A), reduction of area (Z), yield strength and tensile strength, etc. Among them, A and Z are important parameters to characterize the plasticity of materials. [0003] like figure 1 As shown, when measuring A and Z, it is generally necessary to overlap and butt the tensile fractures 21 of the two parts of the disconnected material first, and the tensile fractures 21 must be completely overlapped and the cross-sections are coaxial during the butt joint, so as to achieve composite tensile failure. The overall...

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Problems solved by technology

[0005] (1) When the tensile fracture 21 is butted and replicated manually, the inevitable contact and friction between the tensile fractures 21 will damage the shape of the tensile fracture 21 of the sample, thereby affecting the subsequent tensile fracture 21. micro analysis;

[0006] (2) When manually operating the butt joint of the tensile fracture 21, the requirements for the operator's operating skills and working conditions are high. If the butt joint operation of the tensile fracture 21 is too tight, too loose, or out of axis, there will be problems caused by human operation. deviation;

[0007] (3) For some special, toxic and harmful tensile failure samples, such as radioactive samples and corrosion samples, manual operation cannot be performed because the samples are harmful to the human body

[0009] (1) Damage to the specimen fracture cannot be avoided during device operation;

[0010] (2) The device needs to be operated by test personnel, so it is only suitable for the operation of ordinary materials, and cannot be applied to the operation of toxic and harmful samples, such as radioactive samples and corrosive samples;

[0011] (3) The operation of the device is relatively simple for the test personnel, but it is still relatively complicated for the automatic auxiliary device. incapable of acting

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