CN-122016506-A - Calculation method for area reduction rate of round bar-shaped metal material

Abstract

The invention relates to the technical field of material experiments, in particular to a calculation method of the reduction of area of a round bar-shaped metal material, which comprises the steps of taking a tensile sample with a round bar-shaped section for a high-temperature tensile experiment, selecting one of two sections of samples broken by the high-temperature tensile experiment, taking the straight line of the diameter of a fracture section circle as an x axis, taking the straight line of the axis of the sample as a y axis, and establishing a rectangular coordinate system, wherein the side surface of the broken sample presents a curve in the established rectangular coordinate system, determining the total length, the total elongation and half of the original length of the two sections of samples before the whole sample is deformed, and calculating the reduction of area.

Inventors

• ZHAO BAOCHUN
• HUANG LEI
• YUAN HUI
• MA HUIXIA
• WANG XIAOFENG
• Tian Huijie

Assignees

• 鞍钢股份有限公司

Dates

Publication Date

20260512

Application Date

20260209

Claims (4)

1. 1. The method for calculating the area reduction rate of the round bar-shaped metal material is characterized by comprising the following steps of: s1, taking a tensile sample with a round bar-shaped section for high-temperature tensile experiment, wherein the radius of the round bar-shaped section of the sample is Length of ; S2, selecting one of two sections of samples broken by a high-temperature tensile test, taking a straight line where the diameter of a fracture section circle is located as an x axis, taking a straight line where the axis of the sample is located as a y axis, and establishing a rectangular coordinate system, wherein the side surface of the broken sample presents a curve in the established rectangular coordinate system; S3, determining the characteristic length; The total length of the two sections of samples is When the test piece is broken by stretching, the total elongation is Then Half of it is I.e. =2 ; Taking one of the two broken samples for analysis, wherein the original length of the sample before deformation is half of the original length of the whole sample before deformation, and setting the original length as The original length of the whole sample before deformation is 2 ; S4, calculating the area reduction rate; ; Wherein, the The shrinkage of the sample was measured.
2. 2. The method for calculating the reduction of area of a round bar-shaped metal material according to claim 1, wherein one of two broken samples is taken for analysis, the original length of the sample before deformation is half of the original length of the whole sample before deformation, and the relationship between the curve equation of the side surface of the broken sample in an established rectangular coordinate system and the volumes of the tensile samples participating in deformation before and after deformation is unchanged, The calculation formula is as follows: ; Wherein, the The radius of the cross-section circle at the fracture site of a selected one of the two fracture specimens.
3. 3. The method for calculating the reduction of area of a round bar-shaped metal material according to claim 2, wherein the curve equation of the side surface of the broken sample in the established rectangular coordinate system is: ; Wherein, the Is a constant to be determined; The coordinates of the curve equation passing through two points are respectively ,0)、( , + ) Then solve for the undetermined constant : ; 。
4. 4. The method for calculating the reduction of area of a round bar-shaped metal material according to claim 3, wherein the volume of the tensile sample participating in the deformation is unchanged before and after the deformation, and the method is characterized by comprising the following formula: ; Wherein, the To assist in the raw volume calculation of the deformed sample portion, The formula is calculated for the volume of the portion of the sample after deformation.

Description

Calculation method for area reduction rate of round bar-shaped metal material Technical Field The invention relates to the technical field of material experiments, in particular to a calculation method of the reduction of area of a round bar-shaped metal material. Background The high-temperature tensile test can reflect the comprehensive influence of external force and temperature on the performance of the metal material. In scientific experiments or accident analysis, it is necessary to know the characteristic values, characteristic curves, such as maximum stress, reduction of area, elongation, true stress-true strain curves, etc., of the material at various temperatures. At present, a thermal simulation testing machine is generally adopted, a sample is heated to a high temperature area according to the continuous casting process of a casting blank, the temperature is maintained for a period of time in the high temperature area, then the temperature is reduced to a certain temperature, finally, high-temperature stretching is carried out at a certain stretching rate until the sample is broken, and the cross section area of the broken sample is analyzed, so that the reduction of area is obtained, and the plasticity of the casting blank in the continuous casting process is studied. Because the material has certain fluidity in a high-temperature state, and the temperature distribution of the sample has a certain gradient when the sample is heated by the thermal simulation tester, the whole sample does not participate in deformation when the sample is deformed in a stretching way, and the performance of the sample is more obvious on the resistance type thermal simulation tester. If the sample deformation is considered to be uniform during the calculation of the reduction of area, larger errors are necessarily generated, and the quality of the plasticity of the continuous casting billet has close relation with whether the casting billet generates cracks after the continuous casting to the bending and straightening process, therefore, the accurate calculation of the reduction of area of the sample after the fracture is important. The patent with the application number 201110081820.4 is a clamping device for measuring the elongation after breaking and the reduction of area of a columnar tensile sample, the broken sample is centered and fastened together by designing a set of device, and then related measurement is carried out by adopting a vernier caliper. The adopted method for calculating the reduction of area is also to reduce the systematic error through the optimization design of the device, and meanwhile, the method possibly has accidental errors introduced by a measurer, and the result is inconsistent. These methods for calculating the reduction of area are all based on specific measuring devices, and the measured numerical precision of the reduction of area is closely related to the measuring precision of the devices. Therefore, the systematic error caused by measuring the fracture cross section of the sample by using the measuring device is avoided, the reduction of area of the high-temperature tensile sample is rapidly and accurately calculated, and a better measuring and calculating method is required to be developed. Disclosure of Invention The invention provides a calculation method of the area shrinkage of a round bar-shaped metal material, which can rapidly and accurately calculate the area shrinkage of a sample after being broken, and a specific measuring device is not needed to be used, so that a foundation is laid for analyzing high-temperature stretching data of the material. In order to achieve the above purpose, the invention is realized by adopting the following technical scheme: a calculation method for the area reduction rate of a round bar-shaped metal material comprises the following steps: s1, taking a tensile sample with a round bar-shaped section for high-temperature tensile experiment, wherein the radius of the round bar-shaped section of the sample is Length of ; S2, selecting one of two sections of samples broken by a high-temperature tensile test, taking a straight line where the diameter of a fracture section circle is located as an x axis, taking a straight line where the axis of the sample is located as a y axis, and establishing a rectangular coordinate system, wherein the side surface of the broken sample presents a curve in the established rectangular coordinate system; S3, determining the characteristic length; The total length of the two sections of samples is When the test piece is broken by stretching, the total elongation isThenHalf of it isI.e. =2 ; Taking one of the two broken samples for analysis, wherein the original length of the sample before deformation is half of the original length of the whole sample before deformation, and setting the original length asThe original length of the whole sample before deformation is 2 ; S4, calculating the area reduction rate; ;