CN108956702A - A kind of nail-free riveting joint quality checking method of metal material - Google Patents

Abstract

The present invention is a kind of nail-free riveting joint quality checking method of metal material, the following steps are included: establishing quality detecting system, using D.C. resistance test machine, using the method measured according to four electrode resistances, resistance test machine will provide the instantaneous voltage of the Constant Direct Current current measurement different phase connector of certain current strength, initial resistance and the connection resistance in different punching press stages before calculating connector riveting, to rivet the initial resistance of front connector as benchmark resistance, calculate the resistance delta of different punching press stage connectors, repeat preparation multiple groups tool joint monitor, statistics obtains connection resistance increment, relationship between connector defect and bonding strength, utilize the material resistance feature sensitive to material internal defect, pass through on-line checking, resistance variations of the comparison riveting material in riveting process, to realize the reliable inspection of nail-free riveting joint quality It surveys.

Description

A quality inspection method for nailless riveted joints of metal materials

technical field

The invention relates to a quality detection method for riveted joints, in particular to a quality detection method for nailless riveted joints of metal materials.

Background technique

With the development of the times and the progress of society, more and more joints of metal materials are connected by nailless riveting. In the existing technology, there are two methods for testing the quality of nailless riveting joints. One is offline detection. The advantage of this detection method is that it is simple to operate and easy to implement. Its disadvantage is that the range of manual spot checks is too small to ensure that the quality of all joints meets the requirements, and there are certain errors in manual measurement. The tensile failure test will increase the production cost. The other is on-line detection. However, in actual production, the material usually undergoes a certain processing deformation before connection. This processing deformation will cause changes in the mechanical properties of the material, affecting Detection accuracy.

Contents of the invention

Aiming at the problems existing in the above-mentioned prior art, the present invention provides a quality inspection method for nailless riveted joints of metal materials, which utilizes the characteristic that material resistance is sensitive to internal defects of materials, and compares the resistance change of riveting materials during the riveting process through online detection and comparison , so as to realize the reliable detection of the quality of nailless riveted joints.

In order to achieve the above object, the present invention is achieved through the following technical solutions: a method for detecting the quality of a nailless riveted joint of metal materials, comprising the following steps:

(1) Establish a quality inspection system, including but not limited to data acquisition unit, data analysis unit and quality control unit;

(2) According to step (1), the data acquisition unit is connected with the riveting machine and the quality control unit respectively;

(3) According to step (2), the data control unit can make single-chip microcomputer, industrial computer or numerical control system, and the data transmission collected is stored in single-chip microcomputer, industrial computer or numerical control system;

(4) According to step (3), the data acquisition can use but not limited to DC resistance testing machine, and its four electrodes are firmly fixed on the joint riveting part according to the method of four-electrode resistance measurement, wherein the positive voltage electrode and current electrode Fixed on one side of the upper plate, the negative voltage pole and current pole are fixed on the other side of the lower plate;

(5) During the connection process, starting from the punch contacting the upper plate, the resistance testing machine will provide a constant DC current of a certain current, measure the instantaneous voltage of the joint at different stamping stages, transmit and store it in the single-chip microcomputer, industrial computer or numerical control system, and sent to the data analysis unit;

(6) According to step (5), the data analysis unit performs data analysis on the data collected by the data acquisition unit. The data analysis unit can be written in general computer programming languages such as but not limited to C, C++, VB and VC, including but not limited to data Functions such as calculation, analysis, feedback, graph and table display;

(7) Substituting the voltage value measured in step (5) into the data analysis in step (6), calculate the initial resistance before joint riveting and the joint resistance of different stamping stages;

(8) According to the initial resistance of the joint calculated in step (7) and the resistance at different stamping stages, the initial resistance of the joint before riveting is used as the reference resistance to calculate the joint at different stamping stages;

(9) Detect the quality of the nailless riveted joint after riveting, and perform a shear tensile test;

(10) According to the resistance increment, joint defect and joint strength calculated in step (8) and step (9), the relationship between statistical joint resistance increment, joint defect and connection strength;

(11) Repeatedly prepare multiple groups of joints, and determine the joint resistance incremental threshold of qualified joints according to the data analysis in step (10), and input them into the quality inspection unit;

(12) The quality inspection unit is respectively connected with the data acquisition unit, the data analysis unit and the riveting machine, and has the functions of measurement data input, quality criterion input, data comparison, quality evaluation, result output, display and alarm;

(13) Input the joint resistance incremental threshold value obtained in step (11) into step (12), and compare the resistance change of the riveting material during the riveting process online and compare it with the resistance incremental threshold value in real time.

Further, in the step (4), the position of the joint is located on the diagonal of a pair of voltage poles or current poles.

Further, when measuring the riveted joints, ensure that the voltage pole is located 4-7 mm outside the overlapping portion of the upper and lower plates, and the current pole is located 9-13 mm outside the voltage pole when measuring all the riveted joints.

Further, when the riveted joints are measured, it is ensured that the voltage pole is located at ≤ 5 mm outside the overlapping part of the upper and lower plates, and the current pole is located at ≤ 10 mm outside the voltage pole when measuring all the riveted joints. Glue fixed;

The beneficial effect is that the material resistance is sensitive to internal defects of the material, and the reliable detection of the quality of the nailless riveted joint is realized through online detection and comparison of the resistance change of the riveted material during the riveting process.

Detailed ways

A method for detecting the quality of a nailless riveted joint of metal materials, comprising the following steps:

(1) Establish a quality inspection system, including but not limited to data acquisition unit, data analysis unit and quality control unit;

(2) According to step (1), the data acquisition unit is connected with the riveting machine and the quality control unit respectively;

(3) According to step (2), the data control unit can make single-chip microcomputer, industrial computer or numerical control system, and the data transmission collected is stored in single-chip microcomputer, industrial computer or numerical control system;

(4) According to step (3), the data acquisition can use but not limited to DC resistance testing machine, and its four electrodes are firmly fixed on the joint riveting part according to the method of four-electrode resistance measurement, wherein the positive voltage electrode and current electrode Fixed on one side of the upper plate, the negative voltage pole and current pole are fixed on the other side of the lower plate;

(5) During the connection process, starting from the punch contacting the upper plate, the resistance testing machine will provide a constant DC current of a certain current, measure the instantaneous voltage of the joint at different stamping stages, transmit and store it in the single-chip microcomputer, industrial computer or numerical control system, and sent to the data analysis unit;

(6) According to step (5), the data analysis unit performs data analysis on the data collected by the data acquisition unit. The data analysis unit can be written in general computer programming languages such as but not limited to C, C++, VB and VC, including but not limited to data Functions such as calculation, analysis, feedback, graph and table display;

(7) Substituting the voltage value measured in step (5) into the data analysis in step (6), calculate the initial resistance before joint riveting and the joint resistance of different stamping stages;

(8) According to the initial resistance of the joint calculated in step (7) and the resistance at different stamping stages, the initial resistance of the joint before riveting is used as the reference resistance to calculate the joint at different stamping stages;

(9) Detect the quality of the nailless riveted joint after riveting, and perform a shear tensile test;

(10) According to the resistance increment, joint defect and joint strength calculated in step (8) and step (9), the relationship between statistical joint resistance increment, joint defect and connection strength;

(11) Repeatedly prepare multiple groups of joints, and determine the joint resistance incremental threshold of qualified joints according to the data analysis in step (10), and input them into the quality inspection unit;

(12) The quality inspection unit is respectively connected with the data acquisition unit, the data analysis unit and the riveting machine, and has the functions of measurement data input, quality criterion input, data comparison, quality evaluation, result output, display and alarm;

(13) Input the joint resistance incremental threshold value obtained in step (11) into step (12), and compare the resistance change of the riveting material during the riveting process online and compare it with the resistance incremental threshold value in real time.

In the step (4), the position of the joint is located on the diagonal of a pair of voltage poles or current poles, which ensures that the current passes through the deformation area during the connection process, and accurately measures the change of resistance with the deformation of the material.

When measuring the riveted joints, it is ensured that the voltage pole is located 4-7mm outside the overlapping portion of the upper and lower plates, and the current pole is located 9-13mm outside the voltage pole when measuring all the riveted joints, which ensures the accuracy of the measurement.

When measuring the riveted joints, ensure that the voltage pole is located at ≤ 5 mm outside the overlapped part of the upper and lower plates, and the current pole is located at ≤ 10 mm outside the voltage pole when measuring all the riveted joints. The electrodes are all fixed with conductive glue. It is obtained through experiments that the measurement accuracy at this time is the highest.

Claims (4)

1. a nailless riveted joint quality detection method of metal material, is characterized in that, comprises the following steps: (1) Establish a quality inspection system, including but not limited to data acquisition unit, data analysis unit and quality control unit; (2) According to step (1), the data acquisition unit is connected with the riveting machine and the quality control unit respectively; (3) According to step (2), the data control unit can be a single-chip microcomputer, an industrial computer or a numerical control system, and the collected data is transmitted and stored in the single-chip microcomputer, an industrial computer or a numerical control system; (4) According to step (3), the data acquisition can use but not limited to DC resistance testing machine, and its four electrodes are firmly fixed on the joint riveting part according to the method of four-electrode resistance measurement, wherein the positive voltage electrode and current electrode Fixed on one side of the upper plate, the negative voltage pole and current pole are fixed on the other side of the lower plate; (5) During the connection process, starting from the punch contacting the upper plate, the resistance testing machine will provide a constant DC current of a certain current, measure the instantaneous voltage of the joint at different stamping stages, transmit and store it in the single-chip microcomputer, industrial computer or numerical control system, and sent to the data analysis unit; (6) According to step (5), the data analysis unit performs data analysis on the data collected by the data acquisition unit. The data analysis unit can be written in general computer programming languages such as but not limited to C, C++, VB and VC, including but not limited to data Functions such as calculation, analysis, feedback, graph and table display; (7) Substituting the voltage value measured in step (5) into the data analysis in step (6), calculate the initial resistance before joint riveting and the joint resistance of different stamping stages; (8) According to the initial resistance of the joint calculated in step (7) and the resistance at different stamping stages, the initial resistance of the joint before riveting is taken as the reference resistance, and the resistance increment of the joint at different stamping stages is calculated; (9) Detect the quality of the nailless riveted joint after riveting, and perform a shear tensile test; (10) According to the resistance increment, joint defect and joint strength calculated in step (8) and step (9), the relationship between statistical joint resistance increment, joint defect and connection strength; (11) Repeatedly prepare multiple groups of joints, and determine the joint resistance incremental threshold of qualified joints according to the data analysis in step (10), and input them into the quality inspection unit; (12) The quality inspection unit is respectively connected with the data acquisition unit, the data analysis unit and the riveting machine, and has the functions of measurement data input, quality criterion input, data comparison, quality evaluation, result output, display and alarm; (13) Input the joint resistance incremental threshold value obtained in step (11) into step (12), and compare the resistance change of the riveting material during the riveting process online and compare it with the resistance incremental threshold value in real time. 2 . The method for detecting the quality of a nailless riveted joint of metal materials according to claim 1 , wherein the position of the joint in the step (4) is located on the diagonal of a pair of voltage poles or current poles. 3 . 3. The method for detecting the quality of a nailless riveted joint of a metal material as claimed in claim 1, wherein the riveted joints ensure that the voltage poles of all riveted joints are located at the overlapping of the upper and lower plates during measurement. 4-7mm outside the part, and the current pole is located 9-13mm outside the voltage pole. 4. The method for detecting the quality of a nailless riveted joint of a metal material as claimed in claim 1, wherein the riveted joints ensure that the voltage poles of all riveted joints are located at the overlapping of the upper and lower plates during measurement. ≤5mm outside the part, and the current pole is located at ≤10mm outside the voltage pole, and the electrodes are all fixed with conductive glue.