The bending test of metal is a widely used test method in the field of metal shape and size control. It can be used to measure the load-bearing capacity, plastic deformation and springback of various metal materials. As an important detection method of metal materials, bending test has a certain influence on the quality assessment and determination of metal materials. This article introduces the main technical parameters of the GB232-88 metal bending test method and related precautionary measures for the bending test of metal materials.
GB232-88 Metal Bending Test Method was formulated in 1988 by the National Quality Supervision and Inspection Bureau, which specifies the basic requirements for the test of metal shape and size control. It mainly includes the specific steps and attention matters in the process of bending test, so as to ensure the randomness, fairness and accuracy of the test results.
The metal bending test of GB232-88 consists of three parts: sample preparation, bending process, measurement and calculation. Sample preparation mainly includes sample size requirements, test setup and pre-bending inspection. The bending process mainly includes three parts: bending, jigging and cold correction. The measurement and calculation mainly includes the determination of the angle deviation, the calculation of the bending angle, the calculation of the bending load and the verification of the springback.
1. Sample preparation
First of all, the size of the sample needs to meet the requirements of GB232-88, and the length should not be less than 0.7 mm, and the width and thickness should meet the requirements of specific product forms. The metal samples should be placed in the bending die and jigged in a specified position before testing, and then pre-bent inspection should be carried out to ensure that the metal sample is not distorted before bending test.
2. Bending process
In the bending process, three main operations should be carried out, including bending the sample to the specified angle in the specified direction with the specified speed, correcting the deformation which occurs in the selection process of the dies, and manually correcting the residual deformation according to small scales.
3. Measurement and calculation
First of all, observe the angle deviation of the sample after bending, and then use a protractor or a vernier caliper to measure and calculate the bending angle. Subsequently, the bending force is measured, corrected and calculated to determine the load on the sample surface at a certain angle of bending. Finally, the springback calculation needs to be done to verify the angle deviation of the bending sample to ensure its reliability.
Precautions for metal bending test
1. Clean the metal surface before testing;
2. Use die inserts, counter plates and scale rulers to ensure accuracy;
3. Ensure that the original angle is correct, and the direction of bending should not be changed;
4. Carry out the whole process in accordance with GB232-88 to ensure fairness of the bend test;
5. Pay attention to the springback angle when doing the correction, so as to ensure the accuracy of the measurement results.
In summary, the GB232-88 metal bending test method is widely used in metal shape and size control. It is necessary to pay attention to the bending test process and relevant precautions during the test process, so as to ensure the accuracy and fairness of the test results.
