Pure bending test system and test method for thin-gauge high-strength automotive steel

Abstract

The invention discloses a pure bending test system for automobile steels having thin gauge and high strength and a test method. The system comprises two sets of clamps symmetrically arranged, a forcesensor, and a set of laser displacement test device; each set of clamps comprises a clamp body, a baffle fixed at the bottom of a working side of the clamp body, and a connection slot formed in the working side of the clamp body; the laser displacement test device comprises a chute, n laser displacement rangefinders arranged on the chute, and n + 1 springs arranged on the chute, wherein n is an odd number; n laser displacement rangefinders are equidistantly and symmetrically arranged on the chute between two inner sides of the baffle; and each adjacent two laser displacement rangefinders are connected through the spring, and the laser displacement rangefinder close to the baffle is connected with the inner side of the baffle through the spring. According to the pure bending test system forautomobile steels having thin gauge and high strength and the test method, only the axial force is generated in the whole process, a shear stress is completely avoided, the shear stress interferenceduring the conventional bending test is avoided, and the bending performance of the material is better reflected.

Description

technical field [0001] The invention belongs to the technical field of cold-bending forming performance testing of thin-gauge high-strength metal materials, and specifically refers to a pure-bending test system and testing method for thin-gauge high-strength automotive steel. Background technique [0002] Cold-bending is the most important forming method of high-strength automotive steel. It is generally used to produce key structural parts of automobiles. A steel plate is finally formed into the required part state through multi-pass rolling of rolls. The pass process of rolling is called roll flower, which reflects the process and forming angle of cold forming. Different from general stamping forming: First, the load of cold-formation is mainly bending load, and the tonnage of the required press is small, which is especially suitable for the forming of high-strength steel; second, cold-formation has a smaller Springback, with better part manufacturing precision. With the...

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Problems solved by technology

[0005] At present, the pure bending test solution has the following technical defects: 1. Axial compression of the bending sample is a better solution, but the constraint of the sample fixture on the sample will cause the stress concentration of the sample at the jaw of the fixture, resulting in The sample breaks at the jaws of the fixture in advance; 2. Four-point bending is another solution. The action of the two application points in the middle causes the shear stresses to cancel each other out, and the pure bending is produced in the interval between the two application points in the middle. This method is more suitable for samples with small deflection and high rigidity. It can be approximated that the stress state of the sample is pure bending. However, for thin steel plates with low rigidity, the sample deforms under the action of force. Larger, geometric approximation conditions no longer exist, still subject to interference from fixture constraints, and cannot be equivalent to pure bending load; 3. The traditional bending test can only obtain the curve of force and beam displacement, and cannot measure the bending moment in real time. At the same time, information such as the deflection of the plate bending cannot be obtained, and these process parameters are crucial for determining the bending of the material

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