Device and method for simultaneously testing bending limit and resilience value of magnesium alloy strip material

Abstract

The invention provides a device and a method for simultaneously testing the bending limit and resilience value of a magnesium alloy strip material. The device comprises a three-point bending mold device arranged on a stretcher, a strip fixing device and a tension system; a roller and an upper pressure head are assembled together; the strip fixing device is formed by a trough type supporting seat and a fixed end clamp; the tension system comprises a tension end clamp, a guide wheel supporting seat and a connecting rope, a thermal radiation plate is positioned between two roller seats, and the roller and other parts are positioned in an insulating cover. The method comprises the following steps: (1) heating the strip material, putting into the three-point bending mold device, fixing and applying tension respectively at two ends; (2) controlling the testing temperature of magnesium alloy; (3) starting the stretcher, and acquiring the bending limit according to the stress, strain and pressure head stroke curve; and (4) unloading the upper pressure head, and acquiring the resilience value according to the stroke reading. According to the device and method, the performance, bending limitand resilience of strip materials with different bending curvatures can be measured in one test.

Description

technical field [0001] The invention belongs to the technical field of material bending performance testing, and in particular relates to a device and method for simultaneously testing the bending limit and springback of a magnesium alloy plate and strip. Background technique [0002] Magnesium alloy sheets are widely used in aviation, transportation and electronics industries due to their low density, high specific strength, and good electromagnetic shielding properties. Rolling of magnesium alloy sheets can greatly save space and facilitate transportation, and post-rolling leveling and rolling put forward higher requirements on the bending properties of magnesium sheets. [0003] There are V-shaped bending, three-point bending and four-point bending test methods for sheet metal bending performance; V-shaped bending test needs to be equipped with a V-shaped mold and a bending indenter V-shaped device, three-point bending test needs to be equipped with two A support roller ...

AI Technical Summary

Problems solved by technology

[0004] The traditional V-shaped bending test method is formed by bending on a fixed bending mold, and only one bending angle can be formed at a time, so the utilization rate of the mold is low; it is found through searching the prior art that Chinese patent document number CN203508756 U , public date 2014.04.02, discloses a new technology for improving V-shaped bending dies, including upper and lower dies, upper and lower die bases, upper and lower die support plates, pins, bolts, guide posts and guide sleeves, etc.; The new V-shaped bending mold can adjust the angle of the mold according to different test conditions, which improves the utilization rate of the mold; but it is still impossible to test the bending performance of plates with different curvatures in one bending test

[0005] The three-point bending test method is to use different diameters of rounded upper punches to bend the sheet to a specific angle, and take the minimum radius when there are no cracks on the surface as the bending performance evaluation index; whether it is the traditional unloading pressure, take the piece to observe Cracks, or real-time observation of cracks under pressure, is to bend the plate to an angle, that is, a curvature, and it is impossible to test the bending performance of plates with different curvatures; the four-point bending test method is similar to the three-point bending test method, and the two upper support rollers Bending to a certain angle, only the two upper support rollers can effectively reduce the influence of the shear stress in the plate, and the measured strength is pure bending; but the four-point bending test method also bends the material to a specified angle, which cannot Test the bending properties of plates with different bending curvatures

The above bending methods only obtain the bending properties of the plate, and do not establish a relationship with the leveling and curling properties, bending limit and springback of the plate

Images