Determination method for cupping value of metal material and die

Abstract

The invention discloses a determination method for the cupping value of a metal material and a die. The method comprises the following steps: 1) tightly pressing a test sample, specifically, selecting a proper periphery-pressing force according to the tensile strength of a metal test sample, and tightly pressing the periphery of the test sample by the periphery-pressing force, so as to prevent the flowing of the periphery material of the test sample; 2) stamping the test sample, specifically, lubricating the central part of the test sample by bonding lubricating grease with a polyethylene film, and then stamping the central part by a plunger chip at stamping speed of 0.5-2.0 mm/s; 3) determining the cupping value, specifically, in the stamping process, when a stamping-driving force is reduced by 1-6 kN, stopping stamping, at the moment, a plunger chip displacement corresponding to the maximum stamping-driving force is the cupping value. The die is provided with mutually matched brake beads on a press die and a cushion die. According to the determination method and the die disclosed by the invention, the influence of the periphery-pressing force, the lubricating agent and the stamping speed on the test of the cupping value is adequately considered, quantitative control is performed on crack judgement, and the flowing of the periphery material of the test sample is further prevented by optimizing the structure of the die, thus improving the accuracy of the test result.

Description

technical field [0001] The invention relates to metallurgical testing technology, in particular to a method for measuring the cupping value of metal materials and a mold thereof. Background technique [0002] The Ericson cupping test method (GB / T4156-2007) is a test method for determining the plastic deformation capacity of metal sheets and strips during drawing forming. The principle is to place a punch with a spherical end on the Stamping is carried out with a metal sample clamped in the pad die and the die to form a dent until a penetrating crack appears. At this time, the depth of the dent measured according to the displacement of the punch is the cupping value, and then The cupping value is used as a performance index to judge the ultimate deep-drawing performance of the metal. The larger the cupping value, the better the deep-drawing performance of the material. However, when measuring the cupping value with the standard method of the Ericsson cupping test, there are ...

AI Technical Summary

Problems solved by technology

However, when measuring the cupping value with the standard method of the Ericsson cupping test, there are shortcomings in the accuracy of the cupping value test results, poor stability, and poor comparability and repeatability. These shortcomings are specifically reflected as follows: When materials are tested for cupping value, sometimes there will be test results that are contrary to the actual situation. For example, the cupping value of duplex steel measured by standard methods is greater than that of IF steel, which is inconsistent with the facts; Different lubricants have a great influence on the test results; the accuracy of penetrating crack observation cannot be quantitatively controlled, which leads to the dispersion of the measured cupping value. If the penetrating crack is observed by reducing the stamping speed in the later stage, the stamping speed is ignored. impact on the test structure, which also leads to scattered results

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