Method for testing constitutive relationship of metallic materials

Abstract

The invention relates to a method for testing the constitutive relationship of metallic materials. The method comprises the steps of: (1), preparing a bump sample on the surface of a metallic materialto be tested; (2), performing a compression test on the bump sample by utilizing a pressure rod load loading mechanism, so that a load-displacement curve is obtained; and (3), obtaining a true stress-strain curve by calculation from the obtained load-displacement curve by utilizing a finite element inversion method. Compared with the prior art, the method in the invention is as follows: the bumpsample is prepared on the surface of the metallic material to be tested; then, the bump sample is loaded through the pressure rod load loading mechanism; by adoption of the manner, the metallic material to be tested can be greatly saved; and the test efficiency is increased.

Description

technical field [0001] The invention relates to the technical field of material analysis and testing, in particular to a method for testing the constitutive relationship of metal materials. Background technique [0002] There are a large number of service equipment in thermal power, nuclear power, offshore oil and gas, petrochemical and other industries, and nearly 80% of them are pressure vessels and pipelines. These equipments have long-term service in the harsh environment of high temperature, high pressure, low temperature, neutron radiation or corrosive media, which is easy to cause deterioration and damage of material properties. Traditionally, to evaluate the performance of materials, it is necessary to remove some metal samples from the equipment for testing, which will destroy the original structure of the equipment and affect the safety of the equipment. On the premise of not destroying the equipment, how to quantitatively characterize the mechanical properties of...

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Problems solved by technology

[0003] The prior art adopts the continuous indentation method (also known as the instrumented indentation method) for testing. The continuous indentation method is developed based on the principle of hardness testing. This method uses a spherical indenter to perform multiple indentations on the same part of the metal sample. Loading and unloading (loading load increases successively), the characteristic stress and characteristic strain are obtained through the curve of each unloading, and then the true stress-strain curve of the material is obtained by using it, and then the yield strength and tensile strength of the material are obtained. When the true stress-strain curve is deduced from the characterization stress and characterization strain, it is necessary to assume that the material conforms to a certain constitutive relationship, such as linear hardening, power hardening, etc., but in actual tests, the hardening model of the material is often unpredictable, which will lead to The deviation is large and the test efficiency is low

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