Creep deformation-fatigue crack growth testing device and corresponding testing method

Abstract

The invention relates to a creep deformation-fatigue crack growth testing device and a corresponding testing method. The device comprises a loading system, a temperature control system and a measurement and collection system, wherein the measurement and collection system comprises a load linear displacement measurement system and a crack length measurement system; the upper and lower ends of a test sample are fixedly connected with an upper clamp and a lower clamp respectively; a high temperature furnace is connected with the temperature control system and the measurement and collection system; the test sample is loaded by an alternating current servo motor and a controller. The invention further relates to the corresponding testing method. The testing device provided by the invention is compact in structure and convenient to operate; the testing device adopts an insulating chuck and the insulating chuck ensures that constant-current current passing through the test sample is stable; aiming at the test sample of a creep deformation-fatigue crack growth test, the clamps are designed and machined; the temperature in the furnace is high so that a high-temperature clamping type extensometer is used for introducing load linear displacement out of a heating furnace to be measured. The testing method is simple and convenient to operate; the crack length is measured by using an electric potential method and the continuous test can be carried out for long time.

Description

technical field [0001] The invention belongs to the technical field of measuring equipment, and specifically refers to a creep-fatigue crack growth test device and a corresponding test method. Background technique [0002] Power generation equipment, petrochemical and aerospace high-temperature components are often subjected to cyclical loads at high temperatures, and their materials or structures are subjected to creep-fatigue interactions during operation. These devices are often in the state of repeated start-stop and load fluctuations. These loads will inevitably lead to fatigue cracks in long-term service, and work at a certain steady-state temperature will easily lead to creep crack initiation and growth. Even for newly commissioned equipment, due to the limitations of metallurgy and manufacturing technology, it is impossible to completely avoid defects such as foreign matter inclusions and scratches on props. These defects or cracks expand under the interaction of fa...

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Problems solved by technology

[0003] At present, the test devices and test methods for the creep-fatigue crack growth test at home and abroad are as follows: the inventions of Lin Fusheng, Sun Kang and others have realized the creep-fatigue test of non-defective samples, and the invention of Changchun Mechanical Science Research Institute Co., Ltd. Durable creep fatigue testing machine cannot realize high temperature crack growth test

"Study on Crack Growth Rate Under the Combined Effect of High Temperature Fatigue and Creep of 316L Steel" introduced the flexibility method to measure the crack length, but there are many variables designed in the calculation formula of the flexibility method, and their errors will directly affect the flexibility method. measurement accuracy

The sixth issue of "Acta Dynamics" in 2011 introduced the off-site direct reading method to measure the growth rate of creep fatigue cracks, but this method cannot continue the creep-fatigue crack growth test, and the test needs to be stopped halfway, which is complicated to operate

Nie Hong, Tang Jianfei and others proposed a method for measuring the fatigue crack growth rate based on the potential method, but different test systems are required for the creep-fatigue crack growth test.

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