Investigation of X80 Line Pipe Steel Fracture during Tensile Testing Using Acoustic Emission Monitoring

Abstract

The acoustic emission (AE) monitoring technique is widely used in mechanical and materials research for detection of plastic deformation, fracture initiation and crack growth. However, the quantitative dependences of the AE signal parameters on material fracture parametersare not completely understood. This paper presents recent research results on AE monitoring of the fracture behavior of X80 line pipe steel, a critically important material for the oil and gas transportation industry.Fracture of this steel was studied using tensile testing of small scale specimens coupled with AE monitoring and high speed video camera. The dependence of fracture behavior and AE parameters on loading conditions (strain rate and presence or absence of a notch) was investigated. The AE parameters were analyzed using the “Average Hit” features and “Wave Form and Power Spectrum” methodologies. The fracture surface was characterized using scanning electron microscopy and a dependence of the AE parameters on the average void size has been obtained.

Feasibility of studying 460 MPa high-strength steel affected by strain aging with acoustic emission method

“…The adopted sampling frequency of the AE signals was 3 MHz. According to the major frequencies contained in the AE signals of steel materials (Chuluunbat et al, 2019; Toubal et al, 2020), two RS-2A AE sensors (Softland Times Scientific and Technology Co., Ltd., Beijing, China) with broadband response ranging from 50 to 400 kHz and a maximum sensitivity of 150 kHz were adopted to detect the AE signals. Two 2/4/6 preamplifiers with gains of 40 dB were used along with the two sensors.…”

“…Mojškerc et al (2018) concluded that AE is a reasonable way to monitor the steel quenching process and mechanical properties of quenched workpieces. The AE technique was also adopted to monitor the fracture behavior of steels during tensile tests (Chuluunbat et al, 2019; Lyasota et al, 2019). With the aid of AE, electron backscatter diffraction and transmission electron microscopy, Tian et al (2020) studied the microplastic deformation of a DT4 iron ingot under tensile stress.…”