Fracture toughness evaluation of 37CrNi3MoVE steel used for high-pressure air storage cylinder

Abstract

The air storage cylinders, forming part of the impulse air system for submarine, are high-pressure steel cylinders dome-shaped at each end. To prevent the risk of cylinders rupture, the fracture toughness of cylinders is necessary to be tested. The three-point bending samples used in the fracture toughness experiment were taken from a cylinder made of 37CrNi3MoVE steel. With the consideration of the effect of the manufacturing process, both axial specimens and circumferential specimens were sampled, and the fracture toughness was compared. The effective data obtained from fracture toughness experiments were processed by different standards, such as ISO 12135 standard and ASTM E1820 standard. The fracture surface is analyzed from macroscopic and microscopic perspectives. From the test results of circumferential fracture toughness and axial fracture toughness, it can be clearly seen that under the influence of the processing technology, the circumferential fracture toughness of the cylinder of the high-pressure gas cylinder is smaller than the circumferential fracture toughness. Finally, comparing the fracture toughness values obtained by the ASTM E1820 standard with the fracture toughness values obtained by the ISO 12135 standard, it is found that the fracture toughness values obtained under the ASTM E1820 standard are all greater than the fracture toughness values obtained by the ISO 12135 standard.