An extensive chemical composition and performance analysis has been conducted on a stainless steel flange and its welding materials, confirming that both meet the requirements outlined by relevant industry standards. The flange, designed for use in a pipeline with a working pressure of 1.6 MPa, underwent rigorous testing to evaluate its structural integrity under stress.
During the testing process, the flange was subjected to an experimental pressure of 2.4 MPa, significantly exceeding the design pressure. The pressure was gradually increased to 0.6 MPa, at which point a leakage occurred at one location on the flange. Upon microscopic examination, it was found that the crack was situated at the flange neck and aligned almost parallel to the weld seam. The crack was a circumferential fracture, with the fracture surface nearly perpendicular to the exterior. The fracture did not exhibit significant plastic deformation, ruling out the possibility of flange material failure caused by overpressure.
In addition to pressure testing, Brinell hardness tests were conducted on both the external surface of the flange neck and the sealing face. The test results confirmed that the hardness values met the specifications required by the JB4728-2000 standard, ensuring the material’s reliability and performance in real-world applications.
The analysis results indicate that the stainless steel flange and its welding materials meet the necessary standards for chemical composition, hardness, and pressure resistance. Despite the minor leakage observed during testing, the material's properties and the integrity of the flange appear to be in line with industry requirements. This investigation ensures that the materials used in high-pressure pipeline applications can maintain safety and durability under operating conditions.
