Viscoplastic properties of chromium-nickel steel in short-term creep under constant stress. Part 2

Chromium-nickel steel machining (cutting, pressure shaping) is impossible without taking into account their viscosity and plasticity. The purpose of this paper is studying formation and evolution of viscous deformation in short creep at constant effective stress. Experimental test results of chromium-nickel steel Kh18N10 & Tcy; short creep at room temperature have been given. The distinctive feature of the tests is studying the short creep in a wide range of stress: from the initial yield limit till fracture stress. The experiments were conducted in incrementally increasing load (fluid pressure in a closed pipe) at constant rate of constant effective stress at every stage. It has been demonstrated that the lay-down conditions of the load change, providing constancy of true stress intensity, are violated at rather high stress. The data obtained can be used in engineering calculations and design, as well as in the development of new metal processing technologies. Effective methods for analyzing deformations have been proposed, which make it possible to separate them into the plastic component and deformation due to short-term creep. These methods can be successfully applied both under conditions of stepwise loading and under continuous loading. Interesting results include confirmation of the hypothesis about the similarity of creep curves with sufficient accuracy for practical use. This opens the door to more efficient management of materials under variable load conditions, and provides engineers and designers with valuable tools to optimize processes and improve structural reliability. Additional studies also consider examples of the occurrence and development of deformations during short-term creep under conditions of reduced stress. This allows for a better understanding of the mechanisms underlying these phenomena and the development of more effective deformation prevention strategies in various engineering applications.