Experimental investigation of thin-walled sorbite stainless steel material at elevated temperatures

Thin-walled high-strength sorbite stainless steel specimens were subjected to tensile tests at room temperature and increased temperatures. The test findings obtained at standard room temperature indicated that the stress-strain curve lacked a noticeable yield plateau. The test findings indicated that the stress level and initial modulus of elasticity of the specimens decreased progressively as the temperature increased when the temperature was either less than or equal to 200 degrees C or greater than or equal to 400 degrees C. The strength of specimens remained relatively constant within the temperature range of 200 degrees C to 400 degrees C. At temperatures below 500 degrees C, the stress-strain curve continues to show improvement even after the material has yielded. The enhancement effect in the flat zone was considerably greater than that in the corner zone. At temperatures exceeding 500 degrees C, the stress-strain curve transitions into a state of complete plasticity after the material reaches its yield point. Subsequently, there was no substantial alteration in the stress as the strain continued to increase. Under steady state and transient tests, the stress-strain curves of the specimens in the flat and corner zones were nearly identical when the temperature was below 400 degrees C. When the temperature surpassed 400 degrees C, the curves obtained from the two test procedures were not identical. The test results were used to develop a constitutive model of stainless steel in the flat and corner zones under high-temperature conditions. Additionally, a formula was proposed to calculate the reduction factor of the mechanical parameters.