Abstract:To provide the basis for the fire-resistance analysis and design of bolt connections of steel building, the mechanical properties of the stainless steel bolt at elevated temperature were studied. Two groups of stainless steel bolts with different grades were tested to obtain the full stress-strain curve of stainless steel bolts at different temperatures. The Young’s modulus, 0.2% proof strength and tensile strength of stainless steel bolts were derived. The test results were compared with the mechanical properties of the parent materials and fire-resistant bolts at elevated temperatures, and the recommended values for parent materials in relevant design standards. Based on the experimental data, reduction factors models for tensile strength, Young's modulus and 0.2% proof strength are proposed in this paper for stainless steel bolts at elevated temperatures. The test results shows that the tensile strength degradation of stainless steel bolts in fire are found to be rather close to those recommended by Eurocode 3 for their parent materials, but the reduction factors of Young's modulus are of great discrepancy. At temperatures lower than 650 °C, the 0.2% proof strength of stainless steel bolts decreases more slowly than that of their parent materials. In the temperature range of 500 to 900 °C, the stainless steel bolts retain their tensile strength, Young's modulus and 0.2% proof strength better than fire-resistant bolts.