GB/T 46591.1-2025 is the first part of the series of in-situ test methods for metal materials. It specifies the principle, sample requirements, operation process and data processing specifications of in-situ tensile testing, which is suitable for in-situ tensile performance testing of various metal materials. The standard provides a unified technical basis for the evaluation of mechanical properties of materials in real working conditions, ensures the accuracy and comparability of test data, helps to standardize the in-situ tensile test process of metal materials, and supports material research and development and engineering application Reliability verification.