关键词: 桥梁缆索, 100Si钢, 盐浴热处理, 片层间距, 析出强化

Abstract: The strong plasticity technology of 100Si steel Φ14 mm wire rod is studied by measuring the isothermal TTT curve of 100Si steel wire rod and designing off-line salt bath heat treatment process experiment. The results show that the nasal tip temperature of 100Si steel is about 580 ℃， and the shortest incubation period of the isothermal transition is about 5 s， and the isothermal phase transition behavior of 100Si steel is very sensitive to temperature； With the increase of salt bath isothermal temperature （510 - 580 ℃ ）， the tensile strength and reduction of area of wire rod basically decrease； With the increase of off-line austenitizing temperature， the pearlite pellet size of 100Si steel rod increases； Compared with hot rolled wire rod， the distribution of the lamellar spacing of the bottom wire rod by salt bath heat treatment is more concentrated， and the lamellar spacing decreases with the decrease of salt bath temperature； When the temperature is lower than 920 ℃， V in 100Si steel can be precipitated in austenite with the form of VC， and the precipitation of VC in ferritin occurs after pearlite transformation； At the lower austenitizing temperature and the lower salt bath temperature， the mass fraction of VC particles precipitated is less， which can weaken the precipitation strengthening； The hot-rolled wire rod with 920 ℃ off-line austenitizing and 530 ℃ salt bath isotherm has the best balance between the strengthening effect of sorbitic phase and precipitation strengthening effect， the better mechanical properties are tensile strength 1 650 MPa and reduction of area 32.5% .

Key words: Bridge Cable, 100Si Steel, Salt Bath Heat Treatment, Lamellar Spacing, Precipitation Strengthening