Development of High Strength Weathering Resistant Steel for Railway Vehicle

Q500NQR1 and Q550NQR1 high strength weathering resistant steels were developed, and the microstructures, mechanical properties and corrosion resistance were studied. The results show that the microstructures of the two weathering resistant steels consisted of ferrite, pearlite and bainite. The comprehensive mechanical properties were excellent and met the standard requirements of railway vehicle steel. After periodic immersion corrosion for 72 h, the relative corrosion rates (the contrast material was Q345B steel) of Q500NQR1 and Q550NQR1 weathering resistant steels were 44.5% and 40.1%, respectively, which met the standard requirements of weathering resistant steel for railway, indicating excellent atmospheric corrosion resistance. With the increase of corrosion time, the corrosion products on surface of the two weathering resistant steels bacame globular clusters, and the globular clusters became tight, which enhanced the protection of steel substrate.