High-strength and high-toughness hot-rolled wear-resistant steel and preparation method thereof

Abstract

The invention discloses high-strength and high-toughness hot-rolled wear-resistant steel and a preparation method thereof. The high-strength and high-toughness hot-rolled wear-resistant steel comprises the following chemical ingredients in percentage by weight: 0.20-0.50% of C, 0.8-2.0% of Si, 1.5-3.0% of Mn, not greater than 0.015% of P, not greater than 0.005% of S, 0.02-0.08% of Al, not greater than 0.006% of N, not greater than 30 ppm of O, 0.005-0.015% of Ti, 0.5-2.0% of Ni, and the balance of Fe and inevitable impurities, wherein the sum of Mn and Ni is 3.2-3.6%; the microscopic structure is composed of lath martensites and retained austenites, and the volume percentage content of the retained austenites is 5.0-15.0%; and the high-strength and high-toughness wear-resistant steel obtained by the processes of hot continuous rolling and rapid quenching has a tensile strength of greater than 1500 MPa, a yield strength of 1150-1400 MPa, a thickness of 3-12 mm, a good ductility (of greater than 10%), and a good low-temperature impact toughness (impact energy of 38-48 J at minus 20 DEG C), and shows excellent strong-plastic matching.

Description

technical field [0001] The invention belongs to the field of wear-resistant steel, and relates to a high-strength, high-toughness hot-rolled wear-resistant steel and a manufacturing method thereof. The microstructure is lath martensite and retained austenite, and the volume percentage of retained austenite The content is 5.0-15.0%; the impact energy at -20°C is 38-48J, the yield strength is 1150-1400MPa, the tensile strength is >1500MPa, and the elongation is 12-12.5%. Background technique [0002] Quenching-partitioning steel or Q&P steel is a research hotspot in the field of advanced high-strength steel in recent years. The main process of Q&P steel is: heating the steel to the complete austenite zone, and after holding it for a period of time, it is quickly quenched to M s and M f (M s and M f Respectively represent a certain temperature between the martensite transformation start temperature and end temperature), in order to obtain a martensite + retained austenit...

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Problems solved by technology

[0009] However, one of the most important disadvantages of Q&P steel is low impact toughness, which is mainly due to the rapid TRIP effect of retained austenite during the impact process, resulting in a sharp increase in the strength of the steel, and the high work hardening rate of Q&P steel. There is usually a small amount of massive retained austenite in the upper structure, which leads to the low impact toughness of Q&P

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