The Influence Of ZrC Particles, Y And La On The Microstructure And Properties Of A Kind Of HSLA Steel

HSLA steel is carbon steel on the basis of a small amount of alloying elements to improve the strength, and improve their performance and develop a class of structural steel works. Is well known that the distinction between carbon steel and alloy steel is relatively clear. Carbon steel is iron, carbon, and technology required to produce the normal amount of silicon and manganese, and inevitable impurity elements such as phosphorus and sulfur in steel. Alloy is to obtain a certain combination of properties to join a particular element or combination of steel. Most of the melting of carbon steel with alloying elements are more or less. But these are not intentionally added alloying elements, and the volume is not high, generally below 0.5%. These alloying elements, there are two sources:one is brought Scrap; two is Ore smelting of pig iron brought.In this study, a high-strength low-alloy steel as experimental materials, ZrC particles with different content and rare earth elements yttrium, lanthanum, micro-alloy carbonitride precipitation amount of the size and organizational performance such as by scanning electron microscopy (SEM), XRD analysis, X-ray small-angle scattering (SAXS) and other experimental techniques; system strengthening mechanism of the HSLA steel, that is mainly nano-scale grain refinement and precipitation strengthening precipitates. In addition solid solution strengthening and dislocation strengthening also play an indirect role.From the microstructure point of view of testing the mechanical properties of steel a good reason for in-depth research. The results show that the mechanical properties of experimental steel excellent reasonably attributed to the chemical composition and processes, and its reasonable to add micro-alloying elements. Experiments by studying the different components of micro-alloy steel austenite precipitation behavior of carbon and nitrogen compounds, found: ZrC particles and rare earth elements yttrium, lanthanum not only reduces the ferrite grain growth rate, and the inhibition of eutectoid ferrite formation, extended the ferrite core and the incubation period. When the steel in the ZrC particles and rare earth elements yttrium and lanthanum element content was 2.5%, the ferrite grain size than that without ZrC particles and rare earth elements yttrium and lanthanum elements of the steel small. When the ZrC particles and rare earth elements yttrium and lanthanum content increased to 2.0%, the amount of acicular ferrite increased significantly. When the steel in the ZrC particles and rare earth elements yttrium and lanthanum content of 2.5%, the microstructure of bainite and martensite beam-austenite. When the ZrC particles and rare earth elements yttrium and lanthanum content of 3.0%, significantly lower Ms point, the amount of retained austenite in the steel increases, so martensite-austenite increase in the number. Also increases the strength of steel, but the martensite-austenite occurs, reduce the toughness of the steel.