The Research Of Improvement Of Character Of Steel Bar By Tempcore

Hot rolling steel bar which is used in architecture area is one of the most important steels. The steel bar produced in our country is not as good as that produced by steel developed country in terms of mechanic character such as intention. It is very important to produced high intention steel bar for the marketplace and link orbit of international marketplace. This article aimed at this actuality, on the base of theory analysis and practical experiment, found the way of improving the general mechanical character and intention by the way of control rolling and control cooling. especially the control cooling after rolling.This article start with the composition of the steel bar, by the observe and analysis of the composition of the steel bar in the cross section. Result make clear that the composition is: temper marten site in the surface layer; not marten site in the central part. The thickness of temper marten site is an important factor to the intension of steel bar. At the same time, the armpit composition and, the crack in the steel bar surface and heat effect area of steel bar after welded are analyzed. the observe and analysis of composition make clear that the mechanical character is decided by microstructure. But microstructure is decided by chemic composition, rolling technical and cooling technical. These factors must be adjusted to gain optimizing composition and technical.Correlative analysis of the chemic composition, rolling parameter and mechanic characters make clear that chemic composition, rolling parameter will have effect on the mechanical of steel bar. The analysis of amounts of experimental data approve that the higher composition of C,Mn,Si can get higher mechanical properties. And the adjustment of rolling parameter can get better mechanical character.The control cooling after will decide the last mechanical character. In control cooling ,the cooling parameter is the main factor to mechanical character of steel bar. In actual producing. The two main cooling parameters are cooling times and cooling water amount, these two parameters are related to the length of cooling canal and thepressure of cooling water. By amounts of experimental data and analysis of these data. These two parameters and relations to mechanical character are analyzed. The optimizing cooling parameters were got combining practice.The central problem of control cooling is the establishment of mathematical mold. This article start with theory. On the base of analysis of heat transmission in cooling process, three mathematical mold: beginning cooling mold; cooling water amount mold; temper temperature mold. were established. These molds were predigested mathematically for adapting actual producing. Practice prove that these molds had directed functions on actual producing.This article theory combining practice. The mechanical character of steel bar produced by remainder heat quench can be increased . this article has values in practice and academy.