Study And Development Of Produced Process For Ultrafine Of The Low Carbon And Low Alloy Steels

The work of this paper is carried out taking the low-carbon steel as the object of the study, through industrial experiment, laboratory metallography, and mechanical properties experiment. ANSYS software simulation unifies conducts of the research: to conduct the research and the development to the low-carbon low-alloy ultra fine crystal steel technique of production. The main work involves as follows:It researches through improving to roll and cool processing parameter for 20MnSi and Q235 steel and so on. It sets forth the theroy of grain refining's materials science, analyzes and compares control rolling and cooling with empirical and practical ways in existence. With present production techonlogy, this paper simulates cooling processing. Finally, the HRB335 rank of 20MnSi steel is passed through conventional rolling in order to gain yield strength that is greater than 450Mpa, and achieves elongation ratio that is greater than 27%. Furthermore, it meetsⅣstandard of reinforcement bars.With industrial production condition, we may control the performance of reinforcement bar in certain range through controlling tempering temperature by itself on rolled pieces cold-frame when rolled pieces'finishing temperature is 950~1050℃. It shows that the ferrite grain will be refined under 8μm whenΦ10~20mm reinforcement bars'temperture, which is tempering temperature by itself on cold-frame, is controlled between 620~650℃. Moreover, mechanical property meets required stipulation. This technique can refine ferritic grains and pearlite colony in order to improve quality of regular reinforcement.The software of ANSYS10.0 simulates the temperature field by means of theoretical calculation, modifiability, and setting up model of diverse low-carbon steels in respect of the temperature field in hot rolling process. This paper computes kinetic and thermodynamic parameters by means of VB in order to depict microstructure evolution in whole rolling processes objectively and quantitatively and establish the final mechanical properties base.The ferritic grains are refined under 5~10μm so that low-carbon steels obtain high strength and high toughness by means of ultra-fined grains. The structures of producted ultra-refined low-carbon steels is ferrite and pearlite, and the dimension of ferritic grain is lower than 10μm.