Effect of Secondary Cold Reduction Rates on Microstructure, Texture and Earing Behavior of Double Reduction Tinplate

In order to evaluate the effect of secondary cold reduction rate on the drawing performance of double reduction tinplate and explain the mechanism, a detailed investigation into the microstructural characterization, dissolved carbon atoms, texture characterization by an X-ray powder diffractometer (XRD) and electron backscatter diffraction (EBSD), and earing behavior were carried out with different secondary cold reduction rates of 15%, 20% and 25% for double reduction tinplate. The experimental results indicate that 15% secondary cold reduction rate could obtain a better drawing performance because there are no holes and cracks at the microstructure, and the content of dissolved carbon atom is relatively low; at the same time, it has a better texture distribution and low earing coefficient.

Experimental study of force modes for combined reduction and thinning process

The operation of cold reduction and simultaneous thinning of the wall in the workpiece is considered. The power parameters of this operation are studied. The researches is carried out experimentally. Secondary mathematical models are obtained from the results of the experiment.

Effect of Cold Reduction Rate on Ferrite Recrystallization Behavior during Annealing in Low-Carbon Steel with Different Initial Microstructures

We investigate the effect of the cold reduction rate on ferrite recrystallization behavior during the annealing of low-carbon steel with different initial microstructures. Three types of hot-rolled sheet specimens are prepared: specimens P, B, and M, which consist of ferrite and pearlite, bainite, and martensite, respectively. To evaluate the effect of the cold reduction rate on ferrite recrystallization behavior, hot-rolled sheet specimens are cold-rolled at cold reduction rates of 40% and 67%. The cold-rolled sheet specimens are heated to the target temperature, and then water-quenched to room temperature. Irrespective of the initial microstructures, the ferrite recrystallization is accelerated by increasing the cold reduction rate. In addition, the dislocation densities of specimens P and B increase at the larger cold reduction rate, which accelerates ferrite recrystallization in these specimens. In the case of specimen M, the dislocation arrangement parameter remarkably decreases at the larger cold reduction rate, whereas the dislocation density hardly changes. Thus, we conclude that the accelerated ferrite recrystallization at the larger cold reduction rate for specimen M can be mainly attributed to an increase in the amount of interactions between dislocations in the specimen.

Design and Engineering Application of Direct Mixing Lubrication System for Emulsion Pipeline in Secondary Cold Rolling Mill

With the benefit fierce competition in the steel industry market in recent years, double cold reduction products have been developed towards strength improvement and thickness reduction. The traditional cold-rolling lubrication process with a fixed flow rate and concentration cannot solve the problems which cover uncontrollable shape of strip product and the excessive consumption of lubricating oil. Moreover,based on the analysis of the traditional direct application lubrication system of double cold reduction, a set of design scheme suitable for the emulsion pipeline direct mixing lubrication system of double cold reduction unit is proposed.The design complete the selection of key components which include the static mixer and atomization nozzle selection, pump and oil pump design selection, pipeline design selection, flow type selection, pressure gauge selection, electronic control cabinet design selection and other aspects. Equipment of the emulsion pipeline direct mixing lubrication system of double cold reduction has been developed. Comparing with characteristics of the traditional direct aplication lubrication system, the emulsion pipeline direct mixing lubrication system was better applied to the production practice of a 1220 double cold reduction mill. The consumption of ton of steel was reduced by 9.6%. The rolling energy consumption and oil consumption comprehensive costs decreased by 10.7%, and the strip steel section thickness difference was reduced by 19.3%. In addition, the plate shape quality defect rate decreased by 25.6 %, otherwise creating a large economic benefit for the unit and promoting the application value.

Formation Mechanism and Influence Factors of Roll Surface Oil Film Thickness in the Double Cold Reduction Mill

In the double cold rolling process, the emulsion entering the roll gap during the double cold rolling process has the characteristics of high concentration and small flow rate so that the roll surface oil film thickness will affect roll gap oil film thickness, which in turn affects the rolling friction coefficient. This paper analyzes the formation mechanism and evolution process of the roll surface oil film thickness by considering the equipment and process characteristics of the emulsion direct injection application lubrication system. Then, based on the principle of fluid dynamics, the roll surface oil film thickness model in the double cold rolling process is established, and the prediction of the roll surface oil film thickness during the double cold rolling process is realized. Subsequently, the effects of five factors, such as rolling speed, work roll roughness, maximum contact stress between rolls, emulsion initial dynamic viscosity, and emulsion pressure viscosity coefficient, on the roll surface oil film thickness are quantitatively analyzed, and the corresponding influence laws are given. Finally, the relevant model and software that are applied to the 1220 double cold reduction mill have achieved good results.