| With the continuous rise in price of iron ore, and the profit decrease of the steel, therecycling of the iron scraps has increasingly become the center of interest to the steelindustry. The traditional recovery method of the iron scraps has the followingcharacteristics: low recovery rate, hith evergy-consuming and high pollution, and it can’tmeet the needs of development of modern society. With the development of thetechnology and the manufacturing technique, the solid-state recycling technique is appliedto recycle the iron scraps. The clad bar produced by composite rolling of the iron scrapwith stainless steel coating is an attempt based on this technique, metallurgical bondingwill be formed during the interface with some rolling process using the groove rolling, andsome achievements had made. However, there is little work on the influence of reduction,rolling temperature, heat treatment process on the bonding between the stainless steel andthe iron scraps. Therefore, a kind of composite material made of stainless steel and ironscrap produced by hot rolling, the influence of different processes on the bonding betweenstainless and iron scrap was studied.First, the cold compressing test of the iron scraps was carried out to determine therelation between the compressed stress and the density of the iron scraps. The iron scrapswith stainless steel coating was produced by hot rolling using the plain roller, themechanical property and the element diffusion near the interface between the stainlesssteel and the iron scraps of the composite materimal was studied. The influence ofdifferent passes, reduction, density of the iron scraps, rolling temperature, add graphite onthe bonding property between the stainless steel and the iron scraps.The results indicatedthat it is advantageous to bonding when rising the reduction, density of the iron scraps androlling temperature, the tensile strength increased and the plasticity decreased when addgraphite in the iron scraps.In order to know the distribution of the stainless steel and the flow of the iron scrapsduring the composite rolling process, the finite element modeling of the composite rollingprocess of the iron scraps with stainless steel coating was studied. Firstly, the model of theiron scraps was established as powders through the analysis of the deformation character of the iron scraps. The finite element software Msc.marc was used as the simulation toolof the3-D model of the clad plate, the Powders plug-in in the software was used as thecarrier to describe the iron scraps material model, the Shima-oyane constitutive model wasused as the yield criterion of the iron scraps, finally the3-D model of the compositerolling of the iron scraps with stainless steel coating was established. Then, the rollingprocess of composite rolling was simulated. The distribution of the relative density of theiron scraps and the thickness of the stainless steel was studied; the influence oftemperature and density of the iron scraps on the spread of the workpiece and thedistribution of the stainless steel was studied, the effect of the friction between thestainless steel and the iron scraps on the bonding between the two metals were analyzed. Itwas found that it is advantageous to bonding when increasing the rolling temperature,reduction and density of the iron scraps, but disadvantageous to the distribution of thestainless steel, all will lay the theoretical foundation for the bonding theory between thestainless steel and the iron scraps.The influence of heattreatment process on the bonding interface between stainlesssteel and iron scraps through the heattreatment experiments of the stainless steel/iron scrapclad bar was studied, the influence of different heating temperature, holding time on thebonding property was studied, and the influence of the heating process on the diffusionof element Cr was analyzed using the diffusion theory. The results indicated that it isadvantageous to bonding when increasing the heating temperature and holding time. |
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