| Copper cladding layer has been widely used in field of weapons manufacturing. In this paper, a cladding of Hs201 was cladded on the surface of 35CrMnSiA steel substrate by means of tungsten inert gas (TIG) cladding. On basis of analyzing the temperature field, the influence of processing condition on temperature field, and the law of flow in the cladding layer and the molten pool under the effect of TIG-arc, distribution and concentration of Fe in the copper alloy cladding layer, the evolution of the morphology of Fe in the copper layer, and the content of Fe were studied primarily and systematically.Based on the comprehensive analyses of heat transfer behavior in cladding process, a entity model was presented by using the physical dimensions of cladding layers, the heat source was composed of a segment column heat source and a Gaussian distribution surface heat source, the weaving movement of heat source was achieved by user's defined functions, and temperature fields under different cladding process were simulated. The results showed that the peak temperatures of weld thermal cycle decreased alone with the increasing of the distance from the interface in the steel substrate, cooling velocity also decreased; the peak temperatures of weld thermal cycle at interface is lower in weaving welding than single-pass welding at the same cladding current, the cooling velocity is also lower in weaving welding; the cooling velocity of cladding layer and the steel substrate increased greatly with water cooling to the back of the substrate; compared the results with the experimental data, there was a rather large error at the peak temperature at the interface in cladding on water cooling substrate. The other results obtained by simulation were in good agreement with the experimental ones.Using the results obtained from temperature fields analyze and from the arc pressure test, the law of flowing liquid in cladding layer and the molten pool in substrate. Results showed that following the presumption the paper given, either single phase flow field or double phase flow field became stable in a very short time; in double phase flow field molten steel at the bottom of the molten pool flowed to both sides of the cladding layer, Molten copper alloy at the top of the cladding layer flowed to molten pool. In flow field, rate of flow near the molten bottom was low, but it is high at the top of the cladding layer.The interface and the cladding layer were analyzed by means of optical microscope, SEM, EDXA, and XRD, and the evolution of the distribution and concentration of Fe, the morphology of Fe in the cladding layer was studied with the calculated results. The results showed molten steel was taken out of the molten pool to both sides of the cladding layer, and solidified there; molten copper alloy flowed into the molten pool so that there is little Fe in the middle of the cladding layer and the molten pool. Alone with increasing of cladding current, the morphology of Fe in cladding layer evolved from invisible Fe (I<270A) to fine grain or arborization (I<270A), and to block Fe (I=300A), and finally the interface of Cu/Fe became blurred, molten copper alloy and steel contained each other (I=300A). The content of Fe in cladding layer measured by EDXA, and the model on the relationship between the content of Fe and cladding current was built.At last the factors which could restrain the transfer of Fe were investigated, results show that Fe content decreased by 40% on a water cooling substrate when cladding current was 270A; at the same current, Fe content decreased by 8.6% with hot filler wire.
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