Abstract: The secondary-working characters of in situ TiC_P/Fe composites (heat treatment, welding, machining) are studied and a lot of basic works for using in industrialization producing are done. The results showed that casting stress could be eliminated, microstructures improved, properties raised, and it is improper to change the TiC particle by heat treatment. The TiC particle is not changed in the course of welding and there are not cracks in the weld seam. The weld-ability of the composites is better. The cutting force of TiC/Fe composites is enlarged and its temperature is increased due to the formation of TiC particles. The effect of TiC on the working surface is only a little. The machining quality of the composites is similar to that of 45^# steel.