Forging is applied for many industrial fields. Of course, there is no exception in nipple of automotive hose. Finding method of forging process is metallic stress analysis, and we can predict this possibility by finite element forging analysis. But there are many manufacturing procedure after forging, and additional heat treatment or coating can vary metal texture. So, in this research, we focus on the measuring and analysis of plastic residual stress distribution at overall manufacturing process. First step, we measured real residual stress at each forging process by X ray diffract meter from raw material to final product. Second step, we simulated parts-assembly process by nonlinear finite element analysis. In this step, we can prove how Zn–Ni coating is more contributable to metal strength than Zn coating. And we can conclude for robust design that manufacturing process analysis must be observed carefully from raw material to final manufacturing state.