Abstract: Substituting the hi-frequency straight weld steel pipe for the aluminum alloy pipe to produce the case frame is not only capable of reducing the operation costs,but also enhances the durability of the product.Described in the paper are the manufacture process for and the pass design of the formation die of the said case frame-purpose weld pipe.Also analyzed are the technical tips of the manufacturing process,indicating the cru-cial points concerning production of the pipe.