Group 1 - The company, Boyun New Materials (002297), has a subsidiary, Boyun Dongfang, which is engaged in the production and sales of hard alloys, including ultra-coarse crystal hard alloys used for shield tunneling machine tools [1] - Currently, the sales of shield tunneling machine tool materials are primarily directed towards manufacturers of shield tunneling machines or accessory parts, with no direct supply to China Railway Construction Corporation or China Railway Industry [1] - The overall gross profit margin of hard alloy products, including shield tunneling machine tool materials, is low, and the sales contribution of shield tunneling machine tool materials to Boyun Dongfang's revenue is small, resulting in minimal profit contribution from these materials [1]