Abstract: The modification of the 76mm welded pipe mill line conducted by Xiangxing Steel Tube Co. Ltd.,Qingdao involves such aspects as roll-spacing,bore of the guide cannon,clamping device of the flying-saw and roll structure,etc. As a result,the product-mix of the said mill line has been enlarged,covering both size range under 76mm and size range as 76mm to 95mm.