ZHOUSHAN QUNYING SCREW has strong technical force, equipped with advanced equipment and strict tests. Mostly products materials are selected from high quality powder alloy steel with the best materials to exploit market and most new materials, add reasonable process design through tempering, molding, qualitative, nitriding, fine grinding, polishing process of refining. So that the screw barrel has super-hard resistance wear, corrosion resistance, fracture resistance. In order to meet the needs of our customers, we company also provides product design, surveying and mapping, sample processing and repair manufacturing business. All of our products comply with international quality standards (ISO9001-2000).