According to the analysis of the importance of characteristics of the valve parts, the key technology and quality assurance is in different parts of the requirements, strict implementation is ISO9001-2008 standards and establish perfect quality assurance system, in the production process, in strict accordance with the national requirements for the production of pressure pipeline manufacturing.
1 pressure casting: in order to ensure the surface quality of castings, meet MSS SP55 standard requirements of molding sand quality and other technology standard of our factory, the casting defects of the parts used the riser or placed cold iron, the quality assurance personnel witness consent, be ready to cast blank. In the cast steel water smelting, shall be carried out by infrared spectroscopy for inspection before furnace, when the chemical composition meet the standard requirements, can casting parts, after heat treatment, with the light ray inspection process. And the 1 / 4 of the anatomy is the blank, check the hot junction of slag, porosity, shrinkage, sand, cracks and other casting defects, after passing the test, can be put into mass production.
2 welding process evaluation: the welding of various materials should be process evaluation, evaluation criteria are fully in line with the requirements of ASME standards, qualified by the authority, to determine the welding process of such materials.
3 The sealing surface of welding materials: according to the project requirements, our factory used plasma spraying technology, the base material was put into the hard alloy welding implement sealing surface, so met the alumina sanitary butterfly valve industry requirement such as low maintenance and high reliability requirements.
4 key parts of the body size and shape tolerance, high precision and electric device adopting the unified standards, a positioning and clamping all machining finished in our factory four inversion processing center, ensure the machining precision of the parts, in accordance with the technical documentation requirements.
5 seat special process: using external thread positioning processing seat sealing surface at both ends, to ensure the sealing surface of the valve seat, layer thickness and size is precision, to ensure the accuracy of the wedge angle with the valve assembly, in line with technical documentation requirements.
6 valve seat hole processing: increasing the process weight, eliminating the imbalance in the machining process, to ensure the accuracy of the valve seat hole, surface roughness and shape and position tolerance to meet the technical documentation requirements.
7 stem trapezoidal thread used a high-precision machine tools for high speed low feed cutting. In order to ensure the processing efficiency, ensure the accuracy of the process to meet the technical documentation requirements. Moreover, the special technology of applying the rapid jump knife is adopted. The valve stem is processed without a knife groove, which is easy to meet the strength requirements of the API591 standard.
8 sealing surface grinding: cone sealing surface used imported grinding machine in Italy, so that the grinding line can meet the requirements of diamond mesh.
9 key welding and heat treatment process: automatic spray welding of multilayer Stellite cobalt based alloy coating, ensure size to meet the requirements. And through the heat treatment to ensure that the sealing surface is the specified technical indicators, and the sealing surface of the hardness is each point uniform.