Development Of Flexible Heat Treatment Equipment For Pipes

As a kind of economical material, the steel pipe occupies an important position in the national economy. The heat treatment process is one of the most important ways to improve the performance of steel pipes. By adopting different heating and cooling process, different mechanical properties and microstructures can be obtained, which opens up a new wide space for development of pipe products. In addition, due to the development of flexible heat treatment equipment for pipes, researchers don’t have to heat the samples in the factory, but the functions to be achieved on the complex and lengthy production line are collected in a single equipment instead. By this, instead of delaying the actual production tasks, the efficiency of heat treatment test is remarkably improved, and the heat treatment for steel pipes in the factory could be truly simulated. In a word, the flexible heat treatment equipment plays a very important role on the new product development and the process optimization.The flexible heat treatment equipment for steel pipes can simulate a high accurate heat treatment process for the required plates and pipes on the condition of the protective atmosphere at the different heating and cooling rates. By applying digital control system to automatically control the entire testing process and establishing a database with data storage, query, reporting and other functions, the experimental evidence is provided to researchers for studying heat treatment process and mechanism of pipes and plates. So the development of raw materials and the guidance for pipe heating treatment processes are achieved.Main contents and achievements of this dissertation are as follows:(1) With the pictures of equipment’s components, a detailed description is given which for the performance parameters and functions of the furnace, the fixture system, the vacuum system and the protective gas system. Principles and functions of components in the hydraulic system are briefly discussed.(2) Because of the relative lack of the current research and application about controlled cooling technology for steel pipes, ultra fast cooling is applied to the flexible heat treatment equipment during heat treatment for pipes. Samples can be cooled by different cooling forms, include of direct diffusion cooling, gas jet cooling, water spray cooling and mist spray cooling. In order for the outer wall of sample, especially pipe sample, to be cooled more evenly, the equipment’s water spraying device is designed to periodically swing and spirally spray. With the help of the auxiliary inner water spraying device of the equipment, both the outer and inner wall of the steel pipe will be cooled fast and evenly.(3) Due to the size defects that thermal simulation sample is too small, the subsequent experiments with larger samples can’t be conducted after thermal simulation experiment. Each function system of the equipment is designed in accordance with larger samples, and a wider size range of larger samples can be chosen, heated and cooled during heat treatment, making up the defects of the traditional thermal simulation experiment.(4) In order that researchers might design heat treatment process more flexibly, the equipment’s upper computer is equipped with a feature-rich HMI for setting text parameters. This HMI for setting text parameters contains many heating and cooling parameters, which increases diversity of the heat treatment process. And the purposes that the heat treatment process for plates and pipes could be designed more flexibly can be ultimately achieved.(5) On the basis of design principles of the pipe flexible heat treatment equipment control system, many rational plans are made about system selection, hardware configuration, communication settings, functional assignments, etc. Relying on the existing control system hardware structure, two suitable programming softwares--Lab VIEW2010made by National Instruments Corporation in the United States and STEP7made by Siemens in the German, are adopted to set up a software platform and the software structure is illustrated.(6) In order to make researchers view the test data conveniently, the equipment’s control system is equipped with a powerful database. According to the data size and type, different data storage structures are established. Interface program primarily uses two kinds of database toolkits--LabSQL and Lab VIEW SQL Toolkit to connect and visit to database. All the previous test data saved into the SQL Server database can be queried, modified, deleted, drew and reported on the database management interface to offer a convenient database platform to researchers for studying heat treatment process.