Methods of Cooling a Welded Steel Pipe
With the development of controlled cooling technology, it has been more maturely applied in field of plates, strips, wires, etc. Well, because of its good control of cooling temperature and speed after rolling, the technology really can help improve the organization and performance of steels.
In order to better popularize and apply controlled cooling after rolling technology in seamless pipes production, Tianjin steel pipe group LTD cooperated with northeastern university carried out a series of controlled cooling after rolling simulation experiment research of seamless steel pipes. Early results showed that: rapid cooling of rolled seamless mild steel pipe of low C and low Mn greatly improves overall comprehensive mechanical properties of steels. For carbon-structure steel pipes and alloy- structure steel pipes, adopting appropriate rapid cooling after rolling technology can improve mechanical properties such as the overall strength and toughness at the same time, with no decrease of elongation. And impact toughness increased significantly, effectively improving the low rolling impact toughness. Fast cooling after rolling technology makes the thickness of thick-wall seamless steel pipes have multiple organizations, which is beneficial to the improvement of overall comprehensive performance. For structural pipes, aerosol cooling after rolling gets composite and continuous thickness of steel pipes, advantageous to the improvement of the overall comprehensive performance of steel pipes.
For medium- and thick- walled carbon steel pipes with high quality and low alloy-structure pipes, using aerosol fast cooling after rolling together with the function of their own waste heat tempering increase mechanical properties of the overall strength and toughness of the steel pipes at the same time, with no decrease of extension of plasticity. And impact toughness increased significantly, effectively improving the problem of low impact toughness in rolling state.
Acicular ferrite and binate created by aerosols fast cooling technology provide a new manufacturing method for the future development of thin-walled, medium- and thick-walled structural steel pipe.
Increasing the length of the aerosol cooling device in a proper way can further strengthen the cooling effect. At the same time improve the combined cooler nozzle from rectangular shape to rectangular circular arc shape, making the cooling of steel pipes more uniform. And improve automatic adjustment method of the angle of rotation roller, can further meet the requirements of controlled cooling process with different varieties and of welded steel pipes with different specifications.
Using the characteristics of recrystallization process and phase change process of steel materials can change the grain size of materials and phase constitution, realizing the reduction of the production process through the control of cooling conditions.
And using manufacturing process which can reduce production is able to create energy-saving steel materials with improved and enhanced comprehensive performance. And these steel materials are in line with the scientific outlook on development which emphasizes on sustainable development, and this kind of cooling process is the direction to develop welded steel pipes and production process.
Date：2017-03-15 17:09:14 From：www.hnssd.com