Lagging Material Developed with Local Stuff

The railway design institute of the Ministry of Railways developed lagging for carriage manufacture with locally available materials.


The Railway Design Institute

The Railway Design Institute. (Photo Credit Rodong Sinmun)


The main material used in the development of the lagging is perlite. Generally, perlite is an effusive rock composed of acid volcanic glass. But when it is heated to over 1 000 degrees centigrade, it gets desiccated and becomes expansion perlite which has more than four times the original volume. The generated substance is elastic and highly resistant to fire and has a low thermal conductivity.


The researchers solved technical problems so as to find a rational method of increasing the expansion rate of perlite and improve its qualitative features, and set up an expansion perlite production process.


According to Kang Myong Guk, section chief of the institute, the expansion perlite with a light volume weight and low heat conductivity can be used for heat insulation in various fields such as construction, chemistry, metallurgy and light industry as well as in the manufacture of railway carriages.


The new lagging material developed by the institute was inscribed as an advanced product by the State Commission of Science and Technology in acknowledgement of its low production cost and high quality.


(Pyongyang Times - February 3, 2021)

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