Siemens to Supply Twin RH Vacuum Degassing Plant to Mexican Steel Producer, AHMSA

Siemens Metals Technologies has won an order from Mexican steel producer Altos Hornos de Mexico, S.A.B. de C.V. (AHMSA) to supply a 150-ton, twin RH vacuum degassing plant with mechanical vacuum pumps for converter Steel Works # 2 in Monclova.

It will be able to handle 50 charges per day, the equivalent of about two million metric tons of liquid steel per year. The new plant will allow AHMSA to produce steels with very low hydrogen content, required for applications in the oil and gas industries. The new RH plant is scheduled for commissioning in October 2015.

Computer animated diagram of a double RH vacuum degassing plant from Siemens. An RH plant with a processing capacity of two million metric tons of liquid steel per annum will be constructed in Monclova, Mexico, for Altos Hornos de Mexico (AHMSA).

The main functions of RH degassing plants are the removal of hydrogen, forced decarburization and the chemical heating of the liquid steel which is processed under vacuum conditions with the injection of oxygen. Low hydrogen content is the main prerequisite for producing high-strength steel grades intended for use in the oil and gas industries.

For AHMSA's twin RH plant in Monclova, in the state of Coahuila, Siemens will supply the vessel, mechanical vacuum pumps, the structural steel work and a combined vessel ladle lifting system (CVL). This solution requires little space, enabling vessels to be lifted in places inaccessible to cranes. The scope of supply from Siemens also includes the electrical and automation equipment for the RH plant.

With an annual production of 4.2 million metric tons of liquid steel; which, upon the start-up of its new Electric Arc Furnace in September 2014, its production will increase to 5.5 million metric tons, AHMSA operates the largest integrated steel works in Mexico. The company is the market leader in the production and marketing of flat products, such as hot and cold strip, and tinplate. The product portfolio also includes heavy-sections.

Further information about solutions for steel works, rolling mills and processing lines can be found at


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