Unique rail production begins in China

January 2015

SIEMENS Metals Technologies has received notice from Baotou Iron & Steel (Group) Co Ltd that the in-line “Injector Dual-phase Rail Hardening” (Idrha+) achieved the expected performances for the rail R60 U75V gr.340 according to TB/T2344-2012 norm and has therefore entered the regular commercial production. The rail is the first in the world to be commercially processed through Idrha+, and is now in industrial production already at Baotou Iron & Steel (Group) Co. Ltd in Baotou, Inner Mongolia, China.

The system, contracted to Siemens in December 2012, is capable of improving the rail resistance to both wear and rolling contact fatigue, and was designed by Siemens Metals Technologies and Centro Sviluppo Materiali SpA (RINA-CSM).

Idrha+ enables long hardened rails up to over 100 m length to be in-line processed for improved resistance to contact fatigue and wear.

The grade U75V is one of the most widely produced rails for high-speed application. After head-hardening treatment with Idrha+ process, all the obtained mechanical and metallurgical characteristics of the rails exceed the values required by the applicable standards. In particular, the minimum values of UTS tensile strength and A percentage elongation are 1,180 MPa and 10 per cent, respectively. The measured values of hardness range from 340 to 400 Brinell HBW10/3000 at the surface of the rail head, and from 34 to 42 Rockwell HRC across the rail section, according to the applicable measuring protocol. R60 U75V gr 340 is now in industrial production already at a rate of 15 pieces per hour with a 100 m standard length.

The design of the Idrha+ system is based on thermo-mechanical and metallurgical process models, and validated by experimental trials in a pilot plant.

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