Page 25 - ITAtube Journal 1 2024

Technical Papers
impact the outcome: Alignment of the pass line, condition and adjustment of the rolls, guiding of the billet and hollow bloom, etc.
3 New Piercer Concept
SMS has been continuously working on improving the design of its Piercing Mill. A dedicated design team has been developing significant improvements. The improved design of the SMS piercing mill strives towards the vision of “No eccentricity”. The design team made improvements to some core assemblies, such as:
• Mill stand design,
• Hydraulic adjustment of the piercing rolls,
and
• Diescher Disc adjustment.
The new design of the mill stand requires approx. 30% less height, but simultaneously improving its rigidity. This new symmetric stand design improves the flow of the rolling forces by transmitting the load symmetri- cally in the stand. This symmetric strain in the stand allows an optimized correction behavior during rolling to compensate the mill expansion.
The new mill stand design also consid-
ers changes to the Diescher Disc bearing. In the past, this was separated from the stand. The new solution integrates the disc directly into the mill stand, improving the rigidity of the system and bringing benefits to accessibility and changeover. Further- more, the adjustment of the Diescher Disc has been redesigned allowing an infinite variable positioning of the disc in all three axes. This allows perfect positioning of the disc in relation to the technological process requirements.
Also integrated into the stand is the three- roll-guide at the outlet side of the piercing mill. With the modifications in the mill stand design, the distance of the first guide to
the gorge is shortened, thus optimizing the guiding behavior.
Additionally, a new solution for hydrau- lic adjustment has been integrated. The solution optimizes the original design to a compact solution by substituting the mechanical screw down with hydraulics
ITAtube Journal April 2024
New Piercing Mill Model
and combining it with the already existing hydraulic adjustment solution. This results in better system stability and a reduction of the loads on the roll assemblies.
Aside from the design targets of improving the process, the new design has also been optimized from a maintenance and accessi- bility perspective. One of such optimizations is the improved scale removal concept. The concept contains the scale falling off and guides it into dedicated scale removal pipes toward the flume system. This improves not only the necessary cleaning effort of the mill, but also reduces the risk of failure of assem- blies due to scale particles.
4 Conclusion
Overall, the new design of the SMS Cross Roll Piercing Mill is another technological step in seamless tube technology. The advantages and new features bring new benefits and possibilities to the producer of seamless tubes for the OCTG market on the way to “No-Eccentricity”.
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SMS group GmbH
Ohlerkirchweg 66
41069 Mönchengladbach Germany
Tel: +49 2161 350 0 communications@sms-group.com www.sms-group.com