Page 26 - ITAtube Journal 1 2024

Technical Papers
SMS group GmbH
ERW Tube Welding Line RD 710
A step into new dimensions Author: Christian Haferkamp
1 Introduction
The SMS group is worldwide known for its capabilities to design and build plants for the steel industry. Usually, these are hot rolling mills for different products like plate, beams, sheet or tubes. These mills consist of tons of steel, highly sophisticated technology and automation to make complex processes work. The overall investment in such plants quickly exceeds one billion euros.
Plants for tube-producing Electric resist- ance welded (ERW) tubes are not playing
in the same category, since now. The new RD 710 brings a new dimension of ERW-mill to the market. This largest ERW mill can produce tubes up to a max. diameter of 28”, i.e. 710 mm.
Now why this new dimension of ERW- tubes? There are tube-making processes for this kind of diameter with a submerged arc welding process (SAW). The market for OCTG, automotive or boiler tubes doesn´t use such sizes.
But the construction market does!
2 Hollow structural sections
This ERW mill is capable to produce Hollow Structural Sections (HSS) with dimensions of 22“ square (559 mm x 559 mm) or 34“x10“ (863 mm x 254 mm). These HSS are used as structural elements in buildings and other structures. These buildings are for example stadiums or skyscrapers.
These HSS bring significant benefits versus a comparable open section. The main benefits are:
• High Strength-to-Weight Ratio
• Closed Section
• Aesthetic Appeal
• Cost-efficient production
The high gyration radius brings a high strength-to-weight ratio resulting in less
weight and higher stability. Then, HSS are closed sections, which are advantageous for resisting torsional loads and, since HSS have approximately two-thirds the surface area of an open section of comparable capacity, the efforts in finishing (e.g. coating or painting) is less.
The shapes with smooth sides, rounded corners and closed sections have a natural aesthetic appeal so there is no need for cladding or facing.
On top of that, also the production process is more cost-efficient than the alternative rolling processes due to lower Capex invest- ments and lower conversion costs.
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Figure 1: X-Pact® Quicksetting by SMS group
3 Technical features of the RD 710
The RD 710 has been designed to allow cus- tomers to utilize these benefits and produce high-quality HSS. Not only the size range is pushing the limit, but also the wall thickness is. With up to 1” (25.4 mm) wall, the line is capable to produce thick walled ERW tubes. These dimensional capabilities, combined with production speeds up to 35 m/min allow the RD 710 to run a nominal capacity of 400.000 tons per year.
The line arrangement is quite usual with a strip preparation area, a horizontal strip
ITAtube Journal April 2024