TPi March 2014

7-11 April 2014



in a common hot forming process at around 1,150-1,250°C. The metallurgical connection between the two materials is achieved in the solid state using pressure-accelerated solid state diffusion. A diffusion zone approximately 10µm thick forms between the materials, which is responsible for a high-strength, oxide-free metallurgical bond of materials. The fine microstructure configuration of the layer and base material is preserved, with no variation in the alloy concentration. Smooth surface structures avoid deposition of corrosion- promoting ash and salt particles from the flue gas. Special cross-section forms such as fin tubes, omega tubes or double omega tubes are possible. Cold bending is also possible, since there is no cast structure created by cladding. HUS Ltd, a Bulgarian steel products manufacturer and distributor, is launching a new steel tubes and hollow sections production facility. The factory spreads out over more than 200,000m 2 , with 60,000m 2 covered halls for industrial production, heavy-lifting cranes, administrative building and other assets. The initial tube products range from 10 to 219mm for round pipes; from 10x20 to 100x200mm for rectangular tubes; and from 15 to 150mm for square tubes, with thicknesses of up to 8mm. Production capacity will be up to 12,000mt per month, planned to be implemented in stages. The production lines and machines are brand new, corresponding to the latest technological standards, and the welding equipment is provided by EFD Induction. The company was founded in 1990 and has experience in steel processing, including electro-welded steel tube manufacturing. info@hoesch-profile.com www.hoesch-profile.com HUS Ltd Bulgaria 7C28

For TIG/plasma applications, in-line control of penetration is possible. Unsymmetrical penetration is detected, which can also be caused by arc deviations. The optics developed for laser welding processes allow the recognition of pores and ‘out-of-positions’ of 5/100mm only from the temperature field. All systems evaluate the welding quality automatically and enable universal documentation of the temperature fields.

Extruded tubing with internal and external layer

The classic seamless steel tube for pressure vessels represents a key construction element in the building of thermal plants. The requirements for boiler construction steels become more exacting if, instead of conventional boiler fuels such as coal, oil or gas, other sources of energy are used that result in strongly corrosive combustion products. For instance, boiler tubes in a waste incineration plant are not only exposed to thermal loads, but are also subject to corrosive attack, fundamentally triggered by the chemical element chlorine. For this specific application, the conventional boiler tube used in plant construction with its proven component strength was equipped with a ‘coating’ using a corrosion-resistant austenitic material. The intention behind this combination of materials is to allow the carbon steel to handle the thermal- mechanical load on the tube, while the austenite provides protection against corrosion from the prevailing environment. Clad pipes (where the corrosion- resistant layer is applied to the tube body by welding) have one or two layers of corrosion-resistant outer covering, approximately 2.5mm thick. This is applied using fusion welding, which creates overlapping welding beads. During welding, there is an intermixing of a few tenths of a millimetre between the carbon steel and the austenite. In metallurgical terms this is equivalent to a ‘dilution’ of the high-alloy layer material. Since it is obtained via the liquid phase, the layer material is characterised by a casting structure typical of welding. The development of composite tubing pursued by Hoesch Schwerter Profile GmbH was undertaken with the aim of overcoming the known disadvantages particular to clad pipes. The carbon steel component and austenitic layer of the extrusion billet are manufactured

info@hks-prozesstechnik.de www.hks-prozesstechnik.de

Hoesch Schwerter Profile GmbH Germany 3G25

Hoesch Schwerter Profile develops products in collaboration with specific fields of industry and customers. Modern power stations and industrial plants are two areas where special steel solutions are used that are required to withstand extreme loads.

Visit us at booth number 3F27

Leading stockhoLder in nickeL aLLoys

50 YEARS Hart bv

• Alloy 200/201 • Alloy 400 • Alloy 600 • Alloy 625 • Alloy 825

The establishment of the tube factory is a logical course of action, expressing

www.hartbv.nl | sales@hartbv.nl

86

TUBE PRODUCTS INTERNATIONAL March 2014

www.read-tpi.com