Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 24 Page 25 Page 26 Page 27 Page 28 Page 29 Page 30 Page 31 Page 32 Page 33 Page 34 Page 35 Page 36 Page 37 Page 38 Page 39 Page 4014 APRIL 2017 • FOGHORN FOGHORNFOCUS: SHIPBUILDING S hipbuilders are facing a new challenge to remain competi- tive: With the commitment of steel suppliers to develop steel grades to meet the growing demand for in- novative ship design, now shipbuild- ers have to look into their processing methods and decide how they can maximize on the characteristics of the materials supplied in cost-effective processing. The use of innovative steels drives the need for innovative pro- cessing solutions. An example would be the Tailor Welded Plate® (TWP), a worldwide unique processing method developed by Graebener in Germany to manufacture large deck sections of different plate thicknesses in a fully automated and cost effective way. One of the main reasons for this unstoppable evolution is that ship designers have increasingly looked to steel suppliers for materials that can offer better performance characteris- tics through metallurgical structure, physical properties and tighter di- mensional control. The demand in the shipping industry for higher efficiency in fuel consumption, while not sacrific- ing vessel capacities and performance, are challenging designers even further to apply materials which would be a challenge to the ship builders’ fab- ricating practices. This demand for increased vessel performance can be found in all sectors of the maritime industry. Naval – Commercial – Passenger Vessels For the steel supplier, they have risen to meet these requests by investing in processing improvements that can deliver larger sectional plates and profiles with the design standards met. An example of this evolution is the growing use of thermomechani- cal controlled rolled plate (TMCP) as already outlined in various technical articles. TMCP can offer to the ship- builder--and ultimately the customer- -a wide range of savings in fabrication cost and long-term savings in vessel performance. A short list of savings would be: • HST steels offer enhanced properties in reduced plate sizes. • Reduced plate size offers weight savings in the structures. • HST steels offer greater load capaci- ties in use. • Savings in manufacturing in weld preparation, welding and fabrica- tion. With the development of more demanding designs and the increasing use of TMCP steels the challenge now moves to the ship builder to look for more cost effective processing methods. Typical challenges such as wavy plates, uneven plate edges or welding error must no longer be an issue for ship builders when it comes to process reliability. In the highly competitive field of the world’s leading shipyards, high-precision manufacturing processes with constant quality which ensure an automated, economic and process reliable production of modern ship decks are long established. In the integrated system referenced above, TWP combines milling and laser Innovation and Automation: Driving the Evolution of Shipbuilding By Steve Tesanovich, Graebener, Inc. – USA About the Author Steve Tesanovich, President & CEO of Graebener, Inc. – USA, has 40+ years experience in steel and pipe fabrication, machine design and production. Based in Houston, TX, Graebener is a new PVA Associate member. welding process optimally attuned to the material. Different steel plates with lengths of up to 30 meters and a wall thickness between three and 30 mm are joined to deck sections fully auto- matically. With this system, a process reliable and fully automated produc- tion of ship deck sections of various wall thickness is possible as well. In contrast to the conventional submerged arc welding process with seam opening angles of up to 30 degrees, the TWP process applies the laser-hybrid welding technology. The seam opening angle only is about 8 degrees which saves time and material but also considerably reduces the intro- duction of heat into the material. As a consequence, unwanted tensions in the plate are reduced to a minimum. By means of a MIG torch, the seam edge is melted and filler material is introduced. Due to the penetration welding effect, the trailing focal spot of the laser carries out the melting down to the root. The laser creates a welding joint with small seam opening angles so that the plates now only have to be welded from one side. In addition to this, the laser-hybrid process has the advantage that the welding speed is much higher than with other welding processes. Thus, welding speeds of up to 2,500 mm per minute can be achieved. The main prerequisite for an optimum welding process, however, is an optimum weld seam preparation. In general, milling processes are more favorable than other methods such as for example plasma cutting. Most diverse seam types can be generated without any problems. Chamferings for the compensation of plate thickness deviations are possible. The milling process does not introduce heat into the plate, thus avoiding tensions in the workplace. Due to the metallic bright surfaces after the milling process, no