ArcelorMittal's dual phase steel brings lightweight gas cylinders to the barbecue
Gasflaschenwerk Grünhain (GWG) is Germany’s only manufacturer of welded steel cylinders for liquid gas and refrigerants. One of GWG’s latest innovations is the Premium 21 gas cylinder which has been designed using a dual phase grade DP600 from ArcelorMittal Europe – Flat Products. Commonly used in automotive applications, this high strength grade makes the Premium 21 lighter than its competitors while taking advantage of the safety and strength properties of dual phase steels.
GWG’s Premium 21 BBQ is designed to fit perfectly into the bottom of common gas barbecues sold in Europe. The empty weight of the cylinder is just 6.3 kg, but it can be filled up to 8.2 kg, significantly more than other cylinders on the market.
GWG has also developed a prototype design for a smaller gas cylinder – the Premium 21 Medium. This cylinder weighs just 5 kg empty, but has a filling capacity of 6.5 kg. That’s 1.5 kg (30 percent) more than traditional 5 kg cylinders.
Higher quality and safety with our dual phase steel
The extra capacity of the Premium 21 cylinders is largely thanks to the use of dual phase steels as Hans-Jürgen Werner, GWG’s managing director and executive partner explains: “DP600 offers an excellent combination of strength and deep-drawing capabilities. For GWG’s gas cylinders, this translates into higher product quality and safety, and larger filling capacities.”
The Premium 21 BBQ replaces a gas cylinder designed in 2012. That design utilised a standard mild steel grade (P310), giving the cylinder an unfilled weight of approximately 8.6 kg. Replacing the mild steel with a dual phase grade reduced the weight of the BBQ by 2.3 kg (almost 27 percent).
Technical support from ArcelorMittal vital in early stages
The process of designing the Premium 21 took around 18 months from initial concept to serial production. “We counted on technical assistance and advice from ArcelorMittal throughout the project, but especially in the early design and material selection phases,” notes Hans-Jürgen Werner. “We took advantage of ArcelorMittal’s experience and requested detailed advice such as forming simulations and the temperature behaviour of the material.”
GWG only decided to use a dual phase grade after completing extensive research and discussions with ArcelorMittal. “The technical characteristics, and especially the processing properties of this grade, influenced our choice decisively. As manufacturers of pressure vessels, good formability and weldability of the material were critical factors,” says Hans-Jürgen Werner.
Right cost-benefit balance
A number of technical changes and adjustments were made to GWG’s manufacturing processes to produce the new Premium 21 cylinder explains Hans-Jürgen Werner: “In addition to new forming and drawing tools, we developed different weld preparations to counter the formation of beads. We also finished the cylinder with a multi-layer coating. That required us to change some process parameters related to the pre-treatment of the raw cylinder.”
The cylinder can be produced in almost any colour, depending on the client’s preference. Embossing, silk screening, and stickers can be applied to further customise the finished cylinder.
“The Premium 21 offers clear added value compared to the conventional gas cylinder we made with mild steel,” says Hans-Jürgen Werner. “We knew we would need to convince our customers of these benefits, and the latest figures from 2016 show that this is working. The Premium 21 offers consumers the right balance in terms of costs and benefits!”
GWG has been manufacturing gas cylinders at its modern plant in the Ore Mountains, Germany for more than 85 years. The company produces a wide range of premium cylinders for propane, propellants, and refrigerants.
GWG also offers a repair and revision service for welded gas cylinders used to store liquid gas and refrigerants. The revision procedure includes degassing, thermal, paint stripping, repair, labelling, pressure testing, inspection, and internal cleaning.