Feature Article
SCHMOLZ + BICKENBACH GROUP
Internal combustion engine: Special steels lower emissions and fuel consumption Average CO2 emissions for automobiles are to be lowered from 130 g to 95 g per kilometre by 2020 to meet European Commission standards. Alternative drive concepts are gaining ground. The classic internal combustion engine, however, is a long way from disappearing, not least of all because it still has great potential for improvement. To comply with the emission standards, downsizing is one of the development targets of the automotive industry: Cubic capacity and cylinders of diesel and gasoline engines are becoming smaller overall, but they are expected to remain just as powerful. The key to fuel-efficient and environmentally friendly engines is a higher degree of efficiency which can be provided by direct injection and turbochargers that supply the optimum amount of air and fuel to the combustion chamber under high pressure. At pressures of up to 3,000 bar and temperatures in some cases of over 1,000 °C, modern steel materials are called for that are particularly resistant to heat and pressure, retain their shape, and demonstrate fatigue strength under vibration stresses. One producer of innovative long steel solutions is the SCHMOLZ + BICKENBACH GROUP.
In the discussion on the improvement of vehicle efficiency, for example, through lightweight construction, the focus is often on flat steel products. Yet high-strength and ultra-high-strength long steel products are also needed to reduce fuel consumption and pollutants: without special steels the
high-performance
systems
such
as
direct
injectors
and
turbochargers would be inconceivable. These materials what make
SCHMOLZ + BICKENBACH GROUP Digital text and images for your article can be found on the enclosed USB stick. 1
Feature Article
downsizing the internal combustion engine and thus sustainable mobility possible in the first place. Direct injection has become the main technology used both in gasoline as well as diesel engines due to the precise metering of fuel. Depending on the fuel type, the requirements on the materials used in these systems vary greatly. In the gasoline engine, heavily stressed components such as the high-pressure pump, fuel rail, injection valves and connectors need to be especially resistant to corrosion. "Gasoline is very aggressive. That's why the steel's sulphur content was reduced to a minimum for the high-pressure pump case. This increases its resistance to corrosion and prevents cracking along the welded seams," explains Manfred Maslow, Sales Manager Automotive Stainless at Deutsche Edelstahlwerke GmbH, one of the companies of the SCHMOLZ + BICKENBACH GROUP. Using special melting and rolling processes as well as selective heat treatment, the degree of purity and fine-grained structures are also improved. The steels Acidur 4057, Acidur 4418 and Acidur 4301 are ideal for these applications. Deutsche Edelstahlwerke has optimized Acidur 4057 specifically for welding applications and for the increasing demands, as it has the other two steels.
In the injecton valve, it's all about the magnetic properties. To be able to regulate the efficient injection of fuel as the valve opens and closes, the material used for the valve needs to be electromagnetically actuated. Only a few steel producers have the expertise to produce the required magnetic properties accurately. The secret is selective heat treatment. The correct processing of the steel also plays an important role since the magnetic values are sensitive to mechanical action. In UGIPERM12FM, Ugitech, another SCHMOLZ + BICKENBACH GROUP subsidiary, has introduced a suitable material to the market: the steel combines optimized magnetic properties with good machinability which in turn allows easier fabrication and thereby reduces cycle times for the customer.
SCHMOLZ + BICKENBACH GROUP Digital text and images for your article can be found on the enclosed USB stick. 2
Feature Article
The challenge for connectors in the fuel injection system is tightness and purity as well as the strength of the material. One example is the connectors used on the distribution pipe of the high-pressure rail, the fuel accumulator between the high-pressure pump and injection nozzle. To withstand aggressive gasoline and avoid leakage, pure, corrosionresistant and mechanically strong steels are needed. "We recommend Duplex steels from our UGIPLEX series for these applications," says Raphael Craen, Automotive Sales Director at Ugitech. "Compared to standard steels, they contribute to better corrosion resistance and good mechanical properties. With fewer alloying elements these steels are also interesting in terms of price." High degree of purity for diesel engines The demands placed on components in diesel engines are more extreme than in gasoline engines due to the higher ignition temperature. While the injection system in gasoline engines is subjected to pressures of up to 300 bar, the long-term development in diesel engines is edging towards 3,000 bar. This also increases the demands attendant on downsizing, requiring the use of bar steels with higher static and dynamic strength as well as a higher degree of purity. Even the smallest material inclusions could cause the component to fail given the high, in part changing loads exerted on it. The purer the steel is, the higher forces it can withstand even at small component diameters. One highly stressed component is the injection nozzle that supplies fuel directly to the combustion chamber. The steels used in these components have to hold up under extremely high temperatures. "This is where our Carbodur 5920 (18CrNi8) comes in. It remains stable at high temperatures and under high pressure," reports Ralf Schneider, Sales Manager Stainless Steel and Automotive at Deutsche Edelstahlwerke GmbH. The material gets its high degree of purity from an electro-slag remelting process (ESR). In this process, the ingot is immersed in liquid slag and remelted when an electric current is applied. As it passes through the slag, the steel is refined: impurities and
SCHMOLZ + BICKENBACH GROUP Digital text and images for your article can be found on the enclosed USB stick. 3
Feature Article
oxides are bound in the slag. The remelting process takes place in a water-cooled mould so that the ingot solidifies uniformly. For thin-walled components subjected to high stresses the SCHMOLZ + BICKENBACH GROUP offers ESR in a protective gas atmosphere at their steel mills. This produces an even higher degree of purity. This material is needed for the delicate nozzle body, for example. Firmodur 7228 (50CrMo4) from Deutsche Edelstahlwerke is ideal as a modified tempered steel for the increasing stresses of these applications.
For the high-pressure common rail in diesel engines Deutsche Edelstahlwerke has improved the standard stainless Microdur 5231 (38MnSiVS6+NB) by adding Niobium, thereby increasing its fine grain stability. Users profit from greater strength, better cleanliness and pressure tightness. The machinability of the forged part is not hampered by the high strength. High and higher strength steels for the common rail system The components used in common rail technology, the current standard for diesel engines, are also subject to high stresses. Components such as nozzle and magnetic clamping nuts hold the system together even at pressures above 2,000 bar. High and higher strength grades are needed for the components to withstand changing loads. In addition to dynamic strength, the steel used to produce the clamping nuts must also be easy to machine. "We manage the balance with ETG 100 and HSX 110," explains Dirk Ochmann, Sales Manager at Steeltec AG, a company of the SCHMOLZ + BICKENBACH GROUP. "The special steels are hot drawn and compared to tempered steels combine the apparently contradictory properties as-delivered." This saves additional machining steps and thus time and money.
Steeltec also has an alternative for magnetic applications like the highpressure solenoid valve. ETG 25 is easy to weld and machine compared to conventional soft magnetic materials - important criteria for the
SCHMOLZ + BICKENBACH GROUP Digital text and images for your article can be found on the enclosed USB stick. 4
Feature Article
efficient machining of turned parts. As a special steel, it is ideal for the compact designs generally needed for downsizing. Components can also be manufactured more affordably in regard to the overall process chain.
High boost pressure in superchargers Engine dynamics are directly linked to the boost pressure produced in the supercharger. As an important element of downsizing strategies, the turbine utilizes exhaust gas energy to compress intake air and inject it into the combustion chamber under high pressure. This produces temperatures of up to 1,000 °C. Heat-resistant steels are in demand for this application, such as UGI 4845 and UGI 4828 from Ugitech. These steels are also used to manufacture sleeves as well as fasteners that hold the turbine together. With this in mind, the steel producer guarantees the input stock's high straightness and dimensional accuracy, thereby also guaranteeing precise, non-warping component manufacture and the safe functioning of the component.
The thin-walled sealing sleeve in the compressor is subjected to alternating stresses. The sleeve seals the bearing case against hot exhaust gases from the turbine and keeps it from losing oil. Long steel products with low internal stresses are needed to be able to manufacture dimensionally stable components even at different stresses. Since a large amount of material is removed during manufacture of the sealing sleeves, ETG 100 is recommended for optimum machining results. To ensure that the material strength does not fail at system temperatures of up to 200 °C, Steeltec subjects the material to a preliminary shaping step during manufacture.
Automotive manufacturers use camshaft phasing units, camphasers, for downsizing to improve efficiency during change of the cylinder charge. They control the opening and closing of the valves. The special demands placed on the part are the transverse loads due to lateral and
SCHMOLZ + BICKENBACH GROUP Digital text and images for your article can be found on the enclosed USB stick. 5
Feature Article
shearing stresses. Camphasers are fitted into the engine in the micrometer range and consequently the alignment dimensions and delicate borings must be exact. A low-distortion material with low internal stress is needed. With its homogeneous structure, HSX Z12 is ideal for uniform component design. The mechanical parameters of the special steel from Steeltec AG help it withstand dynamic stresses better than other tempered steels.
Summary The direct injection system and supercharging are important parts of the automotive industry's downsizing strategy to reduce the emission of pollutants and cut fuel consumption. Components are becoming more compact, but still have to withstand higher forces and temperatures. With their own steel mills, technical know-how and state-of-the-art process and testing technologies, the SCHMOLZ + BICKENBACH GROUP can modify long steels to meet the stricter requirements of the automotive industry and make a contribution to the car of the future.
Length:
10680 characters plus spaces
Status:
7 April 2014
Picture 1: How an internal combustion engine works (©iStockphoto – SCHMOLZ + BICKENBACH) Picture 2: Supercharger (© Alterfalter – Fotolia.com) Picture 3: High-pressure common rail for the direct injection of gasoline Picture 4: Electro-slag remelting plant Picture 5: Steel drawing plant Picture 6: Quality assurance system
Caption 1: The injection nozzle in the IC engine is a highly stressed component that injects fuel under high-pressure into the combustion chamber.
SCHMOLZ + BICKENBACH GROUP Digital text and images for your article can be found on the enclosed USB stick. 6
Feature Article
Caption 2: Numerous long steel products hold the supercharger together to provide efficient air intake into the combustion chamber.
Caption 3: High-grade, corrosion-resistant and mechanically stable steels are needed for the connectors on the high-pressure common rail. Caption 4: Sulphur and non-metallic inclusions are filtered out of the steel during remelting. This gives the material an especially high degree of purity. Caption 5: The ETG 100 and HSX 110 special steels from Steeltec AG develop their high strength properties during the hot drawing process.
Caption 6: To meet the highest standards of quality, the SCHMOLZ + BICKENBACH GROUP tests their steel products on state-of-the-art test stands. About SCHMOLZ + BICKENBACH The SCHMOLZ + BICKENBACH GROUP is one of the world’s leading providers of special high-grade steels. The GROUP is one of the leading producers on the global market both in tool steels as well as for stainless long steels and is one of the three largest companies in Europe for alloy and high-alloy special and engineering steels. With circa 10,000 employees and its own production and distribution companies in more than 35 countries on five continents, the company guarantees its customers global support and supply and offers them the entire portfolio consisting of production and Sales & Services at locations worldwide. Customers benefit from the technological expertise of the company, the same high product quality around the world, as well as a detailed knowledge of local markets. About Deutsche Edelstahlwerke GmbH Deutsche Edelstahlwerke GmbH is one of the leading manufacturers of long high-grade steel products worldwide with over 150 years of experience. The product range unrivalled around the world comprises tool steel, stainless, acid, and heat-resistant steel, high-grade construction steel and special materials. The range of dimensions extends from drawn steel 0.8 mm in diameter as well as forged products 1,100 mm in diameter.
SCHMOLZ + BICKENBACH GROUP Digital text and images for your article can be found on the enclosed USB stick. 7
Feature Article
Customers of Deutsche Edelstahlwerke get the complete production chain from a single source: from manufacture and prefabrication to finishing with heat and surface treatment.
About Steeltec AG Steeltec AG is one of Europe’s leading manufacturers of bright steels. With a focus on high-strength and higher-strength special steels and special free-cutting steels, Steeltec has an establish position as an important partner to the automotive and hydraulic industries and the mechanical engineering sector. Steeltec works closely with customers, suppliers and research institutions to continually improve the production and engineering properties of steel, driving competitiveness across the entire value chain. Working within these partnerships, Steeltec develops high-performance steel solutions that meet its customers’ application needs. About Ugitech S. A. Ugitech is one of the leading manufacturers of stainless steel long products worldwide. The company's main products include billets, bar stock, wire rod, drawn wire that the company produces in its own steel mill and in its rolling mills and wire-drawing plants. The stainless steels are known for their excellent mechanical properties. They are used to manufacture a wide range of parts, such as e.g. valves, turbine components, welding wire or surgical instruments. With over 100 years of experience in steel production and ongoing metallurgical research, the company guarantees optimum steel solutions for demanding applications for its customers in the automotive, construction, process and aviation industries and medical technology.
Corporate Contact Dr. Andreas Knaut • SCHMOLZ + BICKENBACH GROUP Director Corporate Communications and Marketing Phone (CH): +41 (0)41 209-5032 • Fax (CH): +41 (0)41 209-5033 Phone (D): +49 (0)211 509-2067 • Fax (D): +49 (0)211 509-1067 E-Mail:
[email protected] Internet: www.schmolz-bickenbach.com
Contact Deutsche Edelstahlwerke GmbH Melanie Biskup Phone: +49 (0) 2302-292216 • Fax: +49 (0) 2302-2 94-9 78 E-Mail:
[email protected] • Internet: www.dew-stahl.com
SCHMOLZ + BICKENBACH GROUP Digital text and images for your article can be found on the enclosed USB stick. 8
Feature Article
Contact Steeltec AG Petra Hausmann Phone: +49 (0) 7728-649 152 • Fax: +49 (0) 7728-825 E-Mail:
[email protected] • Internet: www.steeltec.ch
Contact Ugitech S. A. Frédérique Tissot Phone: +33 (0) 47989-3012 • Fax: +33 (0) 47989-3434 E-Mail:
[email protected] • Internet: www.ugitech.com External media contact Hanna Maurer • additiv pr GmbH & Co.KG Public relations for logistics, steel, industrial commodities and IT Herzog-Adolf-Straße 3 • D-56410 Montabaur Phone: +49 (0)2602 95099-15 • Fax: +49 (0)2602 95099-17 E-Mail:
[email protected] • Internet: www.additiv-pr.de
SCHMOLZ + BICKENBACH GROUP Digital text and images for your article can be found on the enclosed USB stick. 9
