Established brand for the toughest applications

DILLIDUR high-performance steels enable longer service and lifetimes and therefore contribute to much improved cost efficiency. Besides the exceptional wear resistance and quality of the products, especially the integrated range of services at the manufacturer Dillinger Hütte is crucial to success. With ANCOFER Stahlhandel GmbH based in Mühlheim/Germany, Dillinger Hütte has a specialist for wear-resistant steels within the group of companies, which counts especially the manufacturers of construction machines among its customers (Fig. 1).

Unscheduled downtimes caused by wear-related damage lastingly impair productivity and efficiency. To improve the performance and lifetime of heavy-duty machines such as dump trucks, excavator buckets, grapples or backhoes, leading manufacturers and suppliers of construction machines worldwide depend on wear-resistant DILLIDUR brand steel (Fig. 2). With a consistent surface hardness up to 500 Brinell hardness HBW, according to Michael Feldhoff, customer consultant at ANCOFER, it lasts three or more times longer than standard structural steel depending on the application and DILLIDUR steel grade. Thanks to the exceptional hardness and strength, DILLIDUR brand steel enables lighter weight structures with less material input and higher payloads. Crucial for the efficiency of the up to 150-mm-thick and 4500-mm-wide heavy plate in the case of DILLIDUR 400V is also the unique combination of good cutting and welding properties with formability. Despite comparatively low preheating temperatures, high crack resistance is ensured.

Thanks to decades of experience at Dillinger Hütte with ­DILLIDUR and its spectrum of applications, the analysis concept has been optimized accordingly. Combined with excellence levelness and homogeneity, DILLIDUR brand steel therefore offers the best preconditions for efficient machining and high-load structures boasting longer availability. The basis for this special capability of DILLIDUR is the leading-edge technology applied in its production from casting to quenching. Rolling forces of 108 000 kN (around 11 000 t) lead to very high thickness reductions of the up to 450-mm-thick slabs, which are rolled to plate dimensions. This strong deformation is the reason for the excellent homogeneity in the critical core zone of the plate (Fig. 3).

Crucial for success: dependability on the highest level

Kaspar-Heinrich Schlüter, Managing Partner responsible for technology at Schlüter Baumaschinen GmbH based in Erwitte, has relied out of conviction on these high-performance steel and the proven partnership with ANCOFER since 1998. For over 50 years, his company has sold and hired out construction and handling machines in all sizes – from 1.5 t for garden landscaping to 100 t heavy-duty machines. As a system supplier, the company supports its customers with customer-specific application consultation through product selection, sale or hire, engineering of special customized solutions to financing, training and service. With 22 branches and 547 employees, including 60 trainees and apprentices, Schlüter is one of the biggest companies of its type in Germany. As an authorized dealer for Komatsu construction machines, Sennebogen handling equipment, NPK attachments and Topcon machine controls, the company is much in demand as an expert with exclusively internationally established premium products, who closely supports its customers over the entire lifetime of their machines.

In the last 24 months alone, Schlüter has repaired 11 600 machines, within the last twelve months it has designed and manufactured 980 attachments. Besides wear-resistant rock backhoes with a net weight of 15 kg to five tonnes or standard and tip-up buckets, these include extremely durable attachments such as rippers, hammers, protective equipment or snow ploughs as well as adapters and variations on these. Schlüter’s HCT manufacturing for construction machines is always required when customers need individual solutions for basic machines – either as newbuilds or as modifications of factory-standard products. These needs-driven special solutions have to take into account the character of the carrier vehicle as well as optimum adaption and the specific application (Fig. 4).

Tailor-made

For instance, Schlüter is manufacturing a rock backhoe with a net weight of 5.2 t for a 80-t Komatsu PC800 backhoe machine. The front is fitted with shrouds for impact protection and corner shrouds as hard-facing (Fig. 5). Side sections and side blades are made from DILLIDUR 400V to withstand the wear inflicted by the rock for longer. The face of the side blade is further strengthened with hard-facing bars made from a steel composite. Unlike standard backhoes, Schlüter makes the rear trough section not from two 15-mm-thick plates welded on top of each other with additional impact protection bar, but relies directly on 30-mm-thick DILLIDUR 400V (Fig. 6).

A special machine can bend this 3-t-heavy plate over the entire length of 2 m in line with individual customer requirements. The shaping of the opening and closing angle is designed precisely for ball operation to strengthen the rear wall take the enormous strain on take-up of the nine-tonne ball. On customer request, areas under particular strain can be additionally reinforced with a 15-mm-thick impact protection bar. In addition, Schlüter replaces the tooth system delivered as standard with the machine with a system that the customer uses for his entire fleet. As the machine manufacturer does not offer this system, Schlüter modifies the bucket accordingly. It takes around three weeks from receipt of the order to creation of the bill of materials and material requisition to delivery of the required parts. Two days long the shaped parts are flame-cut out of the plates according to a cleverly ­devised nesting plan to minimize offcuts.

Large-size shovel at a limestone quarry

The manufacture of a shovel for a 35 t WA500 wheel loader used in a limestone quarry clearly demonstrates the extensive design and manufacturing potential of HCT manufacturing at Schlüter for construction machines and the range of applications for DILLIDUR 400V (Fig. 7). From the modular system developed by Schlüter over the years, the base body of the shovel is chosen. The rear troughed section is made of 30-mm-thick DILLIDUR 400V curved over the full length,

Characteristic for HCT manufacturing at Schlüter is the design of the apron with corner windows, which improves the range of vision for the machine operator. Side blades and sections are made of 1.5 t wear-resistant DILLIDUR 400V and reinforced at particularly critical areas with impact protection bars. At the front, the shovel is given a wear edge in line with the customer’s individual requirements. As another special feature, Schlüter does not choose the usual tooth system with replaceable cap, as experience has shown that the welded seam required for this can weaken the blade on account of the microstructural change in the material caused by the weld. To reduce the weld seams Schlüter makes the shovel and teeth from one piece of ­DILLIDUR 400V.  The blades are bevel-edged with the in-house CNC flame cutter (Fig. 8), which facilitates penetration into the material to be excavated, the saving in force consequently reducing fuel consumption.

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