EuroWire May 2021

Focus On Germany, Austria & Switzerland New shaving line for non-ferrous wire

Kieselstein International, located in Chemnitz, Germany, is a manufacturer of wire shaving and drawing equipment with more than 100 years’ experience. In the steel wire industry, the company is an expert in surface treatment by the removal of layers with imperfections. The wire shaving or draw-peeling technology

is a combined process with a high level of flexibility and a high production rate. In 2004, the company established a laboratory for testing and development of technology. The focus was initially on wire shaving. With continuous investment in wire shaving machines, additional equipment for fine wire shaving for welding wire applications, and an investment in technology for hot drawing at the end of last year, the company is further developing applications for drawing and shaving. These improvements are expected

on the application, for effective handling of the wire in the machine, the correct choice of corresponding tools and the right set-up of production speed. A newly developed line for a supplier in the aerospace industry is one example of the Kieselstein philosophy to develop projects in close cooperation with the customer. The customer requirements are recorded, and a study of the right technology is carried out. If shaving can provide advantages for the customer and it matches the performance and economic figures, a test-shaving demon- stration on the Kieselstein laboratory in-house machine is suggested. By testing the customer’s wire and the production of samples, which can be small pieces as well as full coils, the customer can anticipate the results and the benefits of a potential investment in the technology. The results can be drawn in the customer’s plant to the final diameter. Kieselstein International GmbH www.kieselstein.com Specimen grips have been developed specifically for wire strand testing, and options are available to test strands without having to use specially attached gripping elements. This development reduces the required sample handling, time and expense for the customer. Grips feature hydro-mechanical and straight mechanical clamping. The remaining portion still needed for the respective test is provided by classic hydro-mechanical clamping via jaws. The combination of these two gripping principles enables the gripping force to be applied in such a manner that jaw breaks are eliminated, and wire strands can be tested without being pre-treated. The specimen grips are flexible and can be used for a wide range of applications. The variably adjustable hydraulic grip- ping force can be easily changed from test to test by regulating the oil pressure. Tests are typically performed with a servo-hydraulic testing machine. ZwickRoell Ltd www.zwickroell.com

to lead to newly designed equipment and to widening the scope for meeting the needs of customers worldwide. materials, shaving can be used to remove oxide layers, imperfections and defects, and to improve quality. The shaved wire is a homogeneous material with performance attributes for high dynamic load and high demands on the surface quality. The equipment is adapted depending For non-ferrous

The new shaving line developed at Kieselstein

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Dynamic testing of pre-stressing steel and stranded wires

ZwickRoell is a supplier of materials and component testing systems. It supplies both standard and tailor-made solutions for demanding requirements, in research and development, production and quality assurance, across more than 20 industry sectors. Pre-stressing steel is a high-strength steel that is primarily used for pre-tensioning in pre-stressed concrete construction. The use of pre-stressing steel makes it possible to increase the properties of concrete structures for static and dynamic loading. The steel may take one of three different forms: steel bar (15 to 36 mm), wire (5 to 16 mm) or strands made of either three or seven individual wires twisted around each other (the nominal diameter of the wires for three-wire strand is 5.2 to 7.5mm, and for seven-wire strand the diameter is 7 to 18mm). These various forms place high demands on materials testing. Manufacturers are required by product standards to perform dynamic tests on stranded wire. These tests are often outsourced to a service provider to

save equipment costs. Additionally, the manufacturers are externally monitored by independent institutes. During fatigue tests on wire strands, the specimen must endure two million test cycles at a maximum test frequency of 20 Hz without breaking. If the specimen breaks nearby or within the gripped portion, the test is invalid and must be repeated. Due to the number of required test cycles, the test lasts several days, so invalid tests are very costly. As stranded wires are extremely stiff, they are also very sensitive to notches. The gripping force causes a load to be superimposed on the dynamic test load in the specimen’s clamped area, which can lead to premature specimen failure. For classic tensile specimens made of solid material, the ends often have larger cross-sections to ensure that the specimen fractures in the free portion between the specimen grips. With wire strands it is not so simple: to obtain satisfactory test results it is necessary to carry out extensive specimen preparation, such as sealing.

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May 2021