Hot goods in aluminium

Photo: ZPF

Whether foil packaging or car body part – aluminium is indispensable as a light metal in many production sectors and branches of industry, despite new materials such as carbon fibre reinforced plastics. Efficient processing of aluminium is ensured by special, energy-saving melting furnaces for instance those produced at ZPF GmbH, located in the German federal state of Baden-Württemberg.

Resistance against gouging and abrasive wear in impact crushing arms cast from Mn-steel, is related to variations of carbon, manganese and the microstructure of the cast steel. Additions of Boron, molybdenum and chromium to the plain Mn-steel casts (0.8-1.4%C-13%Mn) increase its wear resistance and fatigue life time during crushing operation due to enhancement of its strain hardeing capacity, grain refinement and strengthening by solid solution hardening of the matrix. This improvement is due to the intended change in the microstructure where precipitation of boron carbides and chromium carbides inside the austenitic matrix, grain refinement and increasing soluble carbon content in austenite phase is occurred. Solution treated Mn-steels (1050C, 2h, WQ) alloyed with boron showed crushing capacity of about 1200-1550 tones basalt per set depending on their compositions. The hardness of the as water quenched austenite is increased by about 25% to reach 397 HB when alloyed with 0.37%B. However work hardened matrix of Cr+Mo+B modified Mn-steel impact arms showed a bulk hardness of about 498 HB. The fatigue resistance of boron alloyed steel is increased to about 1.4 times over that measured for plain Mn-steel.

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Chips of various morphologies formed during surface grinding of cast AISI 409 stainless steel slabs have been examined in light microscope and SEM. Dynamic nucleation of fresh grains occur in the work hardened layer of chips of various morphologies, but growth of these grains on the chip surface is highly non-uniform. Iron rich oxide nodules also grow on the chip surface.

Enameling steel has important applications in our daily life as in domestic appliances and industry (chemical, agro-food, storage tanks, heat exchangers..etc.) due to its outstanding properties resulting from combined advantages of steel and enamel. The combination of such steel and enamel provides durability and glossy appearance that withstand chemical corrosion, abrasion, thermal shocks and fire. The durability and quality of enameling process depends to a great extent on the quality of substrate (enamel steel). To ensure an acceptable quality of such steel to be enameled, care must be taken during steelmaking and refining such grade to obtain low carbon levels (0.03-0.05%max) and minimum count of inclusions. The morphology of inclusions is adjusted by Ca-cored wire feed technology however melt stirring using Argon is very useful to minimize inclusions and gas contents. Vacuum decarburization of steel melt to ensure low carbon levels prevents the black specks during firing of such steel sheets; however micro-alloying with 0.2-0.5% Ti or V stabilizes the rest of carbon and creates default sites for hydrogen after cold rolling to prevent fish scale phenomena after enameling. Assessment of inclusion counts and their morphology as well as distribution of carbides are carried out using scanning field electron microscopy and ASTM standard.

news in steel

Quick and successful turnaround for an effective rolling process

Following the successful commissioning of the upgraded bar mill at its Basauri location, Spanish company SIDENOR ACEROS ESPECIALES, S.L. has issued the final acceptance certificate (FAC) to SMS group (www.sms-group.com).

SSAB Form Tube Plus – new precision steel tubes with superior properties

SSAB Form Tube Plus is a completely new family of precision steel tubes that provides a unique combination of bendability, dimensional accuracy and superior surface quality suitable for high-gloss painting and chrome plating.

Profiling aluminum vacuum brazing furnaces

Fluke Process Instruments provides a dedicated temperature profiler for aluminum vacuum brazing furnaces. The Datapaq Furnace Tracker system automatically generates CQI-9 and AMS 2750E reports.

Daehan Sinpyeong upgrades rolling mill with new quenching and HSD® lines

South-Korean Daehan Steel Co. Ltd. is modernizing a bar mill . The rolling mill in Daehan´s Sinpyeong works located in the Busan area is designed to produce 130 tons per hour of rebar in diameters from 16 to 32 millimeters up to grade SD 500.