Primary ingot aluminium

Two shaping techniques were found to be acceptable turning on a lathe and cold rolling. In the latter thin plates are prepared from freshly turned pieces. The reduction in thickness must be smaller than 5 % per rolling pass. 

In the case of oxygen and carbon shaping has to be followed by etching. Etching parameters are  

Experiments conducted in parallel in two laboratories have shown that the mechanical surface preparation of the specimen is essential. As appears from Table III-4 slight differences may produce substantial deviations, even after identical chemical etching (2), 

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In addition to emission spectrometry with plasma excitation as described by Grallath et al. (8), which is claimed to be very precise even at the sub-A g/g level, activation analytical methods are well suited for this type of analysis. In the frame of a BCR round robin (Table IV-5) good agreement was obtained between instrumental proton activation analysis and deuteron activation analysis with radiochemical separation of Be or (31). These results indicate that interference from lithium in proton activation analysis is not significant in normal primary ingot aluminium. 

Table IV-5 Results of a BCR round robin for boron in primary ingot aluminium...

The radiochemical separation of after irradiation and sample etching is mandatory. The oxidizing fusion method in helium described in chapter II, section 3.8.2 has been used to determine carbon in primary ingot aluminium. 

As the carbon content of aluminium is generally low, combustion methods as such are only of limited use, as they suffer from blank problems and lack of sensitivity (1 /tg/g). In round robins organized by BCR on the analysis of carbon in primary ingot aluminium (Table V-8) only photon (or helium-3) activation analysis in combination with combustion and deuteron activation analysis in combination with Kjeldahl led to significant, and probably also accurate results. 

The procedure described below was adopted to determine traces of oxygen in primary ingot aluminium (261). Cylindrical samples (diameter 15 mm, thickness 8 mm), weighing about 3.7 g each, are etched just before irradiation at 80°C in 5 volumes nitric, 70 volumes phosphoric and 25 volumes sulphuric acid. After rinsing with distilled water and drying in warm air, they are enveloped (helium blanket) in aluminium foil and irradiated for 4 minutes by photons of 40 MeV maximum energy (mean intensity of electron beam 75 fiA). 

During the seventies important progress has been made in the analysis of oxygen in aluminium as shown in Fig. VII-13 for primary ingot aluminium no longer values of approx. 

Fig. VII-13 Trend of the "apparent oxygen content" of primary ingot aluminium (275)...

Aluminium alloys are cast in the cast houses of aluminium smelters and at the cast houses of the plants for the secondary aluminium. At smelters, the raw liquid aluminium is transported from the reduction shop in the ladles. Primary aluminium ingots are shipped to the cast house of the secondary aluminium plant from the aluminium smelter. The organization of the cast house at the smelter and of that at the secondary aluminium plant has some differences. 

A finai exampie illustrates how LMMS can contribute to the fundamental understanding of processing of materiais. Specific ally, aluminium strips and plates are produced by hot rolling the primary alloy ingots under high pressure and temperature. The iubricating emuisions contain numerous additives, whose composition is empiricaiiy optimized. Sometimes, given constituents adhere or interact with the... 

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