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Influence of Cast Iron Modification on Free Vibration Frequency of Casting

Konopka Z., Łągiewka M., Zyska A.

Archives of Foundry Engineering

2020

Vol. 20, iss. 1

23--26

The paper presents the results of investigations concerning the influence of gray cast iron modification on free vibration frequency of the disc casting. Three different chemical composition melts of gray cast iron were prepared in induction furnace. During gravity casting 0.05% and 0.3% mass of the Inolate modifier was added on stream of metal for changing graphite flakes in castings. Sound signal vibration of cast iron sample was registered by means on microphone for free vibration frequency measurements. Decreasing of free vibration frequency of modified cast iron in comparison with non modified castings was observed. Higher contents of modifier causes more decreasing of free vibration frequency. Cast iron with smaller contents of carbon and silicon have higher free vibration frequency in comparison with eutectic composition cast iron. Hardness of examined cast iron is lower when the more modifier is added during modification process. Free frequency is smaller with smaller Brinell hardness of disc casting. It was concluded that control of free vibration frequency of disc castings by means of chemical composition and modification process can improved comfort and safety of working parts.

Sodium tripolyphosphate and others condensed sodium phosphates production methods

Kowalski Z., Kijkowska R., Pawłowska-Kozińska D., Wzorek Z.

Polish Journal of Chemical Technology

2002

Vol. 4, nr 3

27-33

The paper presents production methods and functions of sodium tripolyphosphate STPP and other phosphates, which can remain a significant activity for chemical industry for the foreseeable future. Raw materials, among them wet-process phosphoric acid (WAPP), for condensed sodium phosphates manufacturing and the STPP production in Poland are discussed. Some effects of ionic impurities, present in WAPP, on the quality of the STPP are considered. Our implemented method allowed replacing part of the expensive thermal phosphoric acid used for STPP production with pre-treated concentrated WAPP. 10,000 tons of pre-treated 75% H3PO4 acid, with sulphate concentration lower than 0.1% of SO4 was produced in 1998. It was used mostly for STPP manufacturing; the waste obtained in the pre-treatment process could be utilised in the feed phosphate production. The use of pre-treated concentrated WAPP results in a decrease of STPP production costs at about 20% (in comparison to the use of thermal phosphoric acid).