SU688531A1 - Modifier - Google Patents

Description

(54) MODIFIER

The yield of the yield, as well as the elimination of the need for subsequent heat treatment, reduces the cost of products from modified cast iron.

Example. Oxides of rare-earth metals, boric anhydride and calcium borate, zircon concentrate, ferrosilicon, aluminum, magnesite, materials containing oxides of phosphorus and flux in the form of lime are used as raw materials in the smelting of the modifier.

The modifier is smelted in an electric arc furnace with a 100 kVA transformer by the aluminothermic method. The chemical composition of the modifier samples is given in the table.

The modifier is easily crushed and this makes it possible to obtain pieces of about 8 mm in size, which are necessary for cast iron castings, and 15-20 mm required for modifying industrial melts.

The test of the complex modifier is carried out in the smelting of iron containing, by weight. %: carbon 3.0-3, b; silicon 2.0-2, b; manganese 0.4-0.9; phosphorus 0.1-0, o; oor 0.005-0.10; rare earth metals 0, OOB-0.03; iron else.

The proposed modifier is introduced at the bottom of the scoop and under the jet during the discharge of the pig iron from the furnace. At the same time, under the same conditions, control melts with the introduction of rare-earth metals and boron from a specially made master alloy of known composition are carried out, zirconium is introduced using silico-zirconium, and phosphorus is introduced with ferrophosphorus.

Samples for testing the quality of the modified cast iron are poured into a trefoid shape for mechanical testing and corrosion resistance tests, as well as into a wedge shape for chill test.

The cast iron treated with the complex modifier according to the invention has a noticeably better fluidity, which allows the use of all 11 lpm forms for the iOiiKocTeHiibi.v o casting. Thus, the fluidity of cast iron treated with the proposed modifier at a pouring temperature of 1280-1320C is equal to L40-1090 mm, and the fluidity of the cast iron treated with a known modifier at the same temperature was 690-830 mm (in the spiral test).

The absorption of alloying and modifying elements from the complex modifier increases on average for REM by 15%, for boron by 10%, for zirconium by 12% and for phosphorus by 10%.

Samples of cast iron treated with a complex modifier have a corrosion rate of 12–14 mg / dm — day versus 16–8 mg / dm – day, tensile strength at stretch is 20–2b kgf / mm versus 15–18 kgf / mm and bleached on the wedge sample it decreases to 0.5 mm versus 4-6 mm in the case of using the known modifier.

For products cast from cast iron modified by the proposed complex modifier, no subsequent thermal extraction is required.

The calculation carried out on the basis of the results of pilot industrial melts shows that at about 2 million pcs. per year, the expected economic effect from the use of the proposed complex modifier will be about 80 thousand rubles. in year.

Claims (1)

Invention Formula A modifier containing rare earth metals, aluminum, silicon, calcium, magnesium, boron, and iron, characterized in that, in order to reduce chill off in thin casting sections, it increases l: fluidity, strength, and corrosion resistance of the iron, it also contains zirconium and phosphorus in the following ratio %: parts weight 1-20 Rare earth metals Aluminum 1-10 Cremium 30-60 Calcium 0.5-5.0 Magnesium 0.1-5.0 Bor 0.1-6.0 Zirconium 0.1-8.0 Phosphorus 0.05-3.0 Else Iron 5 Sources of information taken into account during the examination 6 1. USSR Copyright Certificate No. 441327, cl. C 22C 35/00, 1974.