SU616295A1 - Exothermic compound for treatment of gray iron - Google Patents

Description

The invention relates to foundry, in particular, refining in the modification of liquid iron and can be applied in the secondary furnace (ladle) processing of liquid metal.

Known exothermic mixture L for des Shch1 furii and carburizing liquid iron, which contains, weight%: Calcium carbide 52-7O

Graphite8 -16

Cryolite8-12

Sodium chloride 10-24

This mixture raises the temperature of the metal during bucket processing (desulfuraoin and carburizing). K At subsequent modification of the molten metal after reaching the maximum temperature (1435 ° C). there is a sharp decline.

 The purpose of the invention is a complex treatment of molten iron, which combines exothermic processes. desulfurization and carburizing with modfidirovaviem.

Yes, this known exothermic mixture has been used for desulfurapium and carburization, into which additional crystals have been added in amounts of 300 -30% by weight of the mixture. ..

Privat occurs two processes at the same time: desulfuracenn with exote | mechanical effect and modifying of endothermic effect. The amount of heat released during the passage of the first process partially compensates for heat loss during modification, so the overall temperature decrease of the liquid metal is small, and during the exothermic reaction the temperature rises, which depends on the initial process temperature.

Mixture for complex processing of chu. Guna is a mechanical mixture of the following composition, weight. %: Calcium carbide 4O-O

Graphite6-1O

Cryolit5-1O

Sipikokaltsvyzo-4O The mixtures with different content of ingredients used to process the cast iron are given in table. 1. Data on the sulfur and carbon content in the pig iron, i and also on the depth of oa-white before and after the treatment of the cast iron, are given in table. 2. Data on the absorption of silicon from mod | {ikator, 10), as is known, determines the degree of absorption of the latter by iron, are given in Table. 3, For comparison with tab. 203 provides data on the effect of swishuki. The exothermic mixture exerts on -v and more effective effect at a metal temperature not lower than 14OO C. Of the three tested mixtures, the best results were shown by mixture 1, containing 60% of the calalia carr. In this case, the desuppurability is observed most deeply, the absorption of carbon reaches 98-99%, and the absorption of silica from the mixture is 86-88%. Deep desulfurization, along with high carbon absorption and simultaneous modification, will allow to obtain high-quality cast iron. The effectiveness of the modification can be estimated by reducing the amount of chill off after processing. In this relationship, mixture 1 (see Table 2) is much more effective than calcium powder. .-Table 1

table 2

Claims (1)

1. USSR author's certificate No. 472156, cl. C 21 C 1/02, 1972.