Molten iron melting and test block preparation

(1) Preparation of main metal charge

Weigh and prepare the main metal charge.

(2) Preparation of main accessories

Weigh and prepare the main accessories.

(3) Molten iron smelting

The charge is added in the order of pig iron, recycled iron and scrap steel. Due to the difference factors such as burning loss of furnace charge, the actual element content has a certain deviation from the theoretical burden calculation. After the furnace charge is melted, samples are taken, and the composition of molten iron is detected on the direct reading spectrum and thermal analyzer, and adjusted according to the target composition of the preset scheme.

(4) Molten iron out of furnace

After the composition of molten iron meets the requirements of the preset scheme, the furnace will be discharged when the temperature rises rapidly to 1450-1470 ℃.

(5) Spheroidization and inoculation

Adding proportion, adding auxiliary materials such as spheroidizing agent into the ladle bottom nodularizing agent loading tank in the molten iron, the spheroidizing treatment temperature is controlled at about 1450 ~ 1460 ℃, and the method of “primary inoculation before furnace + secondary inoculation by subcontracting” is adopted to ensure the inoculation effect.

(6) Casting of test block

The final composition analysis of the molten iron after spheroidization and inoculation was carried out. After temperature measurement, when the temperature of molten iron in the ladle reached 1330 ~ 1340 ℃, the casting of test blocks was started, and a total of 9 test blocks were poured. The relevant operation and parameters during the pouring process were implemented and controlled according to the preset scheme, without deviation and abnormality.