Fluoride-free refining slag for 20 Cr structural alloy steel and preparation method thereof

Abstract

The invention discloses fluoride-free refining slag for 20 Cr structural alloy steel and a preparation method thereof. The granularity of the fluoride-free refining slag is 15-35mm, and the fluoride-free refining slag comprises the following components in percentage by weight: 55-60% of CaO, 10-16% of SiO2, 15-20% of Al2O3, 4-6% of MgO, 5-10% of B2O3, less than or equal to 1% of TFe and the balance of impurities. The preparation method of the fluoride-free refining slag comprises that mineral ore raw materials containing CaO, SiO2, Al2O3, MgO and B2O3 are crushed and blended and then moulding and crushing are carried out, so that the fluoride-free refining slag finished product is obtained. The preparation method of the fluoride-free refining slag is simple, and the prepared fluoride-free refining slag has the advantages of environmental friendliness, no fluoride, high slagging speed, strong slag inclusion removal capability, less furnace lining corrosion and strong desulphurization capability.

Description

technical field [0001] The invention relates to a fluorine-free refining slag for 20Cr alloy structural steel and a preparation method thereof, belonging to the technical field of steelmaking. Background technique [0002] 20Cr steel is the most typical basic variety of chromium-based alloy structural steel, and has a huge market demand. It is widely used in the manufacturing industries such as automobiles and mining machinery to manufacture cores that require high strength, wear on the surface, and have a cross-sectional size below 30mm or Carburized parts with complex shapes and low load, such as gears, gear shafts, cams, piston pins, worms, etc.; or parts that require heat treatment with small deformation and high wear resistance, and can be subjected to high-frequency surface quenching after carburizing ; Or quenched and tempered parts with high working speed and medium impact load, which play an important role in my country's national economy and national defense construc...

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Problems solved by technology

[0004] In order to solve the problems of slow melting speed, high melting point and high viscosity of slag in traditional refining slag, CaF 2 , but practice shows that CaF 2 The use of will have many adverse effects: (1) containing CaF 2 The slag erodes the furnace lining seriously, increasing equipment maintenance costs; (2) CaF 2 It reacts with other components in the slag to generate fluorine-containing gas and enters the human body through the respiratory tract, digestive tract and skin, which will cause systemic diseases mainly caused by bone changes; (3) Containing CaF at high temperature 2 The slag will produce a large amount of fluoride, which will cause crop yield reduction and chronic poisoning of livestock if it enters the ecosystem

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