Purpose. Creation of new grades of ferritic high-strength cast irons with nodular graphite to produce cast products from them with improved physical, mechanical and service characteristics.
Specifications. Ferritic high-strength cast iron with a mass fraction of silicon from 2.3 to 2.9%, sulfur 0.014% and phosphorus 0.015% has the following mechanical properties: σB = 497-541 MPa, δ = 22.0-24.7%, KS = 134 -152 J/cm2, hardness 156-170 HB. High-strength cast iron with a sulfur content of 0.024% and phosphorus 0.078%: σB = 482-507 MPa, δ = 18.1-22%, KS = 72-105 J/cm2, hardness 160-170 HB.
Application area. Defense, mechanical engineering, carriage building, shipbuilding, mining, energy and other industries of Ukraine.
Advantages. Reducing the consumption of expensive modifiers, increasing the yield of suitable castings, increasing the mechanical and service properties of the metal without the use of heat treatment.
Technical and economic effect. The technology makes it possible to simultaneously increase the strength, ductility and impact strength of ferritic high-strength cast iron by 20-30%, increase the yield of suitable castings from 45% to 65%, save up to 400 kW/h of electricity when producing 1 ton of castings, increase the service life of cast parts by 1 ,3–1.5 times.
Description. The essence of the technology is the complex modification and refining of the base cast iron melt with ferrosilicon-magnesium-calcium alloys together with calcium fluorite. The low-melting slag of the CaO-SiO2-CaF2 system formed in this case performs the function of refining, reducing the contamination of the melt with non-metallic inclusions. As a result of increasing the degree of refining of the melt with calcium and the resulting liquid-flow slag, the efficiency of the modification process increases by 25-30% (this allows reducing the consumption of the modifying alloy) and ensures the formation of a dense isotropic structure with a high degree of spherodization, graphitization, and ferrite. properties (especially ductility up to 20-25%) of high-strength cast irons in products. The technology ensures the production of cast products (castings) from ferritic high-strength cast iron with increased ductility (δ = 20-25%), which, after treatment with calcium-containing alloys, has a uniform fine-crystalline structure, stable strength indicators (σB = 490-540 MPa, KS = 132 J/ cm2) and hardness (156-170 HB), improved machinability. Such ductile high-strength cast iron is suitable for the manufacture of a wide range of castings for mechanical engineering parts, railway transport parts (axlebox housings, friction wedges, brake system parts), defense purposes (in particular, various projectile bodies), and energy (for the construction of others). industry of Ukraine.