Nodular cast iron

Nodular cast iron It's a high-strength structural material with excellent performance characteristics. Magnesium is added during the melting process, resulting in a cast graphite that is not flake-shaped, but rather a nearly perfect spherical shape. The result nodular cast iron It has better qualities than grey and can challenge steel when comparing some properties.

The alloy smelting process is quite simple. Perhaps the most common method for producing this type of cast iron is the magnesium process. The technology involves adding magnesium alloys and various complex modifiers containing magnesium to molten magnesium metal. Properties spheroidal graphite cast iron The various types of casting materials are varied, but it stands out for its excellent combination of casting properties and high strength. This material is highly ductile, making it easy to machine. It is fairly resistant to variable loads and has low sensitivity to stress concentrators. The metal base structure can be ferritic or pearlitic. Ferritic materials can contain up to 20% of pearlite inclusions, while pearlitic materials can contain up to 20% of ferrite.

Nodular cast iron grades

The marking technology for spheroidal graphite cast irons follows a specific GOST standard and uses both letter and numeric designations. For example, the marking "ВЧ" denotes high-strength cast iron, followed by numbers indicating the tensile strength. The data is provided in MPa; to obtain the full value, the specified value must be multiplied by 10.

The symbol may look like this: ВЧ50 GOST 7293-85, the number 50 indicates the tensile strength of 500 MPa, ВЧ45 - tensile strength of 450 MPa, ВЧ80 - tensile strength of 800 MPa, etc. The listed  grades of spheroidal graphite cast iron It is easy to cut, melts at a lower temperature and has excellent casting and mechanical properties, only slightly worse than steel. Nodular cast iron grades ВЧ100-4-3, ВЧ110-6-5 have a tensile strength of 100-120 kgf/mm² According to GOST 7293-70. These grades are used for casting crankshafts, cylinder liners, camshafts, and other components subject to heavy loads. High-strength grades VCh80 and 100 can be obtained through microalloying followed by normalization of the casting.

High-strength cast iron with spheroidal graphite

Thanks to the fact that ductile iron with nodular graphite The alloy has nodular rather than lamellar graphite inclusions, and is characterized by high strength, wear resistance, and good mechanical and casting properties. Due to this, ductile iron with nodular graphite It is very successfully used for the production of critical parts in mechanical engineering – crankshafts and camshafts, diesel engine pistons, valve rocker arms, various clutch parts and other structures operating under high and varied loads.

The following grades are used for castings: VCh35, VCh40, VCh45, VCh50, VCh60, VCh70, VCh80, and VCh100. It is also used to manufacture high-strength water supply pipes, as well as gas and oil pipelines. Pipes made from this material are quite strong, durable, and characterized by excellent performance properties. According to its characteristics ductile iron with nodular graphite almost completely corresponds to spheroidal graphite cast iron.