A kind of high strength and toughness ductile iron and preparation method thereof

Abstract

The invention provides a high-strength ductile cast iron and a preparation method thereof, belonging to the field of cast iron smelting and casting. Aiming at the problem that the high-strength ductile iron cannot satisfy the high tensile strength and elongation at the same time during sand casting, the composition of a high-strength ductile iron according to the present invention is C: 3.6-4.2%, Si: 2.0-2.5% , Mn: 0.6-1.2%, P: ≤0.1%, S: ≤0.03%, Mg: 0.03-0.08%, and the balance is Fe; special molds for steel plates and cooling pipes are added above and below the sand mold for ductile iron Melting and casting, without heat treatment process, can realize the effective control of pearlite content, and obtain pearlite ductile iron castings with dense structure. The prepared nodular cast iron workpiece has fewer casting defects, excellent mechanical properties, a tensile strength greater than 650MPa, and an elongation greater than 8%, and is suitable for large-scale production applications.

Description

technical field [0001] The invention provides a high-strength ductile cast iron and a preparation method thereof, belonging to the field of cast iron smelting and casting. [0002] technical background [0003] Ductile cast iron is a high-performance cast iron material. It is mainly characterized by containing spherical graphite. It is often used to manufacture parts with high requirements for strength, plasticity, toughness, wear resistance and dimensional stability. It is widely used in rail transit, metallurgical mining, Agriculture, navigation and other industries, especially high-strength ductile iron, can replace the use of cast steel and forged steel, effectively reduce costs, and have a good market prospect. [0004] Sand casting ductile iron is prone to coarse structure, segregation, shrinkage porosity, and poor mechanical properties. It needs to add alloy elements and carry out subsequent heat treatment to increase the number of pearlite and improve strength, which ...

AI Technical Summary

Problems solved by technology

[0004] Sand casting ductile iron is prone to coarse structure, segregation, shrinkage porosity, and poor mechanical properties. It is necessary to add alloy elements and perform subsequent heat treatment to increase the number of pearlite and improve strength, which will lead to long production cycle and high cost.

In addition, in sand casting ductile iron, the strength and plasticity are mutually restricted. Increasing the strength will lead to a significant decrease in plasticity, and the mechanical properties of castings often fail to meet the requirements for use.

Images