Ferrite nodular cast iron and production method thereof

Abstract

The invention discloses a ferrite nodular cast iron and a production method thereof, and belongs to the technical filed of metal smelting. The tensile strength, the elongation percentage and the hardness of the cast iron are 600-700MPa, 15-20% and 150-210HB respectively. The production method comprises the steps of burdening, melting, inoculating and carrying out solid solution reinforcement. The ferrite nodular cast iron has the advantages of high elongation percentage, high strength and low surface hardness, and solves a technical problem that the strength, the elongation percentage and the surface hardness cannot be simultaneously considered.

Description

technical field

[0001] The invention relates to a nodular cast iron and a production method thereof, in particular to a ferritic nodular cast iron and a production method thereof, belonging to the technical field of metal smelting. Background technique

[0002] Ductile cast iron is treated with spheroidization and inoculation, and the graphite form is spherical cast iron, which effectively improves the mechanical properties of cast iron, especially the plasticity and toughness, so as to obtain higher strength than carbon steel. According to different shapes, nodular cast iron Included in: 1. Ferrite has a body-centered cubic lattice, which is an interstitial solid solution of carbon dissolved in α-Fe, which is called ferrite, that is, α-Fe and its based solid solution, represented by the symbol F; 2. Pearlite is a eutectoid of ferrite and cementite formed by eutectoid transformation of austenite. Its form is a layered complex phase in which ferrite thin layers and cementite...

Examples

Embodiment 1

[0025] (a) Furnace charge selection: use high-purity pig iron, low-Mn, low-P, low-S steel scrap, and recarburizer as charge, 70% of high-purity pig iron, 15% of scrap steel, 15% of furnace charge, and a small amount of recarburizer. Guarantee that Mn≤0.2%; P≤0.03%; S≤0.015%, Ti≤0.015% in the furnace charge, the total content of trace impurities ≤0.1%, and the Si content in the ingredients is 1%,

[0026] (b) Smelting: The raw molten iron is smelted in an intermediate frequency induction furnace, and the furnace temperature is 1500°C;

[0027] (c) Select QRMg8RE3 as the nodulizer, the addition amount is 1.4%, select 75Si-Fe as the bottom silicon inoculant, the addition amount is 1.6%, spheroidize and inoculate at the furnace temperature to obtain nodularized molten iron;

[0028] (d) Upside-down inoculation: 75Si-Fe is used as upside-down inoculant, and the addition amount is 1.0%;

[0029] (e) Floating silicon inoculation: use 75Si-Fe as floating silicon inoculation, the addi...

Embodiment 2

[0034] (a) Furnace charge selection: use high-purity pig iron, low-Mn, low-P, low-S steel scrap, and recarburizer as charge, 70% of high-purity pig iron, 15% of scrap steel, 15% of furnace charge, and a small amount of recarburizer. Guarantee that Mn≤0.2%; P≤0.03%; S≤0.015%, Ti≤0.015% in the furnace charge, the total content of trace impurities ≤0.1%, and the Si content in the ingredients is 1%,

[0035] (b) Smelting: The raw molten iron is smelted in an intermediate frequency induction furnace, and the furnace temperature is 1500°C;

[0036] (c) Use QRMg8RE3 as the nodulizer, the addition amount is 1.4%, choose 75Si-Fe as the bottom silicon inoculant, the addition amount is 1.3%, add 0.03% molybdenum iron powder, and the molybdenum content in the molybdenum iron is 60%. Spheroidizing and inoculating at the temperature of the furnace to obtain spheroidized molten iron;

[0037] (d) Upside-down inoculation: 75Si-Fe is used as upside-down inoculant, and the addition amount is 1...

technical field

[0001] The invention relates to a nodular cast iron and a production method thereof, in particular to a ferritic nodular cast iron and a production method thereof, belonging to the technical field of metal smelting. Background technique

[0002] Ductile cast iron is treated with spheroidization and inoculation, and the graphite form is spherical cast iron, which effectively improves the mechanical properties of cast iron, especially the plasticity and toughness, so as to obtain higher strength than carbon steel. According to different shapes, nodular cast iron Included in: 1. Ferrite has a body-centered cubic lattice, which is an interstitial solid solution of carbon dissolved in α-Fe, which is called ferrite, that is, α-Fe and its based solid solution, represented by the symbol F; 2. Pearlite is a eutectoid of ferrite and cementite formed by eutectoid transformation of austenite. Its form is a layered complex phase in which ferrite thin layers and cementite...

Examples

Embodiment 1

[0025] (a) Furnace charge selection: use high-purity pig iron, low-Mn, low-P, low-S steel scrap, and recarburizer as charge, 70% of high-purity pig iron, 15% of scrap steel, 15% of furnace charge, and a small amount of recarburizer. Guarantee that Mn≤0.2%; P≤0.03%; S≤0.015%, Ti≤0.015% in the furnace charge, the total content of trace impurities ≤0.1%, and the Si content in the ingredients is 1%,

[0026] (b) Smelting: The raw molten iron is smelted in an intermediate frequency induction furnace, and the furnace temperature is 1500°C;

[0027] (c) Select QRMg8RE3 as the nodulizer, the addition amount is 1.4%, select 75Si-Fe as the bottom silicon inoculant, the addition amount is 1.6%, spheroidize and inoculate at the furnace temperature to obtain nodularized molten iron;

[0028] (d) Upside-down inoculation: 75Si-Fe is used as upside-down inoculant, and the addition amount is 1.0%;

[0029] (e) Floating silicon inoculation: use 75Si-Fe as floating silicon inoculation, the addi...

Embodiment 2

[0034] (a) Furnace charge selection: use high-purity pig iron, low-Mn, low-P, low-S steel scrap, and recarburizer as charge, 70% of high-purity pig iron, 15% of scrap steel, 15% of furnace charge, and a small amount of recarburizer. Guarantee that Mn≤0.2%; P≤0.03%; S≤0.015%, Ti≤0.015% in the furnace charge, the total content of trace impurities ≤0.1%, and the Si content in the ingredients is 1%,

[0035] (b) Smelting: The raw molten iron is smelted in an intermediate frequency induction furnace, and the furnace temperature is 1500°C;

[0036] (c) Use QRMg8RE3 as the nodulizer, the addition amount is 1.4%, choose 75Si-Fe as the bottom silicon inoculant, the addition amount is 1.3%, add 0.03% molybdenum iron powder, and the molybdenum content in the molybdenum iron is 60%. Spheroidizing and inoculating at the temperature of the furnace to obtain spheroidized molten iron;

[0037] (d) Upside-down inoculation: 75Si-Fe is used as upside-down inoculant, and the addition amount is 1...