CN102690987A

CN102690987A - Microalloyed high-strength synthetic gray cast iron and casting method thereof

Info

Publication number: CN102690987A
Application number: CN2012102050580A
Authority: CN
Inventors: 宋向阳; 宋建恩; 靳存文
Original assignee: HENAN GOLDEN SUN CASTING CO Ltd
Current assignee: Henan Jintaiyang precision casting industry Limited by Share Ltd
Priority date: 2012-06-20
Filing date: 2012-06-20
Publication date: 2012-09-26
Anticipated expiration: 2032-06-20
Also published as: CN102690987B

Abstract

The invention discloses microalloyed high-strength synthetic gray cast iron and a casting method thereof. The microalloyed high-strength synthetic gray cast iron comprises the following chemical components in percentage by mass: 2.8-3.4% of C, 1.6-2.4% of Si, 0.5-1.2% of Mn, less than or equal to 0.06% of P, 0.03-0.12% of S, 0.005-0.012% of N, 0.2-0.6% of Nb, 0.1-0.3% of Zn and the balance of Fe. In the invention, while optimizing the adding proportions of the waste steel, recarburizer, silicon carbide and cast iron foundry returns, the alloy elements such as nitrogen, niobium, zinc and the like are added for microalloying treatment; the recarburizer and silicon carbide are used as a carbon and silicon increasing agent; and the microalloyed synthetic gray cast iron with relatively high tensile strength and hardness is obtained finally.

Description

Synthetic graphitic cast iron of a kind of micro-alloying and castmethod thereof

Technical field

The present invention relates to a kind of novel gray cast iron material and castmethod thereof, particularly relate to tensile strength and the higher synthetic gray cast iron material of hardness requirement.

Background technology

At present, some manufacturers are more and more stricter to the quality and the performance requriements of the key components and parts material of graphitic cast iron material.But in recent years, along with the continuous development of cast iron, pig iron resource is in short supply day by day, and supply falls short of demand especially for high duty pig iron, and price goes up day by day.Therefore,, improve product competitiveness and business economic benefit, press for a kind of high-strength gray cast iron material of exploitation for satisfying the demand of market to high-strength gray cast iron.

Summary of the invention

The invention provides synthetic graphitic cast iron of a kind of micro-alloying and castmethod thereof, adopt synthetic graphitic cast iron also to handle through the microalloying of elements such as nitrogen, niobium, zinc.

For realizing above-mentioned purpose, technical scheme of the present invention is to implement like this:

A kind of micro-alloying synthesizes graphitic cast iron, comprises following chemical ingredients, by mass percentage; C:2.8～3.4%, Si:1.6～2.4%, Mn:0.5～1.2%; P :≤0.06%, S:0.03～0.12%, N:0.005～0.012%; Nb:0.2～0.6%, Zn:0.1～0.3%, Fe surplus.

With steel scrap, cast iron foundry returns is main raw material, carries out microalloying through adding N, Nb, Zn alloying element and handles, and the solid solution of N ability is strengthened matrix, and can be formed nitride with Nb in matrix, improves the foundry goods wear resistance; Nb ability refinement cast iron eutectic cell is prone to form carbon, nitride, is present in the cast iron with fine particle, improves intensity and wear resistance; Zn ability deoxidation, refinement graphite increase the combined carbon amount, improve intensity and hardness.

Beneficial effect of the present invention is:

The present invention carries out microalloying with alloying elements such as N, Nb, Zn and handles, and under carbon equivalent high, obtains high-tensile and hardness graphitic cast iron; Simultaneously, utilize silit to replace the pig iron and ferrosilicon to come carburetting to increase silicon, graphitic cast iron is synthesized in melting.Compare with plain cast iron, the synthetic cast iron cost reduces, and iron liquid sulphur content is low, high purity, and inclusion is few, good fluidity, metallurgical quality is higher, and yield rate improves.

Description of drawings

Fig. 1 amplifies 100 times graphite form for HT300;

Fig. 2 amplifies 100 times matrix for HT300.

Embodiment

Below in conjunction with embodiment the present invention is further described.

Utilize the synthetic graphitic cast iron of microalloying to produce HT300 SA-5 chock and pour into a mould Φ 30mm coupon in this instance.Concrete technological process is following:

Adopt the furane resin sand molding; With steel scrap, cast iron foundry returns main raw material, its mass percent is: steel scrap 60-70%, cast iron foundry returns 40-30%.All the other furnace charges and the mass percent that accounts for main raw material thereof are respectively: carburelant 2.5%, silit 1.5%, ferromanganese 1.8%, nitrogenize ferromanganese 0.2%, pure zinc 0.3%, ferro-niobium 0.6%; Melting in medium-frequency induction furnace; Steel scrap, cast iron foundry returns are in when filling with substance is packed stove into; Add carburelant, silit in the furnace charge fusing in batches; Add ferromanganese, nitrogenize ferromanganese, ferro-niobium when molten iron temperature reaches 1450 ℃, come out of the stove when molten iron temperature is 1480～1500 ℃ and breed, pure zinc pours in the bag with nucleating agent; Inoculated technology adopts in the bag and breeds and current-following inoculation, and nucleating agent is a silico-calcium barium, and add-on is 0.4% of a molten steel quality, and the nucleating agent quality accounts for 80% of nucleating agent total amount in the bag, and current-following inoculation agent quality accounts for 20% of nucleating agent total amount; Teeming temperature is 1350 ℃.

The as-cast structure of Φ 30mm coupon is graphite+pearlitic structure, and wherein graphite is the A type, 4～6 grades, and content of pearlite in alloy＞96%, as depicted in figs. 1 and 2.Its chemical ingredients and mechanical property are as shown in table 1.

Synthetic graphitic cast iron chemical ingredients of table 1 microalloying and mechanical property

Claims

1. the castmethod of the synthetic graphitic cast iron of micro-alloying is characterized in that: adopt the furane resin sand molding; Furnace charge is a main raw material with steel scrap, cast iron foundry returns, is that less important raw material is adjusted chemical ingredients with carburelant, silit, ferromanganese, nitrogenize ferromanganese, pure zinc, ferro-niobium; Melting in medium-frequency induction furnace; Steel scrap, cast iron foundry returns are in when filling with substance is packed stove into; Carburelant, silit add in fusing in batches; Molten iron temperature reaches 1450 ℃ and adds ferromanganese, nitrogenize ferromanganese, ferro-niobium, comes out of the stove when molten iron temperature reaches 1480～1500 ℃ and breeds, and pure zinc pours in the bag with nucleating agent; Inoculated technology adopts in the bag and breeds and current-following inoculation, and nucleating agent is a silico-calcium barium, and add-on is 0.4% of a molten steel quality; The nucleating agent quality accounts for 80% of nucleating agent total amount in the bag, and current-following inoculation agent quality accounts for 20% of nucleating agent total amount; Teeming temperature is 1350 ℃, and casting obtains the synthetic graphitic cast iron of said micro-alloying.

2. the method for claim 1, it is characterized in that: the mass percent of steel scrap, cast iron foundry returns is respectively in the said main raw material: steel scrap 60-70%, cast iron foundry returns 40-30%.

3. the method for claim 1, it is characterized in that: the mass percent that said carburelant, silit, ferromanganese, nitrogenize ferromanganese, pure zinc, ferro-niobium account for main raw material is respectively: carburelant 2.5%, silit 1.5%, ferromanganese 1.8%, nitrogenize ferromanganese 0.2%, pure zinc 0.3%, ferro-niobium 0.6%.

4. a micro-alloying synthesizes graphitic cast iron, and it is obtained by each described castmethod among the claim 1-3, it is characterized in that: under carbon equivalent high, obtain the synthetic graphitic cast iron of HS, high firmness, comprise following chemical ingredients; By mass percentage, C:2.8 ~ 3.4%, Si:1.6 ~ 2.4%, Mn:0.5 ~ 1.2%; P :≤0.06%, S:0.03 ~ 0.12%, N:0.005 ~ 0.012%; Nb:0.2 ~ 0.6%, Zn:0.1 ~ 0.3%, Fe surplus.