CN106702257A - Cast iron piston ring and preparation method thereof - Google Patents

Abstract

The invention discloses a cast iron piston ring and a preparation method thereof. The weight percentage of the cast iron piston ring is C2.9-3.3%, Si2.2-2.4%, Mn0.8-1.1%, B0.04 ~0.06%, P0.3~0.45%, S≤0.08%, the balance is Fe. The preparation method includes batching, preheating, smelting, quick analysis before furnace, final deoxidation, nodular ink treatment, inoculation treatment and pouring. The method has a simple smelting process, and through controlling the addition of carbon, silicon and boron in the cast iron and spheroidizing treatment, the high-performance friction-reducing ductile iron is cast, and the production cost is reduced at the same time, which is especially suitable for casting piston rings.

Description

A kind of cast iron piston ring and its preparation method

technical field

The invention relates to the technical field of ferrous metal production, in particular to a cast iron piston ring and a preparation method thereof.

Background technique

my country has been producing nodular cast iron since 1950, and has developed rich rare earth resources since the 1970s. Therefore, on the basis of magnesium nodular cast iron, my country's unique rare earth nodular cast iron has been developed and has become an important casting material. Boron-containing nodular cast iron is an excellent wear-reducing material, which has the characteristics of high hardness and prolonging the service life of castings. Boron-containing ductile iron only needs to add boron to the cast iron, and the matrix structure hardly changes, only a part of boron carbides appear in the austenite. Since the apparent hardness of borocarbide is higher than HV=1100, the wear reduction performance is improved, and the borocarbide is evenly distributed in the matrix, so it does not bring many difficulties to the processing performance. Therefore, the development of boron-containing anti-friction ductile iron to prolong the service life of castings.

Contents of the invention

The purpose of the present invention is to address the above problems, to propose a cast iron piston ring and a preparation method thereof, by controlling the addition of carbon, silicon and boron in the cast iron and spheroidizing treatment, to cast high-performance friction-reducing nodular cast iron.

The technical solutions adopted by the present invention to solve the technical problems are: C2.9～3.3%, Si2.2～2.4%, Mn0.8～1.1%, B0.04～0.06%, P0.3～0.45%, S≤ 0.08%, the balance is Fe.

A method for preparing cast iron piston rings, comprising the following steps:

The first step: ingredients: steel scrap, recycled material, pig iron, ferromanganese, ferrosilicon, pure boron according to C2.9～3.3%, Si2.2～2.4%, Mn0.8～1.1%, B0.04～0.06% , P0.3～0.45%, S≤0.08%, and the balance is Fe weight percentage;

Step 2: Preheating: Put the optimized calculated steel scrap, recycled material and pig iron into the medium frequency induction furnace for preheating;

The third step: smelting: After melting the steel scrap, recycled material, and pig iron in the intermediate frequency induction furnace, put in a deoxidizer whose amount is 18-28% of the furnace charge, and whose composition is 70% lime + 30% fluorite for pre-deoxidation, and then put in For baked ferromanganese, ferrosilicon and pure boron, when the temperature of molten iron rises to 1400-1460°C, add 0.1% slag remover to remove slag once, and then cover with heat preservation agent to wait for sampling and analysis;

Step 4: Quick analysis before the furnace: Take the molten iron and analyze it with a front-of-the-furnace spectrometer combined with carbon-silicon thermal analysis for rapid analysis, and adjust the chemical composition according to the analysis results;

Step 5: Final deoxidation: raise the temperature of the molten iron to 1480-1640°C, and put in aluminum whose amount is 0.1-0.3% of the molten iron for final deoxidation;

Step 6: Spheroidization treatment and inoculation treatment: The molten iron flows from the intermediate frequency induction furnace to the ladle, and the spheroidization treatment, inoculation treatment and secondary slag removal treatment are performed in the ladle, and the amount added is 1.2 to 1.4 of the molten iron amount % nodulizer, the particle size of the nodulizer is 8-26mm, and the nodulizer is FeSiMg8Re3; the amount of the nodulizer is 1-1.2% of the amount of molten iron, the particle size of the inoculant is 4-8mm, and the inoculant is 75 silicon Iron; add 0.1% slag remover whose amount is the amount of molten iron, remove the slag immediately after the spheroidization reaction and pour the triangular test piece and spectrometer to analyze and detect the spheroidization and chemical composition of the molten iron before pouring;

Step 7: Pouring: The pouring temperature is 1480-1520°C. When the ladle is pouring, add a secondary inoculant with an amount of 0.08-0.16% of the molten iron. The particle size of the inoculant is 2-6mm, and the inoculant is 75 Ferrosilicon to obtain boron-containing nodular cast iron piston ring castings.

The beneficial effect of the invention is that the smelting process is simple, and by controlling the addition of carbon, silicon and boron in the cast iron and spheroidizing treatment, the high-performance friction-reducing nodular cast iron can be cast, and the production cost can be reduced at the same time, which is especially suitable for casting piston rings.

detailed description

Example 1:

A kind of method for preparing cast iron piston ring of this example, comprises following several steps:

The first step: ingredients: steel scrap, recycled materials, pig iron, ferromanganese, ferrosilicon, pure boron according to C2.9%, Si2.2%, Mn0.8%, B0.04%, P0.3%, S≤ 0.08%, and the balance is batched in the form of Fe weight percentage;

Step 2: Preheating: Put the optimized calculated steel scrap, recycled material and pig iron into the medium frequency induction furnace for preheating;

The third step: smelting: After melting the steel scrap, recycled material, and pig iron in the intermediate frequency induction furnace, put in a deoxidizer whose amount is 18% of the furnace charge, and whose composition is 70% lime + 30% fluorite for pre-deoxidation, and then put into baking For the processed ferromanganese, ferrosilicon and pure boron, when the temperature of the molten iron rises to 1400°C, add 0.1% slag remover to remove the slag once, and then cover the heat preservation agent and wait for sampling and analysis;

Step 4: Quick analysis before the furnace: Take the molten iron and analyze it with a front-of-the-furnace spectrometer combined with carbon-silicon thermal analysis for rapid analysis, and adjust the chemical composition according to the analysis results;

Step 5: Final deoxidation: raise the temperature of the molten iron to 1480°C, and put in aluminum whose amount is 0.1% of the molten iron for final deoxidation;

Step 6: Spheroidization treatment and inoculation treatment: The molten iron flows from the intermediate frequency induction furnace to the ladle, and the spheroidization treatment, inoculation treatment and secondary slag removal treatment are carried out in the ladle, and the amount of 1.2% balls is added to the amount of molten iron. The particle size of the nodulizer is 8mm, and the nodulizer is FeSiMg8Re3; the amount of the inoculant added is 1% of the amount of molten iron, the particle size of the inoculant is 4mm, and the inoculant is 75 ferrosilicon; the amount added is the amount of molten iron The amount of 0.1% slag removal agent, after the spheroidization reaction, remove the slag immediately and pour the triangular test piece and the spectrometer to analyze and detect the spheroidization and chemical composition of the molten iron before pouring;

Step 7: Pouring: The pouring temperature is 1480°C. During the pouring of the ladle, 0.08% of the secondary inoculant is added with the amount of molten iron. The particle size of the inoculant is 2 mm, and the inoculant is 75 ferrosilicon to obtain boron-containing Ductile iron piston ring castings.

Example 2:

A kind of method for preparing cast iron piston ring of this example, comprises following several steps:

The first step: ingredients: steel scrap, recycled materials, pig iron, ferromanganese, ferrosilicon, pure boron according to C3.1%, Si2.3%, Mn0.95%, B0.05%, P0.375%, S≤ 0.08%, and the balance is batched in the form of Fe weight percentage;

Step 2: Preheating: Put the optimized calculated steel scrap, recycled material and pig iron into the medium frequency induction furnace for preheating;

The third step: smelting: After melting the steel scrap, recycled material, and pig iron in the intermediate frequency induction furnace, put in a deoxidizer whose amount is 23% of the furnace charge, and whose composition is 70% lime + 30% fluorite for pre-deoxidation, and then put into baking For the treated ferromanganese, ferrosilicon and pure boron, when the temperature of the molten iron rises to 1430°C, add 0.1% slag remover to remove the slag once, and then cover the heat preservation agent and wait for sampling and analysis;

Step 4: Quick analysis before the furnace: Take the molten iron and analyze it with a front-of-the-furnace spectrometer combined with carbon-silicon thermal analysis for rapid analysis, and adjust the chemical composition according to the analysis results;

The fifth step: final deoxidation: the temperature of molten iron is raised to 1510°C, and aluminum whose amount is 0.2% of molten iron is put into it for final deoxidation;

Step 6: Spheroidization treatment and inoculation treatment: The molten iron flows from the intermediate frequency induction furnace to the ladle, and the spheroidization treatment, inoculation treatment and secondary slag removal treatment are carried out in the ladle, and the amount is 1.3% of the molten iron amount. The particle size of the nodulizer is 17mm, and the nodulizer is FeSiMg8Re3; the amount of the inoculant added is 1.1% of the amount of molten iron, the particle size of the inoculant is 6mm, and the inoculant is 75 ferrosilicon; the amount added is the amount of molten iron The amount of 0.1% slag removal agent, after the spheroidization reaction, remove the slag immediately and pour the triangular test piece and the spectrometer to analyze and detect the spheroidization and chemical composition of the molten iron before pouring;

Step 7: Pouring: The pouring temperature is 1500°C. When the ladle is pouring, 0.12% of the secondary inoculant is added with the amount of molten iron. The particle size of the inoculant is 4 mm, and the inoculant is 75 ferrosilicon to obtain boron-containing Ductile iron piston ring castings.

Example 3:

A kind of method for preparing cast iron piston ring of this example, comprises following several steps:

The first step: ingredients: steel scrap, recycled materials, pig iron, ferromanganese, ferrosilicon, pure boron by 3.3%, Si2.4%, Mn1.1%, B0.06%, P0.45%, S≤0.08% , the balance is carried out batching in the mode of Fe weight percent;

Step 2: Preheating: Put the optimized calculated steel scrap, recycled material and pig iron into the medium frequency induction furnace for preheating;

The third step: smelting: After melting the steel scrap, recycled materials, and pig iron in the intermediate frequency induction furnace, put in a deoxidizer whose amount is 28% of the furnace charge, and whose composition is 70% lime + 30% fluorite for pre-deoxidation, and then put into baking For the processed ferromanganese, ferrosilicon and pure boron, when the temperature of the molten iron rises to 1460°C, add 0.1% slag remover to remove the slag once, and then cover the heat preservation agent and wait for sampling and analysis;

Step 4: Quick analysis before the furnace: Take the molten iron and analyze it with a front-of-the-furnace spectrometer combined with carbon-silicon thermal analysis for rapid analysis, and adjust the chemical composition according to the analysis results;

The fifth step: final deoxidation: the temperature of molten iron is raised to 1640°C, and aluminum whose amount is 0.3% of molten iron is put into it for final deoxidation;

Step 6: Nodularization treatment and inoculation treatment: The molten iron flows from the intermediate frequency induction furnace to the ladle, and the nodularization treatment, inoculation treatment and secondary slag removal treatment are carried out in the ladle, and the amount of 1.4% balls added is 1.4% of the molten iron amount. The particle size of the nodulizer is 26mm, and the nodulizer is FeSiMg8Re3; the amount of the inoculant added is 1.2% of the amount of molten iron, the particle size of the inoculant is 8mm, and the inoculant is 75 ferrosilicon; the amount added is the amount of molten iron The amount of 0.1% slag removal agent, after the spheroidization reaction, remove the slag immediately and pour the triangular test piece and the spectrometer to analyze and detect the spheroidization and chemical composition of the molten iron before pouring;

Step 7: Pouring: The pouring temperature is 1520°C. When the ladle is pouring, 0.16% of the secondary inoculant whose amount is the amount of molten iron is added along with the pouring. The particle size of the inoculant is 6 mm, and the inoculant is 75 ferrosilicon to obtain boron-containing Ductile iron piston ring castings.

The specific embodiments of the present invention have been described above, but these descriptions can not be interpreted as limiting the scope of the present invention, and the protection scope of the present invention is defined by the appended claims, and any modification on the basis of the claims of the present invention , equivalent replacements and improvements, etc., all fall within the protection scope of the present invention.

Claims (2)

1. a kind of cast-iron piston ring, it is characterised in that：The percentage by weight of its composition is：C2.9~3.3%, Si2.2~ 2.4%th, Mn0.8~1.1%, B0.04~0.06%, P0.3~0.45%, S≤0.08%, balance of Fe.

2. a kind of method of the cast-iron piston ring prepared described in claim 1, it is characterised in that:Including following several steps：

The first step：Dispensing：By steel scrap, foundry returns, the pig iron, ferromanganese, ferrosilicon, pure boron press C2.9~3.3%, Si2.2~2.4%, Mn0.8~1.1%, B0.04~0.06%, P0.3~0.45%, S≤0.08%, the mode of balance of Fe percentage by weights are matched somebody with somebody Material；

Second step：Preheating：Will optimize calculate steel scrap, foundry returns, the pig iron input intermediate frequency furnace in preheated；

3rd step：Melting：By the steel scrap in intermediate frequency furnace, foundry returns, the pig iron fusing after, put into its quantity for furnace charge 18~ 28%, composition carries out pre-deoxidation for the deoxidier of lime 70%+ fluorites 30%, then puts into ferromanganese, ferrosilicon and pure boron that baking is processed, When bonded hard ferrite magnet is warming up to 1400~1460 DEG C, add 0.1% deslagging agent once to remove the gred, be then covered by be sampled point of heat preserving agent etc. Analysis；

4th step：Both analysis：Iron liquid is taken quickly to be analyzed with stokehold spectrometer analysis combination carbon silicon heat analysis, according to Analysis result adjusts chemical composition；

5th step：Final deoxidizing：Bonded hard ferrite magnet is warming up to 1480~1640 DEG C, the aluminium that its quantity is iron liquid 0.1~0.3% is put into Carry out final deoxidizing；

6th step：Spheroidising and inoculation：Iron liquid flows to casting ladle from intermediate frequency furnace, carried out in casting ladle spheroidising, Inoculation and secondary except Slag treatment, adds 1.2~1.4% nodulizers that its quantity is iron liquid amount, the granularity of nodulizer for 8~ 26mm, nodulizer is FeSiMg8Re3；Add 1~1.2% inovulant that its quantity is iron liquid amount, the granularity of inovulant for 4~ 8mm, inovulant is 75 ferrosilicon；Add 0.1% deslagging agent that its quantity is iron liquid amount, cast triangle of being skimmed at once after spheroidizing reacion Test piece and spectrometer analysis detect that liquid iron balling and chemical composition are poured into a mould after qualified；

7th step：Cast：1480~1520 DEG C of pouring temperature, as cast its quantity of addition is iron liquid amount when casting ladle is poured into a mould 0.08~0.16% post inoculant, the granularity of inovulant is 2~6mm, and inovulant is 75 ferrosilicon, obtains being lived containing boron spheroidal cast iron Plug ring casting.