CN102051545B - Wear-resistant and heat-resistant mottled cast iron material and preparation method thereof - Google Patents

Abstract

The invention provides a wear-resistant and heat-resistant mottled cast iron material and a preparation method thereof. The material has good properties. The preparation method has simple process, low production cost and is suitable for industrialized production. The wear-resistant and heat-resistant mottled cast iron material uses mottled cast iron as a matrix, and metal wire clusters formed by iron wires are distributed in the matrix. The diameter of the iron wires used is 0.2-2mm, and the diameter of the metal wire clusters is 10-15cm. The volume percentage is 5-40%.

Description

A wear-resistant and heat-resistant mottled cast iron material and its preparation method

technical field

The invention belongs to the field of metal materials, and relates to a wear-resistant and heat-resistant mottled cast iron material and a preparation method thereof.

Background technique

In the field of metal materials, wear-resistant and heat-resistant cast iron has been widely valued as a low-cost wear-resistant and heat-resistant material.

Zhang Shangang and others studied the design and preparation of low-alloy anti-wear hemp cast iron in the second phase of casting technology in 2003. The main chemical composition of the test material is: 2.5% ~ 3.5% C; 1.0% ~ 2.0% Si; 0.5% ~ 1.5% Mn; 0.5% -2.0 % (Co+Cu); less than 1.0% Cr, Mo. But mottled iron is mainly composed of cementite, which is hard but brittle. The toughness of the material is low. It is not conducive to the improvement of the wear resistance and heat resistance of the material.

CN200610163305.X application discloses a high-silicon ferritic heat-resistant cast iron with improved high-temperature strength and oxidation resistance, including: 2.5-3.8wt% of C, 5.0-7.0wt% of Si, 0.2-0.8wt% of Mn , 0.05wt% or less P, 0.02wt% or less S, 0.5-1.2wt% Mo, 0.1wt% or less Co, 0.5wt% or less V, 0.01-0.1wt% Cr, 0.05wt% or less Sb, and balance Fe. Although the cast iron uses a lot of rare and precious elements such as Mo, Co, V, etc., a large amount of silicon is used, and the toughness and tensile strength of the material are greatly limited.

Contents of the invention

The object of the present invention is to provide a wear-resistant and heat-resistant hemp-mouthed cast iron material with good performance in view of the above-mentioned technical defects.

Another object of the present invention is to provide a preparation method of wear-resistant and heat-resistant mottled cast iron material. The preparation method has simple process, low production cost and is suitable for industrial production.

The purpose of the present invention is achieved through the following technical solutions:

A wear-resistant and heat-resistant hemp cast iron material, the material uses mottled cast iron as a matrix, and metal wire clusters formed by iron wires are distributed in the matrix. The diameter of the iron wire used is 0.2-2mm, and the diameter of the metal wire clusters is 10-15cm , the volume percentage of iron wire in the material is 5-40%;

The weight percentage of the chemical composition of the mottled cast iron matrix: C is 2.6%~3%, Si is 2.1%~2.4%, Mn is 0.3-0.4%, Gd is 0.5-1%, P<0.08%, S< 0.25%, the rest is Fe;

The weight percentage of the chemical composition of the iron wire is: C is 0.08-0.12%, Si is 0.3%-0.5%, Mn is 0.3-0.50%, P<0.02%, S<0.025%, and the rest is Fe.

Compound Co3C, Co2Si, Cr3Si and Cr23C6 particles are also distributed in the matrix.

A method for preparing a heat-resistant mottled cast iron material is characterized in that it comprises the following steps:

Preparation of chrome-plated iron wire and cobalt-plated iron wire: the diameter is 1-2mm, the composition weight percentage: C is 0.08-0.12%, Si is 0.3%-0.5%, Mn is 0.3-0.50%, P<0.02%, S <0.025%, the rest is iron wire of Fe, the volume percentage of the iron wire is 5-40% of the material; according to the conventional method, the surface of half of the iron wire is plated with chromium, and the surface of the other half of the iron wire is plated with cobalt to form chrome-plated iron wire and cobalt-plated iron wire respectively; The thickness is 100-500 microns,

According to the conventional method of cleaning ball production, take one of the above-mentioned chrome-plated iron wire and cobalt-plated iron wire to form a spherical mixed double-wire wire group, the diameter of the metal wire group is 10-15cm, put several metal wire groups into the lower mold In the mold cavity, the degree of tightness of the wire cluster is determined by the volume percentage of the iron wire to the material, so as to ensure that the wire cluster is just filled with the mold; after the arrangement is completed, cover the upper mold of the mold on the lower mold, and wait for molten iron pouring;

Preparation of hemp cast iron material matrix: by weight percentage, C is 2.6%~3%, Si is 2.1%~2.4%, Mn is 0.3-0.4%, Gd is 0.5-1%, P<0.08%, S< 0.25%, the rest is Fe mottled cast iron raw materials for batching; mottled cast iron raw materials are melted in an induction furnace to form liquid molten iron, and the melting temperature is 1460-1490 ° C;

The above-mentioned mottled cast iron molten iron is poured into a dry sand casting mold with metal wire clusters, the liquid molten iron surrounds chrome-plated iron wires and cobalt-plated iron wires, and then cools and solidifies to form a material based on mottled cast iron with metal wire clusters distributed therein .

Compared with the prior art, the beneficial effects of the present invention are as follows:

1. Iron wire itself has considerable strength and high toughness in the material of the present invention. The matrix of iron wire and mottled iron is iron. Therefore, iron wire and mottled iron are easily combined to form a good metallurgical bond. In this way, the iron wire is distributed in the brittle mottled iron, which has a good strengthening and toughening effect on the material.

2. When the molten iron enters the mold cavity and contacts the iron wire, Co and Cr on the surface of the iron wire melt into the molten iron, and C, Si in the molten iron react with Co and Cr on the surface of the iron wire to form Co2Si, Cr3Si, Co3C and Cr23C6, which promotes the formation of molten iron C is precipitated in the form of carbides, and these reactants are harder than cementite. The special compound formed further increases the wear and heat resistance of the material.

3. Gd has a significant refinement effect on the structure of mottled iron, and plays an important role in the toughening of mottled iron. In addition, C and Gd will also form C and Gd compound Gd2C, which is distributed in the matrix and also helps to improve the wear resistance and heat resistance of the material. P and S are impurities in the material of the present invention, which are controlled within the allowable range.

4. The material of the present invention does not use precious elements, and the main alloy elements are brought in by iron wire. The cost of the iron wire material is low, the preparation process is simple, the production cost is low, the produced alloy material has good performance, and is very convenient for industrial production.

The material properties of the present invention are shown in Table 1.

Description of drawings

Fig. 1 is the metallographic structure of the wear-resistant and heat-resistant mottled cast iron material prepared in Example 1 of the present invention.

Figure 1 shows that the mottled cast iron is well combined with the iron wire.

Detailed ways

The following examples are only used to illustrate the present invention, and the weight percentages can be replaced by weight g, kg or other weight units. The following iron wires are purchased from the market, and the coating is self-made.

Embodiment one:

Preparation of chrome-plated iron wire and cobalt-plated iron wire:

Take an iron wire with a diameter of 1mm, a composition of 0.08% C, 0.3% Si, 0.3% Mn, P<0.02%, S<0.025%, and the rest is Fe. The volume percentage of the control iron wire in the material is 5%.

Chromium-plated on the surface of half of the iron wire according to the conventional method, and cobalt-plated on the surface of the other half of the iron wire to form chrome-plated iron wire and cobalt-plated iron wire of equivalent length respectively; the thickness of the coating is 100 microns;

According to the conventional method of cleaning ball production, each of the above-mentioned chrome-plated iron wire and cobalt-plated iron wire is taken to form a spherical mixed double-wire wire group (two wires are formed at the same time to form a double-wire wire group, and the molding can be used for washing dishes. Cleaning balls or called steel balls), the diameter of the metal wire ball is 15cm, put a number of metal wire balls into the lower mold cavity of the mold, the tightness of the metal wire balls is determined by the volume percentage of the iron wire in the material, to ensure that the metal The silk ball is just filled with the mold; after the arrangement is completed, cover the upper mold of the mold on the lower mold, and wait for the molten iron to be poured after the box is closed;

Preparation of mottled cast iron material matrix: by weight percentage, C is 2.6%, Si is 2.1%, Mn is 0.3%, Gd is 0.5%, P<0.08%, S<0.25%, and the rest is Fe mottled cast iron The raw materials are batched; the mottled cast iron raw materials are melted in an induction furnace, and the melting temperature is 1475-1485 °C;

The above-mentioned mottled cast iron molten iron is poured into a dry sand casting mold with metal wire clusters, the liquid molten iron surrounds chrome-plated iron wires and cobalt-plated iron wires, and then cools and solidifies to form a material based on mottled cast iron with metal wire clusters distributed therein .

Embodiment two:

The matrix composition of hemp cast iron material is by weight percentage: C is 3%, Si is 2.4%, Mn is 0.4%, Gd is 1%, P<0.08%, S<0.25%, and the rest is Fe for batching.

The composition of iron wire is 0.12% C, 0.5% Si, 0.50% Mn, P<0.02%, S <0.025%, and the rest is Fe. The wire diameter is 2mm. The volume percentage of the control iron wire accounting for the material is 40%.

According to the conventional method, the surface of half of the above-mentioned iron wires is respectively chrome-plated, and the surface of the other half of the iron wires is plated with cobalt to form chromium-plated iron wires and cobalt-plated iron wires with equivalent lengths; the thickness of the coatings is 500 microns. The conventional method that cleaning ball is produced makes the double-wire wire group that two kinds of metal wires of band plating mix, and the wire group diameter is 12cm.

The preparation process is the same as in Example 1.

Embodiment three:

The matrix composition of hemp cast iron material is by weight percentage: C is 2.8%, Si is 2.2%, Mn is 0.35%, Gd is 0.8%, P<0.08%, S<0.25%, and the rest is Fe for ingredients.

The composition of iron wire is 0.09% C, 0.4% Si, 0.4% Mn, P<0.02%, S <0.025%, and the rest is Fe. The wire diameter is 1.2mm. Iron wire accounts for 3% of the volume of the material.

According to the conventional method, the surface of half of the above-mentioned iron wires is respectively chrome-plated, and the surface of the other half of the iron wires is plated with cobalt to form chrome-plated iron wires and cobalt-plated iron wires with equivalent lengths respectively; the thickness of the coatings is 300 microns. The conventional method that cleaning ball is produced makes the two-wire wire group that two kinds of metal wires of band plating mix, and the wire group diameter is 12cm.

The preparation process is the same as in Example 1.

Comparative example four: the example that raw material proportioning is not within the scope of the present invention

The matrix composition of hemp cast iron material is by weight percentage: C is 2.3%, Si is 1%, Mn is 0.1%, Gd is 0.1%, P<0.08%, S<0.25%, and the rest is Fe for batching.

The composition of iron wire is 0.02% C, 0.2% Si, 0.2% Mn, P<0.02%, S <0.025%, and the rest is Fe. The wire diameter is 0.8mm. Iron wire accounts for 4% by volume of the material. The surface of the wire is neither cobalt nor chrome plated. Make double wire (two strands of iron wire) wire group by the conventional method that cleaning ball produces, and the wire group diameter is 12cm.

The preparation process is the same as in Example 1.

Comparative example five: the example that raw material proportioning is not within the scope of the present invention

The matrix composition of hemp cast iron material is by weight percentage: C is 4%, Si is 2.8%, Mn is 0.5%, Gd is 2%, P<0.08%, S<0.25%, and the rest is Fe for batching.

The composition of the iron wire is 0.2% C, 0.6% Si, 0.6% Mn, P<0.02%, S <0.025%, and the rest is Fe. The wire diameter is 3mm. Iron wire accounts for 45% of the volume of the material.

According to the conventional method, the surface of half of the above-mentioned iron wires is respectively chrome-plated, and the surface of the other half of the iron wires is plated with cobalt to form chromium-plated iron wires and cobalt-plated iron wires respectively; the thickness of the coatings is 600 microns. The conventional method that cleaning ball is produced makes two kinds of double-filament wire clusters that the metal wire of coating is mixed, and the diameter of wire clusters is 12cm.

The preparation process is the same as in Example 1.

Table 1

As can be seen from the above table, C, Si, and Mn increase in the chemical composition of mottled iron and iron wire in the material of the present invention, which is beneficial to the improvement of material hardness. But too much will reduce the brittleness of the base material. The increase of P and S will also reduce the toughness of the matrix material.

The increase of Gd in the mottled iron of the present invention is not only beneficial to the improvement of hardness, but also beneficial to the improvement of toughness. However, too much leads to the increase of Gd and C compounds, reducing the toughness of the material.

The increase of iron wire volume percentage is beneficial to the improvement of material toughness. But too much, reduces the hardness of the material, so also reduces the wear resistance and heat resistance of the material.

The thickness of the cobalt and chromium plating layer in the material is increased, which is beneficial to the alloying of molten iron and can improve the wear resistance and heat resistance of the material; but too much cobalt and chromium are not easy to melt into the molten iron in a short time, resulting in waste of elements.

Claims (1)

1. heat-resisting mottled cast iron preparation methods, it is characterized in that: it may further comprise the steps:

The preparation of chromium plating iron wire and cobalt plating iron wire: cut-off is 0.08-0.12% for 1-2mm, composition weight percentage: C directly, and Si is 0.3%～0.5%, and Mn is 0.3-0.50%; P < 0.02%; < 0.025%, all the other are the iron wire of Fe to S, and the volume percent that the control iron wire accounts for material is 5-40%; In half iron wire surface chromium plating respectively, second half iron wire surface cobalt plating forms chromium plating iron wire and cobalt plating iron wire respectively by ordinary method; The thickness of coating is the 100-500 micron,

Ordinary method by cleaning ball production is respectively got rhizoid formation globular mixing mariages wire group with above-mentioned chromium plating iron wire and cobalt plating iron wire; Wire group's diameter is 10-15cm; Number of metal silk group is put into casting mold mo(u)ld bottom half die cavity; The tightness of wire group guarantees that by the volume percent decision that iron wire accounts for material wire group just in time piles casting mold; After deploying, the mo(u)ld top half of casting mold is placed on the mo(u)ld bottom half, molten iron pouring is waited in the mould assembling back that finishes;

The preparation of mottled cast iron material matrix: percentage composition C is 2.6%～3% by weight, and Si is 2.1%～2.4%, and Mn is 0.3-0.4%, and Gd is 0.5-1%, and < 0.08%, < 0.25%, all the other prepare burden for the mottled cast iron raw material of Fe S P; The mottled cast iron raw material melts in induction furnace, forms liquid molten iron, and temperature of fusion is 1460-1490 ℃;

Above-mentioned mottled cast iron molten iron is poured into the dry sand casting mold that wire group is housed, and liquid molten iron surrounds chromium plating iron wire and cobalt plating iron wire, cooled and solidified then, form with the mottled cast iron be base wherein be distributed with the material that wire is rolled into a ball.