Iron alloy and part for motor vehicle comprising said alloy

Abstract

The invention relates to an iron alloy comprising the following terms in wt%: C ranging from 3.1 to 3.9; si in the range of from 1.8 to 2.8; mn in the range of from 0.5 to 0.9; v ranging from 0.2 to 0.6; mo

Description

Technical Field

[0001] The present invention generally relates to ferroalloys, and more particularly to ferroalloys intended to be incorporated into motor vehicles.

[0002] Specifically, the present invention relates to a specific ferroalloy, a part for a motor vehicle comprising said ferroalloy, and a motor vehicle comprising said part. Background Art

[0003] During the braking process, when the brake rotor and the brake lining come into contact, fine particles are emitted. These particles generated by braking are harmful to health and are of particular concern to the European Commission.

[0004] More specifically, the particles generated by braking originate from the wear of the friction track of the brake rotor and the wear of the brake lining that comes into contact with it.

[0005] Currently, brake rotors are made of cast iron (i.e., the material of a specific ferroalloy). This material results in high emissions of fine particles, which is the reason for the work carried out by the European Commission.

[0006] The wear of the brake friction track can depend on the hardness of the material constituting the brake rotor. The harder the material, the more robust it is, and the lower the wear of the friction track of the brake rotor. Less wear results in reduced particle emissions caused by braking.

[0007] Various ways have been explored to improve the hardness of this material. In particular, enhancing the material by depositing an additional coating has been studied. Even though this actually improves the surface hardness of the material, the associated costs are still extremely high. This is because the capital costs are high and additional costs for the parts to be developed are incurred.

[0008] Therefore, there is a need for available ferroalloys that exhibit improved hardness and improved wear. Summary of the Invention

[0009] Therefore, an object of the present invention is to provide a ferroalloy that exhibits improved hardness and improved wear.

[0010] Therefore, the subject of the present invention is a ferroalloy comprising, in weight %, the following:

[0011] C in the range from 3.1 to 3.9;

[0012] Si in the range from 1.8 to 2.8;

[0013] Mn in the range from 0.5 to 0.9;

[0014] V in the range from 0.2 to 0.6;

[0015] Mo ≤ 0.7;

[0016] Cu < 0.6;

[0017] Cr ≤ 0.35;

[0018] Ni < 0.2;

[0019] S < 0.15;

[0020] P < 0.1;

[0021] Sn < 0.1;

[0022] Iron and inevitable impurities.

[0023] In the ferroalloy according to the invention, the weight percentage (wt%) is defined relative to the total weight of the ferroalloy.

[0024] Another subject of the invention is a part for a motor vehicle, such as a brake rotor, which part comprises at least one ferroalloy according to the invention.

[0025] Another subject of the invention is a motor vehicle which comprises at least one part for a motor vehicle according to the invention.

[0026] Thanks to the ferroalloy according to the invention, an improvement in hardness and a reduction in wear are obtained.

[0027] Other features, aspects, subjects and advantages will emerge from the following description and the following examples given by way of illustration only.

[0028] Within the meaning of the present invention, the expression "at least one" is equivalent to the expression "one or more".

[0029] Furthermore, unless otherwise specified, the limiting values of a value range are included in that range, particularly in the expressions "between... and..." and "from... to...".

[0030] Furthermore, "<" should be understood to mean strictly less than. For example, Ni < 0.2 means that the nickel content is strictly less than 0.2 wt% relative to the total weight of the ferroalloy. Furthermore, "≤" should be understood to mean less than or equal to. For example, Cr ≤ 0.35 means that the chromium content is less than or equal to 0.35 wt% relative to the total weight of the ferroalloy.

[0031] Thus, within the meaning of the present invention, the expression "from... to <..." should be understood to mean that the lower limit of the value range is included within the range, but the upper limit is excluded from the value range. For example, "a range of Cu from 0.2 to <0.6" means that 0.2 is included within the range and 0.6 is excluded from the range. In other words, "a range of Cu from 0.2 to <0.6" means that the copper content is greater than or equal to 0.2% by weight relative to the total weight of the ferroalloy and strictly less than 0.6% by weight.

[0032] Within the meaning of the present invention, the term "inevitable impurities" should be understood to mean atoms or groups of atoms other than C, Si, Mn, V, Mo, Cu, Cr, Ni, S, P, and Sn, which are present in an amount less than or equal to 0.1% by weight relative to the total weight of the ferroalloy, with the exception of Zn, where the content is less than or equal to 0.2% by weight relative to the total weight of the ferroalloy. In other words, each inevitable impurity is present in an amount less than or equal to 0.1% by weight relative to the total weight of the ferroalloy, with the exception of Zn, where the content is less than or equal to 0.2% by weight relative to the total weight of the ferroalloy.

[0033] As pointed out above, the subject matter of the present invention is the ferroalloy as defined above.

[0034] Advantageously, the combined inevitable impurities are present in an amount less than or equal to 0.5% by weight relative to the total weight of the ferroalloy.

[0035] Advantageously, the ferroalloy contains at least 80% by weight of iron, preferably at least 85% by weight of iron, relative to the total weight of the ferroalloy.

[0036] Advantageously, the ferroalloy contains, in % by weight, the following: Cu in a range from 0.2 to <0.6, preferably in a range from 0.4 to <0.6.

[0037] According to a first preferred embodiment, the ferroalloy contains, in % by weight, the following: Cr in a range from 0.2 to 0.35.

[0038] Preferably, in this first embodiment, the ferroalloy may contain, in % by weight, the following: V in a range from 0.2 to 0.3.

[0039] Preferably, in this first embodiment, the ferroalloy may contain, in % by weight, the following: Mo <0.1.

[0040] According to a preferred embodiment, the ferroalloy contains, in % by weight, the following:

[0041] Cr in a range from 0.2 to 0.35;

[0042] V in a range from 0.2 to 0.3; and

[0043] Mo < 0.1.

[0044] According to another preferred embodiment, the ferroalloy comprises the following in wt%:

[0045] Cu in the range from 0.2 to <0.6;

[0046] Cr in the range from 0.2 to 0.35;

[0047] V in the range from 0.2 to 0.3; and

[0048] Mo < 0.1.

[0049] According to a more preferred embodiment, the ferroalloy comprises the following in wt%:

[0050] Cu in the range from 0.4 to <0.6;

[0051] Cr in the range from 0.2 to 0.35;

[0052] V in the range from 0.2 to 0.3; and

[0053] Mo < 0.1.

[0054] According to the second embodiment, the ferroalloy comprises the following in wt%: Cr < 0.25.

[0055] Preferably, in this second embodiment, the ferroalloy may comprise the following in wt%: V in the range from 0.4 to 0.6.

[0056] Preferably, in this second embodiment, the ferroalloy may comprise the following in wt%: Mo in the range from 0.5 to 0.7.

[0057] According to a preferred embodiment, the ferroalloy comprises the following in wt%:

[0058] Cr < 0.25;

[0059] V in the range from 0.4 to 0.6; and

[0060] Mo in the range from 0.5 to 0.7.

[0061] According to another preferred embodiment, the ferroalloy comprises the following in wt%:

[0062] Cu in the range from 0.4 to <0.6;

[0063] Cr < 0.25;

[0064] V in the range from 0.4 to 0.6; and

[0065] Mo ranging from 0.5 to 0.7.

[0066] Advantageously, the ferroalloy consists of the following by weight %:

[0067] C ranging from 3.1 to 3.9;

[0068] Si ranging from 1.8 to 2.8;

[0069] Mn ranging from 0.5 to 0.9;

[0070] V ranging from 0.2 to 0.6;

[0071] Mo ≤ 0.7;

[0072] Cu < 0.6;

[0073] Cr ≤ 0.35;

[0074] Ni < 0.2;

[0075] S < 0.15;

[0076] P < 0.1;

[0077] Sn < 0.1;

[0078] The balance consisting of iron and inevitable impurities.

[0079] Another subject of the present invention relates to a part for a motor vehicle, such as a brake rotor, which part comprises at least one ferroalloy according to the present invention as described above.

[0080] Another subject of the present invention is a motor vehicle which comprises at least one part for a motor vehicle according to the present invention as described above.

[0081] The following examples are used to illustrate the present invention, however, they do not show a limiting nature.

[0082] Examples

[0083] Prepare the ferroalloys as described in Table 1 below: The contents are expressed as weight % relative to the total weight of the ferroalloy.

[0084] [Table 1]

[0085]

[0086]

[0087] Therefore, alloy A is a comparative ferroalloy. Alloys B to D are alloys according to the present invention. Alloys B to D are obtained by the same preparation method as alloy A, while adjusting the burden ratio of the alloying elements (V, Mo, Cr, Cu) of the present invention added.

[0088] Then, the alloy is converted into discs with a diameter < 150 mm and a thickness ≤ 15 mm, and then characterized. The chemical composition is determined by spectrometric medals cast during the manufacture of the discs.

[0089] Evaluation of hardness

[0090] The hardness of the various alloys is evaluated according to the standard NF EN ISO 6506-1 of November 22, 2014. The Brinell hardness is expressed as HB.

[0091] The results are tabulated in Table 2 below:

[0092] [Table 2]

[0093] Alloy A B C D Brinell hardness (HB) 160-230 250 280 300

[0094] Obviously, the ferroalloys B, C and D according to the present invention exhibit significantly higher Brinell hardness than the comparative ferroalloy A.

[0095] Therefore, the ferroalloys according to the present invention exhibit improved hardness.

[0096] Wear evaluation

[0097] The wear of alloys A to C is evaluated on a slug / disc workbench. Under a given pressure and a given linear velocity, a slug made of brake lining material is brought into surface contact with a disc made of ferroalloy. After a fixed friction time, the wear volume of the friction surface of the disc made of ferroalloy is measured and correlated with the distance traveled under friction in order to determine the wear rate in mm 3 / km.

[0098] The results are tabulated in Table 3 below:

[0099] [Table 3]

[0100] Alloy A B C <![CDATA[Wear rate (mm 3 / km)]]> <![CDATA[5.9×10 -4 > <![CDATA[4.6×10 -4 > <![CDATA[2.8×10 -4 >

[0101] Obviously, the ferroalloys B and C according to the present invention exhibit significantly lower wear rates than that of the comparative ferroalloy A. It is particularly found that when the ferroalloy C according to the present invention is used, it can be observed that the wear rate is half of that of the comparative ferroalloy A.

[0102] Thus, the ferroalloys according to the invention exhibit improved wear behavior.

[0103] Thus, the ferroalloys according to the invention exhibit improved hardness and improved wear, i.e. greater hardness and reduced wear. With the reduction of wear, the emissions of particles generated by braking can be reduced, and the service life of parts used in motor vehicles, such as brake rotors, can be improved.

Claims

1. An ferroalloy, the ferroalloy comprising the following in weight %: C in the range from 3.1 to 3.9; Si in the range from 1.8 to 2.8; Mn in the range from 0.5 to 0.9; V in the range from 0.2 to 0.6; Mo ≤ 0.7; Cu < 0.6; Cr≤0.35； Ni < 0.2; S<0.15； P<0.1； Sn < 0.1; iron and inevitable impurities.

2. The alloy according to claim 1, the alloy comprising at least 80% by weight of iron, preferably at least 85% by weight of iron, relative to the total weight of the ferroalloy.

3. The alloy according to claim 1 or 2, the alloy comprising: Cu in the range from 0.2 to <0.6, preferably in the range from 0.4 to <0.

6.

4. The alloy according to any one of the preceding claims, the alloy comprising: Cr in the range from 0.2 to 0.

35.

5. The alloy according to any one of the preceding claims, the alloy comprising: V in the range from 0.2 to 0.

3.

6. The alloy according to any one of the preceding claims, the alloy comprising: Mo < 0.

1.

7. The alloy according to any one of claims 1 to 3, the alloy comprising: Cr < 0.

25.

8. The alloy according to claim 7, the alloy comprising: V in the range from 0.4 to 0.

6.

9. The alloy according to claim 7 or 8, the alloy comprising: Mo in the range from 0.5 to 0.

7.

10. A part for a motor vehicle, such as a brake rotor, the part comprising at least one ferroalloy according to any one of the preceding claims.

11. A motor vehicle, the motor vehicle comprising at least one part for a motor vehicle according to claim 10.

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