Search

US-20260125782-A1 - CAST IRON, IN PARTICULAR FOR COMPONENTS OF DISC BRAKES

US20260125782A1US 20260125782 A1US20260125782 A1US 20260125782A1US-20260125782-A1

Abstract

A gray cast iron comprising carbon, silicon, vanadium, manganese, nickel, chromium, molybdenum, copper, sulfur, phosphorus, tin and titanium, wherein: the percentage by weight of carbon is from 3.70-3.90%, the percentage by weight of silicon is from 1.30-2.10%, the percentage by weight of vanadium is from 0.12-0.14%, the percentage by weight of manganese is from 0.60-0.90%, the percentage by weight of nickel is from 0.05-0.50%, the percentage by weight of chromium is from 0.20-0.35%, the percentage by weight of molybdenum is not higher than 0.10%, the percentage by weight of copper is not higher than 0.35%, the percentage by weight of sulphur is lower than 0.10%, the percentage by weight of tin is lower than 0.10%, the percentage by weight of titanium is lower than 0.01%, the remainder by weight being constituted of iron.

Inventors

  • Bozena DUDZIK
  • Mariusz BIERONSKI
  • Fabiano Carminati

Assignees

  • BREMBO S.P.A

Dates

Publication Date
20260507
Application Date
20251027
Priority Date
20190724

Claims (20)

  1. 1 . A grey cast iron comprising carbon, silicon, vanadium, manganese, nickel, chromium, molybdenum, copper, sulphur, phosphorus, tin and titanium, wherein the percentage by weight of carbon is from 3.70-3.90%, the percentage by weight of silicon is from 1.30-2.10%, the percentage by weight of vanadium is from 0.12-0.14% the percentage by weight of manganese is from 0.60-0.90%, the percentage by weight of nickel is from 0.05-0.50%, the percentage by weight of chromium is from 0.20-0.35%, the percentage by weight of molybdenum is not higher than 0.10% the percentage by weight of copper is not higher than 0.35%, the percentage by weight of sulphur is lower than 0.10%, the percentage by weight of tin is lower than 0.10%, the percentage by weight of titanium is lower than 0.01%, the remainder by weight being constituted of iron.
  2. 2 . The grey cast iron of claim 1 , wherein the percentage by weight of carbon is from 3.70 to 3.86%.
  3. 3 . The grey cast iron of claim 1 , wherein the percentage by weight of silicon is from 1.40 to 2.08%.
  4. 4 . The grey cast iron of claim 1 , wherein the grey cast iron has a higher wear resistance with a weight percentage of vanadium from 0.12-0.14% than with a weight percentage of vanadium outside of 0.12-0.14%.
  5. 5 . The grey cast iron of claim 1 , wherein the grey cast iron has a lower wear resistance with a weight percentage of vanadium lower than 0.12% and higher than 0.14%.
  6. 6 . The grey cast iron of claim 1 , wherein the grey cast iron resists wear less when the weight percentage of V is below 0.12%.
  7. 7 . The grey cast iron of claim 1 , wherein the grey cast iron resists wear 25-50% less when vanadium equals 0.08% compared to when vanadium equals 0.12-0.14%.
  8. 8 . The grey cast iron of claim 1 , wherein the grey cast iron resists wear at least 50% less when vanadium equals 0.18% compared to when vanadium equals 0.12-0.14%.
  9. 9 . The grey cast iron according to claim 1 , wherein the percentage by weight of manganese is from 0.63 to 0.85%.
  10. 10 . The grey cast iron according to claim 1 , wherein the percentage by weight of nickel is between 0.06 and 0.47%.
  11. 11 . The grey cast iron according to claim 1 , wherein the percentage by weight of chromium is between 0.21 and 0.35%.
  12. 12 . The grey cast iron according to claim 1 , wherein the percentage by weight of titanium is between 0.0079 and 0.01%.
  13. 13 . The grey cast iron according to claim 1 , consisting of 3.86% by weight of carbon, 1.85% by weight of silicon, 0.12% by weight of vanadium, 0.63% by weight of manganese, 0.06% by weight of nickel, 0.21% by weight of chromium, 0.002% by weight of molybdenum, 0.19% by weight of copper, 0.065% by weight of sulphur, 0.04% by weight of phosphorus, 0.023% by weight of tin, and 0.0079% by weight of titanium, the remainder by weight being iron.
  14. 14 . The grey cast iron according to claim 1 , consisting of 3.70% by weight of carbon, 2.08% by weight of silicon, 0.12% by weight of vanadium, 0.658% by weight of manganese, 0.47% by weight of nickel, 0.255% by weight of chromium, 0.0312% by weight of molybdenum, 0.238% by weight of copper, 0.0463% by weight of sulphur, 0.031% by weight of phosphorus, 0.038% by weight of tin and 0.01% by weight of titanium, the remainder by weight being iron.
  15. 15 . The grey cast iron according to claim 1 , further comprising tungsten, wherein the weight percentage of tungsten is between 0.10 and 0.14%.
  16. 16 . The grey cast iron according to claim 1 , wherein a matrix of said grey cast iron is pearlitic, wherein the percentage by weight of perlite is not lower than 95%.
  17. 17 . The grey cast iron according to claim 1 , comprising ferrite in a percentage by weight lower than 5%.
  18. 18 . The grey cast iron according to claim 1 , comprising cementite and free carbides with a percentage by weight not higher than 1%.
  19. 19 . A brake disc for a disc brake comprising a braking surface made in a cast iron according to claim 1 .
  20. 20 . A grey cast iron consisting of carbon, silicon, vanadium, manganese, nickel, chromium, molybdenum, copper, sulphur, phosphorus, tin and titanium, wherein the percentage by weight of carbon is from 3.70-3.90%, the percentage by weight of silicon is from 1.30-2.10%, the percentage by weight of vanadium is from 0.12-0.14% the percentage by weight of manganese is from 0.60-0.90%, the percentage by weight of nickel is from 0.05-0.50%, the percentage by weight of chromium is from 0.20-0.35%, the percentage by weight of molybdenum is not higher than 0.10% the percentage by weight of copper is not higher than 0.35%, the percentage by weight of sulphur is lower than 0.10%, the percentage by weight of tin is lower than 0.10%, the percentage by weight of titanium is lower than 0.01%, the remainder by weight being constituted of iron.

Description

FIELD OF APPLICATION The present invention relates to a cast iron, in particular for making a brake disc, and to a brake disc for a disc brake made with said cast iron. BACKGROUND ART As known, brake discs made of gray cast iron are subject to wear at the braking bands over time. Inevitably, such phenomena affect the duration of the discs. Therefore, the need to manufacture brake discs made of cast iron which have high wear resistance is greatly felt in the automotive field, and in particular for high-performance vehicles. An increased wear resistance thus results in a reduction of metal powders being released into the environment. However, the increased wear resistance in discs made of gray cast iron must be achieved taking into account the mechanical and thermal stresses of high intensity to which the brake discs are subjected. Such stresses result in the attainment of high temperatures on the braking bands, which can result in decreases in the braking performance, and even in the formation of cracks on the braking band. The need is also felt for brake discs made of gray cast iron to have high corrosion resistance so as to increase the duration thereof. Therefore, increased wear resistance must not have a negative impact on the corrosion resistance. In the art, gray cast iron solutions capable of simultaneously combining high wear resistance with high performance in terms of mechanical resistance, heat resistance, and corrosion resistance are not known. PRESENTATION OF THE INVENTION It is the object of the present invention to provide a gray cast iron which overcomes the drawbacks stated with reference to the prior art. Such drawbacks are overcome by a gray cast iron according to claim 1. Other embodiments of the cast iron according to the invention are described in the following claims. Further features and advantages of the present invention will become more apparent from the description given below of preferred, non-limiting embodiments thereof. DETAILED DESCRIPTION According to a general embodiment, the gray cast iron of the present invention comprises in the alloy: carbon, silicon, vanadium, manganese, nickel, chromium, molybdenum, copper, sulfur, phosphorous, tin and titanium. Such alloying elements are contained in the cast iron with the following ranges of percentage by weight on the total weight of the cast iron: carbon from 3.70 to 3.90% by weight,silicon from 1.30 to 2.10% by weight,vanadium from 0.12 to 0.14% by weight,manganese from 0.60 to 0.90% by weight,nickel from 0.05 to 0.50% by weight,chromium from 0.20 to 0.35% by weight,molybdenum no more than 0.10% by weight,copper no more than 0.35% by weight,sulfur less than 0.10% by weight,phosphorus less than 0.10% by weight,tin less than 0.10% by weight,titanium no more than 0.01% by weight,the remainder by weight being iron. Preferably, the percentage by weight of carbon is from 3.70 to 3.86%, Preferably, the percentage by weight of silicon is from 1.40 to 2.08%, Preferably, the percentage by weight of manganese is from 0.63 to 0.85%, Preferably, the percentage by weight of nickel is from 0.06 to 0.47%. Preferably, the percentage by weight of chromium is from 0.21 to 0.35%, Preferably, the percentage by weight of copper is from 0.19 to 0.35%, Preferably, the percentage by weight of tin is no more than 0.09%, Preferably, the percentage by weight of titanium is from 0.0079 to 0.01%. According to a first preferred embodiment, the gray cast iron has the following composition: 3.86% by weight carbon;1.85% by weight silicon;0.12% by weight vanadium;0.63% by weight manganese;0.06% by weight nickel;0.21% by weight chromium;0.002% by weight molybdenum;0.19% by weight copper;0.065% by weight sulfur;0.04% by weight phosphorous;0.023% by weight tin;0.0079% by weight titanium;the remainder by weight being iron. According to a second preferred embodiment, the gray cast iron has the following composition: 3.70% by weight carbon;2.08% by weight silicon;0.12% by weight vanadium;0.658% by weight manganese;0.47% by weight nickel;0.255% by weight chromium;0.0312% by weight molybdenum;0.238% by weight copper;0.0463% by weight sulfur;0.031% by weight phosphorous;0.038% by weight tin;0.01% by weight titanium;the remainder by weight being iron. Advantageously, the gray cast iron can additionally comprise tungsten, with a percentage by weight from 0.10 to 0.14%, and preferably equal to 0.12%. According to a third particularly preferred embodiment, the gray cast iron has the following composition: 3.75% by weight carbon,1.40% by weight silicon,0.14% by weight vanadium;0.12% by weight tungsten,0.85% by weight manganese,0.1% by weight nickel,0.35% by weight chrome,0.1% by weight molybdenum,0.35% by weight copper,<0.1% by weight sulfur,<0.1% by weight phosphorous,0.09% by weight tin,0.01% by weight titaniumthe remainder by weight being iron. Preferably, the ferrous matrix of the cast iron is of the pearlite or fine lamellar type. In particular, the percentage by weight of