Grinding wheel for roll grinding application and method of roll grinding thereof

• US 8,029,338 B2
• Filed: 03/08/2004
• Issued: 10/04/2011
• Est. Priority Date: 12/23/2003
• Status: Active Grant

• Current Assignee: Diamond Innovations Incorporated (Sandvik AB)
• Original Assignee: Diamond Innovations Incorporated (Sandvik AB)
• Inventors: Varghese, Biju, Kumar, Kris V.
• Primary Examiner(s): Eley; Timothy V
• Application Number:
  US10/596,710
• Publication Number:
  US 20070099548A1
• Time in Patent Office: 2,766 Days
• Field of Search: 451/11, 451/8, 451/9, 451/49, 451/283, 451/548, 451/57, 451/58, 148/400, 148/320
• US Class Current: 451/49
• CPC Class Codes: B21B 28/04 while in use, e.g. polishing or grinding while the rolls are in their stands
• CPC Class Codes: B24B 1/00 Processes of grinding or polishing; Use of auxiliary equipment in connection with such processes
• CPC Class Codes: B24B 5/37 for grinding rolls, e.g. barrel-shaped rolls
• CPC Class Codes: B24D 3/14 ceramic, i.e. vitrified bondings
• CPC Class Codes: B24D 5/00 Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting only by their periphery; Bushings or mountings therefor

Abstract

Iron and steel rolls are ground to production quality requirements with a grinding wheel that requires minimal wheel wear compensation, profile error compensation or taper error compensation during the grinding process. The grinding wheel consists essentially of a superabrasive material selected from the group of natural diamond, synthetic diamond, cubic boron nitride, and mixtures thereof, in a bond system, for a grinding wheel with extended wheel life, and which removes minimum amount of stock off the roll to achieve desired roll geometry.

Claims

1. A method of grinding a ferrous roll having a rotating roll surface with a rotating grinding wheel, the ferrous roll having a hardness greater than 65 SHC and a minimum diameter of at least 10 inches and a length of at least 2 feet, the method comprising:

a) mounting a grinding wheel on a machine spindle and setting an angle between the grinding wheel rotational axis and roll rotational axis less than about 25 degrees;

b) bringing the rotating wheel into contact with the rotating roll surface and traversing the wheel across an axial roll length of the roll, while maintaining a ratio of axial taper tolerance (TT) to radial wheel wear compensation (WWC) of greater than 10; and

c) grinding the roll surface to a surface roughness R_a of less than 5 micrometer while leaving the roll surface substantially free of feed marks, chatter marks, and surface irregularities.

2. The method of claim 1, wherein the roll is ground to a surface roughness R_a of less than 3 micrometer.

3. The method of claim 1, wherein the ferrous roll surface is substantially free of thermal degradation.

4. The method of claim 1, wherein the ratio of TT to WWC is greater than 25.

5. The method of claim 1, wherein said grinding wheel includes a layer comprising of a superabrasive material having a Knoop hardness greater than 3000 KHN, selected from the group of natural diamond, synthetic diamond, cubic boron nitride, and mixtures thereof, with or without a secondary abrasive with Knoop hardness less than 3000 KHN, in a bond system.

6. The method of claim 5, wherein the superabrasive material comprises cubic boron nitride, and the amount of cubic boron nitride in said grinding wheel bond system is in the range of 10 to 60 volume %.

7. The method of claim 5, wherein the bond system is one of:

a) a vitrified bond comprising at least one of clay, feldspar, lime, borax, soda, glass frit, fritted materials and combinations thereof; and

b) a resin bond system comprising at least one of a phenolic resin, epoxy resin, polyimide resin, and mixtures thereof.

8. The method of claim 1, wherein the grinding wheel is rotated from 3600 to 12000 fpm.

9. The method of claim 1, wherein said method further comprises the step of removing stock off the ferrous roll in one pass or multiple passes.

10. The method of claim 1, wherein the grinding is carried out at a G ratio of at least 20.

11. The method of claim 1, wherein the grinding wheel has an axis of rotation that is substantially parallel to the rotational axis of the roll.

12. The method of claim 1, wherein said ferrous roll is a solid revolution having a surface geometry selected from one of:

a convex crown, a concave crown, a continuous numerical profile, and a polynomial shape along the axis of the roll, ground to a form profile tolerance of less than 0.05 mm.

13. The method of claim 1, wherein said grinding wheel has a traverse rate of at least 50 mm/min.

14. The method of claim 1, wherein said grinding wheel removes a stock grind amount of less than about 0.2 mm from the minimum worn roll diameter.

15. A method of grinding a ferrous roll having a rotating roll surface with a rotating grinding wheel, the method comprising:

a) mounting the grinding wheel on a machine spindle;

b) bringing the rotating wheel into contact with the rotating roll surface and traversing the wheel across an axial roll length of the roll; and

c) grinding the roll surface while at least one or both of said grinding wheel rotational speed and said mill roll rotational speed is varied in an amount of +/−

1 to 40% in amplitude, with a period of 1 to 30 seconds;

wherein a ratio of TT to WWC is greater than 25.

16. The method of claim 15, wherein the bond system is one of:

a) a vitrified bond comprising at least one of clay, feldspar, lime, borax, soda, glass frit, fritted materials and combinations thereof; and

b) a resin bond system comprising at least one of a phenolic resin, epoxy resin, polyimide resin, and mixtures thereof.