Centrifugally cast, hot-rolling composite roll

Patent metadata

Field	Value
Publication number	US-9815098-B2
Application number	US-201414912727-A
Country	US
Kind code	B2
Filing date	Sep 17, 2014
Priority date	Sep 25, 2013
Publication date	Nov 14, 2017
Grant date	Nov 14, 2017

Abstract

A centrifugally cast, hot-rolling composite roll comprising an outer layer formed by a centrifugal casting method, and an inner layer made of ductile cast iron and integrally fused to the outer layer; the outer layer having a chemical composition comprising by mass 1.6-3% of C, 0.3-2.5% of Si, 0.3-2.5% of Mn, 0.1-5% of Ni, 2.8-7% of Cr, 1.8-6% of Mo, 3.3-6.5% of V, and 0.02-0.12% of B (or 0.01-0.12% of B, and 0.05-02% of S), the balance being Fe and inevitable impurities, and meeting the relation expressed by Cr/(Mo+0.5W)≧−2/3[C−0.2(V+1.19Nb)]+11/6, wherein W=0, and Nb=0, when W and Nb are not contained, and containing by area 1-15% of MC carbide, 0.5-20% of carboboride, and 1-25% of Cr-based carbide.

First claim

What is claimed is:

1. A centrifugally cast, hot-rolling composite roll comprising an outer layer formed by a centrifugal casting method, and an inner layer made of ductile cast iron and integrally fused to said outer layer;
said outer layer having a chemical composition comprising by mass 1.6-3% of C, 0.3-2.5% of Si, 0.3-2.5% of Mn, 0.1-5% of Ni, 2.8-7% of Cr, 1.8-6% of Mo, 3.3-6.5% of V, and 0.02-0.12% of B, the balance being Fe and inevitable impurities, and meeting the relation expressed by the following formula (1):
Cr/(Mo+0.5W)≧−2/3[C−0.2(V+1.19Nb)]+11/6  (1),

wherein W=0, and Nb=0, when W and Nb, optional components, are not contained;
said outer layer containing by area 1-15% of MC carbide, 0.5-20% of carboboride, and 1-25% of Cr-based carbide, and
wherein said outer layer further comprises 0.01-0.07% by mass of N.

2. The centrifugally cast, hot-rolling composite roll according to claim 1 , wherein said outer layer further comprises 2.5% or less by mass of Nb and/or 3% or less by mass of W.

3. The centrifugally cast, hot-rolling composite roll according to claim 1 , wherein said outer layer further comprises by mass 2.5% or less of Nb and/or 3% or less of W, and 0.01-0.07% N.

4. The centrifugally cast, hot-rolling composite roll according to claim 1 , wherein said outer layer further comprises by mass at least one selected from the group consisting of 5% or less of Co, 0.5% or less of Zr, 0.5% or less of Ti, and 0.5% or less of Al.

5. The centrifugally cast, hot-rolling composite roll according to claim 1 , wherein said outer layer further comprises by mass 0.01-0.07% of N, and at least one selected from the group consisting of 5% or less of Co, 0.5% or less of Zr, 0.5% or less of Ti and 0.5% or less of Al.

6. The centrifugally cast, hot-rolling composite roll according to claim 1 , wherein said outer layer further comprises by mass 2.5% or less of Nb and/or 3% or less of W, and at least one selected from the group consisting of 5% or less of Co, 0.5% or less of Zr, 0.5% or less of Ti and 0.5% or less of Al.

7. The centrifugally cast, hot-rolling composite roll according to claim 1 , wherein said outer layer further comprises by mass 2.5% or less of Nb and/or 3% or less of W, 0.01-0.07% by mass of N, and at least one selected from the group consisting of 5% or less of Co, 0.5% or less of Zr, 0.5% or less of Ti and 0.5% or less of Al.

8. The centrifugally cast, hot-rolling composite roll according to claim 1 , wherein said outer layer meets the relation expressed by the following formula (2):
87.56+3.80×(area ratio of MC carbide)−3.06×(area ratio of Cr-based carbide)−11.26×(area ratio of carboboride)≦50  (2).

9. The centrifugally cast, hot-rolling composite roll according to claim 1 , wherein said outer layer has Vickers hardness Hv of 500 or more.

10. The centrifugally cast, hot-rolling composite roll according to claim 1 , wherein the outer layer has a P content of 0.09% or less by mass.

11. A centrifugally cast, hot-rolling composite roll comprising an outer layer formed by a centrifugal casting method, and an inner layer made of ductile cast iron and integrally fused to said outer layer;
said outer layer having a chemical composition comprising by mass 1.6-3% of C, 0.3-2.5% of Si, 0.3-2.5% of Mn, 0.1-5% of Ni, 2.8-7% of Cr, 1.8-6% of Mo, 3.3-6.5% of V, 0.01-0.12% of B, and 0.05-0.2% of S, the balance being Fe and inevitable impurities, and meeting the relation expressed by the following formula (1):
Cr/(Mo+0.5W)≧−2/3[C−0.2(V+1.19Nb)]+11/6  (1),

wherein W=0, and Nb=0, when W and Nb, optional components, are not contained; and
said outer layer containing by area 1-15% of MC carbide, 0.5-20% of carboboride, and 1-25% of Cr-based carbide.

12. The centrifugally cast, hot-rolling composite roll according to claim 11 , wherein said outer layer further comprises 2.5% or less by mass of Nb and/or 3% or less by mass of W.

13. The centrifugally cast, hot-rolling composite roll according to claim 11 , wherein said outer layer further comprises 0.01-0.07% by mass of N.

14. The centrifugally cast, hot-rolling composite roll according to claim 11 , wherein said outer layer further comprises by mass 2.5% or less of Nb and/or 3% or less of W, and 0.01-0.07% N.

15. The centrifugally cast, hot-rolling composite roll according to claim 11 , wherein said outer layer further comprises by mass at least one selected from the group consisting of 5% or less of Co, 0.5% or less of Zr, 0.5% or less of Ti, and 0.5% or less of Al.

16. The centrifugally cast, hot-rolling composite roll according to claim 11 , wherein said outer layer further comprises by mass 0.01-0.07% of N, and at least one selected from the group consisting of 5% or less of Co, 0.5% or less of Zr, 0.5% or less of Ti and 0.5% or less of Al.

17. The centrifugally cast, hot-rolling composite roll according to claim 11 , wherein said outer layer further comprises by mass 2.5% or less of Nb and/or 3% or less of W, and at least one selected from the group consisting of 5% or less of Co, 0.5% or less of Zr, 0.5% or less of Ti and 0.5% or less of Al.

18. The centrifugally cast, hot-rolling composite roll according to claim 11 , wherein said outer layer further comprises by mass 2.5% or less of Nb and/or 3% or less of W, 0.01-0.07% by mass of N, and at least one selected from the group consisting of 5% or less of Co, 0.5% or less of Zr, 0.5% or less of Ti and 0.5% or less of Al.

19. The centrifugally cast, hot-rolling composite roll according to claim 11 , wherein said outer layer meets the relation expressed by the following formula (2):
87.56+3.80×(area ratio of MC carbide)−3.06×(area ratio of Cr-based carbide)−11.26×(area ratio of carboboride)≦50  (2).

20. The centrifugally cast, hot-rolling composite roll according to claim 11 , wherein said outer layer has Vickers hardness Hv of 500 or more.

Assignees

• Hitachi Metals Ltd

Inventors

• Hattori Toshiyuki
• Oda Nozomu
• Nozaki Yasunori

Classifications

• C22C38/60

  containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur · CPC title

• C22C38/46

  with vanadium · CPC title

• C22C38/44

  with molybdenum or tungsten · CPC title

• C22C38/40

  with nickel · CPC title

• C22C37/08

  with nickel · CPC title