Piston rings in cast tool steels and process for the manufacture thereof

Patent metadata

Field	Value
Publication number	US-10309536-B2
Application number	US-201615772044-A
Country	US
Kind code	B2
Filing date	Oct 24, 2016
Priority date	Oct 29, 2015
Publication date	Jun 4, 2019
Grant date	Jun 4, 2019

Abstract

A piston ring in cast tool steels including a ring of a tempered material having a chemical composition including a percent weight concentration of C from 0.80 to 1.40, Cr from 2.50 to 4.20, Mn from 0.10 to 1.00, Mo from 1.00 to 2.00, Nb from 2.50 to 4.50, P of no more than 0.05, S of no more than 0.05, Si from 0.10 to 1.00, Ti from 0.10 to 0.30, V from 1.00 to 3.00, W from 1.00 to 3.00, and a remaining concentration balance of Fe. The tempered material may have a microstructure including a matrix of tempered martensite with precipitation of at least one of secondary M 2 C carbides and MC carbides, M being at least one of V, Mo, Cr, and W. The microstructure may include NbC eutectic carbides having a cubic morphology. The tempered material may have a hardness from approximately 400 HV to 800 HV.

First claim

The invention claimed is:

1. A piston ring in cast tool steels, comprising:
a ring including of a tempered material having a chemical composition including:
a concentration of C from 0.80 to 1.40 percent weight;
a concentration of Cr from 2.50 to 4.20 percent weight;
a concentration of Mn from 0.10 to 1.00 percent weight;
a concentration of Mo from 1.00 to 2.00 percent weight;
a concentration of Nb from 2.50 to 4.50 percent weight;
a concentration of P of no more than 0.05 percent weight;
a concentration of S of no more than 0.05 percent weight;
a concentration of Si from 0.10 to 1.00 percent weight;
a concentration of Ti from 0.10 to 0.30 percent weight;
a concentration of V from 1.00 to 3.00 percent weight;
a concentration of W from 1.00 to 3.00 percent weight; and
a remaining concentration balance of Fe;

a microstructure of the tempered material configured as 1) a matrix of tempered martensite with a toughness improving precipitation of at least one of secondary M 2 C carbides and MC carbides having a size of approximately 3 μm or less, and 2) NbC eutectic carbides having a cubic morphology, a volumetric fraction from approximately 1% to 4%, a size from approximately 3 μm to 7 μm, and a homogeneous distribution;
wherein M is at least one of V, Mo, Cr, and W; and
wherein the tempered material has a hardness from approximately 400 HV to 800 HV.

2. The piston ring as claimed in claim 1 , wherein the ring is a gravity casted ring.

3. The piston ring as claimed in claim 1 , wherein the ring is a centrifugal casted ring.

4. The piston ring as claimed in claim 1 , wherein the ring is produced utilizing at least one of molds of green sand, molds of sand-resin, and ceramic molds.

5. The piston ring as claimed in claim 1 , wherein the ring is produced via a process including:
annealing the ring at a temperature from 600° C. to 800° C.;
heat treating the ring via quenching at a temperature from 900° C. to 1150° C.; and
tempering the ring at a temperature of 650° C. or less.

6. The piston ring as claimed in claim 5 , wherein the ring is quenched in a furnace having a controlled atmosphere.

7. The piston ring as claimed in claim 5 , wherein the ring includes a contact face configured to contact a piston cylinder, wherein the contact face includes an antiwear coating disposed thereon via at least one of a galvanic process, spraying, and physical vapor deposition.

8. The piston ring as claimed in claim 1 , wherein the ring includes at least one surface including at least one of a nitridation and an antiwear coating.

9. The piston ring as claimed in claim 8 , wherein the nitridation is provided via at least one of a gas, a plasma, and a salt bath.

10. The piston ring as claimed in claim 1 , wherein the ring includes a contact face configured to contact a piston cylinder, wherein the contact face includes an antiwear coating disposed thereon via at least one of a galvanic process, spraying, and physical vapor deposition.

11. A piston ring in cast tool steels, comprising:
a tempered ring including a contact face configured to contact a piston cylinder, the ring having a chemical composition including:
a concentration of C from 0.80 to 1.40 percent weight;
a concentration of Cr from 2.50 to 4.20 percent weight;
a concentration of Mn from 0.10 to 1.00 percent weight;
a concentration of Mo from 1.00 to 2.00 percent weight;
a concentration of Nb from 2.50 to 4.50 percent weight;
a concentration of P of no more than 0.05 percent weight;
a concentration of S of no more than 0.05 percent weight;
a concentration of Si from 0.10 to 1.00 percent weight;
a concentration of Ti from 0.10 to 0.30 percent weight;
a concentration of V from 1.00 to 3.00 percent weight;
a concentration of W from 1.00 to 3.00 percent weight; and
a remaining concentration balance of Fe;

wherein the ring has a microstructure including 1) a matrix of tempered martensite with precipitation of at least one of V 2 C carbides, VC carbides, Mo 2 C carbides, MoC carbides, Cr 2 C carbides, CrC carbides, W 2 C carbides, and WC carbides having a size of approximately 3 μm or less, and 2) NbC eutectic carbides having a cubic morphology, a volumetric fraction from approximately 1% to 4%, a size from approximately 3 μm to 7 82 m, and a homogeneous distribution, and wherein the ring has a hardness from approximately 400 HV to 800 HV.

12. The piston ring as claimed in claim 11 , wherein the ring is annealed at a temperature from approximately 600° C. to 800° C., quenched at a temperature from approximately 900° C. to 1150° C., and tempered at a temperature of approximately 650° C. or less.

13. The piston ring as claimed in claim 11 , wherein the ring includes at least one surface including at least one of a nitridation and an antiwear coating.

14. The piston ring as claimed in claim 13 , wherein the nitridation is provided via at least one of a gas, a plasma, and a salt bath.

15. The piston ring as claimed in claim 13 , wherein the contact face includes the antiwear coating, and wherein the antiwear coating is disposed via at least one of a galvanic process, spraying, and physical vapor deposition.

16. The piston ring as claimed in claim 11 , wherein the ring is one of a gravity casted ring and a centrifugal casted ring.

17. A piston ring in cast tool steels, comprising:
a tempered ring structured of a material having a chemical composition including:
a concentration of C from 0.80 to 1.40 percent weight;
a concentration of Cr from 2.50 to 4.20 percent weight;
a concentration of Mn from 0.10 to 1.00 percent weight;
a concentration of Mo from 1.00 to 2.00 percent weight;
a concentration of Nb from 2.50 to 4.50 percent weight;
a concentration of P of no more than 0.05 percent weight;
a concentration of S of no more than 0.05 percent weight;
a concentration of Si from 0.10 to 1.00 percent weight;
a concentration of Ti from 0.10 to 0.30 percent weight;
a concentration of V from 1.00 to 3.00 percent weight;
a concentration of W from 1.00 to 3.00 percent weight; and
a remaining concentration balance of Fe;

wherein the ring has a microstructure including 1) a matrix of tempered martensite with precipitation of at least one of V 2 C carbides, VC carbides, Mo 2 C carbides, MoC carbides, Cr 2 C carbides, CrC carbides, W 2 C carbides, and WC carbides having a size of approximately 3 μm or less, and 2) NbC eutectic carbides having a cubic morphology, a volumetric fraction from approximately 1% to 4%, a size from approximately 3 μm to 7 μm, and a homogeneous distribution, and wherein the ring has a hardness from approximately 400 HV to 800 HV and includes at least one surface including a nitridation.

18. The piston ring as claimed in claim 17 , wherein the nitridation is provided via at least one of a gas, a plasma, and a salt bath.

19. The piston ring as claimed in claim 17 , wherein the ring is one of a gravity casted ring and a centrifugal casted ring.

20. The piston ring as claimed in claim 17 , wherein the ring is annealed at a temperature from approximately 600° C. to 800° C., quenched at a temperature from approximately 900° C. to 1150° C., and tempered at a temperature of approximately 650° C. or less.

Assignees

• Inst De Pesquisas Tecnologicas Do Estado De Sao Paulo S/A
• Mahle Metal Leve Sa
• Mahle Int Gmbh
• Instituto De Pesquisas Tech Do Estado De Sao Paulo S/A

Inventors

• Boccalini Jr Mario
• Albertin Eduardo
• Leite De Lima Moyses
• Marques Araujo Gisela

Classifications

• F16J9/26 Primary

  characterised by the use of particular materials · CPC title

• C23C8/02

  Pretreatment of the material to be coated (C23C8/04 takes precedence) · CPC title

• C23C4/02

  Pretreatment of the material to be coated, e.g. for coating on selected surface areas · CPC title

• C22C38/28

  with titanium or zirconium · CPC title

• C22C38/26

  with niobium or tantalum · CPC title