# US 10,309,536 B2 · Piston rings in cast tool steels and process for the manufacture thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,309,536 B2 - Document ID: US10309536B2 - Status: Granted - Kind: B2 - Application number: 15/772,044 - Filed: 2016-10-24 - Published: 2018-11-01 - Granted: 2019-06-04 - Earliest claimed: 2015-10-29 - Assignees: Instituto De Pesquisas Technologicas Do Estado De Sao Paulo S/A; Mahle Metal Leve S/A; Mahle International GmbH - Applicants: Instituto De Pesquisas Tecnologicas Do Estado De Sao Paulo S/A; Mahle Metal Leve S/A; Mahle International GmbH - Inventors: Mario Boccalini, Jr.; Eduardo Albertin; Moyses Leite De Lima; Gisela Marques Araujo - Web page: https://patentgrep.com/patent/US10309536B2 ## CPC - F16J 9/26: characterised by the use of particular materials - C21D 1/18: Hardening (C21D1/02 takes precedence); Quenching with or without subsequent tempering (quenching devices C21D1/62) - C21D 1/25: Hardening, combined with annealing between 300 degrees Celsius and 600 degrees Celsius, i.e. heat refining ("Vergüten") - C21D 1/74: Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material - C21D 9/40: for rings; for bearing races - C22C 1/02: by melting {(C22C1/1036 takes precedence)} - C22C 38/12: containing tungsten, tantalum, molybdenum, vanadium, or niobium - C22C 38/18: containing chromium - C22C 38/22: with molybdenum or tungsten - C22C 38/24: with vanadium - C22C 38/26: with niobium or tantalum - C22C 38/28: with titanium or zirconium - C23C 4/02: Pretreatment of the material to be coated, e.g. for coating on selected surface areas - C23C 8/02: Pretreatment of the material to be coated (C23C8/04 takes precedence) - C23C 8/26: of ferrous surfaces - C21D 2211/004: Dispersions; Precipitations - C21D 2211/008: Martensite - Y02P 10/20: Recycling - F16J: PISTONS {(specially adapted for dampers F16F9/32)}; CYLINDERS; SEALINGS - C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B) - C22C: ALLOYS (treatment of alloys C21D, C22F) - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## 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 M2C 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. ## Claims ### Claim 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 M2C 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. ### Claim 2 (depends on 1) The piston ring as claimed in claim 1, wherein the ring is a gravity casted ring. ### Claim 3 (depends on 1) The piston ring as claimed in claim 1, wherein the ring is a centrifugal casted ring. ### Claim 4 (depends on 1) 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. ### Claim 5 (depends on 1) 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. ### Claim 6 (depends on 5) The piston ring as claimed in claim 5, wherein the ring is quenched in a furnace having a controlled atmosphere. ### Claim 7 (depends on 5) 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. ### Claim 8 (depends on 1) 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. ### Claim 9 (depends on 8) 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. ### Claim 10 (depends on 1) 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. ### Claim 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 V2C carbides, VC carbides, Mo2C carbides, MoC carbides, Cr2C carbides, CrC carbides, W2C 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. ### Claim 12 (depends on 11) 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. ### Claim 13 (depends on 11) 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. ### Claim 14 (depends on 13) 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. ### Claim 15 (depends on 13) 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. ### Claim 16 (depends on 11) The piston ring as claimed in claim 11, wherein the ring is one of a gravity casted ring and a centrifugal casted ring. ### Claim 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 V2C carbides, VC carbides, Mo2C carbides, MoC carbides, Cr2C carbides, CrC carbides, W2C 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. ### Claim 18 (depends on 17) 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. ### Claim 19 (depends on 17) The piston ring as claimed in claim 17, wherein the ring is one of a gravity casted ring and a centrifugal casted ring. ### Claim 20 (depends on 17) 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.