# US 10,309,034 B1 · Metal block for fluid transportation

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- Number: US 10,309,034 B1
- Document ID: US10309034B1
- Status: Granted
- Kind: B1
- Application number: 15/923,248
- Filed: 2018-03-16
- Granted: 2019-06-04
- Earliest claimed: 2018-02-05
- Assignees: Unilock Corporation
- Applicants: UNILOK Corporation
- Inventors: Myoung Ho Yoo
- Web page: https://patentgrep.com/patent/US10309034B1

## CPC

- C25F 3/24: of iron or steel
- C23C 8/26: of ferrous surfaces
- C23C 8/38: Treatment of ferrous surfaces
- C23C 8/80: After-treatment
- C23C 28/042: {including a refractory ceramic layer, e.g. refractory metal oxides, ZrO2, rare earth oxides}
- C23F 17/00: Multi-step processes for surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by subclass C21D or C22F or class C25 (coating for obtaining at least two superposed coatings either by methods not provided for in a single one of main groups C23C2/00 - C23C26/00, or by combinations of methods providedfor in subclasses C23C and C25D, C23C28/00)
- C25F: PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
- 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)
- C23F: NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE (working metal by laser beams B23K26/00; desurfacing by applying flames B23K7/00; working of metal by electro-erosion B23H; producing decorative effects by removing surface material, e.g. by engraving, by etching, B44C1/22; electrolytic etching or polishing C25F); INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25

## Abstract

Provided are a method for manufacturing a metal block which has a complex shape and can maintain a firm sealed unit even when it is repeatedly assembled and the metal block according thereto. To achieve the objective, the present disclosure performs a first electrolytic polishing of the metal block made of stainless steel having a chromium oxide layer, forms an ion-nitrided layer by carrying out an ion-nitriding process, performs a second electrolytic polishing to efficiently remove part of the ion-nitrided layer and induces complex diffusion of high-concentration surface N and C in order to surface-harden a surface layer having a precipitate phase. Accordingly, the present disclosure can increase hardness of the sealed unit inside the metal block up to Hv 400 or more with its corrosion resistance kept, thereby effectively sealing metal.

## Claims

### Claim 1

A metal block manufactured by a manufacturing method comprising:
machining a sealing component having a predetermined shape made of a stainless steel matrix having a chromium oxide layer;
forming an ion-nitrided layer by performing an ion-nitriding process on the sealing component; and
electrolytically polishing the sealing component having the formed ion-nitrided layer to form an additional chromium oxide layer.

### Claim 2 (depends on 1)

The metal block of claim 1, wherein the manufacturing method comprises first electrolytically polishing the sealing component prior to the forming the ion-nitrided layer.

### Claim 3 (depends on 2)

The metal block of claim 2, wherein the manufacturing method further comprises burnishing the sealing component prior to the first electrolytically polishing or the electrolytically polishing the sealing component having the formed ion-nitrided layer.

### Claim 4 (depends on 1)

The metal block of claim 1, wherein the ion-nitrided layer is formed to have a thickness of 10 μm to 40 μm and then, by performing the electrolytically polishing, the additional chromium oxide layer is formed to have a thickness of 1 μm to 5 μm.

### Claim 5 (depends on 1)

The metal block of claim 1, wherein the ion-nitrided layer is formed as a complex diffusion layer of nitrogen, N, and carbon, C.