Test coupon and test method

Patent metadata

Field	Value
Publication number	US-11099111-B2
Application number	US-201716344475-A
Country	US
Kind code	B2
Filing date	Oct 4, 2017
Priority date	Nov 4, 2016
Publication date	Aug 24, 2021
Grant date	Aug 24, 2021

Abstract

A test coupon (1) for an ISO-standard-conforming test method for testing a material hardness of gearwheels. The test coupon (1) is designed as a two-piece test coupon (1) including a casing body (2) and a test body (3). The test coupon (1) being tested by an ISO-standard-conforming test method for determining a material hardness of the gearwheels.

First claim

The invention claimed is:

1. A test coupon for an ISO-standard-conforming test method for testing a material hardness of a gearwheel, the ISO-standard-conforming test method being a test method which under same conditions as a corresponding ISO Standard method, gives the same results as the corresponding ISO Standard method, but uses a two-piece test coupon and does not make use of a test coupon as defined in the corresponding ISO Standard method,
the test coupon being a two-piece test coupon comprising a casing body and a test body,
the casing body comprising steel, such that the material and production of the test body corresponds to the gearwheels to be tested,
the test body and the casing body together with the gearwheels to be tested being heat treated, and
the test coupon being designed such that an investigation of material properties and a consequent destruction being carried out exclusively on the test body while, in contrast, the casing body being preserved and being reusable.

2. The test coupon according to claim 1 , wherein the casing body is cylindrical and has a concentric and disk-shaped recess, at one end of the cylinder, for holding the test body.

3. The test coupon according to claim 2 , wherein the casing body has a lateral bore, which connects an outside of a cylinder outer surface of the casing body to the recess, and the cylinder outer surface being fully received within the recess.

4. The test coupon according to claim 1 , wherein the casing body comprises steel according to AISI 310.

5. An ISO-standard-conforming test method for testing a material hardness of a gearwheel by a test coupon, wherein an ISO-standard-conforming test method is a test method which, under same conditions as a corresponding ISO Standard method, produces the same results as the corresponding ISO Standard method, but uses a two-piece test coupon and does not use a test coupon as defined in the corresponding ISO Standard, the two-piece test coupon comprising a casing body and a test body, the casing body comprising steel, such that the material and production of the two-piece test coupon corresponds to the gearwheel to be tested, the two-piece test coupon together with the gearwheel to be tested are heat treated, and the two-piece test coupon is designed such that an investigation of material properties and a consequent destruction are carried out exclusively on the test body while, in contrast, the casing body being preserved and being reusable, the method comprising:
producing the test body with an identical production process and from an identical material as the gearwheels to be tested,
inserting the test body into a concentric and disk-shaped recess on a cylinder end of the casing body,
heat treating the test coupon together with the gearwheel to be tested,
removing the test body from the casing body,
determining a material hardness of the test body, and
determining, with reference to the material hardness of the test body, the material hardness of the gearwheel.

6. The method according to claim 5 , further comprising determining the material hardness of the test body spatially in a middle of the test body.

7. A nonstandard test coupon for testing a material hardness of gearwheels with an ISO-standard-conforming test method, the ISO-standard-conforming test method being a test method which, under identical conditions as a corresponding ISO Standard method, produces results for the nonstandard test coupon that are at least substantially identical to results produced for a standard test coupon by the corresponding ISO Standard method, the nonstandard test coupon comprising:
a two-piece test coupon comprising a casing body and a test body, and the casing body being fabricated from steel according to AISI 310;
the test body and the gearwheel being tested are formed from a same material and produced, in a corresponding manner, in which the test body, the casing body and the gearwheel being tested are heat treated; and
the nonstandard test coupon being designed such that an investigation of material properties and a consequent destruction are carried out exclusively on the test body while, in contrast, the casing body being preserved and being reusable.

Assignees

• Zahnradfabrik Friedrichshafen
• Zf Padova S R L
• Zf Padova Srl

Inventors

• Zanato Marco
• Marangon Paolo
• Fincato Alessandro

Classifications

• G01M13/021

  Gearings · CPC title

• G01N2203/027

  Specimens with holes or notches · CPC title

• G01N3/42 Primary

  by performing impressions under a steady load by indentors, e.g. sphere, pyramid (G01N3/54 takes precedence) · CPC title

• G01N2203/0298

  Manufacturing or preparing specimens · CPC title

• G01N2203/0405

  Features allowing alignment between specimen and chucks · CPC title