Testable materials

Steel | Aluminium | Nickel | Titanium | Copper

The indentation method applies to metallic materials,

    • which undergo plastic deformation
    • which, when the indenter penetrates, produce a throw-up in the edge region of the test indentation
    • whose grain size is at most 1/3 of the indentation diameter
    • which do not contain lamellar graphite/spherical graphite/high porosity

The method can be supplemented by material- and sample-specific adaptation (calibration). It delivers quantitative results independent of direction. If the penetration depth is small, the method can be used qualitatively to assess direction-dependent flow curves and comparative characteristic values.

Korrelation von Zugfestigkeit Rm zwischen Zugversuch und Eindruckverfahren für Stahl
Correlation to the comparability of the tensile strength Rm from the tensile test (y-axis) and the indentation method (x-axis)

Notes on the comparability of the indentation method with the tensile test

The mean value of three measurements with the indentation method (or five for austenitic stainless steels and aluminium) was compared with the result of a tensile test. One point in the diagram corresponds to the result of the indentation process (x-axis) and the tensile test (y-axis).

In the verification of steel materials for the indentation method, we tested samples of the following materials and compared them with the tensile test:

  • Structural steel (heat-resistant, unalloyed and fine-grained structural steel)
  • Case hardened steel
  • Working steel (roller bearing steel, spring steel)
  • Tempered steel
  • Cast Steel
  • Free cutting steel
  • Cold forming steel
  • Fine-grained cold pressed steel
  • High alloy martensitic steel
  • High alloy austenitic-ferritic steel

High-alloy austenitic steel cannot be tested at the current status (05.2019).

For structural steel, the comparative yield strength RI0.2 corresponds to the lower yield strength ReL from the tensile test.

For verification purposes, a distinction is made between high-alloy and low-alloy steels (see points 1-8 above). In the following the mean deviations of the two groups are shown:

Comparability to the tensile test

Low-alloy steels:

Mean value deviation RIp0,2:

4,3%

Mean value deviation RIm:

2,3%

Standard Deviation RIp0,2:

5,4%

Standard Deviation RIm:

2,9%

95,5%-Confidence Interval:

10,8%

95,5%-Confidence Interval:

5,8%

High-alloy steels:

Mean value deviation RIp0,2:

4,6%

Mean value deviation RIm: 2,3%
Standard Deviation RIp0,2:

6,0%

Standard Deviation RIm: 3,0%
 95,5%-Confidence Interval:

12,0%

95,5%-Confidence Interval: 6,0%

Korrelation Stahl

The aluminium alloys were divided into two groups for verification purposes: cast and wrought alloys. In the following, the materials are listed which, among other things, were tested for verification with the indentation method.

Casting alloys:

Die-casting from aluminum-silicon

EN-AC-43500
EN-AC-46000

Wrought alloys:

EN-AW-5082
EN-AW-5083
EN-AW-5754
EN-AW-6060
EN-AW-6061
EN-AW-6063
EN-AW-6082

Casting alloys produced in investment casting, sand casting or gravity die casting cannot be tested at the current status (04.2019). Also no die casting alloys of aluminium-magnesium and no 2000 and 7000 wrought alloys.

Comparability to the tensile test

Aluminium Die Casting Alloys:

Mean value deviation RIp0,2:

4,0%

Mean value deviation RIm:

5,3%

Standard Deviation RIp0,2:

5,0%

Standard Deviation RIm:

6,4%

95,5%-Confidence Interval:

10,1%

95,5%-Confidence Interval:

12,8%

 

Aluminium wrought alloys:

Mean value deviation RIp0,2:

6,9%

Mean value deviation RIm:

3,8%

Standard Deviation RIp0,2:

9,3%

Standard Deviation RIm:

4,9%

95,5%-Confidence Interval:

18,5%

95,5%-Confidence Interval:

9,8%

Korrelation Aluminium

When verifying nickel alloys for the indentation method, we tested samples of the following materials and compared them with the tensile test:

  • 2.4360
  • 2.4668
  • 2.4816
  • 2.4819
  • 2.4856
  • 2.4858

Comparability to the tensile test:

Mean value deviation RIp0,2:

8,9%

Mean value deviation RIm:

2,3%

Standard Deviation RIp0,2:

11,5%

Standard Deviation RIm:

2,8%

95,5%-Confidence Interval:

23,1%

95,5%-Confidence Interval:

5,7%

Korrelation Nickel

Titanium:

z.B. 3.7165

Please contact us for other titanium, magnesium and copper alloys.

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