Testable materials

Steel Aluminium Nickel Titanium Copper

The imprinting process applies to metallic materials,

  • which deform plastically
  • which, when penetrated by the indenter, produce an impact at the edge of the test indentation
  • whose grain size is a maximum of 1/3 of the indentation diameter
  • which do not contain lamellar graphite/spheroidal graphite/high porosity

The method can be supplemented by a material- and sample-specific adaptation (calibration). It provides quantitative direction-independent results. At low penetration depths, the method can be used qualitatively to assess direction-dependent flow curves and comparative characteristic values.

Correlation of tensile strength Rm between tensile test and indentation method for steel
Correlation for comparability of tensile strength Rm from tensile test (y-axis) and indentation test (x-axis)

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

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

In the verification of steel materials for the indentation process, we have tested samples from the following materials, among others, and compared them with the tensile test:

  • Structural steel (high-temperature, unalloyed and fine-grained structural steel)
  • Case hardening steel
  • Working steel (rolling bearing steel, spring steel)
  • Quenched and tempered steel
  • Cast steel
  • Free cutting steel
  • Cold-formed steel
  • Fine-grain cold-pressed steel
  • High alloy martensitic steel
  • High alloy austenitic-ferritic steel

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

For structural steel, the comparative yield strengthRI0.2 corresponds to the lower yield strengthReL from the tensile test.

Verification distinguishes between high-alloy and low-alloy steels (see cues 1-8 above). The average deviations of the two groups are shown below:

Comparability to the tensile test

Low alloy steels:

Mean value DeviationRIp0.2:

4,3%

Mean Deviation RIm:

2,3%

Standard deviationRIp0.2:

5,4%

Standard deviation RIm:

2,9%

95.5% confidence interval:

10,8%

95.5% confidence interval:

5,8%

High alloy steels:

Mean value DeviationRIp0.2:

4,6%

Mean Deviation RIm:2,3%
 Standard deviationRIp0.2:

6,0%

Standard deviation RIm:3,0%
 95.5% confidence interval:

12,0%

95.5% confidence interval:6,0%

Correlation steel

The aluminium materials were divided into two groups for verification: Cast alloys and Wrought alloys. The following is a list of the materials that were tested for verification using the indentation method, among others.

Casting alloys:

Aluminium-silicon die casting

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 by fine, sand or gravity die casting cannot be tested at the current status (04.2019). Likewise, no die casting alloys made of aluminium-magnesium and no 2000 and 7000 wrought alloys.

Comparability to the tensile test

Aluminum die casting alloys:

Mean value DeviationRIp0.2:

4,0%

Mean Deviation RIm:

5,3%

Standard deviationRIp0.2:

5,0%

Standard deviation RIm:

6,4%

95.5% confidence interval:

10,1%

95.5% confidence interval:

12,8%

Wrought aluminium alloys:

Mean value DeviationRIp0.2:

6,9%

Mean Deviation RIm:

3,8%

Standard deviationRIp0.2:

9,3%

Standard deviation RIm:

4,9%

95.5% confidence interval:

18,5%

95.5% confidence interval:

9,8%

Correlation aluminum

In the verification of nickel materials for the indentation process, we have tested samples from the following materials, among others, 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 DeviationRIp0.2:

8,9%

Mean Deviation RIm:

2,3%

Standard deviationRIp0.2:

11,5%

Standard deviation RIm:

2,8%

95.5% confidence interval:

23,1%

95.5% confidence interval:

5,7%

Correlation nickel

Titanium:

e.g. 3.7165

Please contact us for further titanium, magnesium and copper materials.

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