Microindentation

Plot showing the mean and standard deviation of the HV 30 hardness measurement for 316 stainless steel polished to different surface roughnesses. The 0.3 micron collodial silica step results in the most accurate result (i.e. closest to the accepted 316 hardness value). The precision of the measurements, as noted by the error bars showing the standard deviation, are similar for the samples polished using 1200 grit SiC sandpaper and 0.3 micron collodial silia, and significantly better compared to the error for the 600 grit sample.

Micro-hardness testing permits measuring the hardness of a material on a microscopic scale. The Qness Q60 A+ microindenter is a fully automated system with quick and precise positioning relative to the sample. The machine is equipped with three different magnification lenses (10X, 40X, and 65X) and three indenters (Vickers, Knoop and Brinell), which facilitate hardness measurements across a broad range of materials. Samples with varying heights and tilts can be indented at the same time with the Qness CAS sample holders. Additionally, the indenter can be adapted to the respective contour of the test sample such that different material regions (i.e. e.g. layers) can be tested precisely. Additionally, users can obtain the hardness distribution across a segment or whole plane of the test sample using the 2D/3D mapping tool.


With the Qness Q60 A+ microindenter, we are able to conduct the following hardness tests:

Indenter type Load range Avaliable test types
Vickers 0.25 g - 60 kg

HV 0.00025; HV 0.0005; HV 0.001; HV 0.002; HV 0.005; HV 0.01;
HV 0.015; HV 0.02; HV 0.025; HV 0.05;  HV 0.1; HV 0.2; HV 0.3;
HV 0.5; HV 1; HV 2; HV 2.5; HV 3; HV 5; HV 10; HV 20; HV 30;
HV 50; HV 60

Knoop 200 g - 2 kg HK 0.2; HK 0.3; HK 0.5; HK 1; HK 2
Brinell (1 mm ball) 1 kg - 30 kg HBW 1/1; HBW 1/2.5/ HBW 1/5; HBW 1/10; HBW 1/30

 


Example #1: Rapid collection of large data sets for statistical analysis

The influence of the sample preparation on the hardness measurement variability was investigated, to understand the effects of surface polish on the accuracy and precision of the hardness measurement. A total of three samples were extrated from one 316 stainless steel additive manufactured build (fabricated using the laser powder bed fusion technique). The analyzed sample surface is transverse to the height of the sample (the x-y processing plane). The samples were polished to different levels  using SiC sandpaper and collodial silica. Using the Qness Q60 A+ microindenter, a series of 200+ Vickers hardness measurements (HV 0.3/10) were completed in only 2 hours for each sample.

Summary of Vickers measurements on additive manufactured 316 stainless steel

  600 grit SiC sandpaper 1200 grit SiC sandpaper 0.3 µm colloidal silica
Mean ± Std. Dev.
(HV 0.3 value)
232.1 ± 21.9 232.9 ± 14.1 226.2 ± 14.4