Test system and method for measuring and calculating hardness of material

A method for measuring a hardness value of a material, the method comprising:

• creating, via an indenter with a load, an indent on a surface of the material;
• measuring, via an instrument, a 3D topography of the indent and generating a set of raw data comprising 3D data values in X-Y-Z direction;
• inputting the set of raw data into a processing unit, wherein the processing unit comprises computer program code for performing a method, that when executed by the processing unit, causes the processing unit to:
• generate a complete data set, CDS, from the set of raw data by processing the set of raw data based on measuring quality of the instrument;
• convert the CDS to a two-dimensional, 2D, data set, CDS_2D, in an X-Y coordinate plane representing a 2D picture having a circle in the middle representing the indent;
• divide the CDS into two data sets by using the X-Y coordinate of the circle in CDS_2D, a first data set, CDS1, comprising data inside the circle, a second data set, CDS2, comprising the remaining data outside the circle;
• calculate a tilting factor based on the CDS2 in the X-Y coordinate plane;
• generate a levelled complete data set, CDS_L, by adjusting the CDS with the tilting factor and regenerate from CDS_L, a first levelled data set, CDS1_L, comprising data inside the circle, a second levelled data set, CDS2_L, comprising the remaining data outside the circle;
• calculate a mean value, ZL, in Z-direction from the CDS2_L, wherein the ZL represents an average height of the surface of the material;
• define a zero plane, ZP, representing an original surface of the material by setting ZL value as a zero level in the CDS_L;
• calculate a roughness value, Ra1, of the material surface from CDS2_L;
• generate a complete data set of indent, CDSI, from the CDS1_L by finding all data in the CDS1_L below the zero plane, minus the Ra1;
• select a sphere shape by fitting the shape of the sphere to all data values in CDSI using the least squares method, wherein a diameter of the sphere is referred to as Sphere_1 and an origin of the sphere on the X-Y plane is referred to as Origin of Sphere_1;
• adjust the CDS_L such that all data in the CDS_L are centered on the Origin of Sphere_1;
• calculate a second diameter, Diameter_2, of an intersection of the zero plane, ZP, and the sphere;
• calculate a first Hardness Brinell value, HB_1, based on the second diameter Diameter_2;
• and
• output results of the measurement.

A test system for measuring a hardness value of a material comprising:

• a load with an indenter for creating an indent on a surface of the material;
• a 3D measurement instrument for measuring a 3D topography of the indent and generating a set of raw data comprising 3D data values in X-Y-Z direction;
• a processing unit comprising computer program code for performing a method, when executed in the processing unit, comprising:
• generating a complete data set, CDS, from the set of raw data by processing the set of raw data based on measuring quality of the instrument;
• converting the CDS to a two-dimensional, 2D, data set, CDS_2D, in an X-Y coordinate plane representing a 2D picture having a circle in the middle representing the indent;
• dividing the CDS into two data sets by using the X-Y coordinate of the circle in CDS_2D, a first data set, CDS1, comprising data inside the circle, a second data set, CDS2, comprising the remaining data outside the circle;
• calculating a tilting factor based on the CDS2 in the X-Y coordinate plane;
• generating a levelled complete data set, CDS_L, by adjusting the CDS with the tilting factor and regenerating from CDS_L, a first levelled data set, CDS1_L, comprising data inside the circle, a second levelled data set, CDS2_L, comprising the remaining data outside the circle;
• calculating a mean value, ZL, in Z-direction from the CDS2 L, wherein the ZL represents an average height of the surface of the material;
• defining a zero plane, ZP, representing an original surface of the material by setting ZL value as a zero level in the CDS_L;
• calculating a roughness value, Ra1, of the material surface from CDS2_L;
• generating a complete data set of indent, CDSI, from the CDS1_L by finding all data in the CDS1_L below the zero plane, minus the Ra1;
• selecting a sphere shape by fitting the shape of the sphere to all data values in CDSI using the least squares method, wherein a diameter of the sphere is referred to as Sphere_1 and an origin of the sphere on the X-Y plane is referred to as Origin of Sphere_1;
• adjusting the CDS_L such that all data in the CDS_L are centered on the Origin of Sphere_1;
• calculating a second diameter, Diameter_2, of an intersection of the zero plane, ZP, and the sphere;
• calculating a first Hardness Brinell value, HB_1, based on the second diameter Diameter_2.