Measurement Error of Handheld Brinell Hardness Tester

Error factors of handheld Brinell hardness tester:
Indenter:
(1) Permanent deformation of steel balls;
(2) Diameter difference of steel ball;
(3) Corrosion, abrasion or scratch of steel balls;
(4) The part of the steel ball breaking out sleeve is less than one third of the suitable diameter of the californium ball;
(5) Overconcentricity of center line between steel ball and press handle.

Load:
(1) The knife is loose, charming or fractured;
(2) Overweight in weight;
(3) Load lever deformation;
(4) The three blades of the load lever are not on the same plane;
(5) Insufficient lifting distance at the top of the spindle makes the load not be tested by all the actors;
(6) Poor installation of hardness tester causes pile collision between weight and body
(7) Inclination of spindle.

Measuring device
(1) Incorrect marking or blurred marking of the dividing board;
(2) The magnification is not discussed;
(3) The lens is dirty or bloody;
(4) Differential cylinder screw wear;
(5) Zero position of differential cylinder is wrong;
(6) Improper understanding；
(7) Improper choice of maximum multiple.

Specimen:
(1) Insufficient surface finish;
(2) Work hardening;
(3) Surface decarbonization, the hardness is not uniform;
(4) The oxide layer on the surface has not been removed;
(5) K-test surface is not fair.

Experimental conditions:
(1) Room temperature does not meet the requirements;
(2) The speed of adding anthracene is not right;
(3) The load holding time is not right;
(4) Vibration.

Operator:
(1) Improper selection of workbench;
(2) Improper selection of twist and load;
(3) The distance between two adjacent indentations is too close, or the indentation is too close to the edge.