How to measure the hardness of small cylindrical workpieces?

Test samples and requirements:

Measured workpiece: Motor shaft (Figure one)

Product dimension: φ5.17×84.72mm

Product material: SUS420J2

Hardness requirement: 43~52HRC

Measurement requirements: Fully check the hardness of the motor shaft

Instrument used: Motorized ultrasonic hardness tester SU-300M

Figure 1. Motor Shaft


Current pain points:

The customer needs a hardness testing solution with precision, fast-speed and NDT 

It is known that Rockwell hardness tester has a large indentation, and the measured product cannot be used after the testing. It is not suitable for mass nondestructive measurement or full inspection.


Vickers hardness tester need operators with experienced skills and low efficiency, and it is not suitable for customers to test large quantities of products.


Portable Leeb hardness tester is not suitable for such small parts due to the diameter is too small to test.

Our Sinowon solution:

According to the current pain points of measurement, we decided to use an ultrasonic hardness tester to measure the sample.


Sinowon Ultrasonic Hardness Tester SU-300M adopts 3N test force, which can fully inspect the hardness of the motor shaft without damaging the workpiece, effectively guaranteeing the production quality of the product.


Because the single measurement time of the ultrasonic hardness tester is about 6 second per time, the efficiency is improved by 17 times compared with the desktop Rockwell hardness tester. And the indentation diameter after the ultrasonic hardness tester is 0.026mm, and the indentation diameter after the Rockwell hardness tester is 0.484mm (see Figure two for the indentation). The ultrasonic hardness tester does not affect the subsequent assembly and use.



Figure 2. The size comparation between UCI Vickers indention and Rockwell HRC indention.


Test results:


Testing time 1 2 3 4 5 Average value(HRC) Repeatability(HRC)
Hardness
HRC
value
48.0 49.1 47.9 48.2 47.7 48.1 1.4



Note: Maximum  Value: 49.1HRC, Minimum value: 47.7HRC



Figure 2. On-site measurement by Ultrasonic Hardness Tester SU-300M



Test conclusion:

SU-300M is able to measure the hardness of hardness of small cylindrical workpieces with precision, fast-speed and NDT solution.


SU-300M ultrasonic hardness tester has simple operation and high reliability. It only needs to prepare a standard sample to calibrate the instrument, which can achieve accurate hardness measurement.



While using the ultrasonic hardness tester to improve the quality control of the enterprise, it also reduces the loss and increases the profit of the enterprise.


If you have any need, please feel free to contact us. We look forward to the pleasure of serving you.