Situation
Surface hardening improves the wear resistance and fatigue strength of dynamically stressed components. These functional characteristics are mainly determined by surface hardness, hardening depth and residual stress. An essential quality feature of the surface hardening process is the thickness of the hardened layer (SHD). Currently, the hardened layer can only be tested in random samples using destructive methods, a procedure that is both costly and time-consuming.
Solution
In collaboration with the Fraunhofer Society, an ultrasonic testing device was developed that allows the Surface Hardening Depth (SHD) to be checked quickly and non-destructively. The inspection effort is reduced while costs are lowered, enabling fast in-process control and ensuring consistently high product quality. The testing device is used for optimizing production parameters, reducing downtime after inductor changes, rapid production monitoring, and in quality assurance.
Advantages
short setup times
simple, uncomplicated calibration
Fast, uncomplicated testing
high test sensitivity
comfortable sensor handling
sensor adaptable to complex geometries
visualization of the current test point
testing at small radii and undercuts possible
individual report templates
storage of results in data base
analysis and revaluation of test results
line scans and circumferential scans
automation possible
Method
The test method is based on the effect that the hardened layer is almost transparent to ultrasonic waves while the non-hardened material scatters them back. The backscattered signal received by a probe, is processed by the UT hardware and automatically evaluated by the software. The Surface Hardening Depth (SHD) is calculated and displayed by the software.
In most cases the results comply with the results of destructive methods. SHD values > 1.2 mm are determined using standard equipment. Lower SHDs can be tested with special probe systems.
More Information
Figure: Ultrasonic Backscatter Technique
Contact:
Dipl.-Ing. Tobias Müller
Phone: + 49 (0) 681/9767153
Fax: + 49 (0) 681/9767158
Features
• 4 ultrasonic channels
• built for industrial use (IP65)
• portable for mobile use
• inspection frequencies: 5-25 MHz
• measurement repeatability: ± 0.2 mm
Inspection Software “SHD-Studio”
• setup mode
• custom test programs
• import / export of test programs
• tools for visualization and analysis of test results
• individual test reports
Figure: Screenshot of the test software “SHD-Studio”
