Rotating bending testing machine for springs and anti-roll bars

Rotating Bending Testing Machine (RBTM)

The trend towards smaller and weight reduced springs and stabilizer bars as required by the car industry, equals a demand for higher allowable stresses. The application of high stresses, however, requires spring steels of high purity.

By use of the Rotating Bending Testing Machine (RBTM) the purity of spring steels can be evaluated and exactly defined before processing the final product (springs, stabilizer bars etc.). This early quality assessment prevents the use of inadequate materials and ensures high-quality standards of the products. Especially if very high reliability is to be guaranteed, the purity of the steel must be considered in addition to the normal S-N-Curve obtained from component tests.

The offered Rotating Bending Testing Machine is designed for the assessment of the fatigue strength of round bars and tubes, as used in the production of suspension springs and stabilizer bars for passenger cars. Using an IABG-fixture for shouldered cylindrical specimen, also smaller and shorter specimen can be tested.

Technical Specifications
Diameter of the specimen: d = 8 - 30 mm
Length of the specimen (recommended): Lp = 60 ⋅ d + 140 mm (max. 1800 mm)
Test frequency: 5 to 50 Hz


Advantages Compared to Existing Machines:

• No gripping of the round bars necessary
• Surface under tension stress is untouched
• Large and therefore representative material volume
• High-testing frequency
• Short set-up time (approx. 5 min.)
• Low energy consumption

Purpose of Rotating Bending Tests:

• Investigation of fatigue strength before the raw material is formed to final product
• Optimization of material and production process (e.g. type of material, heat treatment, shot peening, reduction of scatter etc.)
• Determination of flaws, inclusions, and similar defects in material
• Evaluation of the surface quality
• Quality control

Evaluation of Typical Results:

• Fatigue Life and influence of material defects
• Fatigue strength and Statistical evaluation of endurance limit
• Probability distribution of material defect size

Optionally, we offer a fixture for testing of shouldered. This enables for testing shorter material specimen and hence broadens the range of possible applications significantly.

More information here >>>