iABG Rotating Bending Testing Machine

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A testing machine to assess the fatigue strength of round bars and tubes, as used in the production of suspension springs and stabilizer bars for passenger cars.

[Rotating bending test of a round bar with a diameter of d = 26 mm]
Technical Specification:

- Specimens    : machined or unmachined cylindrical bars or tubes
- Bar diameter : d = 10 to 30 mm
- Bar length   : L = 60*d + 140 mm
- Test frequency : f = 5 to 50 Hz (variable)
- Installation : < 1 KW, no variation, low noise
- Weight       : 1,000 Kg
- Dimensions   : L=2,600mm, W=1,000mm, H=1,500mm
- Loading      : load input via crowned and non-wearing plastic rings
- Load (stress) and strain measurement

Advantages Compared to Existing Machines:

- No gripping of the round bars necessary
- Surface under tension stress is untouched
- Large and therefore representative material volume
- Short set-up time (app. 5 min)

Purpose of Rotating Bending Tests:

- Comparison of fatigue strength before the raw material is formed to final product
- Material optimization (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

Typical Results:

- Fatigue strength in the finite life region
- Endurance limit
- Scatter of both
- Fractography (e.g. photos below)

20x 1000μ
150x 100μ
	(a) bulk material defect	(b) surface defect

of shot peened bars with a diameter of d = 22 mm manufactured of spring steel

Typical Customers:

- Manufacturers of wire for suspension springs and stabilizer bars
- Manufacturers of springs and stabilizer bars
- Manufacturers of high performance spring steels

Another Rotating Bending Testing Machine based on the same technical principle is available for bars up to a diameter of d = 60.0 mm.