PSI - Issue 18

4

Author name / Structural Integrity Procedia 00 (2019) 000–000

Markus Berchtold et al. / Procedia Structural Integrity 18 (2019) 532–537

535

Fig. 1 Woehler diagram steel 50CrMo4 37HRC on 95Hz, 1000Hz, 20kHz testing frequency, A. Giertler 2019

3.2. Temperature records RUMUL could look into heating up behavior of material samples in the last years. The specimens have been provided by interested laboratories. For Temperature recording a type K thermocouple was attached on the specimen. Compressed air was used to mitigate heating up if required. Load ratio was selected -1 for all tests.

Table 1. Temperature recordings of various materials during fatigue testing

Material

Specimen

Testing condition

Frequency

Load amplitude Temperature

Gauge diam. 7 mm

1011 Hz

8.5 kN (220 MPa)

Nodular Iron

load increasing 0.2*106cycles / step compr. air cooling load increasing, 2*106cycles / step compr. air cooling const. load 106cycles / step no cooling load increasing, 106cycles / step no cooling, (Fig.2)

38°C

round, cyl. and hour glass, w. thread

9% Cr-steel

1024 Hz

18.6 kN (373 MPa)

round, hour glass, w. thread 8 mm

26°C 54°C 1)

Ti alloy

996 Hz

5.52 kN (280 MPa)

35°C

round, hour glass, w. thread 5 mm

1023 Hz

17 kN (337 MPa)

Ferritic steel HV30 ~ 220

62°C 2)

round, cyl. w/o thread

8 mm

1) 2)

Cooling temporarily off

Temperature is not stabilizing, probably softening effect (see 2.3)