PSI - Issue 5

Hirotaka Tanabe et al. / Procedia Structural Integrity 5 (2017) 1005–1010 H Tanabe et al. / Structural Integrity Procedia 00 (2017) 000 – 000

1007

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2.3. Laser heat treatment

For the laser heat treatment, a high power diode laser (Laser line, LDM 3.000-10, Germany, Maximum power 3 kW) was used. Figure 2 shows the schematic illustration of the laser irradiation method. The laser irradiation conditions are summarized in Table 1. The laser wavelength was 935 nm. The laser beam shape on the specimen surface was a rectangle of 3mm × 5mm. In order to obtain a ring-shape quenched area fit to the P.C.D of the balls of 51305 bearing (38.6mm), the specimen was rotated with irradiating the laser on the specimen surface. The rotation speed of the specimen was 12.4 rpm. Laser power P was changed from 800W to 900W. The hardness distribution on the cross-sectional surface of laser quenched area was measured. The hardness measurement area and the results are shown in Figure 3 and 4, respectively.

Fig. 2. Schematic illustration of laser irradiation method

Table 1 Laser irradiation conditions

Laser power, P [W] Laser beam shape Laser beam size [mm]

800 ～ 900 Lectangle

3 × 5 12.4 38.6

Rotation speed of specimen, w [rpm]

Rotation diameter, D [mm]