Laser hardening for TAKRAF: Gears for use in open-cast mining

Surface hardening of the tooth flanks of 16 gear segments for TAKRAF – one of the leading suppliers of mining technology. The finished gears have a diameter of 9 meters and consist of eight segments, which will later be used in bucket wheel excavators in opencast lignite mining near Neyveli (India).

The task:

Each segment weighs 950 kg, is almost 4 meters long and has 38 teeth. The material: 42CrMo4. The goal: an extremely hard and wear-resistant surface on the tooth flank and tooth base with a tough component core.

The solution:

Laser hardening using scan optics. This surface hardening allows an entire tooth flank to be hardened in just one track without creating a tempering effect – precisely, reproducibly and with minimal distortion. The result is hardness values of up to 55 HRC with a hardening depth of around 1 mm.

The advantages of laser hardening:

• Homogeneous hardness and no tempering effect thanks to scan optics
• No heating of the entire component as with oven hardening
• Minimal distortion – hardly any rework required
• Precise positioning and simple system operation thanks to macros

Conclusion:

The laser-hardened segments are assembled into a ring gear and then installed in bucket wheel excavators. They are a key component for the reliable rotation of the uppercarriage during operations under extreme conditions – and an example of how modern laser technology from Dresden makes international mining more efficient and economical.

Would you like to find out more about wear protection using laser hardening? We look forward to providing you with comprehensive advice.