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Doosan IMGB
  • LP Rotor Shaft
  • Generator Rotor Shaft
  • HP Rotor Shaft

Since the early 70s, Doosan IMGB became heavy forgings main supplier for fossil-steam turbine generators ranging from 6 to 1000MW and generator shafts up to 1600 MW. In 1980, after an important investment program and a Japanese license assimilation, the manufacturing capacity and capability increased,therefore a large number of forged components such as HP, IP, HP-IP, LP turbine and generator rotors and shafts, in rough or semi-finished condition, has been delivered to our clientsin Asia, South and North America and Europe.

The forging and the process design are performed by experienced engineers using standard reliable procedures and instructions which are periodically upgraded /updated, considering the most recent developments in the field. For special tasks the Process Engineering Team receives support from Doosan Corporate R & D Institute in Changwon.

  • Steel Melting
  • 12000Ton Forging Press
  • 150mTon Vertical Water Spray Quenching

The forging and the process design are performed by experienced engineers using standard reliable procedures and instructions which are periodically upgraded /updated, considering the most recent developments in the field. For special tasks the Process Engineering Team receives support from Doosan Corporate R & D Institute in Changwon.

Our equipment and technology are suitable for production of single or multi-heat heavy forgings.

The steel is melted in two 55 / 70 Ton BEAF. Secondary treatment is done under vacuum in 70 Ton VAD/VOD (Standard-Messo) unit or 70 / 140 Ton LRF. Pouring is done under vacuum (p<0.50Torr). Low-Si steel may be produced as per client’s spec. Double-degassing technique (VD and VSD) is employed in order to reduce the gas content; especially H2 level is kept under 2 ppm (aim <1.5 ppm). Selected scrap with low levels of P, Sn , Sb , As is used.

Usually, the steel ingots available are within 65 to 240 Ton weight range and have the H/D ratio of around 1:1. However, based on a JSW license upgraded by our own experience and Doosan Heavy Industries & Construction Changwon Plant developments, the maximum ingot weight which can be produced exceeds 400 Ton.

The forging process is carried out on 120 MN free-forging press, equipped with a 240 Ton manipulator. Special forging techniques as JTS and WHF may be applied to compact the center zone of the ingot. PHT process is performed on modernized gas-fired, car-bottom furnaces (21 m length, 100 sq. m, and 250 Ton max. weight). Depending on forging size, shape and alloy, thermal treatment consists in normalizing, double normalizing & tempering.

Usually, QHT is performed in vertical position (three electric furnaces with 30, 90 and 175 Ton maximum load are in operation) after rough machining.

Depending on the rotor’s usage, size and steel grade, quenching may be performed in various cooling environments: fan, mist or water-spray in gashed or ungashed condition. For forgings weighting up to 40 Ton oil or water quenching is a possible option. When accepted, in case of heavy rotors exceeding our vertical treatment capability, horizontal heat treatment with quenching by water-immersion in the new quenching tank located in the forging shop may be considered an alternative.

Such flexibility allows us to reach a large spectrum of material properties and to satisfy various requirements.

TBN HP, IP, LP & Rotor GEN

60 Ton Rough Machined Generator Rotor made from EN 27NiCrMoV15.6 steel grade