Technology

Material Analysis and Measurement Testing

The Center operates a material analysis laboratory staffed by experts in the field of superalloys and performs life assessment and material analysis of turbine components and related parts.

Welding

High-temperature gas turbine components such as buckets/blades, nozzles/vanes, combustion liners, and transition pieces may experience cracks, wear, and fracture due to thermal stress, high- and low-cycle fatigue, and hot corrosion when operated for long periods at high temperatures or exposed to repeated start-up and shutdown cycles.
To restore damaged components to their original condition, welding and ADH are performed. Materials used for gas turbine hot gas path components are mainly nickel- and cobalt-based superalloys designed to withstand high temperatures. Accordingly, welding work is mainly performed using GTAW, Gas Tungsten Arc Welding.
Depending on the material, the Center has been qualified by GE for approximately 40 welding procedures and maintains welding quality through periodic qualification evaluations.

Striping

Stripping is a process that removes existing coating layers without damaging the base material by using chemical and physical methods for damage inspection, refurbishment maintenance, and coating processes of gas turbine components.
The Center is equipped with systems such as a Metal Finish Waste Water Pretreatment System and an Air Scrubber System, and also focuses on purifying and discharging heavy metals and toxic gases emitted during the stripping process.

Coating

The efficiency of a gas turbine is determined by the expansion ratio of combustion gas, which is closely related to combustion temperature.
Recently developed gas turbines are designed to operate at ultra-high temperatures, and heat-resistant materials, superalloys, have been developed and used.
However, superalloys have already reached their limits in terms of high-temperature strength and high-temperature corrosion resistance.
As a countermeasure, the Center performs coating work for high-temperature corrosion prevention and thermal barrier protection.
Major coating methods include thermal spray coating and pack diffusion coating.

Machining and Balancing

Turbine components are mainly made of heat-resistant alloys with high-temperature strength, heat resistance, and corrosion resistance.
Therefore, selecting tools and equipment suitable for the characteristics of the material is very important in machining. Selecting machining conditions to achieve optimal production efficiency is also a key factor for successful machining.
The Center operates machine tools such as vertical and horizontal boring and turning mills, ultra-large lathes, grinding machines, electro discharge machines, and small- and medium-sized lathes and milling machines. It also has highly skilled technical personnel to operate this equipment.

Electro Discharge Machining

Electro Discharge Machining is a special non-traditional machining method that converts electrical energy into thermal energy to melt, evaporate, and remove material.
It is highly useful for machining difficult-to-cut materials such as superalloys without requiring high cutting resistance or power, and it is an essential machining method for final drilling work on gas turbine components.
The Center operates die sinking EDM and super drilling EDM equipment, which are currently used for cooling hole machining of stationary blades and rotating blades, as well as forming of three-dimensional curved surfaces.
The Center is also conducting research to apply this technology to high-precision micro deep-hole drilling.

Heat Treatment

In general, when metals are operated at high temperatures for long periods, the physical and mechanical properties and weldability of the base material deteriorate.
To restore these degraded properties and improve weldability, heat treatment is performed before and after welding and after coating.
Vacuum Furnaces : Under high vacuum conditions, vacuum furnaces provide a cleaning effect by removing foreign substances from component surfaces and microcracks. They also restore the material properties of components for reuse and are used for furnace brazing.
Electric Furnaces : Electric furnaces can perform heat treatment at temperatures up to 1,200°C under atmospheric or argon gas conditions. The maximum load size is approximately 1,800 × 1,800 × 1,800 mm.

Non-Destructive Testing

Through receiving and incoming inspection of maintenance components, the Center accurately identifies defect conditions before maintenance and provides data required to determine maintenance feasibility, maintenance scope, and reuse suitability.
In-process inspection and final inspection are performed to identify defects that may occur during the process of restoring the shape and material properties of components.
Non-destructive testing is carried out as an essential process to ensure maintenance reliability and maintenance quality.

Localization Manufacturing and Reverse Engineering

Through material analysis in the laboratory, three-dimensional measurement using CMM, and CAD systems, the Center performs reverse engineering across industrial fields, including gas turbines and power generation facilities.
It prepares precision drawings required for production and achieves import substitution and technological self-reliance through localization manufacturing of various turbine components.
(Siemens W501D5 high-temperature components such as 1st to 3rd stage blades, transition pieces, and combustor baskets)

• Obtained quality certification from the Ministry of Commerce, Industry and Energy (NT, EM): manufacturing of various gas turbine spare parts (GE, Siemens, Alstom)