SECOND STAGE NOZZLE

PART CHARACTERISTICS
Ansaldo Thomassen P/N:
76BXT200-G004

Interchangeable with GE P/N:
119E2434G008

Kit includes:
12x nozzle segments
2x split line nozzle segments
2x instrumented nozzle segments
Assembled with diaphragms
Installation hardware

Base alloy:
Alloy-222

Coating:
Aluminide diffusion coating

Type:
Non-pressurized

Firing temperatures:
Up to 1140°C (2084°F)

Inspection intervals:
24.000 EOH

COMPONENT HIGHLIGHTS
Operating conditions
Due to the specific design the Ansaldo Thomassen 6B second stage nozzle is suitable for:

PG6581 configuration
Firing temperatures up to 1140°C (2084°F)
All gas turbine fuels

Design
The nozzles are fabricated with the investment casting process and are made of a nickel base superalloy. This weldable superalloy naturally has a high resistance to corrosion combined with a good creep rupture strength.

The nozzle segment holds three hollow airfoils. Cooling air enters the nozzle cavities through AISI 321 core inserts that control the distribution of cooling air in the airfoil cavity. The trailing edge sections are film cooled by a fine distribution of cooling holes. The air boxes are welded to the nozzles during final assembly. The second stage nozzle is of the non‑pressurized design for optimal wheelspace temperatures and performance.

In the standard configuration, the second stage nozzles are coated with an aluminide diffusion coating. This purpose of this coating is to enhance the oxidation resistance of part. Ansaldo Thomassen can advice on coating solutions for specific operating conditions.

The second stage diaphragms are made of alloy Ni-resist D-2. This casting alloy maintains good corrosion properties at the higher operating temperatures. The nozzle/diaphragm assemblies are delivered with dog bone type seal strips.

Before delivery a harmonic analysis is conducted on all nozzles to verify the assembly sequence. The delivery includes all applicable installation hardware.

The nozzles are fully interchangeable with GE P/N 119E2434G008, without any modification to the gas turbine.

DESIGN LIFE
The estimated life is 72.000 EOH based on standard operating conditions and regular inspection intervals.