1.Overview
1.1 Material Grade:gh5188(gh188)
1.2 Similar grades:haynes alloy no.188 (HA188), UNSR30188 (USA), KCN22W (France).
1.3 Technical Standards:GJB 3317-1998 "Specification for Hot-rolled Plate of Superalloy for Aviation".
1.4 Chemical Composition:
c：0.05～0.15
cr：20.0～24.0
ni：20.0～24.0
co: Yu. w：13.0～16.0
fe：≤3.0
b：≤0.015
la：0.03～0.12
mn：≤1.25
si：0.20～0.50
p: not greater than 0020
s: not greater than 0015
ag: not greater than 00010
bi: no more than 00001
pb: not greater than 00010
cu: not greater than 007
1.5 Heat treatment system:
Hot rolled plate: 1170 1190, air cooled.
Cold rolled strip and plate: 1165 1230, fast air cooling.
Bars and forgings: 1180 10, fast air cooling.
1.6 Product Specifications & Status:
Cold-rolled sheet: δ05～4mm
Hot-rolled medium plate: δ4 14mm
Cold rolled strip: δ005～0.8mm
Bars, forgings, welding wires and precision castings.
1.7 Melting and Casting Process:
The alloy is produced by vacuum induction melting plus electroslag remelting or vacuum arc remelting.
Precision castings are made by vacuum remelting of master alloy ingots after vacuum induction melting.
1.8 Application Overview and Special Requirements:
It is widely used in the manufacture of high-temperature parts for gas turbines and missiles, such as combustion chambers, tail nozzles, heat exchangers and other parts in the nuclear energy industry.
In China, high-temperature components such as flame cylinders and guide vanes used in aero engine combustion chambers have passed long-term test tests and have been put into production and application.
In the manufacturing process, any process (such as heat treatment, welding, etc.) should be protected from carburizing and copper contamination, so as not to damage the mechanical properties and corrosion resistance of the alloy.
2.Microstructure of the alloy
Solution state:These include austenitic matrix, M6C primary carbide, lanthanum-rich compounds, small amounts of M3B2, and TIC phases.
After long-term exposure to high temperatures:M6c may resolve M23C6 and in some cases may precipitate the L phase.
Performance & Requirements
3.1 Formability
Forging:The heating temperature is 1180, the final forging temperature is not less than 980, and the casting structure can be broken with a large amount of deformation.
After solution treatment:It has good plasticity and can be used in any cold forming process.
3.2 Heat treatment grain size:
Effect of solution temperature (holding time 10min) on the grain size level of the plate.