1. Hot Isostatic Pressing Technology for Indian Test Blanket Module Fabrication
Dr. G. Appa Rao
Defence Metallurgical Research Laboratory
Kanchanbagh PO, Hyderabad , India.
22 July 2008.

2. Introduction
Selection of appropriate materials and fabrication technologies for various components for fusion reactors relies on trade-off between multiple requirements which are mainly driven by:
Economic
Safety and
Environmental effects
Materials:
Martensitic steels
Non-Ferrous alloys
Ceramics
Vanadium alloys
SiC/SiC Composites
Ti and Cr alloys
Fabrication Technologies:
Cutting and machining
Special welding techniques
Investment casting
Hot isostatic pressing (HIP)

3. Significance of HIP Technology
Implementation and joining of F/M steels are an important
goal due to the complex geometry of the blanket modules.
Necessity for reducing the leak level and maintenance.
Advanced techniques based on solid or powder HIP are to
be established

4. Principles of Isostatic Pressing
Pascal’s Law

5. Warm Isostatic Pressing Hot Isostatic Pressing Cold Isostatic Pressing
(WIP) 1960
Hot Isostatic Pressing
(HIP) 1955
Cold Isostatic Pressing
(CIP) 1913
Isostatic Pressing
Temp.
RT.
~300 ºC
2000 ºC
Pressure
medium
Water +oil
Inert gas
400 MPa
200 MPa
Powder
container
Rubber
Steel,
Ceramic & Glass
Extent of
densification
Green compaction
Full density

6. Hot Isostatic Pressing
HIP is a an innovative thermal treatment process subjects the
material / component to a combination of high pressure and
elevated temperature
HIP results in near theoretical density, uniform microstructure
and consistent mechanical properties
HIPing Parameters:
Temperature : Tm
Pressure : MPa
Time : h.

7. Details of HIP Equipment

8. Densification Mechanisms of HIPing
Particle rearrangement
Plasticity
Power-law creep and
Volume and grain boundary diffusion

9. Stages of HIP Densification

10. HIP Diagrams

11. Applications of HIP Technology
Cladding
Diffusion Bonding
Consolidation of Encapsulated Powder
Densification of Metal castings
Specialized Applications:
Medical Implants
HIP of ultra fine Tungsten Carbide Cobalt Hard Metals
Rejuvenation of Deteriorated Components
Formation and Control of Pores
Joining of Fusion Reactor Components

12. Cost Reduction Potential for a Selected Group of Superalloy Parts25 50 75
100
AS-HIP
HIP +
H .W
Conventional
Processing
Cost Reduction Potential, %

13. CIP and HIP Facilities at DMRL
(200 Dia. X 600 HT.) mm
400 MPa
(100 Dia. X 200 HT.) mm, 200 MPa
1450, 2000 ºC
(650 Dia. X 1200 HT.) mm, 200 MPa
1450ºC
(270 Dia. X 990 HT.) mm, 200 MPa
1450ºC

14. HIPing of Stainless Steel Powder
40 mm
As-HIPed
Spec.
G. Appa Rao and M.Kumar, Mater.Sci. and Technol. 1997

15. Potential of HIP for Complex Shapes
Stainless Steel Integral Turbine Rotor
Superalloy 718 Integral Turbine Rotor

16. HIP Diffusion Bonding of Materials
Advantages:
Similar and dissimilar material can be joined
Complex shape can be joined easily
Original microstructure remains intact
ODS and FRM can be joined
Joint integrity is better than that of conventional one
Material forms for HIP bonding:
Powder-powder
Powder-solid
Solid -solid

17. Microstructure of HIP Diffusion Bonded Materials
Cu-Solid
Cu-Powder
SS -Solid
SS-Powder
Shaft alloy
Disk alloy
G. Appa Rao et. al, DMRL TR (2000)

18. Mechanical Properties of HIP Diffusion Bonded Alloys
DMRL
Spec.
DMRL
Spec.
Failure did not occur at the joint

19. P/M(HIP) Diffusion Bonded Hardware (DMRL)
Prototype thrust chamber clouseout
Ni-base superalloy components

20. Overview of Blanket Module Fabrication
(Literature)
Reduced Activation Ferritic Martensitic (RAFMA) steel is the
structural material for TBMs
Fabrication concepts rely on plates with internal cooling channels
Main technologies for fabrication of TBMs:
Cutting and machining of semi finished products
Joining of parts to produce the plates with internal channels
Bending of cooling plates
Heat treatment to improve the structure and properties

21. Configuration Details of Blanket Module

22. First Wall Fabrication Procedures
(a) Two-Step HIPing Method:
Involves machined grooved plates
Use of Mo- alloy massive stiffening / supporting plates between
the encapsulation and the FW/CP plates
HIPing at low pressure to achieve bonding at the Interface
Removal of encapsulation and Mo plates and drilling of channels
The FW is further HIPed at high pressure to achieve full bonding
Heat treatment, testing and evaluation

23. (b) Single High Pressure HIPing Method / HIP forming Process:
Involves insertion of round tubes in the rectangular grooves
Ends of the tubes are welded to the plates but the tubes are not closed
During HIPing, the tubes expand and conform to the grooves
Mo- alloy supporting plates are not required
Heat treatment, testing and evaluation.

24. (c) Rectangular Tube (RT) Process:
Involves diffusion welding of RTs. and cover plates
HIPing to improve the joint integrity
No need for stiffening plates
There is a scope for bending the RTs. and cover plates before HIPing.
Heat treatment, testing and evaluation

25. FW mock up manufactured by HIP forming ( top: parts before HIP;
bottom: mock up after HIP, bending and marching.

26. Conclusions challenging task
Fabrication of test blanket modules (TBMs) is a technologically
challenging task
Hot isostatic pressing (HIP) is a promising technology for
fabrication of TBMs
Considerable expertise on several aspects of HIP technology is
available at DMRL to address various issues in this
field
Study on development of prototype TBM components can be
taken up with the existing infrastructure.

27. Thank you