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High Performance Materials

Heat Exchanger [Ta] [Nb]

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Ta/Nb/Zr/Ti heat exchangers from ULVAC use welds developed from vacuum techniques and are subject to a rigorous inspection system. ULVAC can boast of over 40 years of achievements in the manufacture of heat exchangers, and its products are highly rated in the chemical, pharmaceutical, and nuclear industries.

Welding techniques

High quality atmosphere-controlled in-chamber welding
As tantalum, niobium, titanium, and zirconium are highly active metals, welding in the air causes contamination by atmospheric gases, preventing the construction of high quality welded structures. ULVAC conducts all its welding of active refractory metal either in inert gas substitution chambers that are highly atmosphere-controlled or by using electron beam welding, enabling the production of extremely high quality welded structures without contamination.
Control of characteristics after welding
To control contamination, the hardness of tantalum is controlled within base material + 40 HV, and the O and N increase amount within 100 ppm.

Comparison of welded portions of tantalum

<Hardness>
In-house control value: Base material + 40 HV

(Unit: HV)

  Base material Welded portion Difference
ULVAC 115 135 20
Manufacturer A 120 153 33
Manufacturer B 100 476 376

<Analysis>
In-house control value: O, N = Base material + 100 ppm (Unit: ppm)

(Unit: ppm)

  O N
ULVAC +30 +30
Manufacturer A +100 +40
Manufacturer B +200 +250

Material characteristics

The values below are officially recognized in the processes from “dissolution” through “rolling” to “welding” for Ta products of ULVAC. All processes are conducted in our plants.

<Tantalum>

  RT 100℃ 200℃ 300℃ Remarks
Modulus of longitudinal
elasticity
(N/mm2)
185000 183000 180000 177000 From in-house data
Allowable stress
(N/mm2)
58 51 51 55 Conforming to ASME* Code
From in-house data
Yield point
(N/mm2)
170 147 147 167 From in-house data

* ASME:American Society of Mechanical Engineers


Coil type heat exchanger


Ta coil:Φ48.6mm × t1.5 220℃ 0.74MPa

Structures of tantalum foils with different grain sizes after pressing

 Φ1500mm × 2500L Class 1 pressure vessel

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