Pyrosil

Technical Data Ref: TMTB 2/IMP

Pyrosil. The ultimate protection for thermocouples at high temperatures

Pyrosil products from Tyco Thermal

Controls provide exceptional mechanical

strength, good corrosion resistance and

low drift for N and K type thermocouples.

Applications

Pyrosil thermocouple cable and protection

tube performs well in these industrial

processes: Heat treatment, chemical and

petrochemical processing, furnaces, steel

works, flue gases (especially in aluminum

anode bake furnaces), ceramics industry,

automotive, power generation, and most

general industrial processes.

In some applications Pyrosil sheathed

thermocouples can replace R and S types

at significantly lower cost.

This bulletin concentrates on the

performance elements of the product.

For size, construction or other elements,

refer to other technical bulletins.

Exceptional Mechanical StrengthStress Rupture StrengthPyrosil has good stress rupture strength in comparison with other Nickel-Baseheat resistant alloys.

Tensile StrengthThe chart shows the tensile and elongation properties of Pyrosil.

Operating temperatureRecommended for continuous use up to 2280F, brief excursions to 2335F arepossible although life may be considerably shortened.

Coefficient of Thermal Expansion(from 68F to temperature shown)

C 500 600 700 800 900 1000 m/m/C 14.56 14.98 15.59 16.15 16.81 17.30

With a coefficient of thermal expansion close to that of the core rods the fatigueand conductor breakage associated with differential expansion is minimized,resulting in longer life for N type thermocouples made with this sheath.

100

10

1

0.1

Stre

ss -

ksi

Larson-Miller Parameter = (T+460)(20+log(rl)) x 10-3 (T in F, rl in hours)35 40 45 50 55 60 65

900

800

700

600

500

400

300

200

100

0

100

80

60

40

20

0

Stre

ngth

- M

Pa

Elon

gatio

n %

Temperature F0 390 750 1100 1500 1850 2200 2500

INCONEL alloy 617

PYROSIL

INCONEL alloy 601

INCONEL alloy 600

Tensile Strength MPa

Yield Strength MPa

Elongation %

Physical Properties

Pyrosil Inconel 601

Density

lb/ in3 0.308 0.29

Melting Range

F 2516-2552 2408-2498

*

*

Oxidation Resistance at 1850F(Air + 5% H20)At 1850F Pyrosil sheaths have a stable oxide with very littlespalling, when compared with othermaterials - especially the Steel 310in this example.

Exceptional Mechanical Strength

Excellent Corrosion Resistance Pyrosil sheathed thermocouples give excellent oxidation and nitridation corrosion resistance. They also have excellentresistance to degradation in carbon based atmospheres.

Pyrosil is not recommended above 930F in reducing sulphurous atmospheres.

Oxidation Resistance The alloy has been tailored to provide improved oxidation resistance over stainless steels and higher nickel alloys at temperatures up to 2282F. The resistance to oxidation corrosion is the result of a strongly adhering protective hightemperature oxide film - one that does not affect the stability of the thermocouple alloys and that reduces the rate ofmass change.

Oxidation Resistance at 2000F(Air + 5% H20)At the higher temperature of 2000Fthe effect is more pronounced, withPyrosil exhibiting significantly betterresistance to corrosion than 601.

Oxidation Resistance at 2200F(Air + 5% H20)At 2200F Pyrosil gives excellentperformance compared to othercommon thermocouple sheathingmaterials.

5

3

1

-1

-3

-5

-7

-9

-11

-13

-15

Wei

ght C

hang

e - m

g/cm

3

20

0

-20

-40

-60

-80

-100

-120

-140

-160

Wei

ght C

hang

e - m

g/cm

3

Exposure Time - Hours0 2000 4000 6000 8000 10000

Exposure Time - Hours0 1000 2000 3000 4000 5000 6000 7000 8000

50

0

-50

-100

-150

-200

-250

-300

-350

-400

Wei

ght C

hang

e - m

g/cm

3

Exposure Time - Hours0 500 1000 1500 2000 2500 3000

INCONEL alloy HX

AISI 310

INCONEL alloy 600

INCONEL alloy 617

PYROSIL

PYROSIL

INCONEL alloy 617

INCONEL alloy 601

INCONEL alloy HX

PYROSIL

INCONEL alloy 601

INCONEL alloy 617

*

*

*

2200

F20

00F

1850

F

Nitridation Resistance

Good Corrosion Resistance

Chemical Composition

Sheath AlloysCr Si Mg Nb Others

Pyrosil A 14.2 1.4 0.15 - Bal NickelPyrosil B 14.7 1.4 0.15 1.5 Bal NickelPyrosil C 24 1.4 0.15 0.5 Bal NickelPyrosil D 22 1.4 - - Mo 3%, rare earths trace Bal Nickel

Core RodsN Pos 14.3 1.5 - - Bal Ni (Nicrosil)N Neg - 4.5 - - Bal Ni (Nisil)K Pos 9.2 0.4 - - Bal NiK Neg - 2.5 - - Co 1.2, Cu 2.4, Bal Ni

Product Range

Thermocouple Cable: Type N and K EMF outputs Diameters of 0.040"* to 0.500" Simplex, Duplex and Triplex conductor

configuration Standard and Heavy Wall designs Note: Not all variants possible in 1 cable

Protection Products: Tubes at 1 outside diameter and 3/4 outside diameter

*Smaller diameters by special request.

Nitridation Resistanceat 2050FCompared to other sheath materials,Pyrosil absorbs less nitrogen andso is more stable in the process.Lacking the alloying elements thatform internal nitrides such as Nb orAl, Pyrosil sheaths exhibit freedomfrom microstructural degradation andbrittleness. This makes Pyrosil

especially valuable where mechanical damage is likely.

7

6

5

4

3

2

1

0

Wei

ght C

hang

e - m

g/cm

3

Exposure Time - Hours0 200 400 600 800 1000 1200

PYROSIL

AISI 314

INCONEL alloy 600

10

5

0

-5

-10

-15

-20

-25

-30

-35

Tem

pera

ture

Dev

iatio

n C

from

BS6

0

Time - Months0 1 2 3 4 5 6

N 310 at 1300C (2370F)

N PYROSIL at 1300C (2370F)

K 310 at 1150C (2100F)

N PYROSIL at 1150C (2100F)

Low Drift for N TypeThe compatibility of the sheath and conductor material gives Pyrosil outstanding performance characteristics in terms ofstability and range.

As the chemistry of the Pyrosil sheaths and N type conductors are similar, this reduces the potential for diffusion ofelements between the alloy thus reducing the change in output and subsequent drift. In addition the lack of Mn and Al alsoprevents cross contamination - and drift - of the thermocouple legs.

Low Drift at High Temperatures

*

*

2050 F2100 F2370 F

www.tycothermal.com

Pyrotenax and Pyrosil are trademarks of Tyco Thermal Controls LLC and its affiliates in designated countries

All of the information contained in this publication, including illustrations, is believed to bereliable. Users however, should independently evaluate the suitability of each product for theirapplication. Tyco Thermal Controls makes no warranties as to the accuracy or completeness ofthe information and disclaims any liability regarding its use. Tyco Thermal Controls only obligations are those in the Standard Terms and Conditions of Salefor this product and in no case will Tyco Thermal Controls be liable for any incidental, indirect orconsequential damages arising from the sale, resale, use or misuse of the product. Tyco ThermalControls Specifications are subject to change without notice. In addition Tyco Thermal Controlsreserves the right to make changes in materials or processing, without notification to the buyer,which do not affect compliance with any applicable cable specification.

INCONEL is a trademark of the Special Metals Corporation Group of companies.

*Data Courtesy of Special Metals

Tyco Thermal Controls UK Limited

3 Rutherford Road,

Stephenson Industrial Estate,

Washington, Tyne & Wear,

NE37 3HX. United Kingdom

Tel: +44 (0) 191 419 8200

Fax: +44 (0) 191 419 8201

Tyco Thermal Controls Canada Limited

250 West Street,

Trenton, Ontario,

Canada.

K8V 5S2

Tel: (1) 613-392-6571

Fax: (1) 613-392-3999

Publication No: TMTB 2/IMP Published October 2004

Low Drift