Watlow Heater Catalog

Reference Data (Imperial Unit)

Power Calculations Heat Loss Curves

Some Material Emissivities/Metals - Ref. 3

Emissivity

Specific Heat Btu/lb - °F

Material

Polished Surface

Medium Oxide

Heavy Oxide

Blackbody Aluminum Brass Copper Incoloy ® 800 Inconel ® 600 Iron, Cast Lead, solid Magnesium Nickel 200

0.75 0.11 0.35 0.03 0.60 0.60 0.80 0.28

1.00 0.22 0.60 0.65 0.92 0.92 0.85

0.24 0.10 0.10 0.12 0.11 0.12 0.03 0.23 0.11 0.11 0.04 0.12 0.11 0.11

0.09 0.04 0.04 0.20 0.20 — — — —

— — — — —

— — — —

Nichrome, 80-20 Solder, 50-50 Steel mild

— —

0.10 0.17 0.17

0.75 0.57 0.57 — 0.25

0.85 0.85 0.85

stainless 304 stainless 430

Tin Zinc

0.056 0.10

— —

— —

Some Material Emissivities/Non-Metals - Ref. 4

Specific Heat Btu/lb - °F

Material

Emissivity

Asbestos Asphalt Brickwork Carbon

0.25 0.40 0.22 0.20 0.20 0.45 0.2-0.5 0.40 0.20-0.23 — 0.57

Glass Paper Plastic Rubber Silicone Carbide Textiles Wood, Oak

Most non-metals: 0.90

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