Special alloys

DESCRIPTION

ХН78Т – a special heat-resistant alloy based on nickel and chromium is designed for continuous operation at temperatures up to 1100 °C. It has such properties as excellent resistance to oxidizing environments at temperatures up to 1100 °C, good mechanical properties at temperatures up to 1000 °C, resistance to the formation of oxide on the surface at temperatures up to 1000 °C, good metallurgical stability. It is melted in open electric furnaces and by using different types of melting.

Main application ХН78Т – unloaded or low-loaded details operating in corrosive gas environments with temperatures of 550-1100 °C (II group); loaded details with 100-1000 hours of work at temperatures up to 1000 °C (III group). For example: flame tube, combustion chamber, flues, covers for thermocouples, etc.

CHEMICAL COMPOSITION

Nom. composition С Si Mn S P Сr Ni Fe Ti Al
Min 19.00 Rest 0.15
Max 0.12 0.80 0.70 0.010 0.015 22.00 1.00 0.35 0.15

PHYSICAL PROPERTIES

Temperature 20°С 100°С 200°С 300°С 400°С 500°С 600°С 700°С 800°С 900°С
Coefficient of elasticity, 10-5 MPа 2.24 2.19 2.13 2.06 2.00 1.93 1.84
Coefficient of linear expansion, ɑ x 10-6 12.20 13.00 13.40 13.80 14.10 14.70 15.40 15.50
Thermal conductivity, W/mK 14.60 16.70 18.50 20.60 22.70 24.80 26.80 28.90
Resistance, ῼ mm2/m 1.09  1.099  1.108  1.117 1.127  1.153 1.135 1.126 1.123  –

MECHANICAL PROPERTIES

Tensile strength, sв Yield strength, sT Elongation, d5 Contraction ratio, y Hardness
N/mm2 (kgf/mm2) N/mm2 (kgf/mm2) % % НВ
> 700 (71) >300 (40) >30 >50 <230.00

PRODUCT RANGE

Finish Diameter, mm Standard (chemical composition) Standard (product range)
Hot rolled 8.00 – 75.00 ГОСТ 5632-72 ГОСТ 2590-2006; ГОСТ 2590-88; ГОСТ 5949-75; ГОСТ 2591-88; ТУ 14-1-1671-76
Forgings 75.00 – 350.00 ГОСТ 5632-72 ГОСТ 25054-81; ТУ 14-1-1530-75; ТУ 14-1-1531-75; ТУ1 4-1-2902-80

ANALOGUES

W.N EN International name UNS
2.4951 NiCr20Ti Alloy 75 N06075