Relevance
Heat-resistant nickel-based alloy KhN77TU (EI437A) is used in production of disks, rings, turbine blades at t° up to 750 °C. In modern engines the material for turbine parts should have high resistance to destruction under low cycle and thermal fatigue which is the main cause of destruction today. The risk of fracture can be exacerbated by surface reactions associated with grain boundary loosening and gas corrosion. The main requirements to the material for turbine blades are caused by the latest developments in engine design, increased ductility, heat resistance, resistance to low-cycle and thermal fatigue, as well as resistance to gases. Hardness of rod XN77TU grade according to GOST 23 705−79 is HB 10−1 = 255 — 321MPa.
Percentage composition (GOST 5632−72)
| Si |
C |
Fe |
Mn |
P |
S |
Ni |
Cr |
Al |
Ti |
Ce |
Pb |
B |
|---|
| up to 0.6 |
up to 0.07 |
up to 1 |
up to 0.4 |
up to 0.015 |
to 0.007 |
70.083 — 77.4 |
19 — 22 |
0.6 — 1 |
2.4 — 2.8 |
up to 0.02 |
up to 0.001 |
up to 0.003 |
Mechanical characteristics at t° 20 °C.
| Products |
Dimension. |
Size |
d5 |
y |
in |
sT |
Heat treatment. |
KCU |
|---|
| - |
- |
mm |
% |
% |
MPa |
MPa |
- |
kJ/m2 |
| Bar, GOST 23 705−79, temperature-700 °С |
|
|
5 |
12 |
610 |
|
Aging and hardening |
|
Physical properties of the alloy:
| Description |
Designation |
|---|
| — Alloy data acquisition temperature [Grad] |
— T |
| — Modulus of elasticity of the 1st kind, [MPa] |
— E |
| — Coefficient of thermal linear expansion (at 20°C), [1/Grad] |
-a |
| — Specific electrical resistance [Ohm-m] -R |
-R |
| — Specific gravity [g/cm3] -r |
-r |
| — Heat transfer coefficient [W/(m-grad)] -l |
-l |
| — Specific heat capacity (at 20°C), [J/(kg-grad) |
-C |
Mechanical properties:
| Description |
Designation |
|---|
| — Ultimate yield strength (yield strength for permanent deformation) [MPa] |
sT |
| — Tensile strength [MPa] |
sT |
| — Ratio constriction [ % ] |
y |
| — Tensile elongation [ % ] |
d5 |
| — Brinell hardness, in [MPa] |
HB |
| — Impact toughness [ kJ/m2 ] |
KCU |
Weldability:
| Designation |
Description |
|---|
| limited weldable |
— Must be preheated to 100−120°C with subsequent heat treatment |
| no restrictions |
— No need for preheating and final heat treatment |
| Difficult to weld |
— need preheating to 200−300 ° C with the final heat treatment |
Buy at best price
Evek GmbH manufactures a wide range of CrNi7Tu products to suit every customer. The price is determined by the technological features of production without including additional costs. All products are certified. With us it is easy to buy the necessary products in bulk for large-scale projects, we also offer favorable conditions for retail customers. Technological configuration of each production stage gives us the opportunity to fulfill individual orders of non-standard parameters. Products are manufactured by strictly following the technological process, which guarantees the highest quality, stored under cover or indoors to protect against mechanical damage, contact with moisture and aggressive substances. The terms of realization of orders are minimal. Wholesale customers receive discounts.
