7H3 (8x3)
For tool for hot heading, stamp details.
tools (punches, matrices) hot landing fasteners and pieces of carbon and low-alloy structural steels on horizontal forging machines, dies parts (matrices, punches, ejectors) for hot pressing and extrusion of these materials on crank presses, bending, cut and grooved stamps.
Classification
| Country |
Section |
Category |
| CIS, Russia, Ukraine |
Tool steel |
Die tool steel |
Chemical composition
| Standard |
Fe, % |
Si, % |
Mn, % |
Cr, % |
Ti, % |
Cu, % |
Ni, % |
V, % |
P, % |
C, % |
S, % |
Mo, % |
W, % |
|---|
| GOST 5950-2000 |
93.26–95.9 |
0.1–0.4 |
0.15–0.45 |
3.2–3.8 |
< 0.03 |
< 0.3 |
< 0.4 |
< 0.15 |
< 0.03 |
0.65–0.75 |
< 0.03 |
< 0.2 |
< 0.2 |
Information on suppliers
Mechanical properties at 20 °C
| Rolling |
Standard |
Size, mm |
Tension |
Classifiers |
$$\sigma _{U}$$, $$MPa$$ |
$$\sigma_{P}$$, $$MPa$$ |
$$\epsilon_L$$, % |
$$\psi$$, % |
$$KCU\cdot 10^{3}$$, $$\frac{J}{m^2}$$ |
Treatment |
|---|
| Alloy |
|
|
|
|
1320 |
1240 |
10 |
36 |
370 |
Tempering 870 ° C, oil, leave 500 ° C, 2 h |
Brinell hardness number
| Rolling |
Standard |
Classifiers |
Value, HBW |
| Alloy |
GOST 5950-73 |
annealing |
229 |
Technological Properties
| Weldability |
Flake Susceptibility |
Propensity to temper brittleness |
|---|
| Not applicable for welded structures |
sensitive |
inclined |
Critical point temperatures
| Ac1, K |
Ac3(Acm), K |
Mn, K |
|---|
| 770 |
730 |
400 |
Analogues
Standards
Description of chemical elements
| Element |
Units of measurement |
Description |
| Fe |
% |
Iron |
| Si |
% |
Silicon |
| Mn |
% |
Manganese |
| Cr |
% |
Chrome |
| Ti |
% |
Titan |
| Cu |
% |
Copper |
| Ni |
% |
Nickel |
| V |
% |
Vanadium |
| P |
% |
Phosphorus |
| C |
% |
Carbon |
| S |
% |
Sulfur |
| Mo |
% |
Molybdenum |
| W |
% |
Tungsten |
Description of mechanical properties
| Parameter |
Units of measurement |
Description |
| $$\sigma _{U}$$ |
$$MPa$$ |
Ultimate tensile strength |
| $$\sigma_{P}$$ |
$$MPa$$ |
Proportionality limit |
| $$\epsilon_L$$ |
% |
Elongation at break (longitudinal) |
| $$\psi$$ |
% |
Reduction in cross section on fracture |
| $$KCU\cdot 10^{3}$$ |
$$\frac{J}{m^2}$$ |
Impact toughness |
Designation of types of weldability
| Parameter |
Units of measurement |
Description |
| no limits |
|
Welding is performed without heating and without subsequent heat treatment |
| Boundedly welded |
|
Welding is possible with heating up to 100–120 °C and subsequent heat treatment |
| Difficult to weld |
|
For obtaining quality welded joints, additional operations are required: heating up to 200–300 °C for welding, heat treatment after welding — annealing |
| Not applicable for welded structures |
|
|
Description of temperatures of critical points
| Parameter |
Units of measurement |
Description |
| Ac1 |
K |
|
| Ac3(Acm) |
K |
|
| Mn |
K |
|