U9 steel
U9 Steel
Steel U9: A Handbook of Steels and Alloys. Below is systematized information on the purpose, chemical composition, types of supply, substitutes, critical point temperatures, physical, mechanical, technological and foundry properties for the grade — Steel U9.
General information on steel U9
| Substitute for the grade |
| Steel grade: U7A, U7, U8A, U8. |
| Type of delivery |
| Sections, including shaped: GOST 1435−74, GOST 2590−71, GOST 2591−71, GOST 2879−69. Calibrated rod GOST 1435−74, GOST 7417−75, GOST 8559−75, GOST 8560−78. Grinded rod and silversilver GOST 1435−74, GOST 14955−77. Tape GOST 2283−79, GOST 10234−77. Tape GOST 103−76, GOST 4405−75. Forgings and forged blanks GOST 1435−74, GOST 4405−75, GOST 1133−71. |
| Application |
| The tools working in the conditions which do not cause the heating of the edge: a tool for woodworking, welding and assembly tools, the calibers of a simple form and the lowered classes of accuracy. |
Chemical composition of steel U9
| Chemical element |
% |
| Silicon (Si) |
0.17−0.33 |
| Manganese (Mn) |
0.17−0.33 |
| Copper (Cu), not more |
0.25 |
| Nickel (Ni), not more than |
0.25 |
| Sulfur (S), not more than |
0.028 |
| Carbon (C) |
0.86−0.93 |
| Phosphorus (P), not more than |
0.030 |
| Chromium (Cr), not more than |
0.20 |
Mechanical properties of U9 steel
Mechanical properties
| Heat treatment, delivery condition |
σB, MPa |
δ5, % |
| Rolled section 0,1−4,0 mm. |
| Cold rolled annealed strip |
750 |
10 |
| Cold-rolled annealed strip |
750−1200 |
|
| Cold-rolled flat steel strip, strength class H1 |
750−900 |
|
| Cold-rolled flat steel strip, strength class H2 |
900−1050 |
|
| Cold-rolled flat steel strip, strength class H3 |
1050−1200 |
|
| Strip annealed of the highest quality category. |
700 |
15 |
Technological properties of steel U9
| Forging temperature |
| Beginning 1125, end 750. |
| Weldability |
| Not applicable for welded structures. |
| Tendency to tempering ability |
| is not prone to |
| Flockability |
| is not sensitive |
Steel U9 critical point temperature
| Critical point |
°С |
| Ac1 |
740 |
| Ac3 |
760 |
| Ar1 |
700 |
| Mn |
190 |
Hardness of steel U9
| Delivery condition, heat treatment regime |
HRCe surface |
HB |
| 750−770 C annealing. |
|
192 |
| Tempering 760−780 C, water. |
63 |
|
| Springs. Isothermal hardening 770 C, cooling in an alkaline bath at 340−360 C. Tempering for 10−15 minutes. Tempering at 170 C. |
45−50 |
|
| Tempering at 800 °C with water. Tempering at 200 C. |
61 |
|
| Hardening 800 C, water. Tempering at 300 °C. |
52 |
|
Hardenability of steel U9
Hardening at 760 °C.
| Distance from end face, mm / HRCe |
| 1.5 |
3 |
4.5 |
6 |
9 |
12 |
15 |
18 |
30 |
42 |
| 63 |
61 |
58 |
53,5 |
48 |
46 |
45,5 |
45,5 |
44,5 |
42,5 |
| Crit. dia. in water, mm |
Crit. dia. in oil, mm |
| 15−20 |
4−6 |
Physical properties of steel U9
| Test temperature, °С |
20 |
100 |
200 |
300 |
400 |
500 |
600 |
700 |
800 |
900 |
| Modulus of normal elasticity, E, GPa |
207 |
|
|
|
|
|
|
|
|
|
| Torsional shear modulus of elasticity G, GPa |
79 |
|
|
|
|
|
|
|
|
|
| Steel density, pn, kg/m3 |
7745 |
7726 |
7717 |
7690 |
7686 |
7655 |
7622 |
7586 |
7568 |
7523 |
| Thermal conductivity coefficient W/(m — °C) |
|
49 |
48 |
46 |
43 |
40 |
37 |
33 |
|
|
| Electrical resistivity (p, nominal value — m) |
|
253 |
329 |
418 |
525 |
646 |
789 |
943 |
1155 |
1198 |
| Test temperature,°C |
20−100 |
20−200 |
20−300 |
20−400 |
20−500 |
20−600 |
20−700 |
20−800 |
20−900 |
20−1000 |
| Coefficient of linear expansion (a, 10−6 1/°C) |
11.3 |
12.1 |
12.9 |
13.6 |
14.2 |
14.7 |
15.2 |
14.0 |
|
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