Steel 15KH25T (ЭИ439)
Designation
| Name |
The value |
| Designation GOST Cyrillic |
15Х25Т |
| Designation GOST Latin |
15X25T |
| Transliteration |
15H25T |
| The chemical elements |
15Cr25Ti |
| Name |
The value |
| Designation GOST Cyrillic |
ЭИ439 |
| Designation GOST Latin |
EI439 |
| Transliteration |
EhI439 |
| The chemical elements |
- |
Description
15KH25T steel is used: for the manufacture of welded structures (as a substitute of steel 12KH18N10T), not exposed to shock loads when the operating temperature is not below -20 °C and for operation in more corrosive environments than steel 08KH17T; for the manufacture of pipes of heat-exchange equipment operating in aggressive environments; for production of equipment, parts, thermocouple sheaths, electrodes incendiary spark candles, pipes pyrolysis plants, heat exchangers; as a cladding layer in the manufacture of hot-rolled dual-layer corrosion-resistant sheets.
Note
Steel corrosion and heat-resistant ferritic class.
Temperature intense scaling in air +1050 °C.
Steel heat-resistant up to +1100 °C.
It is not recommended to operate in the temperature range of +400−700 °C.
Standards
| Name |
Code |
Standards |
| Sheets and stripes |
В23 |
GOST 103-2006 |
| Sectional and shaped rolling |
В22 |
GOST 1133-71, GOST 2590-2006, GOST 2591-2006, GOST 2879-2006 |
| Sheets and stripes |
В33 |
GOST 4405-75, GOST 5582-75, GOST 7350-77, GOST 10885-85 |
| Classification, nomenclature and general norms |
В30 |
GOST 5632-72 |
| Sectional and shaped rolling |
В32 |
GOST 5949-75, GOST 7417-75, GOST 8559-75, GOST 8560-78, GOST 14955-77, TU 14-11-245-88 |
| Pipes steel and connecting parts to them |
В62 |
GOST 9940-81, GOST 9941-81, TU 14-3-949-80, TU 14-3-1654-89 |
| Bulls. Blanks. Slabs |
В31 |
OST 3-1686-90, TU 14-1-565-84 |
| Thermal and thermochemical treatment of metals |
В04 |
STP 26.260.484-2004, ST ЦКБА 016-2005 |
Chemical composition
| Standard |
C |
S |
P |
Mn |
Cr |
Si |
Ni |
Fe |
Cu |
V |
Ti |
Mo |
W |
| GOST 5632-72 |
≤0.15 |
≤0.025 |
≤0.035 |
≤0.8 |
24-27 |
≤1 |
≤1 |
The rest |
≤0.3 |
≤0.2 |
0.5-0.9 |
≤0.3 |
≤0.2 |
Fe is the basis.
Mechanical characteristics
| Section, mm |
sT|s0,2, MPa |
σB, MPa |
d5, % |
y, % |
kJ/m2, кДж/м2 |
Brinell hardness number, MPa |
| Blank pieces of pipe fittings according to ST CKBA 016-2005. Annealing at 730-780 °C, air cooling or water |
| ≤60 |
≥294 |
≥441 |
≥20 |
≥45 |
- |
143-163 |
| Bars. Annealing at 760-780 °C, cooling in water |
| - |
- |
≥77 |
≥48 |
≥93 |
- |
- |
| Bars. Specified Sepang plastic deformation in % |
| - |
- |
≥600 |
≥15 |
- |
- |
- |
| Hot rolled sheet (of 1.5-3.9 mm) and cold rolled (0,7-3,9 mm) steel according to GOST 5582-75. Annealing or vacation at 740-780 °C |
| - |
- |
≥530 |
≥17 |
- |
- |
- |
| Bars. Annealing at 760-780 °C, cooling in water |
| - |
- |
≥26 |
≥104 |
≥99 |
- |
- |
| Bars. Specified Sepang plastic deformation in % |
| - |
- |
≥700 |
≥10 |
- |
- |
- |
| Hot rolled sheet (4,0-25,0 mm) and cold rolled (4,0-5,0 mm) steel according to GOST 7350-77. Annealing or vacation at 740-780 °C, cooling in water |
| - |
- |
≥440 |
≥14 |
- |
≥196 |
- |
| Bars. Annealing at 760-780 °C, cooling in water |
| - |
- |
≥19 |
≥153 |
≥99 |
- |
- |
| Bars. Specified Sepang plastic deformation in % |
| - |
- |
≥760 |
≥8 |
- |
- |
- |
| Bars hot rolled and forged according to GOST 5949-75. Annealing at 730-770 °C, air cooling or water |
|
≥295 |
≥440 |
≥20 |
≥45 |
≥490 |
- |
| Bars. Annealing at 760-780 °C, cooling in water |
| - |
- |
≥11 |
≥148 |
≥100 |
- |
- |
| Bars. Specified Sepang plastic deformation in % |
| - |
- |
≥800 |
≥7 |
- |
- |
- |
| Tubes in the delivery condition (in cross-section shows the thickness of the wall) |
| 3.5-32 |
- |
≥441 |
≥17 |
- |
- |
- |
| Bars. Annealing at 760-780 °C, cooling in water |
| - |
- |
≥8 |
≥139 |
≥100 |
- |
- |
| Bars. Specified Sepang plastic deformation in % |
| - |
- |
≥840 |
≥6 |
- |
- |
- |
| Tubes in the delivery condition (in cross-section shows the thickness of the wall) |
| 0.2-22 |
- |
≥461 |
≥17 |
- |
- |
- |
| Bars. Specified Sepang plastic deformation in % |
| - |
- |
≥860 |
≥5 |
- |
- |
- |
| - |
- |
≥450 |
≥32 |
- |
- |
- |
Description mechanical marks
| Name |
Description |
| Section |
Section |
| sT|s0,2 |
Yield strength or limit of proportionality with a tolerance for residual deformation of 0.2% |
| σB |
Limit short-term strength |
| d5 |
Elongation after rupture |
| y |
The relative narrowing |
| kJ/m2 |
Toughness |
Physical characteristics
| Temperature |
Е, ГПа |
r, кг/м3 |
l, Вт/(м · °С) |
R, НОм · м |
a, 10-6 1/°С |
С, Дж/(кг · °С) |
| 0 |
204 |
7600 |
17 |
710 |
- |
- |
| 20 |
204 |
7600 |
17 |
710 |
- |
- |
| 100 |
200 |
- |
- |
- |
101 |
462 |
| 200 |
197 |
- |
- |
- |
107 |
- |
| 300 |
189 |
- |
- |
- |
11 |
462 |
| 400 |
176 |
- |
- |
- |
108 |
- |
| 500 |
164 |
- |
- |
- |
112 |
- |
| 600 |
140 |
- |
- |
- |
115 |
- |
| 700 |
124 |
- |
- |
- |
113 |
- |
| 800 |
119 |
- |
- |
- |
116 |
- |
| 900 |
109 |
- |
- |
- |
122 |
- |
A description of the physical symbols
| Name |
Description |
| Е |
The normal elasticity modulus |
| r |
Density |
| l |
Coefficient of thermal conductivity |
| R |
UD. the resistivity |
Technological properties
| Name |
The value |
| Weldability |
Difficult weldability. In automatic welding recommended wire SV-07Х25Н12ТЮ SV-13Х25Н18 flux an-26. In the case of manual welding, good plasticity provide the electrodes with a wire of steel SV-13Х25Н18 (Brand 03Л-9) or by wire SV-07CR25NI13 type EA-2 and EA-2B. Requires heating to 150-200 °C and subsequent heat treatment - vacation 600 °C. |
| Propensity to temper brittleness |
Inclined in the range of from 450 to 520 °C. |
| Forging temperature |
Start - 1160 °C, the end - of 800 °C. |
| Workability by cutting |
In the annealed condition with NV 149-163 Kn TV.SPL.=0,9 Kn b.St.=0,6. |
| Features of heat treatment |
To obtain characteristic values of mechanical properties and hardness set ST CKBA 010 and to achieve maximum corrosion resistance, parts (workpiece) valves shall be subjected to annealing. Steel products ferritic to eliminate the tendency to intergranular corrosion and maximum plasticity should be heated to 730-770 °C, aging at the rate of 30 min + 1 min per 1 mm maximum material thickness, cooling in water or air. Weldment of steel 15KH25T should be subjected to annealing at 720-780 °C for 1-2 h, air cooling. Not allowed to leave the products at 450-550 °C, since this leads to the "475 ° embrittlement". |
