Steel 25L
Designation
| Name |
The value |
| Designation GOST Cyrillic |
25Л |
| Designation GOST Latin |
25L |
| Transliteration |
25L |
| The chemical elements |
25 |
Description
25L steel is used: for the manufacture of castings, machine beds, rolling mills, pulleys, traverse, pistons, books, covers, cylinders, flat plates, frames, rollers, and trucks, troughs, bearing housings, parts of welded-cast structures and other parts operating at temperatures from -40 to +450 °C under pressure; casting parts for gas turbines and axial compressors operating at temperatures from -40 to +350 °C; casting the 2nd and 3rd parts of pipe fittings with the working environment temperature from -30 to +450 °C without restriction of the nominal working pressure; casting parts mining and metallurgical equipment; stationary parts of steam turbines operating at temperatures up to 425 °C; cast of the centres of wheelsets of locomotives and motor cars of electric and diesel trains of the Railways of 1520 mm in climatic design UHL; casting equipment parts (valves) for nuclear power stations, heat supply stations, heat and power plants, experimental and research nuclear reactors and installations; tsentrobezhnolityh pipes used as components in equipment for metallurgical, engineering, glass, ceramic, mining and processing petrochemical industry and is intended for the manufacture of blanks and parts used in the composition of the products of aviation and the nuclear industry.
Note
Steel pearlitic class.
Allowed to apply casting parts of pipe fittings of steel grade 25L to the operating temperature minus 40 °C subject to thermal treatment in the hardening regime plus vacation or normalizing plus a vacation with the testing of impact toughness KCU-40≥200 kJ/m2 (2,0 kgf·m/cm2).
Standards
| Name |
Code |
Standards |
| Bandages. Wheels. Axes |
В41 |
GOST 4491-86 |
| Castings, steel |
В82 |
GOST 977-88, OST 108.961.04-80, OST 26-07-402-83, OST 24.920.01-80, OST 3-4365-79, OST 5Р.9285-95, TU 26-02-19-75, TU 108.11.352-87, TU 108-11-539-87, TU 108-23.45-88, TU 108.671-84, TU 108-978-80, TU 4112-091-00220302-2006, TU 03.12290-95, ST ЦКБА 014-2004, TU 5.961-11151-92 |
| Castings with special properties (cast iron and steel) |
В83 |
OST 108.961.02-79, OST 108.961.03-79, KSt 81-033:2009, TU 4112-78269737-008-05 |
| Classification, nomenclature and general norms |
В20 |
OST 84-218-85 |
| Welding and cutting of metals. Soldering, riveting |
В05 |
RTM 108.020.122-78 |
| Pipes steel and connecting parts to them |
В62 |
TU 1333-003-76886532-2014 |
Chemical composition
| Standard |
C |
S |
P |
Mn |
Cr |
Si |
Ni |
Fe |
Cu |
| OST 108.961.02-79 |
0.22-0.3 |
≤0.025 |
≤0.025 |
0.4-0.9 |
≤0.3 |
0.2-0.52 |
≤0.3 |
The rest |
≤0.3 |
| KSt 81-033:2009 |
0.22-0.3 |
≤0.04 |
≤0.04 |
0.45-0.9 |
- |
0.2-0.52 |
- |
The rest |
- |
| OST 108.961.03-79 |
0.22-0.27 |
≤0.025 |
≤0.025 |
0.4-0.9 |
≤0.3 |
0.2-0.52 |
≤0.3 |
The rest |
≤0.3 |
| GOST 4491-86 |
0.22-0.3 |
≤0.025 |
≤0.03 |
0.6-0.9 |
≤0.5 |
0.2-0.52 |
≤0.5 |
The rest |
≤0.4 |
| TU 5.961-11151-92 |
0.22-0.3 |
≤0.025 |
≤0.025 |
0.45-0.9 |
- |
0.2-0.52 |
- |
The rest |
- |
Fe is the basis.
According to GOST 977-88 the mass fraction of S and P content is indicated for 1 group of castings from the main steel. The content of sulfur and phosphorus in the castings of groups 2 and 3, in sour and basic open-hearth steel - see Table 4a in GOST 977-88.
According to OST 5R.9285-95, in the case of steel smelted in the main electric furnaces as cold-resistant (technical conditions of the order or requirements of the drawing), the sulfur and phosphorus content should not be more than 0.020% of each. As agreed by the manufacturer with the developer OST 5P.9285-95 (CRI "Prometey"), the content of sulfur and phosphorus is allowed up to 0.030% of each.
According to TU 5.961-11151-92 for castings of grades 1 and 2 the mass fraction of cobalt in steel should not exceed 0.20%, and for castings in the direct irradiation zone - 0.15%.
Mechanical characteristics
| Section, mm |
sT|s0,2, MPa |
σB, MPa |
d |
y, % |
kJ/m2, кДж/м2 |
Brinell hardness number, MPa |
| Quenching with 870-890 °C, air cooling + Vacation at 610-630 °C, air cooling |
| 100-300 |
≥202 |
≥386 |
≥13 |
≥11 |
≥300 |
- |
| Normalization at 900 °C, air cooling + Vacation at 620-680 °C, air cooling |
| - |
235-265 |
490 |
22-26 |
37-51 |
- |
- |
| Annealing at 900 °C (indicated temperature and time of heat exposure) |
| - |
≥245 |
≥490 |
≥23 |
≥35 |
- |
- |
| Quenching with 870-890 °C, air cooling + Vacation at 610-630 °C, air cooling |
| 100 |
≥294 |
≥491 |
≥22 |
≥33 |
≥343 |
- |
| Normalization at 900 °C, air cooling + Vacation at 620-680 °C, air cooling |
| - |
225 |
460 |
16-20 |
40-45 |
- |
- |
| Annealing at 900 °C (indicated temperature and time of heat exposure) |
| - |
≥220 |
≥475 |
≥26 |
≥47 |
- |
- |
| Casting parts of gas turbines. Normalization at 880-900 °C, air cooling + Vacation at 610-630 °C, air cooling |
| - |
≥235 |
≥441 |
≥19 |
≥30 |
≥392 |
124-150 |
| Normalization at 900 °C, air cooling + Vacation at 620-680 °C, air cooling |
| - |
225 |
470 |
14-17 |
24-31 |
- |
- |
| Castings for shipbuilding. Normalization when 880-910 °C + Vacation at 630-670 °C, air cooling |
| - |
≥240 |
≥450 |
≥20 |
≥30 |
≥400 |
124-151 |
| Normalization at 900 °C, air cooling + Vacation at 620-680 °C, air cooling |
| - |
225 |
430 |
18-21 |
54-62 |
- |
- |
| Casting of body parts stationary steam turbines. Normalization at 880-930 °C + vacation at 620-650 °C, air cooling |
| - |
≥240 |
≥450 |
≥19 |
≥30 |
≥392 |
- |
| Normalization at 900 °C, air cooling + Vacation at 620-680 °C, air cooling |
| - |
185 |
245 |
22 |
70 |
- |
- |
| Centers cast of railcar wheel pairs according to the GOST 4491-86. Normalization at 940-960 °C (exposure for 2.5-3.0 h), accelerated cooling to 300-400 °C at a speed of at least 0.4 °C·s-1 + Vacation at 640-660 °C, exposure for 2.5-3.0 h (KCU+20°/KCU-60°) |
|
≥265 |
≥470 |
≥20 |
≥30 |
≥490/245 |
- |
| Normalization at 900 °C, air cooling + Vacation at 620-680 °C, air cooling |
| - |
130 |
145 |
22-27 |
73 |
- |
- |
| Annealing at 900 °C, furnace cooling |
| - |
205-255 |
420-480 |
22-33 |
37-51 |
- |
- |
| - |
195-225 |
400-450 |
15-27 |
36-46 |
- |
- |
| - |
165-195 |
360-420 |
16-28 |
40-58 |
- |
- |
| - |
155-195 |
370-450 |
14-26 |
34-43 |
- |
- |
| - |
155-195 |
340-450 |
15-28 |
30-60 |
- |
- |
| - |
125-160 |
225-295 |
26-34 |
60-75 |
- |
- |
| - |
80-120 |
110-160 |
24-36 |
59-73 |
- |
- |
| Casting of body parts stationary steam turbines. Normalization at 880-930 °C + vacation at 620-650 °C, air cooling |
| - |
≥200 |
- |
- |
- |
- |
- |
| - |
≥180 |
- |
- |
- |
- |
- |
| - |
≥160 |
- |
- |
- |
- |
- |
| - |
≥140 |
- |
- |
- |
- |
- |
| Castings with wall thickness up to 100 mm in the delivery state on the other 5.961-11151-92. Normalization at 880-900 °C + Vacation at 610-670 °C. the Critical temperature of brittleness of TKO ≤ 50 °C. |
| - |
≥235 |
≥440 |
≥19 |
≥30 |
≥392 |
124-151 |
| - |
≥180 |
≥420 |
- |
≥30 |
- |
- |
| - |
≥170 |
≥380 |
- |
≥28 |
- |
- |
| - |
≥150 |
≥370 |
- |
≥26 |
- |
- |
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 |
| d |
Elongation after rupture |
| y |
The relative narrowing |
| kJ/m2 |
Toughness |
Physical characteristics
| Temperature |
r, кг/м3 |
l, Вт/(м · °С) |
a, 10-6 1/°С |
С, Дж/(кг · °С) |
| 20 |
7830 |
51 |
- |
- |
| 100 |
- |
76 |
115 |
470 |
| 200 |
- |
65 |
129 |
470 |
| 300 |
- |
44 |
13 |
- |
| 400 |
- |
38 |
132 |
483 |
| 500 |
- |
- |
132 |
- |
| 700 |
- |
- |
135 |
- |
| 600 |
- |
- |
- |
525 |
| 800 |
- |
- |
- |
571 |
A description of the physical symbols
| Name |
Description |
| Е |
The normal elasticity modulus |
| r |
Density |
| l |
Coefficient of thermal conductivity |
| С |
Specific heat |
Technological properties
| Name |
The value |
| Weldability |
Limited weldability. Welding methods: SMAW, ADS under gas protection electroslag welding. Recommended heating and subsequent heat treatment. After repair of defects by welding is applied leave in 619-660 °C. |
| Propensity to temper brittleness |
Tend not. |
| Flock-sensitive sensitivity |
not sensitive. |
| Workability by cutting |
In heat treated condition with HB of 160 Kn TV.SPL.=1,25 Kn b.St.=1,0. |
| Surfacing |
Surfacing of sealing surfaces of valves in accordance with OST 26-07-2028-81 is made by manual arc welding electrodes type e-20X13 with plaster SSSI-13НЖ, NII-48, NII-48Ж-1 or SV wire-12H13 or SV-20X13. Surface preparation for overlay welding is performed by machining. Surfacing is performed with preliminary and accompanying heating to 400-450 °C is not less than 3 layers with thickness not less than 4 mm, excluding allowance for machining. Heat treatment after welding is produced by tempering at 550-600 °C (delay of 2-5 h) hardness HB=301-350, at 600-650 °C (delay of 2-5 h) hardness HB=240 to 300, at 400-450 °C (delay of 2-5 h) hardness HB=351-400. The temperature of the furnace when loading the details for the home should be no more than 300 °C. |
| Defect welding |
Welding defects of castings after cutting is usually carried out without prior and concomitant heating. By semiautomatic welding in carbon dioxide environment used welding wire SV-08G2S diameter of 2 mm at a current of 380-420 A. Welding defects by manual welding is done with electrodes Э42А type (GOST 9467) brand SSSI-13/45. When welding the hard contour of the casting or of the sample volume more than 2000 cm3 is recommended before applying the first roller to pre-heating at 120-150 °C. When welding is sample size more than 5000 cm3 it is necessary to produce preliminary and accompanying heating to 150-180 °C. |
