Steel 20K
Designation
| Name |
The value |
| Designation GOST Cyrillic |
20К |
| Designation GOST Latin |
20K |
| Transliteration |
20K |
| The chemical elements |
20 |
Description
20K steel is used: for the manufacture of flanges, bottoms, telecomandi and welded the drums of steam boilers; coupling parts, chassis bodies and other parts of the boiler and vessels, working under pressure and at temperatures up to +450 °C; as a base layer in the manufacture of hot-rolled dual-layer corrosion-resistant sheets.
Standards
| Name |
Code |
Standards |
| Sheets and stripes |
В33 |
GOST 10885-85, TU 14-1-3922-84, TU 14-1-4088-86 |
| Sheets and stripes |
В23 |
GOST 5520-79, GOST 19903-74, GOST 19903-90 |
| Classification, nomenclature and general norms |
В30 |
TT 232-41-2007 |
| Bulls. Blanks. Slabs |
В31 |
TU 05764417-013-93 |
Mechanical characteristics
| Section, mm |
sT|s0,2, MPa |
σB, MPa |
d5, % |
y, % |
kJ/m2, кДж/м2 |
Brinell hardness number, MPa |
| Steel hot-rolled sheet in the delivery condition |
| 21-40 |
≥240 |
≥410 |
≥24 |
- |
≥637 |
- |
| 4-20 |
≥250 |
≥410 |
≥24 |
- |
≥686 |
- |
| 41-60 |
≥230 |
≥410 |
≥24 |
- |
≥588 |
- |
| Casting as supplied. Without heat treatment |
| - |
≥220 |
≥420 |
≥22 |
≥35 |
≥490 |
- |
| Sheet gracieacademy (specified time and temperature of exposure) |
| - |
235-245 |
425 |
30-32 |
59-83 |
- |
- |
| - |
185-215 |
350-360 |
27-31 |
65-68 |
- |
- |
| - |
235 |
395 |
32 |
62 |
- |
- |
| - |
175-195 |
360 |
30-33 |
62-64 |
- |
- |
| - |
210 |
395 |
29-31 |
60-62 |
- |
- |
| Sheets hot rolled 37-40 mm |
| - |
215-245 |
400-440 |
30 |
56 |
- |
- |
| - |
195 |
390 |
20 |
47-55 |
- |
- |
| - |
195 |
- |
15-17 |
39 |
- |
- |
| - |
165 |
- |
23 |
44-51 |
- |
- |
| - |
165 |
370 |
24 |
61 |
- |
- |
| - |
155 |
250 |
23 |
61 |
- |
- |
| - |
59 |
110 |
31-37 |
73-81 |
- |
- |
| Sheets hot rolled 37-40 mm. Annealing at 880-900 °C |
| - |
245 |
400-430 |
30 |
55-60 |
- |
- |
| - |
180-225 |
350-500 |
17-28 |
43-62 |
- |
- |
| - |
145-185 |
350-510 |
24 |
52-60 |
- |
- |
| - |
135-175 |
320-400 |
22-33 |
60-73 |
- |
- |
| - |
120-150 |
200-270 |
24-43 |
71-83 |
- |
- |
| - |
69-98 |
110-150 |
36-48 |
84-91 |
- |
- |
| Procurement for vessels working under pressure on the other 05764417-013-93 supplied after the main heat treatment (samples for forgings, longitudinal, - transverse; KCU - after mechanical aging) |
|
≥275 |
430-590 |
≥23 |
≥55 |
≥290 |
≥140 |
| Sheet metal, steel, 20KA at TT 232-41-2007 after heat treatment. In the graph indicated the value of KCU KCV |
|
≥275 |
430-590 |
≥23 |
- |
≥490 |
- |
| Leaves categories: 2-5, 10, 11, 16, 18-21 (KCU - as supplied / after mechanical aging) |
| ≤5 |
≥245 |
≤510 |
≥25 |
- |
- |
- |
| 21-40 |
≥235 |
400-510 |
≥24 |
- |
≥540/245 |
- |
| 41-60 |
≥225 |
400-510 |
≥23 |
- |
≥490/245 |
- |
| 5-20 |
≥245 |
400-510 |
≥25 |
- |
≥588/294 |
- |
| The plates on the other 14-1-3922-84. Normalized samples |
|
≥206 |
≥392 |
≥20 |
- |
≥490 |
- |
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 |
207 |
7850 |
- |
- |
- |
- |
| 20 |
211 |
7870 |
- |
200 |
- |
482 |
| 100 |
204 |
7840 |
51 |
219 |
- |
486 |
| 200 |
201 |
7810 |
49 |
292 |
119 |
470 |
| 300 |
196 |
7780 |
46 |
381 |
128 |
483 |
| 400 |
187 |
7740 |
42 |
487 |
132 |
533 |
| 500 |
176 |
7710 |
39 |
601 |
136 |
538 |
| 600 |
162 |
7670 |
36 |
758 |
136 |
584 |
| 700 |
- |
7630 |
- |
925 |
- |
571 |
| 800 |
- |
7640 |
- |
1094 |
139 |
703 |
| 900 |
- |
7610 |
- |
1135 |
- |
703 |
| 1000 |
- |
7550 |
- |
1167 |
- |
695 |
| 1200 |
- |
- |
- |
1219 |
- |
687 |
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 |
Welded without any restrictions. The welding methods of SMAW, ADS submerged arc and gas protection electroslag welding. |
| Propensity to temper brittleness |
Tend not. |
| Forging temperature |
Start - 1260 °C, the end - 750 °C. |
| Flock-sensitive sensitivity |
not sensitive |
| Workability by cutting |
In the annealed condition with NV 121-126 and blower SB=390 MPa Kn TV.SPL.=1,50 Kn b.St.=Of 1.35. |
| Macrostructure and contamination |
The macrostructure of the steel on the etched templeto should not be visible during visual inspection of cracks, delamination, placenow, bubbles. Allowed black travelmasti without discontinuity of metal with a length of not more than 15 mm, and a separate slag inclusions. The amount of nonmetallic inclusions (in points), estimated collectively defined by GOST 1778, shall not exceed the standards for average score: sulfides, oxides, stroke, silicates fragile 2.5 points for each parameter; the non-deformed silicates - 3.0 points. Sulfide and oxide nonmetallic inclusions should have a shape close to globular. Allowed separate sulfide inclusions elongated shape. |
| Microstructure |
The size of the actual grain should be no larger than 7 numbers according to GOST 5639. The banding structure of sheet metal must not exceed a score of 3 on a scale GOST 5640. |
