Steel 15K
Description
Steel 15K
Steel 15K: brand of steels and alloys. Below is a systematized information on the purpose, chemical composition, types of supplies, substitutes, temperature of critical points, physical, mechanical, technological and casting properties for the grade — Steel 15K.
General information of 15K steel
| Substitute brand |
| steel 20K |
| Delivery type |
| Thick sheet GOST 5520−79, GOST 19903−74. |
| Application |
| Flanges, bottoms, solid forged and welded drums of steam boilers, apparatus bodies and other parts of boiler construction and vessels, work under pressure at temperatures up to 450 ° C. |
Chemical composition of steel 15K
| Chemical element |
% |
| Silicon (Si) |
0.15−0.30 |
| Manganese (Mn) |
0.35−0.65 |
| Copper (Cu), no more |
0.30 |
| Arsenic (As), no more |
0.08 |
| Nickel (Ni), no more |
0.30 |
| Sulfur (S), no more |
0.040 |
| Carbon (C) |
0.12−0.20 |
| Phosphorus (P), no more |
0.04 |
| Chromium (Cr), no more |
0.30 |
Mechanical properties of steel 15K
| Heat treatment, delivery condition |
Section, mm |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
KCU, J / m 2 |
| KCU — as delivered / after mechanical aging |
| Category sheets: 2−5, 10, 11, 16, 18 |
<20 |
225 |
370−480 |
27 |
68/34 |
| Category sheets: 2−5, 10, 11, 16, 18 |
21−40 |
215 |
370−480 |
26 |
64/29 |
| Category sheets: 2−5, 10, 11, 16, 18 |
41−60 |
205 |
370−480 |
25 |
59/29 |
Mechanical properties at elevated temperatures
| test t, ° C |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
KCU, J / m 2 |
| Hot-rolled sheets 37−40 mm thick |
| 20 |
225 |
420 |
thirty |
56 |
62−103 |
| 100 |
195 |
390 |
|
|
88−167 |
| 200 |
195 |
470 |
|
|
73−137 |
| 300 |
165 |
470 |
|
|
64−113 |
| 400 |
160 |
370 |
|
60 |
54−78 |
| 500 |
155 |
250 |
|
61 |
44−73 |
| Sheets 37−40 mm thick. Annealing 880−900 ° С |
| 20 |
245 |
400−430 |
thirty |
55−60 |
73−98 |
| 200 |
180−225 |
350−500 |
17−28 |
43−62 |
83−118 |
| 300 |
145−185 |
350−510 |
24 |
52−60 |
78−93 |
| 400 |
140−175 |
320−400 |
22−33 |
60−73 |
59−73 |
| 500 |
120−150 |
200−270 |
24−33 |
71−83 |
49−64 |
| 600 |
69−98 |
110−150 |
36−48 |
84−91 |
113 |
Mechanical properties depending on heat treatment
| Heat treatment, delivery condition |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
KCU, J / m 2 |
| Delivery condition — hot rolled. Exposure 20,000 h, 450 ° С |
225 |
370 |
33 |
74 |
161 |
| Delivery condition — hot rolled. Exposure 40,000 h, 450 ° С |
180 |
350 |
34 |
73 |
|
| Delivery condition — hot rolled. Exposure 20,000 h, 550 ° С |
200 |
320 |
40 |
76 |
|
Mechanical properties when tested for long-term strength
| Creep limit, MPa |
Creep rate,% / h |
t test, ° С |
Long-term strength, MPa |
Duration tests, h |
t test, h |
| 108 |
1/100000 |
400 |
127 |
10000 |
450 |
| 94 |
1/10000 |
450 |
93 |
100,000 |
450 |
| 63 |
1/100000 |
450 |
76 |
10000 |
500 |
| |
|
|
54 |
100,000 |
500 |
Technological properties of steel 15K
| Forging temperature |
| Beginning 1260, end 750. |
| Weldability |
| Can be welded without restrictions. Submerged arc welding methods for RDS, ADS and gas shielding. |
| Tendency to release ability |
| Not inclined. |
| Flock sensitivity |
| Not sensitive. |
Temperature of critical points of steel 15K
| Critical point |
° C |
| Ac1 |
724 |
| Ac3 |
860 |
| Ar3 |
830 |
| Ar1 |
676 |
Impact strength of steel 15K
Impact strength, KCU, J / cm 2
| Delivery status, heat treatment |
+20 |
-20 |
-40 |
| Hot rolled condition |
88 |
49 |
39 |
Yield strength of steel 15K
| Test temperature, ° C / s 0.2 |
| 200 |
250 |
300 |
350 |
400 |
450 |
| 175 |
165 |
135 |
120 |
98 |
78 |
Physical properties of steel 15K
| Test temperature, ° С |
20 |
100 |
200 |
300 |
400 |
500 |
600 |
700 |
800 |
900 |
| Normal elastic modulus, E, GPa |
207 |
204 |
201 |
196 |
187 |
176 |
162 |
|
|
|
| Torsional shear elastic modulus G, GPa |
78 |
77 |
76 |
73 |
69 |
66 |
59 |
|
|
|
| Density of steel, pn, kg / m 3 |
7850 |
|
|
|
|
|
|
|
|
|
| Thermal conductivity coefficient W / (m ° С) |
|
57 |
53 |
|
45 |
|
38 |
|
|
|
| Test temperature, ° С |
20−100 |
20−200 |
20−300 |
20−400 |
20−500 |
20−600 |
20−700 |
20−800 |
20−900 |
20−1000 |
| Linear expansion coefficient (a, 10−6 1 / ° С) |
|
11.9 |
12.8 |
13.2 |
13.6 |
13.9 |
|
|
|
|
| Specific heat (C, J / (kg ° C)) |
470 |
483 |
|
525 |
571 |
|
|
|
|
|