Steel 22K
Description
Steel 22K
Steel 22K: 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 22K.
General information about steel 22K
| Substitute brand |
| steel 25K |
| Delivery type |
| Thick sheet 22k GOST 5520−79, GOST 19903−79. |
| Application |
| Flanges, bottoms, one-piece forged and welded drums of steam boilers, half-couplings, branch pipes and other parts operating under pressure and at temperatures from -40 to 450 ° C. |
Chemical composition of steel 22K
| Chemical element |
% |
| Silicon (Si) |
0.17−0.40 |
| Manganese (Mn) |
0.7−1.0 |
| Copper (Cu), no more |
0.30 |
| Arsenic (As), no more |
0.08 |
| Nickel (Ni), no more |
0.30 |
| Sulfur (S), no more |
0.035 |
| Carbon (C) |
0.19−0.26 |
| Phosphorus (P), no more |
0.040 |
| Chromium (Cr), no more |
0.30 |
Mechanical properties of steel 22K
| 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 |
<60 |
265 |
430−590 |
59 |
59/29 |
| Category sheets: 2−5, 10, 11, 16, 18 |
> 60 |
255 |
430−590 |
59 |
59/29 |
Mechanical properties versus test temperature
| test t, ° C |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
KCU, J / m 2 |
| Hot-rolled sheets 30−70 mm thick |
| 20 |
245−295 |
500−520 |
22−26 |
50−61 |
83−113 |
| 100 |
225−275 |
460−490 |
|
|
69 |
| 200 |
215−265 |
|
|
|
39−108 |
| 300 |
215−235 |
|
|
|
22−103 |
| 400 |
225 |
450−470 |
|
59−63 |
49−76 |
| 500 |
195 |
280−310 |
19−29 |
60−68 |
44−60 |
| 600 |
110−130 |
135−165 |
20−34 |
60−68 |
53−71 |
| Sheets 30−70 mm thick, heating 930 ° C, holding for 2 h, cooling at a speed of 80−100 deg / h. Vacation 600−650 ° С, cooling 50 deg / h |
| 20 |
225−245 |
460−470 |
31−36 |
61−66 |
118−157 |
| 200 |
185−215 |
390−430 |
26−27 |
64−65 |
206−235 |
| 300 |
165−185 |
390−430 |
25−27 |
59−62 |
216−284 |
| 400 |
155−165 |
390 |
27−29 |
73−75 |
127−186 |
| 500 |
135−145 |
255−265 |
28−31 |
80−82 |
88−108 |
| 600 |
110 |
160 |
33−41 |
87−88 |
206−255 |
| Rolled sample 6 mm thick, 30 mm long. Deformation rate 16 mm / min. The beformation rate is 0.09 1 / s. |
| 700 |
81 |
120 |
57 |
90 |
|
| 800 |
56 |
72 |
49 |
63 |
|
| 900 |
49 |
84 |
60 |
86 |
|
| 1000 |
45 |
59 |
59 |
86 |
|
| 1100 |
26 |
42 |
75 |
100 |
|
Mechanical properties depending on heat treatment
| Heat treatment, delivery condition |
σ 0.2, MPa |
σ B, MPa |
δ,% |
ψ,% |
KCU, J / m 2 |
| Heating 920−940 ° C, cooling 100 deg / h, tempering 600 ° C, cooling 50 deg / h. |
| Heat exposure 20,000 h, 450 ° С |
230 |
470 |
29 |
59 |
82 |
| Heat exposure 30,000 h, 450 ° С |
240 |
470 |
25 |
59 |
|
| Heat exposure 20,000 h, 500 ° С |
230 |
440 |
31 |
64 |
98 |
| Heat exposure 30,000 h, 550 ° С |
255 |
435 |
34 |
64 |
78 |
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 |
| 132 |
1/100000 |
400 |
139 |
10000 |
450 |
| 208 |
1/10000 |
400 |
98 |
100,000 |
450 |
| 63 |
1/100000 |
450 |
59 |
100,000 |
500 |
| 94 |
1/10000 |
450 |
47 |
100,000 |
525 |
Technological properties of steel 22K
| Forging temperature |
| Beginning 1280, end 700. Sections up to 400 mm are cooled in air. |
| Weldability |
| Limited weldability. Submerged arc welding method for RDS, ADS and gas shielded. Heating and subsequent heat treatment are recommended. EShS — heat treatment required. |
| Tendency to release ability |
| Not inclined. |
| Flock sensitivity |
| Not sensitive. |
Temperature of critical points of steel 22K
| Critical point |
° C |
| Ac1 |
724 |
| Ac3 |
845 |
| Ar3 |
815 |
| Ar1 |
682 |
Impact strength of steel 22K
Impact strength, KCU, J / cm 2
| Delivery status, heat treatment |
+20 |
-20 |
-40 |
| Sheets 30−70 mm thick, heating 930 C, holding for 2 h, cooling 80−100 deg / h, tempering 600−650 C, cooling 50 deg / h |
118−157 |
77−113 |
11−138 |
Yield strength of steel 22K
| Test temperature, ° C / s 0.2 |
| 200 |
250 |
300 |
320 |
350 |
| 215 |
205 |
190 |
185 |
175 |
Physical properties of steel 22K
| Test temperature, ° С |
20 |
100 |
200 |
300 |
400 |
500 |
600 |
700 |
800 |
900 |
| Normal elastic modulus, E, GPa |
207 |
|
|
|
|
|
|
|
|
|
| Thermal conductivity coefficient W / (m ° С) |
50 |
48 |
46 |
44 |
|
|
|
|
|
|
| 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) |
11.0 |
12.6 |
13.4 |
13.6 |
|
|
|
|
|
|
| Specific heat (C, J / (kg ° C)) |
470 |
483 |
|
525 |
571 |
|
|
|
|
|