Carbon steel SA210A-1, SA210C, 20G comparative analysis

2021-11-12
Comparison and analysis of carbon steel SA210 A-1, SA210 C, 20G Tubes for high pressure boiler


 
SA210 A-1, SA210 C, 20G High Pressure Boiler Tubes
The main parameters of the subcritical and above the boiler unit pressure parts with carbon steel materials are mainly three kinds: 20G, SA210A-1, SA210C, basically for low temperature superheater, low temperature reheater, water wall and economizer, etc. Parts in the heating surface tube, pipe metal design temperature is usually 350 ℃ ~ 425 ℃.
 
Since the reinforcing elements of carbon steel are C and Mn, the boiler manufacturer usually limits the C content from welding performance considerations.

As described in ASME, 0.01% reduction in carbon content below the maximum carbon content allows an increase of 0.06% manganese content above the specified maximum manganese content, but the maximum shall not exceed 1.35%. Indicating that the loss of a carbon content caused by the loss of strength is generally required to make up for six manganese content, but the actual supply of steel pipe factory found an interesting phenomenon: that the domestic SA210A-1 seems to have no distinct ingredients blank, Or in the form of SA210A, or by 20G billet, this phenomenon can be in Table 1 randomly selected part of the batch SA210A-1, SA210C, 20G composition and performance data comparison to get an intuitive impression, the difference is more clearly reflected in the Mn content. The same is SA210A-1, Table 1 in the serial number 6,7,8 composition and performance and 20G equivalent, No. 9 ingredients and performance and SA210C considerable. So can this alternative ensure that the SA210A-1 meets the material standards and product design requirements? The following follows the standard context and is used in conjunction with the conditions of use of the product.


Table 1  SA210 A-1, SA210 C, 20 G Comparison of Chemical Composition and Tensile Properties (Material Data)

No. Grade specification Boiler number chemical composition/% Tensile properties
C Mn Si S P Rp/MPa Rm/MPa A/%
1 20G 51*10 15FA019-1 0.19 0.49 0.2 0.004 0.011 313 463 40.5
2 20G 38*4 15FA046 0.2 0.5 0.21 0.003 0.009 347 505 36.5
3 20G 57*4 15FA076-1 0.2 0.49 0.2 0.002 0.008 349 473 40
4 15FA076-11 0.19 0.48 0.22 0.002 0.006 333 474 34
5 15FA076-14 0.2 0.49 0.19 0.002 0.008 335 479 29
6 SA210A-1 51*7 15FA037-1 0.22 0.48 0.2 0.002 0.007 351 491 33.5
7 15FA060-10 0.18 0.46 0.24 0.007 0.016 312 459 50
8 15FA060-12 0.19 0.47 0.23 0.007 0.017 315 465 50
9 SA210A-1 60*4.1 min 1013-0274 0.2 0.85 0.24 0.003 0.009 352 509 30
10 SA210C 42*4 15F001-1 0.21 0.82 0.22 0.002 0.009 399 555 28
11 SA210C 38*7 15FA016-1 0.23 0.86 0.22 0.003 0.009 350 509 34

 
 
1.comparison and analysis
 
1.1 Comparative analysis of SA210 A-1 and SA210 C
SA210A-1 is the steel number in ASME SA210M, and its main difference with 210C is the C content (Table 2), which reflects that the strength of SA210C is about 10% higher than that of SA210A-1 (Table 3) The design allowable stress at the design temperature of 350 ° C to 425 ° C is 10% higher than that of SA210A-1 (Table 4), which means that the pipe wall thickness of SA210C can be reduced by about 10% compared with SA210A-1 under the same working conditions SA210A-1 with SA210C blank that means the wall thickness margin can be increased by 10%.
 
Table 2  Comparison of Chemical Compositions of SA210A-1, SA210C (Standard Data)

Standard Geade C Mn Si S P
SA210M SA210 A-1 ≤0.27 ≤0.93 ≥0.1 ≤0.035 ≤0.035
SA210 C ≤0.35 0.29-1.06 ≥0.1 ≤0.035 ≤0.035

 
Table 3  Comparison of normal temperature and high temperature performance of SA210A-1, SA210C (standard data)

Grade SA210 A-1 SA210 C
Yield Strength/MPa ≥255 ≥275
Tensile Strength/MPa ≥415 ≥485
High temperature yield strength/MPa 100 233 251
150 225 244
200 219 237
250 210 227
300 200 216
350 187 202
400 176 191
450 167 180
500 158 171
Note:Room temperature performance data from SA210M; high temperature performance data from SAME material properties

 
Table 4  SA210 A-1, SA210 C Allowable Stress Comparison (MPa)

Temperature Grade
Grade SA210A-1 SA210C
100 118 138
150 118 138
200 118 138
250 118 138
300 118 138
350 117 135
400 88.9 101
425 75.3 83.8
450 62.7 67
475 45.5 51
 
Note: The data in the table is derived from ASME material properties
 
Table 1 shows that although the actual feed of SA210C carbon content is not high, but the increase in Mn content to make up for the impact of C on the strength reduction.

 
1.2 Comparative analysis of SA210A-1 and 20G
 
20G is the steel number in GB 5310-2008, and the 20G and SA210A-1 components are compatible with the composition list (Table 5). It seems that the two can be substituted for each other, but from the high temperature yield and allowable stress (Table 6) SA210A-1 high temperature yield higher than 20G 10%, SA210A-1 350 ℃ ~ 425 ℃ interval design allowable stress than the average 20G average of about 10%, which shows SA210A-1 use 20G billet, from the performance up Said that the low generation is high, if the original SA210A-1 wall thickness margin is not sufficient, is implied a certain risk.

Table 5 chemical composition comparison of SA210 A-1 and 20G
 
Standard Grade Chemical composition 
C Mn Si S P
GB 5310 20G 0.17~0.23 0.35~0.65 0.17~0.37 ≤0.025 ≤0.015
ASTM SA210 SA210 A-1 ≤0.27 ≤0.93 ≥0.1 ≤0.035 ≤0.035
 
 
Table 6  Comparison of normal temperature and high temperature performance of SA210A-1, 20G (standard data)
 
Grade SA210A-1 20G
Yield Strength/MPa ≥255 ≥245
Tensile Strength/MPa ≥415 410~550
High temperature yield strength/MPa 100 233  
150 225  
200 219 215
250 210 196
300 200 177
350 187 157
400 176 137
450 167 98
500 158 49
 
 
Table 7  SA210A-1 and 20G Allowable Stress Comparison (MPa)
 
Temperature Grade 
SA210A-1 20G
100 118 152
150 118 152
200 118 143
250 118 131
300 118 118
350 117 105
400 88.9 85
425 75.3 56
450 62.7 49
475 45.5 36
 
 
 
2 verification
 
20G, 20MnG  and  25MnG High Pressure Boiler Tubes
Since 1995, GB 5310 has added corresponding steel grades according to the commonly used foreign standards. For example, the steel grades added relative to sa210a-1 are 20mng, and the steel grades added relative to sa210c are 25mng. As a typical production type standard, gb5310 combined with the use characteristics of domestic boiler steel, refined and limited the broad requirements of the original ASME brand, mainly in the provision of the composition range of C and Mn, especially the lower limit of Mn increased to 0.7%, higher than the upper limit of Mn of 20g. Table 8, table 9 and table 10 are the comparison of the components, properties and allowable stresses of the three steels in the national standard series.
 
Table 8 chemical composition comparison of 20G,20MnG and 25MnG
 
Standard Grade Chemical composition  
C Mn Si S P
GB 5310 20G 0.17~0.23 0.35~0.65 0.17~0.37 ≤0.025 ≤0.015
20MnG 0.17~0.23 0.70~1.00 0.17~0.37 ≤0.025 ≤0.015
25MnG 0.22~0.27 0.70~1.00 0.17~0.37 ≤0.025 ≤0.015
 
 
Table 9  Comparison of normal temperature and high temperature performance of 20G,20MnG and 25MnG (standard data)
 
Grade 20G 20MnG 25MnG
Yield Strength/MPa ≥245 ≥240 ≥275
Tensile Strength/MPa 410~550 415~560 485~640
High temperature yield strength/MPa 100   219 252
150   214 245
200 215 208 237
250 196 179 226
300 177 183 210
350 157 175 201
400 137 168 192
450 98 156 179
500 47 151 172
 
 
Table 10  20G,20MnG and 25MnG Allowable Stress Comparison (MPa)
 
Temperature Grade  
20G 20MnG 25MnG
100 152 146 168
150 152 143 163
200 143 139 158
250 131 131 151
300 118 122 140
350 105 117 134
400 85 103 117
425 56 78 85
450 49 58 59
475 36 40 40
 
From table 10, it can be clearly reflected that in the range of 350 ℃ ~ 425 ℃, the design allowable stress of 20mng equivalent to sa210a-1 is about 10% higher than that of 20g, and that of 25mng equivalent to sa210c is about 20% higher than that of 20g, about 10% higher than that of 20mng, which is consistent with the above results.
 
 
 
3 conclusion
(1) as the commonly used boiler pressure part material with metal design temperature in the range of 350 ℃ ~ 425 ℃, the design allowable stress of sa210a-1 is about 10% lower than sa210c and about 10% higher than 20g.
 
(2) considering the use characteristics of boiler steel, in order to ensure that sa210a-1 meets the material standards and product design requirements, the composition design of sa210a-1 should be optimized, and the lower limit of Mn content of 0.7 should be added to the technical conditions of sa210a-1 small caliber pipe procurement.
 
 
To learn more about SA210 A-1,  SA210 C,  20G,  20MnG  and 25MnG  high pressure boiler tubes, please contact us.

 
 

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