法兰的压力等级或额定值以磅为单位。不同的名称用于表示压力等级。
Forged steel flanges, according to ASME B16.5, are made in seven primary Pressure Classes:
法兰额定值的概念非常明确。300级法兰可以承受比150级法兰更大的压力，因为300级法兰由更多金属制成，可以承受更大的压力。然而，有许多因素会影响法兰的承压能力。
法兰的压力等级或额定值以磅为单位。不同的名称用于表示压力等级。
For example: 150 Lb or 150 Lbs or 150# or Class 150, all are means the same.
法兰额定值的概念非常明确。300级法兰可以承受比150级法兰更大的压力，因为300级法兰由更多金属制成，可以承受更大的压力。然而，有许多因素会影响法兰的承压能力。
法兰的压力等级或额定值以磅为单位。不同的名称用于表示压力等级。
For example: 150 Lb or 150 Lbs or 150# or Class 150, all are means the same.
法兰可以承受不同温度下的不同压力。随着温度升高，法兰的额定压力降低。例如，150级法兰在环境条件下的额定压力约为270 PSIG，在约400°F时为180 PSIG，在约600°F时为150 PSIG，在约800°F时为75 PSIG。
换句话说，当压力降低时，温度升高，反之亦然。另外，法兰可以由不同的材料制成，如不锈钢、铸铁和球墨铸铁、碳钢等。。每种材料都有不同的压力等级。
Below an example of a flange NPS 12 with the several pressure classes. As you can see, inner diameter and diameter of the raised face at all the same; but outside diameter, bolt circle and diameter of bolt holes become larger in each higher pressure class.
The number and diameters (mm) of the bolt holes are:
Pressure-temperature ratings are maximum allowable working gage pressures in bar units at the temperatures in degrees celsius. For intermediate temperatures, linear interpolation is permitted. Interpolation between class designations is not permitted.
Pressure-temperature ratings apply to flanged joints that conform to the limitations on bolting and on gaskets, which are made up in accordance with good practice for alignment and assembly. Use of these ratings for flanged joints not conforming to these limitations is the responsibility of the user.
相应额定压力下显示的温度是部件承压外壳的温度。一般来说，该温度与所含液体的温度相同。根据适用规范和法规的要求，用户有责任使用与所含流体温度不同的压力等级。对于低于-29°C的任何温度，额定值不得大于-29°C的额定值。
| Nominal Designation |
Forgings | 铸造ings | Plates |
| C-Si | A105（1） | A216 WCB组（1） |
A515 组70（1） |
| C Mn Si | A350 Gr.LF2（1） |
... | A516 组70（1）, (2) |
| C Mn Si V | A350 Gr.LF6 Cl 1 (3) |
... | A537 Cl.1 (4) |
| 3.1/2Ni | A350 Gr.LF3 |
... | ... |
笔记：
| Nominal Designation |
Forgings | 铸造 | Plates |
| 16Cr 12Ni 2Mo | A182 Gr.F316L |
... | A240 Gr.316L |
| 18 cr 13倪3莫 | A182 Gr.F317L |
... | ... |
| 18Cr 8Ni | A182 Gr.F304L (1) |
... | A240 Gr.304L (1) |
Note: Do not use over 425°C.
| TEMP(°C) | 150 | 300 | 400 | 600 | 900 | 1500 | 2500 |
| -29 TO 38 | 19.6 | 51.1 | 68.1 | 102.1 | 153.2 | 255.3 | 425.5 |
| 50 | 19.2 | 50.1 | 66.8 | 100.2 | 150.4 | 250.6 | 417.7 |
| 100 | 17.7 | 46.6 | 62.1 | 93.2 | 139.8 | 233 | 388.3 |
| 150 | 15.8 | 45.1 | 60.1 | 90.2 | 135.2 | 225.4 | 375.6 |
| 200 | 13.8 | 43.8 | 58.4 | 87.6 | 131.4 | 219 | 365 |
| 250 | 12.1 | 41.9 | 55.9 | 83.9 | 125.8 | 209.7 | 349.5 |
| 300 | 10.2 | 39.8 | 53.1 | 79.6 | 119.5 | 199.1 | 331.8 |
| 325 | 9.3 | 38.7 | 51.6 | 77.4 | 116.1 | 193.6 | 322.6 |
| 350 | 8.4 | 37.6 | 50.1 | 75.1 | 112.7 | 187.8 | 313 |
| 375 | 7.4 | 36.4 | 48.5 | 72.7 | 109.1 | 181.8 | 303.1 |
| 400 | 6.5 | 34.7 | 46.3 | 69.4 | 104.2 | 173.6 | 289.3 |
| 425 | 5.5 | 28.8 | 38.4 | 57.5 | 86.3 | 143.8 | 239.7 |
| 450 | 4.6 | 23 | 30.7 | 46 | 69 | 115 | 191.7 |
| 475 | 3.7 | 17.4 | 23.2 | 34.9 | 52.3 | 87.2 | 145.3 |
| 500 | 2.8 | 11.8 | 15.7 | 23.5 | 35.3 | 58.8 | 97.9 |
| 538 | 1.4 | 5.9 | 7.9 | 11.8 | 17.7 | 29.5 | 49.2 |
| TEMP (°C) | 150 | 300 | 400 | 600 | 900 | 1500 | 2500 |
| TEMP(°C) | 150 | 300 | 400 | 600 | 900 | 1500 | 2500 |
| -29 TO 38 | 15.9 | 41.4 | 55.2 | 82.7 | 124.1 | 206.8 | 344.7 |
| 50 | 15.3 | 40 | 53.4 | 80 | 120.1 | 200.1 | 333.5 |
| 100 | 13.3 | 34.8 | 46.4 | 69.6 | 104.4 | 173.9 | 289.9 |
| 150 | 12 | 31.4 | 41.9 | 62.8 | 94.2 | 157 | 261.6 |
| 200 | 11.2 | 29.2 | 38.9 | 58.3 | 87.5 | 145.8 | 243 |
| 250 | 10.5 | 27.5 | 36.6 | 54.9 | 82.4 | 137.3 | 228.9 |
| 300 | 10 | 26.1 | 34.8 | 52.1 | 78.2 | 130.3 | 217.2 |
| 325 | 9.3 | 25.5 | 34 | 51 | 76.4 | 127.4 | 212.3 |
| 350 | 8.4 | 25.1 | 33.4 | 50.1 | 75.2 | 125.4 | 208.9 |
| 375 | 7.4 | 24.8 | 33 | 49.5 | 74.3 | 123.8 | 206.3 |
| 400 | 6.5 | 24.3 | 32.4 | 48.6 | 72.9 | 121.5 | 202.5 |
| 425 | 5.5 | 23.9 | 31.8 | 47.7 | 71.6 | 119.3 | 198.8 |
| 450 | 4.6 | 23.4 | 31.2 | 46.8 | 70.2 | 117.1 | 195.1 |
| TEMP(°C) | 150 | 300 | 400 | 600 | 900 | 1500 | 2500 |
As an example, below you will find two tables with material groups acc. to ASTM, and two other tables
with flange pressure-temperature ratings for those ASTM materials acc. to ASME B16.5.
Requirements are valid for normal situation, in special you have to contact us to introduce.
Requirements are valid for normal case, in special case you have to contact the technical department.
Below you will find a short description and definition of each type, completed with an detailed image.
