钢管的承压问题一直是困扰广大钢管从业人员的细节性问题，每个人都能通过钢管压力壁厚对照表来比对钢管的承压能力，但具体到某一根钢管上来讲，这根钢管的承压能力到底有多大，这个问题就有点棘手了。因为通过对照表来查询，这只是最保守的方法，而且这个数据也不是完全正确，这些数据虽然也是通过大量的科学实验得出的，但它也只是一个大体数据并不绝对准确。
因为钢管承压能力这个问题还要受工作环境中温度、内部流体、钢管生产流程等等一系列的问题所影响。如果在我们测算出钢管的外径、壁厚、钢管材质的抗拉强度的情况下，我们可以通过计算分式来计算钢管的承压能力，当然这里面涉及到的数据都是经过实际测算的准确的，且钢管材质的机械性能是有保证的。这样我们获取的数据就有了一定保证。
钢管承压能力和壁厚的计算公式：压力=(壁厚*2*钢管材质抗拉强度)/(外径*系数)
上面所提到的钢管压力系数不是一个固定的数值，它是要根据钢管的实际承压能力而变的。下面就是钢管压力系数的界定范围：当压力P<7Mpa 时，系数为S=8；当7<钢管压力P<17.5时， 系数为S=6；当压力P>17.5时， 系数为S=4。
（一）无缝钢管压力壁厚对照表
| 材质 | PN MPa | DN |
| 10 | 15 | 20 | 25 | 32 | 40 | 50 | 65 | 80 | 100 | 125 | 150 | 200 | 250 | 300 | 350 | 400 | 450 | 500 | 600 | |
| 20# | ≤1.6 | 2.5 | 3 | 3 | 3 | 3 | 3.5 | 3.5 | 4 | 4 | 4 | 4 | 4.5 | 5 | 6 | 7 | 7 | 8 | 8 | 8 | 9 | |
| 2.5 | 2.5 | 3 | 3 | 3 | 2 | 3.5 | 3.5 | 4 | 4 | 4 | 4 | 4.5 | 5 | 6 | 7 | 7 | 8 | 8 | 9 | 10 | |
| 4.0 | 2.5 | 3 | 3 | 3 | 3 | 3.5 | 3.5 | 4 | 4 | 4.5 | 5 | 5.5 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 15 | |
| 6.4 | 3 | 3 | 3 | 3.5 | 3.5 | 3.5 | 4 | 4.5 | 5 | 6 | 7 | 8 | 9 | 11 | 12 | 14 | 16 | 17 | 19 | 22 | |
| 10.0 | 3 | 3.5 | 3.5 | 4 | 4.5 | 4.5 | 5 | 6 | 7 | 8 | 9 | 10 | 13 | 15 | 18 | 20 | 22 | | | | |
| 16.0 | 4 | 4.5 | 5 | 5 | 6 | 6 | 7 | 8 | 9 | 11 | 13 | 15 | 19 | 24 | 26 | 30 | 34 | | | | |
| 20.0 | 4 | 4.5 | 5 | 6 | 6 | 7 | 8 | 9 | 11 | 13 | 15 | 18 | 22 | 28 | 32 | 36 | | | | | |
| 4.0T | 3.5 | 4 | 4 | 4.5 | 5 | 5 | 5.5 | | | | | | | | | | | | | | |
| 10# | ≤1.6 | 2.5 | 3 | 3 | 3 | 3 | 3.5 | 3.5 | 4 | 4.5 | 4 | 4 | 4.5 | 5.5 | 7 | 7 | 8 | 8 | 8 | 8 | 9 | |
| 2.5 | 2.5 | 3 | 3 | 3 | 3 | 3.5 | 3.5 | 4 | 4.5 | 4 | 5 | 4.5 | 5.5 | 7 | 7 | 8 | 9 | 9 | 10 | 12 | |
| 4.0 | 2.5 | 3 | 3 | 3 | 3 | 3.5 | 3.5 | 4 | 4.5 | 5 | 5.5 | 6 | 8 | 9 | 10 | 11 | 12 | 14 | 15 | 18 | |
| 6.4 | 3 | 3 | 3 | 3.5 | 4 | 4 | 4.5 | 5 | 5.5 | 7 | 8 | 9 | 11 | 13 | 14 | 16 | 18 | 20 | 22 | 26 | |
| 10.0 | 3 | 3.5 | 4 | 4 | 4.5 | 5 | 5.5 | 7 | 8 | 9 | 10 | 12 | 15 | 18 | 22 | 24 | 26 | | | | |
| 16.0 | 4 | 4.5 | 5 | 5 | 6 | 7 | 8 | 9 | 10 | 12 | 15 | 18 | 22 | 28 | 32 | 36 | 40 | | | | |
| 20.0 | 4 | 4.5 | 5 | 6 | 7 | 8 | 9 | 11 | 12 | 15 | 18 | 22 | 26 | 34 | 38 | | | | | | |
| 4.0T | 3.5 | 4 | 4 | 4.5 | 5 | 5 | 5.5 | | | | | | | | | | | | | | |
| 16Mn | ≤1.6 | 2.5 | 2.5 | 2.5 | 3 | 3 | 3 | 3 | 3.5 | 3.5 | 3.5 | 3.5 | 4 | 4.5 | 5 | 5.5 | 6 | 6 | 6 | 6 | 7 | |
| 2.5 | 2.5 | 2.5 | 2.5 | 3 | 3 | 3 | 3 | 3.5 | 3.5 | 3.5 | 3.5 | 4 | 4.5 | 5 | 5.5 | 6 | 7 | 7 | 8 | 9 | |
| 4.0 | 2.5 | 2.5 | 2.5 | 3 | 3 | 3 | 3 | 3.5 | 3.5 | 4 | 4.5 | 5 | 6 | 7 | 8 | 8 | 9 | 10 | 11 | 12 | |
| 6.4 | 2.5 | 3 | 3 | 3 | 3.5 | 3.5 | 3.5 | 4 | 4.5 | 5 | 6 | 7 | 8 | 9 | 11 | 12 | 13 | 14 | 16 | 18 | |
| 10.0 | 3 | 3 | 3.5 | 3.5 | 4 | 4 | 4.5 | 5 | 6 | 7 | 8 | 9 | 11 | 13 | 15 | 17 | 19 | | | | |
| 16.0 | 3.5 | 3.5 | 4 | 4.5 | 5 | 5 | 6 | 7 | 8 | 9 | 11 | 12 | 16 | 19 | 22 | 25 | 28 | | | | |
| 20.0 | 3.5 | 4 | 4.5 | 5 | 5.5 | 6 | 7 | 8 | 9 | 11 | 13 | 15 | 19 | 24 | 26 | 30 | | | | | |
（二）直缝焊管承受压力表
| 材料 | PN MPa | DN |
| 200 | 250 | 300 | 350 | 400 | 450 | 500 | 600 | 700 | 800 | 900 | 1000 | 1100 | 1200 | 1400 | 1600 |
| 焊接碳钢管 （Q235A20） | 0.25 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 6 | 6 | 6 | 6 | 6 | 6 | 7 | 7 | 7 |
| 0.6 | 5 | 5 | 6 | 6 | 6 | 6 | 6 | 7 | 7 | 7 | 7 | 8 | 8 | 8 | 9 | 10 |
| 1.0 | 5 | 5 | 6 | 6 | 6 | 7 | 7 | 8 | 8 | 9 | 9 | 10 | 11 | 11 | 12 | |
| 1.6 | 6 | 6 | 7 | 7 | 8 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | | |
| 2.5 | 7 | 8 | 9 | 9 | 10 | 11 | 12 | 13 | 15 | 16 | | | | | | |
| 焊接不锈钢管 | 0.25 | 3 | 3 | 3 | 3 | 3.5 | 3.5 | 3.5 | 4 | 4 | 4 | 4.5 | 4.5 | | | | |
| 0.6 | 3 | 3 | 3.5 | 3.5 | 3.5 | 4 | 4 | 4.5 | 5 | 5 | 6 | 6 | | | | |
| 1.0 | 3.5 | 3.5 | 4 | 4.5 | 4.5 | 5 | 5.5 | 6 | 7 | 7 | 8 | | | | | |
| 1.6 | 4 | 4.5 | 5 | 6 | 6 | 7 | 7 | 8 | 9 | 10 | | | | | | |
| 2.5 | 5 | 6 | 7 | 8 | 9 | 9 | 10 | 12 | 13 | 15 | | | | | | |
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