20 #(Grade 20) seamless steel pipe
product introduction
20 # seamless steel pipe is widely used in petrochemical and other industries for its excellent performance and suitable price. 20 #. There are national standards such as seamless steel tubes for fluid transportation (GB / t8163-2008), seamless steel tubes for low and medium pressure boilers (gb3087-2008), seamless steel tubes for petroleum cracking (gb9948-2013) and seamless steel tubes for high pressure fertilizer equipment (gb6479-2013).
There are great differences in price and effect of 20 # seamless steel pipes of different standards. At present, the price of 20 # seamless steel pipes manufactured according to GB 6479-2013 is about 1000 yuan / ton higher than that manufactured according to GB / T 8163-2008.
standards for 20 # seamless steel pipes
(1) GB / t8163-2008 seamless steel pipe for fluid transportation
(2) gb3087-2008 seamless steel tubes for low and medium pressure boilers
(3) seamless steel tubes for petroleum cracking (GB / T 9948-2013)
(4) seamless pipe for high pressure fertilizer equipment (GB / T 6479-2013)
(5) GB / T 5310-2017 seamless steel tubes for high pressure boilers (in the standard, the steel number is 20g; G refers to boiler steel tubes)
20 # chemical composition
Chemical Composition of 20 # Seamless Steel Pipe
| Standard | Chemical composition |
| C | Si | Mn | Cr | Mo | Ni | Cu | V | P | S |
| ≤ |
| GB/T8163 | 0.17-0.23 | 0.17-0.37 | 0.35-0.65 | 0.25 | -- | 0.30 | 0.25 | -- | 0.035 | 0.035 |
| GB/T 9948 | 0.15 | 0.25 | 0.20 | 0.08 | 0.025 | 0.015 |
| GB/T 6479 |
The content of main elements (such as C, Si, Mn) in the chemical composition of 20 × seamless steel pipe in each material standard is the same. The content of residual elements (such as Ni, CI, Cu, Mo, V) in steel in gb9948-2013 and GB 6479-2013 are the same, but there are slight differences between GB / T 8163-2008 and the above two standards. The main difference of chemical composition lies in the content of P and s.
mechanical properties (mechanical properties)
| Standard | Mechanical Properties |
| Tensile strength/MPa | Yield strength/MPa | Elongation | KV2/J |
| S≤16mm | 16-30mm | ＞30mm | Portrait | Transverse | Portrait | Transverse |
| ≥ | Test temperature/℃ 0℃ |
| GB/T8163 | 410-530 | 245 | 235 | 225 | 20 | --- |
| GB/T 9948 | 410-550 | 245 | 24 | 22 | ≥40 | ≥27 |
| GB/T 6479 | 410-550 | 245 | 16-40mm | ＞40mm | 24 | 22 | ≥40 | ≥27 |
| 235 | 225
|
