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The other day, I was walking down the street when I noticed something strange. A man was walking in the opposite direction, but he was carrying a large, heavy-looking box. I was curious, so I decided to follow him.
Oil tube chinese Best manufacturer,oil tube Chinese high–quality wholesaler,Casing Pipe china Best Company,The man walked for several blocks, and eventually stopped in front of a small, nondescript building. He opened the door and went inside, still carrying the box. I waited outside for a few minutes, and then decided to investigate.

When I opened the door, I was surprised to find a small, but well-stocked library. The man had been carrying a box of books! He was a volunteer librarian, donating his time and resources to help keep the library open.
| tensile and Hardness Requirements | |||||||||
| grade | Yield strength MPa | Tensile Strength | Hardness a,c | specified Wall thickness | Allowable Hardness Variation b | ||||
| type | Total Elongation Under Load | min MPa | max | ||||||
| min | max | HRC | HBW | mm | HRC | ||||
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| H40 | — | 0.5 | 276 | 552 | 414 | — | — | — | — |
| J55 | — | 0.5 | 379 | 552 | 517 | — | — | — | — |
| K55 | — | 0.5 | 379 | 552 | 655 | — | — | — | — |
| N80 | 1 | 0.5 | 552 | 758 | 689 | — | — | — | — |
| N80 | Q | 0.5 | 552 | 758 | 689 | — | — | — | — |
| R95 | — | 0.5 | 655 | 758 | 724 | — | — | — | — |
| L80 L80 | 1 | 0.5 | 552 | 655 | 655 | 23 | 241 | — | — |
| L80 | 9Cr 13Cr | 0.5 | 552 | 655 | 655 | 23 | 241 | — | — |
| 0.5 | 552 | 655 | 655 | 23 | 241 | — | — | ||
| C90 | 1 | 0.5 | 621 | 724 | 689 | 25.4 | 255 | £12.70 | 3 |
| 12.71 to 19.04 | 4 | ||||||||
| 19.05 to 25.39 | 5 | ||||||||
| ³ 25.40 | 6 | ||||||||
| T95 | 1 | 0.5 | 655 | 758 | 724 | 25.4 | 255 | £12.70 | 3 |
| 12.71 to 19.04 | 4 | ||||||||
| 19.05 to 25.39 | 5 | ||||||||
| ³ 25.40 | 6 | ||||||||
| C110 | — | 0.7 | 758 | 828 | 793 | 30 | 286 | £12.70 | 3 |
| 12.71 to 19.04 | 4 | ||||||||
| 19.05 to 25.39 | 5 | ||||||||
| ³ 25.40 | 6 | ||||||||
| P110 | — | 0.6 | 758 | 965 | 862 | — | — | — | — |
| Q125 | 1 | 0.65 | 862 | 1034 | 931 | b | — | £12.70 | 3 |
| 12.71 to 19.04 19.05 | 4 | ||||||||
| 5 | |||||||||
| a In case of dispute, laboratory Rockwell C hardness testing shall be used as the referee method. | |||||||||
| b No hardness limits are specified, but the maximum variation is restricted as a manufacturing control in accordance with 7.8 and 7.9. | |||||||||
| c For through-wall hardness tests of grades L80 (all types), C90, T95 and C110, the requirements stated in HRC scale are for maximum mean hardness number. | |||||||||
I was amazed by the man’s dedication and generosity. He was giving back to his community in a very meaningful way. It was a reminder that even small acts of kindness can make a big difference.
The Benefits of Using steel Casing pipe for Underground construction Projects
| Labels a | Calculated Mass c | ||||||||||
| Nominal linear Mass T& C b,c | Wall Thick- ness | em, Mass Gain or Loss Due to End Finishing d | |||||||||
| Outside diameter | Inside Diameter | Drift Diameter | Plain- end | kg | |||||||
| Round thread | Buttress Thread | ||||||||||
| wpe | |||||||||||
| D | kg/m | t | D | mm | kg/m | Short | Long | RC | SCC | ||
| mm | mm | mm | |||||||||
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
| 13 3/8 | 48 | 339.72 | 71.43 | 8.38 | 322.96 | 318.99 | 68.48 | 15.04 | — | — 17.91 | — |
| 13 3/8 | 54.5 | 339.72 | 81.1 | 9.65 | 320.42 | 316.45 | 78.55 | 13.88 | — | 16.44 | — |
| 13 3/8 | 61 | 339.72 | 90.78 | 10.92 | 317.88 | 313.91 | 88.55 | 12.74 | — | 14.97 | — |
| 13 3/8 | 68 | 339.72 | 101.19 | 12.19 | 315.34 | 311.37 | 98.46 | 11.61 | — | 14.97 | — |
| 13 3/8 | 68 | 339.72 | 101.19 | 12.19 | 315.34 | 311.37 | 98.46 | 11.67 f | — | 14.33 | — |
| 13 3/8 | 72 | 339.72 | 107.15 | 13.06 | 313.6 | 311.15 e | 105.21 | 10.98 | — | 13.98 | — |
| 13 3/8 | 72 | 339.72 | 107.15 | 13.06 | 313.6 | 311.15 e 309.63 309.63 | 105.21 | 10.91 f | — | 14.33 | — |
| 13 3/8 | 72 | 339.72 | 107.15 | 13.06 | 313.6 | 105.21 | 10.98 | — | 13.98 | — | |
| 13 3/8 | 72 | 339.72 | 107.15 | 13.06 | 313.6 | 105.21 | 10.91 e | — | — | ||
| 16 | 65 | 406.4 | 96.73 | 9.53 | 387.4 | 382.57 | 96.73 | 18.59 | — | — 20.13 | — |
| 16 | 75 | 406.4 | 111.61 | 11.13 | 384.1 | 379.37 | 108.49 | 16.66 | — | 18.11 | — |
| 16 | 84 | 406.4 | 125.01 | 12.57 | 381.3 | 376.48 | 122.09 | 14.92 | — | — | — |
| 16 | 109 | 406.4 | 162.21 | 16.66 | 373.1 | 368.3 | 160.13 | — | — | — | |
| 18 5/8 | 87.5 | 473.08 | 130.21 | 11.05 | 450.98 | 446.22 | 125.91 | 33.6 | — | 39.25 | — |
| 20 | 94 | 508 | 139.89 | 11.13 | 485.7 | 480.97 | 136.38 | 20.5 | 27.11 | 24.78 | — |
| 20 | 94 | 508 | 139.89 | 11.13 | 485.7 | 480.97 | 136.38 | 20.61 | 27.26 g 24.27 17.84 | 24.78 | — |
| 20 | 106.5 | 508 | 158.49 | 12.7 | 482.6 | 477.82 | 155.13 | 18.22 | 22 | — | |
| 20 | 133 | 508 | 197.93 | 16.13 | 475.7 | 470.97 | 195.66 | 13.03 | 16.02 | — | |
| NOTE See also Figures D.1, D.2, and D.3. | |||||||||||
| a Labels are for information and assistance in ordering. | |||||||||||
| b Nominal linear masses, threaded and coupled (Column 4) are shown for information only. | |||||||||||
| c The densities of martensitic chromium steels (L80 Types 9Cr and 13Cr) are less than those of carbon steels; The masses shown are therefore not accurate for martensitic chromium steels; A mass correction factor of 0.989 shall be used. | |||||||||||
| d Mass gain or loss due to end finishing; See 8.5. | |||||||||||
| e Drift diameter for most common bit size; This drift diameter shall be specified in the purchase agreement and marked on the pipe; See 8.10 for drift requirements. | |||||||||||
| f Based on 758 mPa minimum yield strength or greater. | |||||||||||
| g Based on 379 mPa minimum yield strength. | |||||||||||
