Twin wall pipe have two layers tube. The outer layer is G20 steel, and the liner is a wear-resistant carbide alloy. With inner wall induction hardened by high frequency, the hardness of wear resistance layer can be HRC 60-64. Thus twin wall tube pipe can guarantees much more concrete pouring cube, and it is better tube for delivery pipe line system.
During concrete pouring, the friction of stones can easily wear out the single-layer pipe. With the better wear resistance layer, the twin wall pipe solves the problem, increases the service life of the pipe, and reduces the replacement cost.
Twin wall pipe outer layer is G20 steel, which has good mechanical strength, high impact resistance, and good weldability. The inner liner is a high chrome wear resistant layer. Double concrete pipe is more choice than single concrete pipe at concrete pump truck.
20 steel has better oxidation resistance, toughness, plasticity, weldability and cold and hot processing performance.
| C | Si | Mn | P | S |
| 0.17 ~ 0.23 % | 0.17 ~ 0.35 % | 0.35 ~ 0.7 % | < 0.025 % | < 0.025 % |
After normalizing air cooling + tempering air cooling heat treatment, the chrome layer have high HRC and wear resistance.
| C | Mn | Si | Ni | Cr | Mo | Cu | P | S |
| 2.0 ~ 3.3 % | ≤ 2.0 % | ≤ 1.5 % | ≤ 2.5 % | 11 ~ 30 % | ≤ 3 % | ≤ 1.2 % | ≤ 0.1 % | ≤ 0.06 % |
Note: Cr content can be adjust, which will have differrent pouring cube.
Depending on the material and thickness of the chrome layer, the service time of the twin wall pipe is different.
The wear resistant chrome layer of the 30,000 twin wall pipe is high chromium 12, and its hardness HRC is 60.
| DN125*3000mm | 2.5mm+2mm | HRC 60 |
| DN125*1840mm | 2.5mm+2mm | HRC 60 |
The wear resistant chrome layer of the 30,000 twin wall pipe is high chromium 20, and its hardness HRC is 62.
| 133*3000mm | 3mm+2mm | HRC 62 |
| 133*2470mm | 3mm+2mm | HRC 62 |
The wear resistant chrome layer of the 30,000 twin wall pipe is high chromium 28, and its hardness HRC is 64.
| DN125*3000mm | 5mm+2mm | HRC 64 |
| DN150*900mm | 5mm+2mm | HRC 64 |
Remarks: Different grades of concrete, the position of the boom tube affect the service life of the tube.
Twin wall pipe usual work at boom, deck for Putzmeister, Schwing, Zoomlion, Sany, CIFA, Sermac, XCMG, DY, Junjin, Everdigm concrete pump. With twin wall elbow, the pipe have good comprehensive performance.