What is the qualified torque for steel pipe fasteners?
2 Answers
Steel pipe fastener torque generally ranges between 40-50. The commonly used fasteners in China are made of cast iron, and their mechanical properties should comply with the "Steel Pipe Scaffold Fasteners" (GB15831-2006) standard, with material quality not lower than KT330-08. There are three types of fasteners: right-angle fasteners, butt fasteners, and swivel fasteners. They are packaged in woven bags, with 25 pieces per bag. Each fastener should weigh 1.1KG (including bolts and nuts). They are used in conjunction with scaffold pipes. Generally, the production and procurement ratio of fastener products is 8:1:1, meaning right-angle fasteners account for 80%, butt fasteners 10%, and swivel fasteners 10%.
This requires detailed explanation. The torque for steel pipe couplers isn't something you can just tighten casually. The national standard GB15831 clearly states: the bolt tightening torque must be between 40N·m and 65N·m to meet specifications. For the commonly used 48mm steel pipes on construction sites, experienced workers typically set their torque wrenches around 45N·m. Remember last year's accident at the neighboring site? It happened because a rookie worker tightened couplers by feel, resulting in scaffolding collapse during rain. Over-tightening can strip bolt threads, while under-tightening won't provide sufficient strength. It's best to use a torque wrench with an audible alert that beeps when reaching target torque. Post-rain re-tightening is also crucial. Safety is something you can't afford to be careless about.
