Is it Better to Tighten the Barrel Plug and Bolts of Steel Drum Enclosure as Tight as Possible?

Closed steel drums have threaded plugs, while open steel drums have nuts on the drum hoops with bolts. Some factory inspectors will tighten loose plugs or bolts during regular inspections, thinking that this will prevent quality issues with steel drums. Experienced barrel makers say that it's best not to do this, because over-tightening plugs and bolts will increase the likelihood of problems.

When it comes to ensuring the efficiency of steel drum closures, it is crucial to follow proper bolt tightening methods. So, what methods are available to control bolt tightening?

Torque control method

Definition: A control method that stops tightening immediately when the tightening torque reaches a set control torque.

Advantages: Simple and direct control system, easy to check tightening quality with torque sensors or high-precision torque wrenches.

Disadvantages: Low control accuracy (torque error ±25%), and it cannot fully utilize the potential of the material.

Torque-angle control method

Definition: A control method that tightens the bolt to a small torque first, and then tightens it a specified angle from this point.

Advantages: High precision of axial preloading of bolts (±15%), and can obtain a large axial preloading force with a value that can be concentrated around the average.

Disadvantages: The control system is more complex, requiring measurement of both torque and angle; and the quality inspection department may not find an appropriate method to check the tightening results.

Yield point control method

Definition: A method of stopping tightening by tightening the bolt to the yield point.

Advantages: Tightening accuracy is very high, with a preloading force error that can be controlled within ±8%, but its precision mainly depends on the yield strength of the bolt itself, which requires careful selection of high-quality steel drum parts.

Disadvantages: The tightening process requires dynamic and continuous calculation and judgment of the slope of the torque and angle curve. The control system requires high real-time performance and computing speed.