Two calibrations of heavy duty chains

A qualified heavy lifting chain needs to be calibrated twice during the production process to make sure that the relevant parameters meet the standards. Thus, it can be normally used in all kinds of chain hoists and binder chain & chain sling rigging.

First calibration

It is mainly to correct the size and typing. There are three types of calibrators, small calibrators, medium calibrators and large calibrators.

① Small calibrator: Advantage: typing is clearer. That is, not at the same time double-ring typing, only single-ring typing, corrected size relative to the medium-sized calibrator and large calibrator for the accuracy of some of the poor.

Calibration range: 6mm-10mm.

② Medium-sized calibrator: capable of simultaneous double-ring or multi-ring typing, high accuracy of the corrected size, double-ring typing is typed on the two adjacent flat rings, rather than the two adjacent rings, the two adjacent flat rings are separated by a vertical ring.

Calibration range: 6mm-10mm

③ Large calibrator: Only single-ring typing is possible, and the calibrated dimensions are highly accurate.

Calibration range: 11mm-16mm.

Secondary calibration

The purpose of secondary calibration is to ensure the test tension of the chain and the precision of the chain size. The test load of the secondary calibration is 2.5 times of the rated load. For example, if the rated load of 8mm chain is 2 tons, the test load is 2.5×2=5 tons.

If the chain breaks during the second comparison process, it is necessary to re-connect the ring and weld it. This process requires a single ring dipping fire. The temperature of single ring dipping fire is about 1000 degrees. Detecting the pulling force of the single ring: Use the industrial pulling machine to detect the pulling force value is 2.5 times of the rated load of the chain. The pulling machine can test the pulling force of the whole chain.