Lifting gear - Wire Ropes , Inspection and defects

 Wire Ropes , Inspection and defects

Rules of thumb to check if Tag showing WLL (SWL)  is correct for a Flexible Steel Wire Rope (FSWR)

                                      SWL (WLL) = D² x 8

 Examples:

(i) 15mm diameter FSWR.  15 mm = 15 x 15 x 8 = 1800 kg  WLL.

(ii) 20mm diameter FSWR.  20 mm = 20 x 20 x 8 = 3200 kg  WLL.

Minimum Allowable  diameter FSWR  for handling Purposes : 5 mm

Maximum allowable handling  temperature : 95 °C (limited due to core material and lubrication seepage)

Construction Notation  and length of FSWR to inspect :

Ex: 6/19 and 12 mm diameter , 6/19 = 6x19 = 114 wires 10% of 114 = 11.4 wires in one rope lay, therefore 11 wires (12 mm x 8 = 96mm length of rope to inspect)

Inspection Of Wire Ropes

Middle of the rope 

End of the rope

Wire rope Defects and criteria for discarding

REDUCED ROPE DIAMETER

 Discard if  5-10% of broken, worn or corroded wires in any length (L= 10 x Rope diameter)

                                   FLATTENED ROPE PORTIONS - WITH OR WITHOUT CORE PROTRUSION

Local changes in cross-section (10% in general and 3% for non-rotating wire ropes) and local rope diameter. Flattened portions or portions with bends ,discard if broken wires, otherwise subject to increase frequency of inspections as exposed to accelerated corrosion

WAVINESS

Discard  if under any load the straight portion of wire condition is: d1>4d/3, where d is a nominal diameter of wire and d1 is the diameter corresponding to the envelope of the deformed wire

KINKS  WITH /WITHOUT BREAKAGE

EXTERNAL WEAR

CORROSION

                   DAMAGE TO STRANDS  

                    (on the reeving face crown break  ---------------- inside  valley breaks)- 

5% of broken, worn or corroded wires in any length (L=10x Rope dia) (crown wire breaks, valley wire breaks -while one valley break may indicate internal rope deterioration, closer inspection required, while 2 or more valleys break, discard shall be considered).

CORE DISTORTION