Heat setting high-performance synthetics:
Higher initial strength at the cost of a reduced service life and reduced abrasion resistance
Higher initial strength at the cost of a reduced service life and reduced abrasion resistance
Some products on the market are based on heat-set high modulus polyethylene (HMPE) fiber. The process results in a rope with some strength gains over the preprocessed rope, but at the expense of other mechanical properties. Tensile fatigue and abrasion resistance are both compromised as a result of this process.
Fatigue lifetime comparison
![Tension Fatigue (Effects of Heat Processing.) AmSteel-Blue v.s. Heat Set Rope. [Graph]](Images/mining/TenFat_Graph.png)
The chart below shows the change in the rope due to fatigue, with the overall
fatigue life shown as a curve. HMPE ropes actually gain strength initially,
then progressively lose strength as the loading cycles increase. Heat stabilizing of HMPE effectively accelerates this initial strength gain, however, by placing the initial strength further along the curve will actually shorten the expected life of the rope (number of cycles to failure). The rope may achieve 25% greater initial strength, but will only have 60% of its fatigue life remaining.
The chart below shows the change in the rope due to fatigue, with the overall
fatigue life shown as a curve. HMPE ropes actually gain strength initially,
then progressively lose strength as the loading cycles increase. Heat stabilizing of HMPE effectively accelerates this initial strength gain, however, by placing the initial strength further along the curve will actually shorten the expected life of the rope (number of cycles to failure). The rope may achieve 25% greater initial strength, but will only have 60% of its fatigue life remaining.FIBER |
Measured Cycles to Failure |
Heat-set HMPE |
11,200 |
Dyneema® SK-75 |
24,700 |
Abrasion resistance
Abrasion testing shows that AmSteel®-Blue has superior abrasion resistance to heat stabilized HMPE ropes. Testing used Samson’s standardized abrasion test and showed heatstabilized HMPE failing at less than half the number of cycles to failure as AmSteel®-Blue.
Abrasion testing shows that AmSteel®-Blue has superior abrasion resistance to heat stabilized HMPE ropes. Testing used Samson’s standardized abrasion test and showed heatstabilized HMPE failing at less than half the number of cycles to failure as AmSteel®-Blue.
Conclusions:
While heat treating HMPE ropes can produce a rope that is initially stronger than AmSteel®-Blue, the rope is proven to have a shorter fatigue lifetime and significantly lower resistance to abrasion.
For more in-depth information, see the Technical Bulletin: HMPE Rope Comparison—Effects of Post-Production Process, available at SamsonRope.com
While heat treating HMPE ropes can produce a rope that is initially stronger than AmSteel®-Blue, the rope is proven to have a shorter fatigue lifetime and significantly lower resistance to abrasion.
For more in-depth information, see the Technical Bulletin: HMPE Rope Comparison—Effects of Post-Production Process, available at SamsonRope.com
