Fatigue Test Method for Roller Chains
The
fatigue strength test is considered to be the closest test method to the actual
use of the chain.
Since
the chain is constantly moving during use, it is also necessary to understand
the fatigue life and endurance limit of the chain.
The
purpose of this test is to find out under what tensile load on the chain will
(theoretically) never break.
For
general chains (excluding stainless steel chains), the fatigue strength is
equivalent to the maximum allowable load.
Fatigue test method
1. Conformity Test
According
to the Conformity test method specified in ISO 15654, the test is carried out
with reference to the minimum fatigue strength (Fd) specified in ISO 606 and
ISO 4347 to verify whether the chain complies with ISO 606 and ISO 4347.
The
test method is to test 3 chains and pass 3 million cycles.
2. Staircase Test
The
test can better obtain the actual fatigue strength of the chain.
According
to the Staircase test method stipulated in ISO 15654, the test load is tested
in stages from large to small (or from small to large) in an arithmetic
progression method, and the ascending or descending load progression is
determined based on whether it passes 10 million cycles. The fatigue test will
be calculated after the tests are done.
The
load, waveform and calculation methods of the fatigue test will be further
explained below.
Fatigue test
procedure
1. Determine
the test conditions, as shown in the figure below:
2. Determine the ascending and descending load progression(d)
3. Start
testing.
If
the chain breaks less than 10 million cycles, replace to a new one and lower
the load by one level and retest.
If
the chain is not broken after 10 million cycles, replace to a new one as well
and increase the load by one level and test again.
4. Required sample pieces
5. Correct the maximum load (Fmax) of the test to the fatigue strength according to the formula
6. Calculate the average fatigue strength, standard deviation and minimum fatigue strength
MAXTOP’s Fatigue
testing machines
The
fatigue testing machine is based on the principle of electromagnetically driven
mechanical resonance to generate dynamic test force.
In
the test, a high frequency cycle fatigue test is performed on the chain stretching
and relaxing repeatedly.
MCC
now has two new fatigue testing machines, namely 2.5 tons (25 kN) and 20 tons
(200 kN) fatigue testing machines.
