Welcome back to the Ask the Expert blog, the blog is designed to help educate you on all things rings and wave springs. This week, the expert fields some questions on the cycle life of wave springs and the materials of wave springs.
Yes, we can estimate the theoretical cycle life of our springs using a series of special equations. Note that theoretical cycle life estimates are just that — estimates. There are a number of variables, including variables specific to the use that your springs will be put to, that will affect the true cycle life.
The theoretical cycle life equations can be found in our catalog or at Smalley.com/engineering. You can also contact a Smalley engineer discuss the specific application parameters of your spring. Smalley also offers cycle testing as an option.
Formula:
Nomenclature
σ = Material tensile strength
S1 = Calculated operating stress at lower work height
S2 = Calculated operating stress at upper work height
Fatigue Stress Ratio | Estimated Cycle Life |
.00 < X < .40 | Under 30,000 cycles |
.40 < X < .49 | 30,000 - 50,000 cycles |
.50 < X < .55 | 50,000 - 75,000 cycles |
.56 < X < .60 | 75,000 - 100,000 cycles |
.61 < X < .67 | 100,000 - 200,000 cycles |
.68 < X <.70 | 200,000 - 1,000,000 cycles |
.70 < X | over 1,000,000 cycles |
Smalley can manufacture wave springs in a variety of exotic alloys, including various types of steel, coppers and, yes, Inconel X-750. Inconel X-750 is a NACE compliant exotic alloy that is commonly used in oil and gas applications.
Remember that it is always best to choose a material based on the requirements of the application and the usage environment. There are a variety of key factors when it comes to choosing the right material for your application including environment, budget, and cycle life. Smalley stocks standard wave springs in carbon steel and 17-7 stainless steel. To learn more about selecting an appropriate material for your application, take a look at our Material Selection Guide.
To request a specific exotic alloy, contact a Smalley engineer today.
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