Sheet Stock Replacement for 1215 Steel
Sheet Stock Replacement for 1215 Steel
(OP)
I am attempting to simulate the wear characteristics of a PTFE coating on a 1215 bearing surface. 1215 is only available in bars and my wear tester is designed for thin coupons. Ideally I would punch 1215 coupons from sheet stock but since it is not available, is there any kind of equivalent steel that is available in sheet for me to use and coat? The possibility exists of having bar stock machined into coupons but that adds expense and time to a project which is limited in both. Any information would be appreciated.





RE: Sheet Stock Replacement for 1215 Steel
RE: Sheet Stock Replacement for 1215 Steel
RE: Sheet Stock Replacement for 1215 Steel
What you say about the availability of 1215 steel in sheet form is true. In fact, I can't recall seeing 1215 steel in anything other than bar form. But if you can't find even a limited quantity of 1215 sheet for your testing, where do you expect to get the material you will need for production?
Good luck to you.
Terry
RE: Sheet Stock Replacement for 1215 Steel
RE: Sheet Stock Replacement for 1215 Steel
The parts will be cylindrical and oscillate axially along a ceramic surface so the production will use 1215 bar. The goal of these tests are to determine wear trending as the coating application process conditions change which leads to a need for a high number of samples that can be produced readily meaning sheet steel with a repeatable surface finish and adhesion properties is preferred.
If an equivalent material is not available then would an experimental redesign be the correct course of action? The coating will be on the order of 50 microns in thickness and the test can be designed not to wear through the entire thickness. By designing the experiment so as to never approach the interface, the surface characteristics shouldn't come into play (as long as there isn't de-lamination of the coating and substrate) correct? Which would free me up to use a more readily available sheet material for the purpose of testing the coating alone I believe.
Thanks for the advice,
E.
RE: Sheet Stock Replacement for 1215 Steel
RE: Sheet Stock Replacement for 1215 Steel
However, based on the description of your testing approach and the related application, I would question whether your test results will be valid or how you will correlate them. For example, your test specimens are coated flat discs, and your production parts are internal bushing surfaces sliding on a cylindrical shaft. The 50 micron PTFE coating will readily displace under even modest contact pressures, so the conformal geometry and stiffness of the mating components would seem to have a significant effect on the test results.
Good luck to you.
Terry
RE: Sheet Stock Replacement for 1215 Steel
RE: Sheet Stock Replacement for 1215 Steel
RE: Sheet Stock Replacement for 1215 Steel
Adhesion depends on the specific coating. Many PTFE coatings use polymeric binders (e.g. epoxy, phenolic, PAI) that provide adhesion via chemical bonding.
RE: Sheet Stock Replacement for 1215 Steel
RE: Sheet Stock Replacement for 1215 Steel
RE: Sheet Stock Replacement for 1215 Steel
You want your test to most accurately simulate what the part you plan to use and what it sees in service. One variable of this experiment is the effect of using resulfurized steel on wear properties, while another is the effect of coating thickness. For this reason, I would suggest cutting and machining your test specimens out of 1215 bar. You can try various thicknesses of coating then to see determine when you would get spallation (higher thickness will reduce interface stress during contact). I would also suggest machining test specimens from a 1000-series carbon steel bar heat treated to about the same hardness. This show you whether the high inclusion content is really a factor in wear spallation.