All of the following is based on the limited amount of information that is available to me about the OX2 engine. AENG may have a completely different solution regarding the wear issue. I can not speak for AENG so the opinions expressed below are mine and as such they represent my methods of addressing the wear issue.
With out getting into material science 101. Here is my take on how the wear problem is resolved if a solution by AENG does not already exist.
Hopefully you agree with the following :
Different combination of mechanical properties can be obtained by the varying the manner in which steels are heated and cooled. I'm focusing on the surface production of martensite by induction heating and rapid quenching.
The amount of carbon and other metals such as nickel, chromium, molybdenum and tungsten present in the steel affects the type of martensite produced. Not having access to any stress / load data, I can not say for certain what the proper combination of metals will be, however I am confident that this method will produce a suitable wearing surface. My best guess for now would be the use of a 1060 steel for those parts subject to wear. Testing will have to be done, if not already done to determine what mix produces the best results form a wear and economic stand point. If the test results were not satisfactory I would go to 1080 or a 1095 steel. I have already inquired (via E-mail) about test data and when it would be published. The reply was that arrangements are being made to perform a 100 hr load test to and those test results will be published on the web site. My understanding is that the test results will be performance oriented. I will send the a company a memo requesting them to consider doing an extensive oil analysis to determine the amount wear metals present after 100 hrs. I also hope to have them consider the inclusion of some IR scanning during the test.
Manufacturing in my opinion, is not problem as the parts are machined to near net tolerances prior to the heat treatment. In order to retain the ductile properties only the surface is hardened to a depth of approx. 0.005. After hardening, the parts are tempered, to eliminate any stresses between the harden layer and the remaining steel. The final piece can be obtained with further machining or grinding.
Correct me if I'm wrong but the mean time between failure of 100,000 miles is your bench mark for use in the auto industry? I have stated earlier that the engine is a long way from Detroit. However it is my belief that the current engine would be suitable in the small engine market. Again, I'm making some large assumptions that AENG does not have any data at this time to support a MTBF of 100,000 miles perhaps they do. I'm sure AENG is getting aggravated by my constant inquiries but the response I get back from AENG leads me to believe that they are addressing these issues and will bring closure to them in the near future.
Several paper I recommend :
"Hardenability Concepts with Applications to Steel" AIME, 1978.
"Structure and Properties of Engineering Alloys" McCGraw-Hill 1981
"The making , Shaping and Treating of Steel" (9th ed, United States Steel Corp 1971
I apologize about the dated material, but hey I'm an old guy.
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