SITIS Archives - Topic Details
Program:  SBIR
Topic Num:  N102-141 (Navy)
Title:  Non Destructive Material Case Depth Verification
Research & Technical Areas:  Materials/Processes

Acquisition Program:  PMA-299, H-60 Helicopter Program
  Objective:  Accurately determine the case depth of hardened (carburized, nitrided, induction, etc.) aerospace materials by non-destructive means without the use of traditional destructive method of cross-sectioned specimens (hardness-traverse method).
  Description:  The Naval aviation community as owner and operator of aerospace systems continuously seeks improvement in the manufacturing arena. The Navy occasionally faces issues with inadequately case hardened aerospace components. One major issue is the determination of case-depth hardness of the materials. The industry standard method is to cross-section the specimen for a hardness-traverse measurement. This destructive inspection requires random sampling and can be quite expensive if there is a suspect population of non-conforming parts and a high demand for the suspect product. Developing a cost effective, accurate, hand held, innovative, non-destructive technology that would allow these case hardened parts to be inspected (measure case depth) without being destroyed, would increase the possibility of identifying non-conforming parts early in the production process. This would result in a decrease in cost to the government or OEMs by removing the need to inspect numerous suspect components by means of destroying potential conforming components. Develop innovative technology capable of measuring the case depth by non-destructive means of carburized aerospace gears (flank, face, pitch circle, fillet radius)l.

  PHASE I: Design and demonstrate feasibility of a technology to measure case depth of hardened aerospace materials (carburized materials, gears).
  PHASE II: Develop, demonstrate and validate the non-destructive case depth measuring technology for carburized materials. Refine the models for accuracy by accounting for geometry, material characteristics, ratio of case thickness to tooth thickness. Refine and conduct a prototype demonstration to characterize technology capability.

  PHASE III: Conduct necessary qualification testing and finalize the non-destructive case depth measuring technology for transition to both military and commercial applications (gears, bearings, splines, shafts, etc). PRIVATE SECTOR COMMERCIAL POTENTIAL/

  DUAL-USE APPLICATIONS: This technology would be applicable to aerospace and non-aerospace case hardening (carburize, nitride, induction, etc.) supply sources.

  References:   1. Chandler, H. (1999). Hardness Testing. Publisher: ASM International; 2 Sub edition 2. Cuffe, J., Sun, H., Plotnikov, Y., Nath, S., & Sheila-Vadde, A. (2008). Eddy Current Measurement of Case Hardened Depth of Steel Components, From 17th World Conference on Nondestructive Testing, Shangahai, China. Accessed online http://www.docstoc.com/docs/15948383/Eddy-Current-Measurement-of-Case-Hardened-Depth-of-Steel

Keywords:  non-destructive inspection; hand held; case hardened; steel; aerospace components; carburized materials

Questions and Answers:
Q: (1) What kind of spatial resolution is expected, like 1mm, 1cm, etc?
(2) Are you more interested in nominal case depth or trying to capture/detect uneven case depth?
(3) Is "hand held" a very high priority requirement? What if we need some laptop PC as an auxiliary equipment in addition to the actual "probes"? Thanks a lot.
A: 1. In Thousands with in 95-98 %
2. Try to capture/detect uneven case depth
3. Hand held is Ok< PC is ok but eventually had to comply with Navy Mil Standards requirements, Phase I is to prove the concept.
Q: 1) What are the steel alloys of interest for this project?
2) Are the steels to be investigated ferromagnetic?
3) What kind of test specimens, if any, will be provided? Or shall a proposal include the generation of adequate test articles?
4) Is there a possibility to review technical drawings of the aerospace gears to be inspected? if you envision an in-situ handheld inspection approach, it would be beneficial to know the geometry and the assessibility of the targeted structure.
5) Do you anticipate multiple awards?
A: 1. 9310 steel, 4310 steel and Pyroware

2. Yes

3. Proposal shall include the generation of test articles.

4. Possible

5. Not sure it all depends on proposals
Q: With respect to your answer to question 4, can you email relevant technical drawings or guide us to an internet webpage that provides these information?
A: Assuming this is question 4:
"4) Is there a possibility to review technical drawings of the aerospace gears to be inspected? if you envision an in-situ handheld inspection approach, it would be beneficial to know the geometry and the accessibility of the targeted structure."

ANSWER:
Clarification: The non-destructive material case depth verification is desired for several different case (carburized, nitrided, etc.) hardened material "locations". These locations would include the following examples:

1) For bearing type applications:
A. An outside diameter
B. An inside diameter

2) For a gear (spur, helical, double helical, spiral bevel, etc.) with either external teeth or internal teeth:
A. Tooth pitch diameter
B. Tooth root radius

The links below are examples:

http://en.wikipedia.org/wiki/Gear

http://www.engineersedge.com/gears/gear_definitions.htm

http://www.google.com/imgres?imgurl=http://www.mechanicalphilosopher.com/invd1.jpg&imgrefurl=http://www.cartertools.com/involute.html&usg=__RKVi_FWznDokYXNp6uDQGXEPURE=&h=384&w=512&sz=34&hl=en&start=1&um=1&itbs=1&tbnid=t_1NL-EX8YfrQM:&tbnh=98&tbnw=131&prev=/images%3Fq%3Dgear%2Broot%2Bdiameter%26um%3D1%26hl%3Den%26sa%3DN%26tbs%3Disch:1
Q: 1) What is the surface finish?
2) What is the typical thickness? As stated above technical drawings would be helpful.
3) What is the environment where the tests will be performed? i.e. manufacturing line, field, post operation...etc.
4) "Try to capture/detect uneven case depth" Is this within a single gear or a part by part variability?
A: 1) What is the surface finish?
Answer: The surface finish of case hardened steels could be between 5-25 AA.

2) What is the typical thickness? As stated above technical drawings would be helpful.
Answer: This will verify by part design and part feature, typical ranges would be from 0.0125" to over 0.500"

3) What is the environment where the tests will be performed? i.e. manufacturing line, field, post operation...etc.
Answer: Typically in a manufacturing/repair facility, with a possible field application.

4) "Try to capture/detect uneven case depth" Is this within a single gear or a part by part variability?
Answer: Both.
Q: Can you elaborate on the resolution requirements?
What are the required spatial and depth resolutions?
I did not understand your previous answer on spatial resolution ('In Thousands with in 95-98 %').
A: The resolution or accuracy is desired to be to the 0.005" (five thousand's of an inch) with a 95-98% confidence.

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