$30 off During Our Annual Pro Sale. View Details »

Clutch Retainer plate failure

Clutch Retainer plate failure

Field failure of a passenger car clutch retainer plate

Raghvendra Gopal

September 21, 2017
Tweet

More Decks by Raghvendra Gopal

Other Decks in Education

Transcript

  1. Materials info consultancy private limited
    www.materials-info.com
    Failure analysis of a clutch Retainer plate field
    Failure

    View Slide

  2. Type Of failure
    Materials info consultancy private limited 2
    Window failure Damper spring
    popping out

    View Slide

  3. Type Of failure
    ➢The clutch Retainer plate was found to have
    failed in the field .
    ➢Due to the failure the damper spring Popped
    out as the plate could not retain the same due
    to window failure
    ➢This resulted in clutch not working in the
    vehicle
    ➢Also abnormal sound was reported during the
    failure
    Materials info consultancy private limited 3

    View Slide

  4. Examination of Failure
    ➢ The Failed clutch was examined Visually.
    ➢ The retainer plate window was found broken and the
    piece had got dislodged.
    ➢ The damper spring was found coming out of the
    window
    ➢ The spring was found to have rubbing marks on its
    surface
    ➢ With careful examination Gouging marks were seen
    on drive plate window sides where damper spring
    was seated.
    Materials info consultancy private limited 4

    View Slide

  5. Examination of Failure
    Materials info consultancy private limited 5
    Drive plate

    View Slide

  6. Examination of Failure
    ➢ The damper spring is located in drive plate window
    and gets retained by retainer plate on both sides.
    ➢ The Drive plate window was found to have deep
    digging ( Gouging ) on both ends where damper
    spring was making contact .
    ➢ This was resulting in damper spring getting loosened
    and coming out and hitting the retainer plate
    ➢ This hitting action was resulting in failure of retainer
    plate window.
    Materials info consultancy private limited 6

    View Slide

  7. Failure Investigation
    ➢ Material and manufacturing process for Retainer plate:
    ➢ Material : IS 513 ( SAE 1010) type D
    ➢ Manufacturing process: Blanking Heat treatment i.e
    Carbonitriding Zinc Phosphating
    ➢ Hardness and case depth were checked for the failed retainer
    plate and were found to conform to the specification with no
    manufacturing or material defects
    Materials info consultancy private limited 7

    View Slide

  8. Failure Investigation
    ➢ Material and manufacturing process for Drive plate:
    ➢ Material : IS 513 ( SAE 1010) type D
    ➢ Manufacturing process: Blanking Heat treatment i.e
    Carbonitriding Zinc Phosphating
    ➢ Hardness and case depth were checked for the failed drive plate
    The effective case depth was found low due to formation of
    intermediate Pearlitic phases in the case.
    Materials info consultancy private limited 8

    View Slide

  9. Failure Investigation
    Materials info consultancy private limited 9
    Pearlite formation in case

    View Slide

  10. Failure Investigation
    ➢ Chemistry was checked for the drive plate and the material was
    found to be Aluminum killed
    ➢ Material : IS 513 ( SAE 1010) type D. Aluminum : 0.023%
    ➢ Use of Aluminum as Deoxidation agent resulted in fine grain size
    ➢ The grain size was measured and found ASTM 8-9
    ➢ The fine grain size resulted in poor hardenability of the steel
    resulting in formation of intermediate phase Pearlite.
    Materials info consultancy private limited 10

    View Slide

  11. Corrective Action
    ➢ While localization, the raw material was developed as Silicon
    killed steel in place of Aluminum as deoxidation.
    ➢ Material : IS 513 ( SAE 1010) type D.
    ➢ The material was blanked and carbonitrided in seal quench
    furnace using LPG and endogas.
    ➢ The case depth was measured using effective case depth method
    by microhardness and also microstructure was analyzed.
    Materials info consultancy private limited 11

    View Slide

  12. Corrective Action
    ➢ The grain size was found 6-7 ASTM.
    ➢ Both microstutcure in case as well as effective case depth values were
    found conforming to specification.
    ➢ Rockwell superficial hardness was measured on components for
    around 25 heat treated batches and case depth was correlated witth
    superficial hardness
    ➢ Ensuring the hardness resulted in attainment of specified case depth.
    Materials info consultancy private limited 12

    View Slide

  13. Testing and confirmation
    ➢ The drive plates were assembled in clutch assembly and were
    evaluated for durability in fatigue rig for required number of
    cycles
    ➢ Few clutch assemblies were tested on vehicles and found to
    cover more than 1.5lac cycles compared to earlier failure cases
    where life was as low as 20000-30000 kms.
    Materials info consultancy private limited 13

    View Slide