Degradation Behavior and Micro-Hardness Analysis of a Coolant Rubber Hose for Automotive Radiator

자동차용 냉각기 고무호스의 노화거동과 미소경도분석

  • 곽승범 (한양대학교 기게공학과) ;
  • 신세문 (한국화학연구원 신뢰성 평가센터) ;
  • 신외기 (평화산업(주)) ;
  • 최낙삼 (한양대학교 기계정보경영공학부)
  • Published : 2007.09.01


Rubber hoses for automobile radiators are apt to be degraded and thus failed due to the influence of contacting stresses of air and coolant liquid under thermal and mechanical loadings. The aging behaviors of the skin part of the hoses due to thermo-oxidative and electro-chemical stresses were experimentally analyzed. Through the thermo-oxidative aging test, it was shown that the surface hardness IRHD(International Rubber Hardness Degrees) of the rubber increased with a considerable reduction of failure strain as the aging time and temperature increased. On account of the penetration of coolant liquid into the skin part influenced by the electro-chemical degradation(ECD) test the weight of the rubber hose increased, whereas their failure strain and IRHD hardness decreased. The hardness of the hose in the side of the negative pole was the most deteriorated at the test site of the hose skin just below the coolant surface.


Micro-hardness;IRHD-hardness;Thermal Oxidative Aging;Electrochemical Degradation;Coolant Rubber Hose;EPDM(ethylene-propylene dine monmer)


  1. Lee, K. J., Bae, H. J., No, S. T. and Kim, W. T., 1987, 'Studies on the Mechanical Properties of Silane Crosslinked EPDM,' Polymer, Vol. 11, No. 6, pp. 547-556
  2. Yeong-Soon Gal, 1999, 'EPDM Rubber and Its Applications,' Polymer Science and Technology, Vol. 109, No. 3, pp. 325-333
  3. Kim, J. K. and Lee, H. K., 2001, 'Study on Manufacturing and Characteristics of Silicone/EPDM Rubber Blend,' Polymer, Vol. 25, No. 3, pp. 406-413
  4. 2001, Coolant hose for automotive radiator guide book RS M0004, Korean Agency for Technology and Standards
  5. 2001, Coolant hose for automotive radiator reliability standards RS M0004, Korean Agency for Technology and Standards
  6. 1994(E), Rubber and plastics hoses and hose assemblies - Hydrostatic testing, INTERNATIONAL STANDARD ISO 1402
  7. 1987(E), Rubber - Coolant hoses and tubing for use on private cars and light commercial vehicles - Specification, INTERNATIONAL STANDARD ISO 4081
  8. Hideo Nakauzi, 2004, 'Failure Analysis and Life Prediction of Automobile Rubber Part.' Korea Matsusita Consulting
  9. Clint D. Gamlin, Naba K. Dutta, Namita Roy Choudhury, 2003, 'Mechanism and Kinetics of the Isothermal Thermodegradation of Ethylene-propyleneiene (EPDM) Elastomers.' Polymer Degradation and Stability, Vol. 80, pp. 525-531
  10. Traian Zaharescu, Viorica Meltzer, Rodica Vilcu, 2000, 'Thermal Properties of EPD/MNR Blends.' Polymer Degradation and Stability, Vol. 70, pp. 341-345
  11. Rajeev, R.S., De, S.K., Anil K. Bhowmick, Baby John, 2003, 'Studies on Thermal Degradation of Short Melamine Fibre Reinforced EPDM, Maleated EPDM and Nitrile Rubber Composites.' Polymer Degradation and Stability, Vol. 79, pp. 449-463
  12. Raluca Nicoleta Darie, Mihai Brebu, Cornelia Vasile, Marek Kozlowski, 2003, 'On the Compatibility of the IPP/PA6/EPDM Blends with and Without Functionalized IPP I. Thermo-oxidative Behaviour.' Polymer Degradation and Stability, Vol. 80, pp. 551-566
  13. 1989(E), Rubber, Vulcanized or Thermoplastic - Resistance to ozone cracking, Part1: Static strain test, INTERNATIONAL STANDARD ISO 1431-1
  14. Teissedre, G., Pilichowski, J.F., Chmela, S., and Lacoste, J., 1996, 'Ageing of EPDM--I Photo and Thermal Stability of EPDM Hydroperoxides' Polymer Degradation and Stability, Vol. 53, pp. 207-215
  15. Zaharescu, T. and Podina, C., 2001, 'Radiochemical Stability of EPDM.' Polymer Testing, Vol. 20, pp. 141-149
  16. Mihaly Kadar, Zoltan Nagy, Tamas Karancsi, Gyorgy Farsang, 2001, 'The Electrochemical Oxidation of 4-bromoaniline, 2,4-dibromoaniline, 2,4,6-tribromoaniline and 4-iodoaniline in Acetonitrile Solution.' Electrochimica Acta, Vol. 46, pp. 3405-3414
  17. Kwak, S. B., Choi, N. S., Kang, B. S. and Shin, S. M., 2005, 'Reliability Analysis and Failure Mechanisms of Coolant Rubber Hose Materials for Automotive Radiator' Transactions of KSAE, Vol. 13, No. 5, pp. 152-162
  18. Kwak, S. B., Choi, N. S., Choi, Y. J. and Shin, S. M., 2005, 'Nondestructive Characterization of Degradation of EPDM Rubber for Automotive Radiator Hoses' Journal of the Korean Society for Nondestructive Testing, Vol. 25, No. 5, pp. 368-376
  19. 1999(E), Rubber, vulcanized - Determination of the effect of liquids, INTERNATIONAL STANDARD ISO 1817
  20. 1998(E), Rubber, Vulcanized or Thermoplastic - Accelerated ageing and Heat Resistance Tests, INTERNATIONAL STANDARD ISO 188
  21. Roger A. Assink, Kenneth T. Gillen, Briana Sanderson, 2002, 'Monitoring the Degradation of a Thermally Aged EPDM Terpolymer by 1H NMR Relaxation Measurements of Solvent Swelled Samples.' Polymer, Vol. 43, pp. 1349-1355
  22. 2000, Test Methods for Evaluating the Electrochemical Resistance of Coolant System Hoses and Materials, SAE J1684
  23. 2001, Hilderbrand Micro IRHD System Manual

Cited by

  1. Electrochemical degradation tests on a carbon-black-filled ethylene propylene diene monomer rubber under tensile strain pp.2041-2991, 2017,
  2. Electrochemical Combined-Stress Degradation Test and Failure Mechanisms of EPDM Rubber for Automotive Radiator Hoses vol.37, pp.1, 2013,