Friction layers produced in two steels during laboratory friction testing

Abstract

The friction layers produced on SAE type 1065 and 20Mn2WNbB steels during laboratory friction testing have been characterised using optical microscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. A white layer is formed on the surface of SAE 1065 steel, composed of abnormal quenched martensite with a microhardness of 1020 HV(100 g). A dark grey friction layer with a microhardness of 600 HV(100 g) is formed on the surface of 20Mn2WNbB steel. This layer consists of tempered lath martensite with a low carbon content. Formation of the white layer in SAE 1065 steel occurs through austenitisation of the steel surface due to friction at a high sliding rate, followed by rapid cooling to a martensite structure. The martensite structure in this white layer exhibits a finer grain size and higher dislocation density than that obtained by normal quenching. However, in 20Mn2WNbB steel, the quenched martensite structure is transformed into tempered martensite by self-tempering during cooling. Charpy impact tests show that the impact toughness of SAE 1065 steel is significantly decreased owing to the presence of the white layer. However, there is only a small effect of the friction layer on the impact toughness of 20Mn2WNbB steel.

Keywords

FRICTION TESTING WHITE LAYER MARTENSITE TOUGHNESS

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References

Miller

B. A.

: Adv. Mater. Process., 2000, 157, 43–46.

Liu

, Zhao

, Liu

and Northwood

D. O.

: in ‘Proceedings of the 9th international conference on creep and fracture of engineering materials and structures’, (ed. Parker

J. D.

), 789-797; 2001, London, The Institute of Materials.

Dikshit

V. A.

: Diss. Abstr. Int., 1992, 53, 276–279.

Yang

, Fang

H. S.

, Zhang

Y. K.

, Yang

Z. G.

and Jiang

Z. L.

: Wear, 1995, 185, 17–22.

Sinha

and Rao

: Wire Ind., 1995, 62, 734–736.

Zhao

, Northwood

D. O.

, Liu

and Liu

: J. Mater. Process. TechnoL, 1999, 89-90,569–573.

Fang

H. S.

: Heat Treat. Met. (China), 1997, 4, 9-12 (in Chinese).

Liu

, Zhao

, Northwood

D. O.

and Liu

: J. Mater. Process. TechnoL, 2001, 113, 556–562.

Liu

Y. X.

: ‘Principles of heat treatment’, 71–127; 1981, Beijing, Mechanical Industry Press (in Chinese).

10.

and Kennon

N. F.

: Mater. Forum, 1992, 16, 43–49.

11.

Liu

: ‘A new 20Mn2VVNbB steel used in steel wire ropes for petroleum drilling’, PhD thesis, Harbin Institute of Technology, China, 1998,39–59.

12.

Bulpett

, Eyre

T. S.

and Ralph

: Wear, 1993, 162–164, 1059-1065.

13.

Akcan

, Shan

, Moylan

, Chhabra

P. N.

, Chandrasekar

and Farris

T. N.

: ASME Int. Cong. and Exhib., Nashville, TN, USA, ASME, Mech. Eng. Division, Vol. 10, 1999, 789–795.

14.

Chou

K. Y.

and Evans

C. J.

: Int. J. Mach. Tools Manuf, 1999, 39, 1863–1881.

15.

Chaffron

, Le Bouari

and Martin

: C. R. Acad. Set (Paris), Sér. IV, 2001, 2, 749–759.

16.

Liu

Y. X.

, Zhao

Z. B.

, Ji

C. T.

and Zhu

Q. H.

: J. Steel Wire Prod., 1995, 21, 8-11 (in Chinese).

17.

Weiss

, Rudney

, Cook

, Loveless

and Black

: Adv. Mater. Process., 1999, 156, 19–23.

18.

Tomota

, Aoyama

, Takenaka

, Kuratomian

and Tanimoto

: Trans. Jpn Soc. Mech. Eng. A, 1996, 62A, 1605-1612 (in Japanese).

19.

Yao

, Shao

and Wang

: J. Xi'an Jiaotong Univ., 1994, 28, 45-50 (in Chinese).