Abstract
Two types of TiN-coated gear cutting hobs were compared in the hobbing of case hardening steel under production conditions. The coating reduced the wear of the hobs significantly, even though 25% and 50% increased cutting speeds as compared to the uncoated hobs were used. The performance of the two types of TiN coatings denoted by A and B differed markedly. The coating B lasted generally from l. 5 to 2 times longer than A. Mechanical testing of hardness and adhesion by a scratch test gave, however, slightly better values for coating A. Nuclear resonance broadening analysis showed coating A to be essentially stoichiometric TiN, while B showed a gradually increasing nitrogen content towards the surface. Scanning electron micrographs revealed columnar microstructure with coating A while B was almost featureless. The columnar microstructure of coating A is suggested as an explanation for the poor performance of coating A as compared to coating B.
Original language | English |
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Pages (from-to) | 2763-2767 |
Number of pages | 5 |
Journal | Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films |
Volume | 4 |
Issue number | 6 |
DOIs | |
Publication status | Published - Nov 1986 |
MoE publication type | A1 Journal article-refereed |