Page 52 - HOLE MAKING CATALOG p311-382

TAPS USER GUIDE

Tap Surface Treatments and Coating Types Hardslick-COATING – Hardslick
Hardslick combines in a novel way the advantages
The high speed steels we use grant high wear resistance of an extremely hard, thermally stable TiAIN-coating
and toughness. For machining certain materials, with the sliding and lubricating properties of an outer
various surface treatments are an advantage. WC/C (Tungsten carbide/carbon) coating. The hardslick
coating has a hardness of approx. 3,000 HV and
Steam Tempered (ST) is temperature-resistant up to approx. 800°. Color:
The steam tempered is a Fe3O4 oxide coating Violet-grey coefficient of friction against steel : 0.2
which reduces the friction between the tool
and workpiece and prevents cold welding. Tolerances According to DIN EN 22857
For taps with ISO metric threads.
Nitriding (NI) The following chart gives a comparison between
Recommended surface treatment for machining hard the new standard DIN EN 22857 and the withdrawn
wear/abrasive materials such as grey cast iron, aluminum standard DIN 802 part 1. An important change is the
alloys with high silicon percentage (more than 10%). re-classification from tap tolerance to tap application class.

TiN Coating (TI) Application Tolerance Allotment of the
The TiN coating has a hardness of approximately class for class to tolerance zones of the
2,300 HV and is temperature resistant up to taps to DIN withdrawn nut thread to be cut
approximately 600°C. This is an excellent golden EN 22857 standard DIN
colored coating for general applications. 802 part 1 4H 5H - - -
Class 1 ISO 1 5G 5G 6H - -
TiCN-COATING – TiCN Class 2 ISO 2 4H - - 6G 7H 8H
TiCN takes place of TiN when the conditions require the Class 3 ISO 3 6H - - - 7G 8G
coating to have a different hardness and toughness. 6G
The TiCN brings an advantage to machining very difficult -- 7G
steels or cutting interrupted bores. The TiCN-coating
has a hardness of approx. 3,000 HV, but is temperature A suitable transition period is to be expected.
resistant up to approx. 400° only. That means TiCN Codes for tolerance classes 7G/8G and <X> tolerance
needs excellent cooling for long service life. Color: zones have yet to be standardized within DIN EN 22857,
Blue-grey coefficient of friction against steel : 0.4 and the values from DIN 802 part will remain valid.

TiAIN-COATING – TiAIN
This is a special coating for machining abrasive materials
such as: grey cast iron, alu-alloys with silicon, fiber
reinforced plastics, etc., or machining under high
temperatures, which means with insufficient cooling, or
high speeds ≥ 600m/min. TiAIN has a hardness of approx.
3,000 HV and is temperature resistant up to approx. 800°.
Color: Violet-grey coefficient of friction against steel : 0.4

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