Page 67 - Aluminum_Machining_catalog_2023

USER GUIDE
TAPS

Tap Surface Treatments and Coating Types

The high speed steels we use grant high wear resistance Hardslick-COATING – Hardslick
and toughness. For machining certain materials, Hardslick combines in a novel way the advantages
various surface treatments are an advantage. of an extremely hard, thermally stable TiAIN-coating
with the sliding and lubricating properties of an outer
Steam Tempered (ST) WC/C (Tungsten carbide/carbon) coating. The hardslick
The steam tempered is a Fe3O4 oxide coating coating has a hardness of approx. 3,000 HV and is
which reduces the friction between the tool temperature-resistant up to approx. 800°C. Color:
and workpiece and prevents cold welding. Violet-grey coefficient of friction against steel : 0.2

Nitriding (NI) Tolerances According to DIN EN 22857
Recommended surface treatment for machining hard For taps with ISO metric threads.
wear/abrasive materials such as grey cast iron, aluminum The following chart gives a comparison between
alloys with high silicon percentage (more than 10%). the new standard DIN EN 22857 and the withdrawn
standard DIN 802 part 1. An important change is the
TiN Coating (TI) re-classification from tap tolerance to tap application class.
The TiN coating has a hardness of approximately
2,300 HV and is temperature resistant up to Tolerance
approximately 600°C. This is an excellent golden Application Class to Allotment of the
Class for
colored coating for general applications. Withdrawn Tolerance Zones of the
Taps to DIN Standard DIN Nut Thread to Be Cut
TiCN-COATING – TiCN EN 22857 802 Part 1
TiCN takes place of TiN when the conditions require the class 1 ISO 1 4H 4H 5H - - -
coating to have a different hardness and toughness. class 2 ISO 2 6H 5G 5G 6H - -
The TiCN brings an advantage to machining very difficult class 3 ISO 3 6G - - 6G 7H 8H
steels or cutting interrupted bores. The TiCN-coating
has a hardness of approx. 3,000 HV, but is temperature - - 7G - - - 7G 8G
resistant up to approx. 400°C only. That means TiCN A suitable transition period is to be expected.
needs excellent cooling for long service life. Color: Codes for tolerance classes 7G/8G and <X> tolerance
Blue-grey coefficient of friction against steel : 0.4 zones have yet to be standardized within DIN EN 22857,
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°C. Color:
Violet-grey coefficient of friction against steel : 0.4

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