Materials

Somta Taps are manufactured from the finest steel available. The heat treatment process is controlled by our metallurgical laboratory using advanced computerised and electronic instrumentation. High Speed Steel contains various elements such as Molybdenum, Tungsten, Cobalt and Vanadium and must be specially treated to produce the ideal combination of strength, toughness and wear resistance. Somta products are manufactured from one of the following High Speed Steels depending on the product and application.

M2 is the standard High Speed Steel and is used where toughness is important, together with a good standard of wear resistance and red hardness.

M35 is a development of M2 and contains 5% cobalt which gives improved hardness, wear resistance and red hardness. It may be used when cutting higher strength materials.

M42 can be heat treated to very high hardness levels of up to 70 HRC (1 000 HV) although normally a slightly lower figure will be employed to retain toughness. The steel is ideal for machining higher strength materials and work hardening alloys such as stainless steels, nimonic alloys etc. Despite its high hardness, M42 has good grindability characteristics due to a lower vanadium content.

M9V material is mainly used in the manufacture of machine taps because of its good wear resistance, good grinding capabilities, high hardness and excellant toughness.

Coatings

Bright Finish
A bright finish has no surface treatment and is suitable for general purpose use.

Blue Finish
A blue finish is achieved by steam tempering - a thermal process which imparts a non-metallic surface to the tool. This surface is porous and by absorbing lubricant, helps prevent rusting, reduces friction and cold welding, resulting in increased tool life. Steam tempered products can successfully be used at slightly increased machining rates or on more difficult to machine materials.

Gold Oxide
This is a metallic brown coloured surface treatment achieved by a low temperature temper and is normally only used on cobalt products for identification purposes

Nitriding
Nitriding imparts a hard surface to the tool and is used for prolonging tool life and machining difficult to machine materials. Because nitriding makes the edge more brittle, care must be exercised in the type of application Nitrided tools are normally also steam tempered.

Titanium Nitride Coating (TiN)
TiN coating is a very hard, gold coloured surface coating a few microns thick which is applied by means of a complex process, called Physical Vapour Deposition (PVD), by advanced modern equipment. The coating is non-metallic and therefore reduces cold welding.

In certain applications increased speed and feed rates can be achieved because of:
a. The hardness of the coating.
b. The reduction in cutting force required due to a decrease in friction between the tool and the workpiece. Tool performance will deteriorate after re-sharpening.

Titanium Carbonitride(TiCN)
The addition of carbon to TiN results in a significant increase in the hardness of TiCN over TiN. TiCN also has a much lower coefficient of friction which enhances the surface finish of components machined with TiCN coated tools, higher productivity can be achieved on a wide range of materials but, in particular stainless steel, titanium and nickel based alloys.

Titanium Aluminium Nitride(TiALN)
In addition to a higher hardness than both TiN and TiCN the aluminium in the coating imparts a much greater oxidation stability. This is as a result of a very thin film of (Aluminium Oxide) being formed on the surface of the TiALN. The film is self repairing, leading to additional increased service life. These improvements allow the coating to withstand much higher temperatures which in turn allows increased cutting conditions, especially usefull when machining Cast Iron and tough steels.