Общий каталог Yamawa 2021 - страница 687

The best surface treatment is applied to each tap depending on the tapping purpose. SP Characteristics and eff ectiveness of surface treatment are introduced at next section.

Oxidizing

• This treatment was processed by using HOMO furnace being made by LEED AND NORTHUP company USA in 1938, and it is called HOMO treatment. This treatment is also called vapor treatment and steam treatment. Through this treatment, Fe O layer of blue black color is

SL 3 4

produced over the tool surface.

• Oxidization treatment produces porous layer on tool’s surface. This porous layer works as oil pocket to reduce friction, to avoid welding and to improve the surface roughness of internal screw. Moreover, longer tool life is expected because the treatment reduces the remaining stress of HSS tools.

PO This treatment does not increase the hardness on tool surface. Using the furnace of YAMAWA original design and choosing the proper

treatment time, we have marked good result of oxidizing for YAMAWA HSS tools.

• Stainless steel and low carbon steel are the materials that are easy to get welding. We are applying this treatment to the special purpose taps for these materials to get good result. Further due to the reduction of friction force, this treatment has good result for wide range of

ST steel type material.

• We combine oxidizing with nitriding for the taps designed for thermal refined steels of high carbon steels and alloy steels. This double treatment wins good reputation of the market.

ROLL

Thickness of oxide layer and the time of treatment Comparison between bright and oxide treated

CARBIDE

(μm) CUTTING CONDITION Tap: SP-VA/M8×1.25/ISO2(6H) Material: AISI304 (165-171HB) LONG Hole size: Ø 6.8 mm Tapping Length: 12 mm (through hole) Tapping Speed: 7.2 m/min Cutting oil: Insoluble oil HAND Tapping Machine: CNC tapping machine

TAPS

EG (STI)

SPECIAL

THREADS,

GAUGES

THREAD

MILLS

DIES

minute SP-VA design SP-VA

(Bright) (Oxide treated) Treatment time

CENTER

DRILLS