Unique Characteristics | General Design Guidelines | Processing Guidelines | Welding Guidelines | Welding Guidelines
NAK55 is a precipitation, or age-hardened mold steel with a through hardness of approximately 40 HRc. NAK55 is ideal for use in plastic and rubber molds and other applications where impact resistance is not critical. It is a super clean, Vacuum-Arc Remelted steel with uniform grain structure, uniform hardness and excellent dimensional stability.
- Vacuum-Arc Remelt manufacturing process
- 40 HRc hardness
- Uniform hardness throughout, even in heavy sections
- When welded, NAK leaves no witness lines after re-aging
- Uniform grain structure with no pin holes, inclusions or hard spots
- Machines up to 50% faster than 30 HRc P20 mold steels
- Never needs stress relieving, even after heavy machining
General Design Guidelines
The optimum cutting conditions for NAK55 vary by machine tools. Cutting tools incorporating the recommended geometries will produce superb finish machined surfaces, often completely eliminating grinding. NAK55 does not work harden.
Material Removal Rates
Consider this: material removal rate during this time span in approximately 300 pounds of steel. It showed that we could remove a lot of steel with moderate surface feet but a heavy chip load. Once again, the clean make-up of the material made this possible.
To Calculate Surface Feed
Surface speed is usually given in feet per minute. It is the distance (in feet) that the outermost cutting edge of a rotating tool (circumference) covers in the span of 1-minute.
To understand how this translates into spindle speed, or revolutions per minute (rpm) that the cutting tool is revolving, review this example:
Surface feet 400 feet per minute Diameter of cutting tool is 4 inches. Revolutions per minute (rpm) if cutting tool is ____
C = Surface feet per minute (feet) D = Diameter of cutting tool (inches) R = Revolutions per minute of cutting tool (rpm)
R = (C x 12) = (400 x 12) = 4800 = 382 rpm
(D x Pi) (4 in. x 3.14) 12.56
If you need to know surface feet per minute and the cutter diameter and spindle speed is known, you will have this equation:
C = Pi x D x R = 3.14 x 4 x 382 = 400 sf.
To Calculate Chip Load
Chip load is the amount of materials (in .001 inches) that each cutting flute or cutting insert of a rotating tool removes.
Chip load is calculated by dividing the distance of the table travel or feed per minute in inches by the spindle speed of the machine. This will give you the distance the cutter traveled in one revolution. This number is then divided by the number of cutting flutes or inserts.
Spindle speed is 450 rpm. Table travel or feed rate is 60 inches per minute. Number of flutes or cutting inserts is 6.
R = Spindle speed (rpm)
I = Number of cutting flutes or inserts
S = Distance of feed rate or table travel in inches.
C = Chip load
|C =||= .13333||= .0222|
To Calculate Feed Rate
S = C x I x R =
S = .0222 x 6 x 450
To find rpm of spindle or R with chip load and feed rate known:
R = S = 60 = 450 rpm
I x C 6 x .0222
Welding of NAK55 should be performed employing only NAK-W Welding Rods. NAK-W Welding Rods are copper-coated for either TIG or Heli-Arc welding. Employ only recognized, safe shop welding practices.
Used in plastic molds, rubber molds, jigs & fixtures, and press dies.