MPI Metallurgical Processing
Providing metal treating & surface solutions
for precision parts & tooling since 1957!

Heat Treating Technical Information

The following sections expand to reveal heat treating and metal treating applications for machines & tools as well as several downloadable spec sheets.

High Performance Coatings

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The gold Titanium Nitride has had much success in a wide application of machining and tooling. It is an excellent, all-around, cost effective and improved to even a higher level of performance than other coatings. BETA coated parts can last up to five times longer than tools uncoated, and improves the wear resistance of the tool and allows for higher operating speeds. The new generation of BETA offers new solutions for new applications.

Material Saftey Data Sheet



The blue-gray Titanium Carbon Nitride is a new functional hard coating that achieves superior results when machining tool steels and steels over 40 HRC. It offers an optimal combination in its layering structure of hardness, toughness and anti-friction characteristics. ALPHA recommended for high-shock resistance such as tapping, interrupted cuts in drilling, milling, and heavy-duty forming operations, such as punching stamping and broaching.

Material Saftey Data Sheet



The white gold Zirconium Nitride is recommended as an alternative to titanium nitride when extra lubricity is needed. It is an excellent functional coating for drilling, forming, punching and machining aluminum, Brass and copper. Like the other coatings, ZETA improves the wear resistance of the tools or wear parts. Also used for many decorative applications.

Material Saftey Data Sheet



The advantage of this silver Titanium Nitride based coating is the improvement of the tribologic behavior of the coated tool in front of "cold welding" well known in the cutting and forming of stainless steels as well as a similar problems with milling, drilling, turning other alloys over 40 HRC such as inconel. GAMMA offers a fracture toughness which means extended lifetime for the tools.

Material Saftey Data Sheet



The Silver-Gray Chromium Nitride is characterized by a favorable combination of resistance to corrosion and oxidation. DELTA CrN exhibits much higher hardness and coating adhesion than chromium coating or platings; corrosion resistance is at least as good as with hard chromium for a given thickness.



UNIVERSAL, a violet Titanium Aluminum Nitride is recommended when extra hardness and heat resistance are required, as when machining abrasive materials such as cast iron, titanium and high silicon-content aluminum alloys. During cutting, an oxide layer forms over the TiAlN coat, providing extremely high heat resistance. The UNIVERSAL coating makes machining at higher speeds possible and smaller amounts of coolant needed.

Material Saftey Data Sheet



UNIVERSAL 4x, a new generation of hard tool coating for premium roughing and finishing endmills. This Titanium Aluminum Carbon Nitride is a high performance coating that combines the properties of TiN (lubricity, universal applications), TiCN (wear and abrasion resistance, superior fracture toughness and shock resistance) and TiAlN (super high hardness and impact resistance, excellent adhesion for heavy chip loads, reduced friction and superior wear protection, temperature and oxidation stability).



UNIMAX is a powerful coating available for high speed, high velocity machining of today's hard to machine materials. This specially designed Aluminum Titanium Nitride coating has the ultimate resistance to heat and premature wear when machining at high speeds and feeds. This gray-back coating features a unique microstructure that allows freer cutting and better chip evacuation in dry machining applications.

Material Saftey Data Sheet




MPI's new nanocomposite UNIMAX Pro AlTiSiN PVD coating is the new benchmark for hard, dry and high-speed machining applications. UNIMAX Pro shows extremely high resistance against oxidation in combination with high thermal hardness. This is the result of a special structural composition deposited in our high performance PL1000 PVD coating system. The properties of the new UNIMAX Pro yield significant advantages for applications formally covered by our standard AlTiN UNIMAX coating.



UNICHROME is newest high-performance coating added to our Universal Series. Once again pushing the envelope for high a high level of oxidation resistance and hot hardness. This special combination of elements give this coating excellent adhesion properties which lead to high wear resistance under severe machining conditions. Recommended for steel in the 40 to 50 HRc range and has proved itself in a wide range of applications.

PVD Key Characteristics

PVD Key Characteristics

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Hardness Conversion Chart

Hardness Conversion Chart

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Approximate Hardness Conversion Numbers for Non-Austenitic Steels

These values are consistent with ASTM E 140 Tables 1 and 2 for non-austenitic steels

Hardness Conversion Precautions

  • Tests should be made on properly prepared specimens on flat surfaces. Readings taken on highly curved surfaces, such as ball bearing balls, will be lower than those taken on a flat surface.
  • Rough ground or machined surfaces offer unequal support to the penetrator, and therefore surface roughness must be much less than the size of the impression. Minimum allowable thickness of a specimen varies according to the hardness, load applied, and the kind of penetrator used.
  • When more than one range of load is available for a given instrument, the largest load should be used that is consistent with the dimensions and the nature of the specimen and with the maximum allowable size of the impression for the indentor.
  • Heterogeneous materials, such as cast iron, should be tested with a penetrator of sufficient size to average the local variance in hardness within these materials. The distance of the center of the indentation from the edge of the specimen or edge of another indentation shall be at least two and half times the diameter of the indentation.
  • The angle between the load line and the normal to the specimen shall not exceed 2 degrees.
  • When converted hardness numbers are reported, the original hardness test should be indicated; for example: 480 BHN (from Rockwell C)

Heat Treatments of Tool Steels before PVD Coating

Heat Treatments of Tool Steels before PVD Coating

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Steel Grade TemperingTemperature (F) Minimum Number ofTemper Cycles HRC HardnessAfter PVD Coating
A-2 950-975 2 53-58
D-2 950-975 2 53-58
S-7 950-975 2 50-56
H-13 950-1050 2 38-42
420 SS 950-975 2 42-50
440C SS 950-975 2 48-56
M-2 1000-1075 2 60-62+
M-42 1000-1075 4 63+
T-15 1000-1075 3 63+

Special Instructions

  • Grinding Coarse grinding can leave high spots which will wear through prematurely. Burrs will break off leaving uncoated edges on tools. Grinding burn, glazing, and cracking must be avoided to provide a surface best suited for PVD coating.
  • Polishing, Burnishing and Buffing Incorporated compounds and stresses into the surfaces must be minimized. Trapped compounds can lead to coating and corrosion difficulties. Relief of residual stresses can cause warpage or dimensional changes.
  • Electro Discharge Machining (EDM) White layer and cracks must be polished out of the EDM surface. Residual stress should be stress relieved below the tempering temperature shown above to insure coatability and performance.
  • Previous Surface Treatments Bare, uncontaminated, unoxidized, un-nitrided, and unplated surfaces are best for PVD coating.
  • Braze Joints Silver braze alloys containing Cadmium (Cd) must be avoided. Silver braze joint with Cadmium can lose as much as 30% of their strength in due to the PVD coating process conditions, and also contaminate the coating chamber. Braze joints must be free of fluxes. Soldered assemblies cannot be PVD coated.
  • Multiple Tempers Are advised for best dimensional and metallurgical structure stability and to promote optimum adhesion.
  • Cryogenic Treatment May prove beneficial for optimum dimensional stability.

Basic Guide to Ferrous Metallurgy

Basic Guide to Ferrous Metallurgy

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From Sub-Zero to White Heat Range

  1. Transformation Range
  2. Lower Transformation Temp
  3. Upper Transformation Temp
  4. Annealing
  5. Normalizing
  6. Forging Range
  7. Burning Range
  8. Stress Relieving
  9. Blue Brittle Range
  10. Preheating for Welding
  11. Carburizing
  12. Nitriding
  13. Spheroidizing

MPI Brochure

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