NITREX HEAT TREATING SERVICES

About Surface & Heat Treating Services

Offering a wide range of heat treating & complementary services
Heat treating, Engineering & Manufacturing

COMPLETE INFO ON
OUR HEAT TREATING SERVICES:

The Nitrex network of heat treating centers is currently composed of five facilities in the United States and additional centers in Canada, China, Mexico, Italy and Poland. Our technologies and capabilities range from individual components of an almost microscopic size to 55,000-pound loads, from cryogenic treatment to high temperature vacuum, from simple annealing to plasma and Nitreg® potential-controlled nitriding, from forging blanks to complex aircraft components, from heat treating to manufacturing operations and engineering services.

Locations

CANADA

NITREX METAL INC.
Heat Treating Services

Website: www.nitrexheattreat.com

3474 Poirier Blvd.

St. Laurent, Quebec, H4R 2J5

toll free +1-877-335-7191

t: +1 514 335 7191

f: +1 514 335 4160

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CHINA

NITREX THERMAL TECHNOLOGY (WUXI) Co., Ltd.
Heat Treating Services

214105

江苏省无锡市锡山经济技术开发区

安泰三路,安泰机械工业园

Website: www.nitrex-ntt.cn

t: +86 (0510) 88788627

f: +86 (0510) 88787627

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ITALY

COLMEGNA Srl
Heat Treating Services

Website: www.colmegna.com

Siziano (PV)

t: 0382-617964 (r.a.)

f: 0382-617760

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MEXICO

Servicios de Tratamientos Térmico
STT Nitrex Querétaro, S. De R.L. De C.V.
Heat Treating Services

Website: www.nitrexheattreat.com

t: +52 442 221 5243

f: +52 1442 185 8922

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POLAND

NITREX METAL Sp. z o.o.
Heat Treating Services

Website: www.nitrexheattreat.com

ul. Jedności 48
41-218 Sosnowiec
Poland

Tel:  +48 32 296 66 30
Fax: +48 32 296 66 20

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USA - CALIFORNIA

“NITREX INC. – West Coast Operations”
(California Corporation)
Heat Treating Services

Website: www.nitrexheattreat.com

441 Perrymont Avenue
San Jose, CA 95125

t: +1 408 275 0330

f: +1 408 659 7195

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USA - ILLINOIS

“NITREX INC. – Chicago Operations”
(Illinois Corporation)
Heat Treating Services

Website: www.nitrexheattreat.com

1900 Plain Avenue
Aurora, IL 60502

t: +1 630 851 5880

f: +1 630 851 0733

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USA - INDIANA

“NITREX INC. – Indiana Operations”
(Indiana Corporation)
Heat Treating Services

Website: www.nitrexheattreat.com

350 Blue Chip Court
Franklin, IN 46131

t: +1 317 346 7700

f: +1 317 346 7704

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USA - MICHIGAN

“NITREX INC. – Michigan Operations”
(Michigan Corporation)
Heat Treating Services

Website: www.nitrexheattreat.com

822 Kim Dr., P.O. Box 155
Mason, MI 48854

t: +1 517 676 6370

f: +1 517 676 6427

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USA - NEVADA

“NITREX INC. – Nevada Operations”
(Nevada Corporation)
Heat Treating Services

Website: www.nitrexheattreat.com

201 E. Mayflower Ave.
North Las Vegas, NV 89030

t: +1 702 399 1554

f: +1 702 639 3819

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Nitrex is a provider of premium quality heat treating services in a growing number of locations worldwide. The individual plants constantly adapt to the changing market conditions by installing additional equipment.

Heat Treating & Metal Surface Treatments Library

A
  • Age/ Precipitation Hardening
    Age or Precipitation Hardening (also Aging) is a change in material properties (generally hardening) effected by holding parts at moderately elevated temperatures, without any change in the chemistry of the alloy.

  • Austenitizing
    Austenitizing is a process designed to induce the formation of austenite on the alloy.

  • Annealing – Conventional
    The main purpose of Annealing is to soften the metal. This process is used as one of the preliminary heat treating operations or as a rescue procedure when a hardening or tempering cycle fails to meet the specification requirement and one has to start over.

  • Annealing –Vacuum
    The process is virtually identical to conventional annealing, except, as is usually the case, this premium quality Vacuum Annealing method protects the components’ surfaces from chemical reactions with gases present in the atmospheres present in the conventional process.

B
  • Brazing – Vacuum
    Vacuum Brazing uses a vacuum furnace but it is not, strictly speaking, a heat treating process. Brazing, in general, is a process of joining two components with a metallic bond by briefly liquefying the latter while the assembly is under vacuum conditions.
C
  • Carbon Restoration
    In the event that in a heat treating operation the components suffered from decarburization (loss of carbon content) of the surface, we are capable of salvaging them using the Carbon Restoration technique.

  • Carbonitriding – Conventional
    Carbonitriding is a process similar to carburizing whereby ammonia is added to the carburizing atmosphere, which results in supplementary nitrogen diffusion into the surface of a treated component.

    Note: carbonitriding is sometimes confused with nitrocarburizing. Please read the descriptions of both processes to avoid misunderstandings.

  • Carbonitriding – Vacuum
    It is a thermal process of simultaneously diffusing both carbon and nitrogen into ferrous alloys under partial pressure. This leads to an extremely hard and wear resistant surface. Vacuum carbonitriding is a significant improvement over conventional gas carbonitriding. The process contains all of the inherent benefits of vacuum carburizing, but also has the additional benefit of precise computer control of surface ammonia content. Furthermore, this process does not require any additional refractory burn-outs so not only is the end product of higher quality, but it is often less expensive than with competing conventional gas processes.
  • Carburizing – Conventional
    Carburizing is a process of controlled diffusion of carbon into the surface of a component, followed by quenching and tempering, with the objective of increasing the component’’s surface hardness. The process is generally applicable to low carbon steels. When conducted in a “conventional”, rather than in a vacuum furnace, we can refer to the process as conventional carburizing.

    In this thermal process ferrous alloys are heated to above their transformation temperature and exposed to carbon rich medium. Processing temperatures fall in the 1450°F – 1900°F (790°C – 1040°C) range. The diffusion of carbon into the part and the subsequent quench leads to a part with a hard, wear resistant surface and a tough shock resistant core.

    Solid, liquid and gaseous carbon-carrying medium may be employed, however, the first two are rarely used. Nitrex-offered carburizing is conducted in computer controlled integral quench and pit gas carburizing furnaces. A full range of case depths if feasible with an economically derived limit of approximately 0.250″ (6.4 mm).

    In addition, Nitrex is capable of selective carburizing where only specific areas of the part are to be treated.

  • Carburizing – Vacuum

    Vacuum carburizing is a state-of-the-art thermal process where carburizing is effected under very low pressures. First the parts are heated in vacuum to above the transformation temperature of the alloy. Then they are exposed to carbon-carrying gas, or gas mixtures, under partial pressure. Nitrex has developed a revolutionary process called “Pulse- Pressure”, a method quickly becoming the industry standard.

    Relative to conventional carburizing, the main advantages of the method are:

    • repeatable results to within ±0.001″ (±25µm)
    • significantly reduced size changes and distortion
    • improved fatigue strength
    • better control of the surface layer chemistry
    • the process is environmentally friendly

    The basic aspects or carburizing in general are described in the Conventional Carburizing section.

  • Clamp Tempering
    Heat treatment is inherently distorting to the parts. To reduce distortion some components must be restrained during tempering by being “clamped”, and process is then called clamp tempering.
  • Cryogenic Treatment / Freezing
    After a successful quench and temper, it is frequently desirable to subject the work piece to a cryogenic treatment, also referred to as freezing (or sub-zero freezing). This process induces carbide particles to precipitate into voids in the iron lattice, thus creating a denser, more stabilized structure that reduces friction, wear and thermal softening.

    Summary of Benefits:

    • Conversion of retained austenite (soft) into martensite (hard)
    • Increased strength, toughness, stability and durability
    • Increased density of the steel structure
    • Lower coefficient of friction
    • Decreased residual stresses and brittleness
    • Significantly improved abrasive wear resistance

F
  • Ferritic Nitrocarburizing – FNC / Nitreg®-C: Potential-Controlled Nitrocarburizing

    A shorter cycle time of the Nitreg® process carried out predominantly on carbon and low alloy materials.

    Nitreg®-–C is a controlled version of nitrocarburizing (nitrocarburising or FNC process). It allows for precise KN control during the process. The additions of carbon bearing gases to the nitriding atmosphere help to increase the relative content of the epsilon phase.

    The advantage of a KN controlled technology is best evidenced when increased wear and/or corrosion resistance is sought. Such properties of the nitrided case are not only influenced by the thickness and relative phase composition of the WL. They also strongly depend on the relative level of porosity developed in the WL.

    The KN control is essential in producing the desired WL configuration

    Example of various porosity levels achieved through KN control are shown below.

    Benefits:

    • Increased wear/corrosion resistance on selected alloys
    • No distortion
    • No brittleness
    • Excellent process reliability
  • Freezing / Cryogenic Treatment
    After a successful quench and temper, it is frequently desirable to subject the work piece to a cryogenic treatment, also referred to as freezing (or sub-zero freezing). This process induces carbide particles to precipitate into voids in the iron lattice, thus creating a denser, more stabilized structure that reduces friction, wear and thermal softening.Summary of Benefits:

    • Conversion of retained austenite (soft) into martensite (hard)
    • Increased strength, toughness, stability and durability
    • Increased density of the steel structure
    • Lower coefficient of friction
    • Decreased residual stresses and brittleness
    • Significantly improved abrasive wear resistance
G
  • Glass Beading
    The surface of metal components may be cleaned by impingement of a jet of glass beads. Nitrex will use this technique occasionally when sand blasting would be considered too rough.
H
  • Hardening / Quenching – Conventional
    Hardening is one of the oldest metallurgical processes known to man, originally in the form of heating a sword in the fire and then throwing it into the lake to make it harder. The more modern approach is to heat components in an atmosphere furnace followed by quenching, generally in heated oil.

    The expression “conventional hardening” is used here to differentiate the process from vacuum hardening. It should also be noted that “hardening” is usually referred to as “quenching”.

    A more refined version of this process is Vacuum Hardening.

  • Hardening – Vacuum 
    Vacuum Hardening is an improvement over Conventional Hardening in that the components’ surfaces are protected from possible negative effects of exposure to a gaseous atmosphere. Vacuum treated material is quenched in gas or liquid, depending on the specification requirements.

    The expression “vacuum hardening” is used here to differentiate the process from conventional hardening. It should also be noted that “hardening” is usually referred to as “quenching”.

I
  • Ion Nitriding / Plasma Nitriding
    As an alternative to gas nitriding, nitriding plasma (ion) nitriding process has been developed to overcome the shortcomings of the earlier traditional uncontrolled gas nitriding processes and to offer certain operational advantages that gas nitriding does not have.

    Plasma is essentially a gas nitriding treatment in which the method of delivering nitrogen atoms to the surface of nitrided components is quite different from the standard gas nitriding processes. It occurs at a very low pressure and under high voltage.

    From the metallurgical, tribological and mechanical properties standpoint the properties of nitrided case obtained with Nitreg® and well controlled plasma technology are comparable.

    Plasma offers certain distinct advantages such as:

    • The ease of masking the component surface where nitriding is to be avoided.
    • Ability to nitride low density powder metallurgy parts

    Ask us for an advice about which nitriding method is better suited to your situation.

    If your drawing calls for “ion” or “plasma” nitriding we are at your service.

N
  • Nitreg®: Potential-Controlled Nitriding
    The main objective of nitriding is to increase the hardness of the component’s surface by enriching it with nitrogen. Of the three traditional methods Nitrex does not employ salt bath techniques due to their environmental and safety risks. Plasma nitriding is described in a separate section and traditional gas nitriding is gradually being phased out thanks to the development of the Nitreg® family of processes. General principles of the various nitriding methods and an explanation of potential-controlled techniques are described in a separate section accessible by clicking here. Nitreg® is a modern process, capable of meeting the metallurgical requirements of all nitriding specifications that may have been originally written for salt bath, plasma or traditional gas nitriding. The ability to control the concentration of nitrogen in the surface allows the user to control the growth of the compound layer virtually independently from developing a desirable diffusion zone. This approach facilitates not only meeting any specification requirements but it also makes it possible to improve on them by allowing tighter tolerances to be satisfied, particularly with regard to the thickness and properties of the compound layer.

    Summary of Benefits:

    • control of the thickness of the compound (white) layer and its properties
    • elimination of closed nitride networks within the diffusion zone
    • control of case depth
    • control of surface hardness
    • no distortion
    • family of derivative and related processes
  • Nitreg®-C: Potential-Controlled Nitrocarburizing (FNC process)
    A shorter cycle time of the Nitreg® process carried out predominantly on carbon and low alloy materials. Nitreg®-–C is a controlled version of nitrocarburizing (nitrocarburising or FNC process). It allows for precise Kn control during the process. The additions of carbon bearing gases to the nitriding atmosphere help to increase the relative content of the epsilon phase.

    The advantage of a KN controlled technology is best evidenced when increased wear and/or corrosion resistance is sought. Such properties of the nitrided case are not only influenced by the thickness and relative phase composition of the WL. They also strongly depend on the relative level of porosity developed in the WL.

    The KN control is essential in producing the desired WL configuration

    Example of various porosity levels achieved through KN control are shown below.

    Benefits:

    • Increased wear/corrosion resistance on selected alloys
    • No distortion
    • No brittleness
    • Excellent process reliability
  • Nitreg®-S: Potential-Controlled Nitriding of Stainless Steel
    The rules applying to nitriding of stainless steel or refractory alloys are no different than those for the other groups of steels, with one exception.

    The exception is the proprietary de-passivation stage that allows for a removal of oxides of alloying elements such as Cr, Ni and others which, if not removed, will effectively block the nitriding process. The same way they block the rust formation on the stainless steel surface.

    All types of stainless steel can be nitrided. The martensitic, austenitic or PH materials inclusive.

    Example of a nitrided stainless steel part

  • Nano-STM: Potential-Controlled Nitriding of Stainless Steel
    NANO-STM is a surface hardening process that improves the wear and galling resistance of stainless steel components without affecting the inherent corrosion resistance.

    Benefits:

    • Attains excellent wear resistance
    • Improves fatigue strength
    • Retains intrinsic corrosion properties
    • Prevents galling
    • Does not alter chemical composition of alloy
    • Has no effect on the steel’’s non-magnetic nature
    • No change in the color, shape or size
    • Uniformly hardened even small bores, tight grooves and sharp edges
    • Green technology, no waste pollution

    Treatable Materials:

    • Austenitic Stainless Steels
    • Martensitic Stainless Steels
    • A286
    • Custom 465
    • Duplex Stainless Steel
    • Hastelloy C22 and C276
    • Inconel 625 and 718
    • Inquire about other materials
  • Nitreg®-Ti: Potential-Controlled Nitriding of Titanium Alloys
    Titanium alloys, used mostly in the aerospace and defense industries can also be successfully gas nitrided leading to an increased wear resistance and providing an attractive golden finish.

    The technology is not widely known since the applications involved are also very specific. For best results consult with our engineers who will advise you on certain unique aspects of the manufacturing sequence of operations.

    Examples of a nitrided titanium alloy parts.

  • Normalizing
    Normalizing is a relatively simple process whose parameters, however, depend greatly on the type of steel and the desired result. The main purpose will usually be an improvement and homogenization of the grain structure.

O
  • ONC®: In-process Post-Nitriding/Nitrocarburizing Oxidation
    When resistance to atmospheric corrosion and an attractive black finish are the predominant requirements, ONC® is the appropriate process.

    Its objective is to transform the very top portion of the WL obtained with either Nitreg® or Nitreg®-C technologies into a complex spinel type structure consisting mostly of Fe3O4 type of iron oxide.

    Such a post-nitriding oxidation treatment has a net effect of enhancing the corrosion resistance of an already nitrided component. This integrated process (i.e. Nitreg®+ ONC® or Nitreg®-C + ONC®) simultaneously enhances corrosion and wear resistance of steel, while giving the surface an attractive dark or black appearance, expressly desired by many customers.

    ONC®, applied in combination with the Nitreg® potential-controlled nitriding process or the Nitreg®-C potential-controlled nitrocarburizing process, is a clean technology that in many instances can replace chrome plating and salt bath nitriding with their inherent problems of pollution and cost.

    Depending on the type of steel, parts treated in the Nitreg®-ONC process can easily pass well over 200 hours of salt-spray test per ASTM B117 before the first corrosion spot appears. Fig. 2 shows a comparison of metallurgical and corrosion test results obtained on three materials treated by the Nitreg®-ONC® process.

    Benefits:

    • Improved corrosion resistance
    • Attractive black surface finish
    • Inherent wear resistance
P
  • Plasma (Ion) Nitriding
    As an alternative to gas nitriding, nitriding plasma (ion) nitriding process has been developed to overcome the shortcomings of the earlier traditional uncontrolled gas nitriding processes and to offer certain operational advantages that gas nitriding does not have.

    Plasma is essentially a gas nitriding treatment in which the method of delivering nitrogen atoms to the surface of nitrided components is quite different from the standard gas nitriding processes. It occurs at a very low pressure and under high voltage.

    From the metallurgical, tribological and mechanical properties standpoint the properties of nitrided case obtained with Nitreg® and well controlled plasma technology are comparable.

    Plasma offers certain distinct advantages such as:

    • The ease of masking the component surface where nitriding is to be avoided.
    • Ability to nitride low density powder metallurgy parts

    Ask us for an advice about which nitriding method is better suited to your situation.

    If your drawing calls for “ion” or “plasma” nitriding we are at your service.

  • Precipitation Hardening 
    Age or Precipitation Hardening (also Aging) is a change in material properties (generally hardening) effected by holding parts at moderately elevated temperatures, without any change in the chemistry of the alloy.

Q
  • Quench & Temper – Conventional
    The words “quench and temper” are not a technology but just an expression. We have included this paragraph for the sake of completeness and to help those unfamiliar with these processes in absorbing these concepts more easily. Quenching and tempering are the most fundamental heat treatments available in that most ferrous alloys must first be hardened (quenched) and then tempered to the appropriate hardness. The expression “quench and temper” (or “harden and temper”, which is the same thing) is so entrenched that some of us forget that in a sequence of conventional processes the two are done in different furnaces, with parts transferred, as quickly as possible, from one to the other.

    Quenching and tempering are described separately in this section.

  • Quenching / Hardening – Conventional
    Hardening is one of the oldest metallurgical processes known to man, originally in the form of heating a sword in the fire and then throwing it into the lake to make it harder. The more modern approach is to heat components in an atmosphere furnace followed by quenching, generally in heated oil.

    The expression “conventional hardening” is used here to differentiate the process from vacuum hardening. It should also be noted that “hardening” is usually referred to as “quenching”.

    A more refined version of this process is Vacuum Hardening.

S
  • Sand Blasting
    Sand blasting is used primarily to remove rust, paint, scale or significant blemishes on the surface of components. Depending on the need, the technique is used either before heat treatment (preparation) or after (e.g., removal of oxidation).

  • Shot Blasting or Peening
    When tiny steel balls are used the process of blasting parts using this medium will be called shot blasting or peening. Jets of shot are aimed at components while they tumble in a rotating chamber. Some differentiate between “blasting” or “peening”, but the process is the same nevertheless. The former expression is used when the objective is to clean the parts or remove sharp edges, while the latter indicates a desire to mechanically compress the surface layer of the material. In this manner compressive stresses are introduced which in most cases will improve the fatigue resistance of the component.

  • Straightening
    Certain types of components, particularly longer objects such as shafts, tend to distort in high temperature treatment. In most cases they can be successfully straightened using special hydraulic presses.

  • Stress Relieving
    As the name of the process clearly indicates, Stress Relieving is used to reduce the residual stresses in the microstructure after machining or certain heat treating operations, to prevent distortion from occurring later.

T
  • Clamp Tempering
    Heat treatment is inherently distorting to the parts. To reduce distortion some components must be restrained during tempering by being “clamped”, and process is then called clamp tempering.

  • Tempering – Conventional
    Tempering is almost always required after hardening (both in an atmosphere furnace as well as in vacuum, as described further), to reduce the hardness (and brittleness) to a desirable level.

    The expression “conventional tempering” is used here to differentiate the process from “vacuum tempering”.

  • Tempering – Vacuum
    Vacuum Tempering is almost always required after hardening (both in an atmosphere furnace as well as in vacuum), to reduce the hardness (and brittleness) of the treated material to a desirable level.

    Generally it is not necessary to use vacuum tempering after vacuum hardening, i.e., conventional tempering is most of the time used. Vacuum tempering may be used on high value products, when totally clean surface appearance is required.

    The expression “vacuum tempering” is used here to differentiate the process from “conventional tempering”.

V
  • Vacuum Annealing
    The process is virtually identical to conventional annealing, except, as is usually the case, this premium quality Vacuum Annealing method protects the components’ surfaces from chemical reactions with gases present in the atmospheres present in the conventional process.

  • Vacuum Brazing
    Vacuum Brazing uses a vacuum furnace but it is not, strictly speaking, a heat treating process. Brazing, in general, is a process of joining two components with a metallic bond by briefly liquefying the latter while the assembly is under vacuum conditions.

  • Vacuum Carbonitriding
    It is a thermal process of simultaneously diffusing both carbon and nitrogen into ferrous alloys under partial pressure. This leads to an extremely hard and wear resistant surface. Vacuum carbonitriding is a significant improvement over conventional gas carbonitriding. The process contains all of the inherent benefits of vacuum carburizing, but also has the additional benefit of precise computer control of surface ammonia content. Furthermore, this process does not require any additional refractory burn-outs so not only is the end product of higher quality, but it is often less expensive than with competing conventional gas processes.

  • Vacuum Carburizing
    Vacuum carburizing is a state-of-the-art thermal process where carburizing is effected under very low pressures. First the parts are heated in vacuum to above the transformation temperature of the alloy. Then they are exposed to carbon-carrying gas, or gas mixtures, under partial pressure. Nitrex has developed a revolutionary process called “Pulse- Pressure”, a method quickly becoming the industry standard.

    Relative to conventional carburizing, the main advantages of the method are:

    • repeatable results to within ±0.001″ (±25µm)
    • significantly reduced size changes and distortion
    • improved fatigue strength
    • better control of the surface layer chemistry
    • the process is environmentally friendly.

    The basic aspects or carburizing in general are described in the Conventional Carburizing section.

  • Vacuum Hardening
    Vacuum Hardening is an improvement over Conventional Hardening in that the components’ surfaces are protected from possible negative effects of exposure to a gaseous atmosphere. Vacuum treated material is quenched in gas or liquid, depending on the specification requirements.

    The expression “vacuum hardening” is used here to differentiate the process from conventional hardening. It should also be noted that “hardening” is usually referred to as “quenching”.

  • Vacuum Tempering
    Vacuum Tempering is almost always required after hardening (both in an atmosphere furnace as well as in vacuum), to reduce the hardness (and brittleness) of the treated material to a desirable level.

    Generally it is not necessary to use vacuum tempering after vacuum hardening, i.e., conventional tempering is most of the time used. Vacuum tempering may be used on high value products, when totally clean surface appearance is required.

    The expression “vacuum tempering” is used here to differentiate the process from “conventional tempering”.