35 Benefits of Nitriding

35 Benefits of Nitriding

Getting into detail on the benefits of Liquid Salt Bath Nitrocarburizing 

Enhanced Surface Hardness

Nitriding achieves enhanced surface hardness by infusing nitrogen and carbon into the metal's surface layer. This infusion forms extremely hard nitride compounds within the material's crystal lattice structure. Consequently, the surface hardness increases significantly, often measured using the Vickers hardness scale. This heightened hardness provides resistance against deformation, indentation, and wear, making the material highly durable and capable of withstanding abrasive forces and surface damage. Nitrided components feature a robust outer layer that greatly contributes to their extended lifespan and exceptional resistance to wear and mechanical stress, making them well-suited for demanding applications.

Wear Resistance 

The enhancement of wear resistance in nitriding results from the formation of robust nitride compounds within the metal's surface structure. As nitrogen atoms infiltrate the crystal lattice of the metal and bond with it, they create exceptionally hard surfaces that exhibit resistance to abrasive forces. This resistance translates into reduced material loss and prolonged component lifespan in applications subjected to sliding, rolling, or abrasive wear conditions. Nitrided parts excel in maintaining their integrity and performance even under demanding mechanical stress, making them ideal for critical applications where durability and reliability are paramount.

Lowers Friction

The reduction in friction is primarily attributed to the smoother and harder surface generated through the nitriding process. Nitrogen and carbon diffusion leads to the formation of hard nitride compounds on the metal's surface, creating a more polished and less abrasive contact interface. This, in turn, diminishes the coefficient of friction during interactions with other materials, resulting in lower energy dissipation, reduced heat generation, and decreased wear on the treated component. The overall effect is improved operational efficiency, prolonged part lifespan, and minimized maintenance requirements.

Lowers Adhesion 

Nitriding reduces the propensity for foreign materials or substances to adhere. Consequently, the nitrided surface exhibits reduced stickiness or bonding when in contact with other materials. This property is especially advantageous in applications where minimizing material buildup or contamination is critical, ensuring smoother and more efficient long-term operation.

Galling Resistance 

Nitrided components, thanks to their improved lubricity and surface hardness, are less prone to galling and associated surface damage, ensuring smoother and more reliable performance, particularly in applications involving metal-to-metal contact subjected to heavy loads or high friction.

Improved Corrosion Resistance

The surface layer compounds formed by the nitriding process serve as a robust shield, effectively preventing the infiltration of moisture, chemicals, or corrosive elements into the underlying metal structure. Consequently, nitrided components exhibit remarkable resistance to corrosion, making them well-suited for applications exposed to aggressive environments or chemical substances. This corrosion resistance not only prolongs the component's lifespan but also ensures reliable performance in challenging conditions, safeguarding the integrity of critical parts.

Increased Fatigue Strength

Reducing the risk of crack initiation and propagation during cyclic loading and mechanical stress, nitriding effectively improves the material's resistance to fatigue failure. Nitrided components exhibit greater endurance, making them well-suited for applications where components are subjected to repeated stress and strain cycles, such as in automotive engine parts and aerospace components. The heightened fatigue strength ensures prolonged reliability and reduced risk of fatigue-related failures.

Low Distortion 

Nearly 100% of nitrided products are finished machined to final tolerances before nitriding. Minimal dimensional change is a distinctive benefit of nitriding. Nitriding introduces nitrogen and carbon into the metal's surface at low temperatures compared to other heat treatments. This ensures that the core properties of the material remain largely unchanged. As a result, nitrided components experience minimal expansion or contraction, preserving their original shape and dimensions. This characteristic is invaluable for parts with tight tolerances or intricate geometries, where maintaining precise dimensions is critical. Nitriding allows for surface enhancement without compromising the component's overall integrity, making it a favored choice in industries where dimensional accuracy is paramount.

Improved Lubricity

Nitriding greatly reduces surface friction and adhesion owing to the formation of a ceramic-like compound layer created at the surface of the part. Not only does nitriding inherently increase lubricity, but it also creates micro-porosity at the surface that acts as a reservoir for holding lubricant, thus enhancing the material's ability to interact with lubricants effectively. As a result, nitrided components exhibit reduced resistance to sliding or rolling motion, improving their overall efficiency and performance. Nitriding provides a lubricious surface that enhances the efficiency and reliability of moving parts.

Enhanced Aesthetics

The process combines nitrocarburizing and black oxidation and it is the post black oxidization that significantly impacts aesthetics. This step results in the formation of a black oxide layer on the surface. This black layer is not only uniform and sleek, but it also provides additional corrosion resistance and reduces light reflection. The resultant matte black finish is particularly desired in various industrial and consumer applications for its enhanced visual appeal, especially when components are exposed in finished products, or when a non-reflective surface is required.

Improved Performance of Extrusion Dies and Molds

Extrusion dies and molds play a critical role in shaping and forming various materials, including plastics and metals. Aluminum extrusion dies & plastic injection molds benefit greatly from nitriding. These components are subjected to high temperatures, mechanical stress, and abrasive materials during the extrusion process, leading to wear, corrosion, and reduced lifespan.

Liquid Nitriding enhances the performance of extrusion dies and molds by creating a hard and wear-resistant surface layer. The nitride compounds formed during the process provide exceptional resistance to wear, heat, and corrosion. Nitriding reduces surface adhesion and helps with mold release. Nitrided dies and molds maintain their precision and durability over extended production runs. This benefit translates into reduced downtime for maintenance, improved product quality, and cost savings in industries such as plastics manufacturing, where the reliability and longevity of extrusion equipment are crucial for efficient production processes. 

Enhanced Resistance to Sea Salt Corrosion

Liquid Nitriding improves a component's resistance to sea salt corrosion by creating a protective surface layer composed of nitride and oxide compounds. These compounds act as barriers, effectively shielding the underlying metal from the corrosive effects of saltwater. As a result, nitrided components are better equipped to withstand exposure to sea salt and humid marine environments, making them ideal for use in marine and offshore applications. This benefit ensures the longevity and reliability of components in conditions where protection against sea salt corrosion is essential, such as shipbuilding, offshore oil and gas platforms, and coastal infrastructure.

Extended Component Lifespan

During liquid salt bath nitrocarburizing, nitrogen and carbon atoms diffuse into the surface layers of the component. This results in the formation of a compound layer and a diffusion layer underneath. The compound layer consists of iron nitrides and carbonitrides, which are extremely hard and thus provide excellent wear resistance. This layer reduces the wear rate of the treated components, extending their operational life.

Additionally, the nitrocarburized surface is more resistant to corrosion, especially in moisture-laden or mildly corrosive environments. This resistance further prevents premature failure due to environmental factors.

Furthermore, the process also enhances the fatigue strength of the treated components. This means that components subjected to cyclic loads (repeated stress and strain) will have a longer life before they fail due to fatigue.

In summary, by improving wear resistance, corrosion resistance, and fatigue strength, liquid salt bath nitrocarburizing significantly extends the lifespan of treated components.

Enhanced Load-bearing Capacity

Nitriding creates a hardened surface, which is substantially harder than the untreated base material. This hardened layer provides improved resistance to surface deformation under load. Essentially, the surface is better equipped to bear loads without undergoing wear, indentation, or other forms of surface degradation.

Furthermore, this nitrided layer provides increased resistance to surface-initiated fatigue failures. When a component is subjected to cyclic or repetitive loads, the hardened surface layer can better resist the initiation and propagation of microscopic cracks that might eventually lead to component failure.

In essence, the enhanced surface hardness and fatigue resistance imparted by liquid salt bath nitrocarburizing enable components to bear greater loads over more extended periods, thereby amplifying their load-bearing capacity.

Improved Thermal Stability

A great example of thermal stability is a product we have nitrided thousands of are diesel engine exhaust brakes. The exhaust brakes heat cycle from cold to up to 800°F. The brake valve cycles thousands of times within a vast temperature range and it was found that nitriding the shaft & bushings (the bearing & seal surfaces) out performed everything else that was tested. 

The nitride layer has higher thermal stability than untreated steel, or other surface treatments or coatings. This means that components treated with liquid salt bath nitrocarburizing can maintain their enhanced surface properties and dimensional integrity even when exposed to elevated temperatures. This improved thermal stability ensures that the component's hardness, wear resistance, and fatigue strength are less likely to degrade in high-temperature applications, making nitrocarburized parts suitable for environments with both mechanical and thermal demands.

Resistance to Fretting Wear

Fretting wear is a specific wear phenomenon that occurs at the contact interface of two materials subjected to oscillatory relative motion of small amplitude, often exacerbated under load. This can lead to material removal and can initiate cracks, potentially resulting in catastrophic failures. This hard, wear-resistant nitride layer provides a robust shield against the microscopic abrasions and stresses associated with fretting. The enhanced surface hardness and the modified tribological characteristics of the nitrided layer drastically reduce the susceptibility of the component to the damaging effects of fretting wear, ensuring a longer and more reliable operational life in conditions where such wear is a concern.

Resistance to Micro-pitting

Micro-pitting is a form of fatigue-driven surface wear that manifests as small pits or fissures on the contact surfaces, particularly observed in gear teeth and rolling bearing applications. These tiny surface defects can grow over time, leading to reduced component performance and eventual failure. The nitride layer has a greater resistance to the initial formation and propagation of these minute pits. Consequently, components treated with liquid salt bath nitrocarburizing have a bolstered defense against the onset and progression of micro-pitting, ensuring they maintain their structural integrity and performance under challenging operational conditions.

Potential Weight Reduction

With enhanced durability and strength concentrated on the surface, designers and engineers can often reduce the bulk or thickness of the treated components without compromising their performance or lifespan. Consequently, this allows for the creation of components that are both lighter and equally, if not more, durable than their non-nitrocarburized counterparts. In applications like automotive or aerospace, where weight is a crucial factor, this potential weight reduction can lead to greater fuel efficiency and overall improved performance.

Reduced Maintenance Costs

As a result of nitriding, the treated components exhibit increased operational longevity and a decreased tendency to fail or degrade under service conditions. This extended durability translates directly to fewer replacements, less downtime, and reduced labor costs associated with maintenance. Furthermore, the enhanced resistance to wear and corrosion can reduce the need for frequent lubrication or protective coatings. Overall, the longer life and reduced care requirements of nitrocarburized components lead to significant savings in maintenance expenditures over the component's operational lifespan.

Environmentally Friendly Process

Liquid salt bath nitrocarburizing is a thermochemical treatment used to enhance the surface properties of ferrous metals. A notable advantage of this process is that it's considered an "Environmentally Friendly Process." Here are ten reasons exemplifying this claim:

  1. Reduced Toxic Waste: Unlike some surface treatments, liquid salt bath nitrocarburizing produces minimal hazardous waste, reducing the environmental footprint associated with waste disposal.
  2. Substitution for Harmful Processes: This treatment can replace more environmentally detrimental processes like chrome plating, which involves toxic hexavalent chromium, or cadmium coatings, which have recognized health and environmental impacts.
  3. Energy Efficiency: Nitrocarburizing operates at lower temperatures than traditional carburizing or hardening, translating to less energy consumption and consequently, reduced greenhouse gas emissions.
  4. Longer Component Lifespan: Treated components last longer, leading to reduced resource consumption for manufacturing replacements and decreased waste from discarded parts.
  5. Decreased Reliance on Lubricants: The enhanced wear resistance of nitrocarburized components can reduce the need for lubrication, decreasing potential environmental contamination from lubricant disposals.
  6. Lesser Use of Protective Coatings: The inherent corrosion resistance provided by nitrocarburizing can diminish the need for additional protective coatings, which might involve environmentally harmful chemicals.
  7. Minimal Water Usage: Compared to other treatments which may require significant water for cooling or rinsing, the liquid salt bath process utilizes a molten salt medium, leading to reduced water consumption.
  8. Reduction in Airborne Pollutants: The process generates fewer volatile organic compounds (VOCs) and other airborne pollutants compared to some alternative treatments.
  9. Safer Work Environment: By using less-toxic chemicals and producing fewer harmful byproducts, the process can create a safer work environment, reducing health risks for workers and surrounding communities.
  10. Less Frequent Maintenance: The enhanced durability of treated components can mean less frequent maintenance, which not only saves costs but also results in fewer maintenance-related environmental impacts like the disposal of worn-out parts or use of cleaning agents.

These reasons underscore how liquid salt bath nitrocarburizing, when compared to many traditional treatments, can be a more environmentally conscious choice.

Environmentally Friendlier than Gas Nitriding

Liquid salt bath nitrocarburizing and gas nitriding are both thermochemical processes aimed at enhancing the surface properties of ferrous metals, but they differ in their environmental impact. Here are ten reasons why liquid salt bath nitrocarburizing might be considered more environmentally friendly than gas nitriding:

  1. Shorter Cycle Times: Liquid salt bath nitrocarburizing achieves desired case depths in tremendously (about 10x) shorter times compared to gas nitriding, leading to quicker processing times and energy savings.
  2. Consistent Treatment: The uniformity of treatment in a liquid salt bath can reduce the number of rejects and reworks, leading to less waste and increased production efficiency compared to potential inconsistencies in gas nitriding.No Ammonia Usage: Gas nitriding employs ammonia, which can decompose into hydrogen and nitrogen, potentially creating greenhouse gases. Liquid salt bath nitrocarburizing doesn't use ammonia.
  3. Reduced Gas Emissions: Gas nitriding involves gaseous emissions that may include unreacted ammonia and other byproducts. In contrast, liquid salt baths produce fewer airborne emissions.
  4. Decreased Risk of Gas Leaks: Handling gaseous reactants, like those in gas nitriding, poses a risk of leaks which could be hazardous to the environment. Liquid salt baths eliminate this concern.
  5. Lesser Need for Gas Storage: Gas nitriding requires storage tanks for gases like ammonia, which come with environmental risks and a larger infrastructure footprint. The salts used in nitrocarburizing are typically stored in solid or liquid form, reducing such concerns.
  6. No Need for Gas Purging: Gas nitriding systems require periodic purging to remove contaminants, resulting in gas waste. Liquid salt bath systems don't have this requirement.
  7. Minimal Utility Infrastructure: Gas nitriding systems may require more extensive utility infrastructure for gas delivery, storage, and exhaust, whereas liquid salt bath systems are typically more straightforward.

Environmentally Friendlier than Chrome Plating

Liquid Salt Bath Nitrocarburizing offers numerous environmental benefits compared to Chrome Plating. Here are ten specific examples:

  1. Reduced Hazardous Chemical Usage: Liquid Nitriding uses nitrogen-bearing salts, which are less toxic and hazardous than the carcinogenic hexavalent chromium compounds used in Chrome Plating. This minimizes worker exposure to harmful chemicals.
  2. Lower Energy Consumption: Liquid Nitriding typically operates at lower temperatures, requiring less energy compared to the energy-intensive electroplating process of Chrome Plating. This results in reduced energy consumption and lower greenhouse gas emissions.
  3. Minimal Water Usage: Liquid Nitriding typically consumes less water than the water-intensive Chrome Plating process, contributing to water conservation efforts and reducing the risk of water pollution from plating bath effluents.
  4. Reduced Waste Generation: Liquid Nitriding generates fewer hazardous waste byproducts than Chrome Plating, such as toxic chromium sludge. This reduces the burden on waste disposal facilities and minimizes environmental contamination risks.
  5. Elimination of Hexavalent Chromium Emissions: Chrome Plating can emit hexavalent chromium particles, a known carcinogen, and air pollutant. Liquid Nitriding does not produce such emissions, contributing to cleaner air quality and reduced health risks.
  6. Improved Safety: Liquid Nitriding is a safer process for workers as it involves fewer hazardous materials and eliminates the need for handling toxic hexavalent chromium compounds.
  7. Lower Environmental Footprint: Liquid Nitriding's reduced use of hazardous materials, lower energy consumption, and minimized waste generation result in a smaller overall environmental footprint compared to Chrome Plating.
  8. Compliance with Regulations: Many regions have stringent regulations regarding the use and disposal of hexavalent chromium in Chrome Plating. Liquid Nitriding often aligns more effectively with these regulations, reducing the risk of non-compliance.
  9. Sustainability Considerations: Liquid Nitriding is increasingly viewed as a sustainable surface treatment option due to its reduced environmental impact, making it an attractive choice for companies aiming to meet sustainability goals.
  10. Longer Component Lifespan: Liquid Nitriding enhances the durability and wear resistance of treated components, reducing the need for replacement and extending the lifespan of parts. This indirectly contributes to resource conservation and waste reduction.

In summary, Liquid Salt Bath Nitrocarburizing offers a multitude of environmentally friendly advantages over Chrome Plating, ranging from reduced hazardous chemical usage and energy consumption to lower waste generation and improved worker safety. These benefits make it a more environmentally responsible choice for various industrial applications.

Resists Weld Spatter

In welding processes, particularly in high-heat applications like arc welding, molten metal droplets or "weld spatter" can splatter and adhere to welding fixtures and tooling. This buildup of spatter can negatively affect the performance and lifespan of these fixtures.

Liquid Nitriding modifies the surface properties of fixtures, making them less prone to the adhesion of weld spatter. By creating a smoother and harder surface layer, the treated fixtures become more resistant to the molten metal droplets, preventing them from sticking. This resistance to spatter adherence is essential in maintaining the integrity and cleanliness of welding fixtures, which, in turn, ensures precise and reliable welding operations. It also reduces the need for frequent cleaning and maintenance of fixtures, leading to cost savings and increased efficiency in welding processes.

Resistance to Stress Corrosion Cracking

Stress corrosion cracking (SCC) is a type of corrosion-related failure that occurs in metals when they are subjected to a combination of tensile stress and corrosive environments. This phenomenon can lead to sudden and catastrophic material failure.

Liquid Nitriding imparts improved resistance to SCC by creating a hardened surface layer with enhanced corrosion resistance. The nitride and oxide compounds formed during the process act as protective barriers, preventing corrosive agents from penetrating into the metal's surface and causing cracking. This resistance is especially valuable in industries where components are exposed to both mechanical stress and corrosive environments, such as the aerospace and oil and gas sectors. The enhanced resistance to stress corrosion cracking ensures the reliability and longevity of critical parts, reducing the risk of unexpected failures and improving safety in various applications.

Enhanced Resistance to Abrasive Wear

Abrasive wear occurs when surfaces are subjected to the rubbing or sliding action of abrasive materials, leading to material loss and surface degradation over time.

Liquid Nitriding significantly improves a component's ability to resist abrasive wear by forming a hard and wear-resistant surface layer. This layer, composed of nitride compounds, is exceptionally tough and capable of withstanding the abrasive forces generated during contact with abrasive particles or surfaces. As a result, nitrided components maintain their surface integrity and dimensions for longer periods, even in harsh and abrasive environments. This property is especially valuable in industries like manufacturing, where equipment and components are exposed to abrasive materials, extending the lifespan of critical parts and reducing maintenance costs.

Resistance to Chemical Corrosion

Chemical corrosion occurs when metals react with and deteriorate due to exposure to aggressive chemical substances or environments.

Liquid Nitriding enhances a component's resistance to chemical corrosion by creating a protective surface layer composed of nitride and oxide compounds. These compounds act as barriers, effectively shielding the underlying metal from the corrosive effects of chemicals. As a result, nitrided components are better equipped to withstand exposure to acids, bases, and other corrosive agents, making them suitable for use in industries where chemical resistance is crucial. This benefit ensures the durability and longevity of components in applications where contact with corrosive substances is common, such as chemical processing, oil and gas, and petrochemical industries.

Enhanced Performance at High Temperatures

This process improves the ability of treated components to maintain their structural integrity and performance under elevated temperatures.

During Liquid Nitriding, the formation of nitride compounds on the surface of the metal enhances its resistance to heat and oxidation. These compounds create a protective layer that prevents rapid degradation of the material at high temperatures. As a result, nitrided components can withstand prolonged exposure to elevated temperatures without suffering from deformation, loss of hardness, or other heat-related issues. This benefit is especially valuable in industries such as automotive, aerospace, and manufacturing, where components operate in high-temperature environments, ensuring the reliability and extended lifespan of critical parts in demanding conditions.

Reduced Risk of Hydrogen Embrittlement

Hydrogen embrittlement is a phenomenon where the absorption of hydrogen atoms into the metal's structure can lead to reduced ductility and increased susceptibility to cracking and failure, especially under stress.

Liquid Nitriding minimizes the risk of hydrogen embrittlement by conducting the process at lower temperatures compared to some other surface treatments that can introduce hydrogen. The nitriding process itself does not typically involve the use of acidic solutions or electroplating, which are known sources of hydrogen in some other treatments. As a result, nitrided components experience reduced hydrogen exposure, making them less prone to embrittlement. This benefit is crucial in industries like aerospace and automotive, where components need to maintain their structural integrity and performance, even under significant stress and potential exposure to hydrogen sources.

Resistance to Hydrogen Sulfide Corrosion

Hydrogen sulfide (H2S) corrosion is a form of corrosion that occurs in environments containing hydrogen sulfide gas, which can lead to the degradation of metal components.

Liquid Nitriding enhances a component's resistance to hydrogen sulfide corrosion by creating a protective surface layer composed of nitride and oxide compounds. These compounds act as barriers, effectively shielding the underlying metal from the corrosive effects of hydrogen sulfide gas. As a result, nitrided components are better equipped to withstand exposure to H2S-rich environments, such as those found in the oil and gas industry, wastewater treatment, and chemical processing plants. This benefit ensures the durability and longevity of components in applications where protection against hydrogen sulfide corrosion is crucial.

Reduced Wear in High-load Applications

In high-load applications where components experience substantial mechanical stress and friction, wear can be a major concern, leading to premature component failure.

Liquid Nitriding significantly reduces wear in these high-load scenarios by creating a hardened surface layer with enhanced wear resistance. The nitride compounds formed during the process are exceptionally hard and durable, capable of withstanding the intense mechanical forces and abrasive conditions prevalent in high-load applications. This results in extended component lifespans, reduced maintenance requirements, and enhanced overall performance in industries such as automotive, industrial machinery, and aerospace, where components endure substantial loads and need to maintain their functionality over extended periods.

Reduced Wear in High-Impact Applications

In high-impact applications, components are subjected to repeated and intense impacts, which can lead to surface damage, wear, and premature failure.

Liquid Nitriding significantly reduces wear in these high-impact scenarios by creating a hardened surface layer with enhanced wear resistance. The nitride compounds formed during the process are exceptionally tough and can withstand the impact forces and abrasive conditions common in such applications. This benefit ensures that components remain durable and reliable, even when exposed to heavy impacts. It is particularly important in industries like automotive, where engine components, transmission parts, and gears are subject to intense mechanical stress, as well as in construction and mining equipment, where machinery must withstand high-impact loads while maintaining performance and longevity.

Resistance to Cavitation Wear

Cavitation wear is a type of damage that occurs when rapid changes in fluid pressure lead to the formation and collapse of vapor-filled cavities near the surface of a material. This process can erode and deteriorate metal components over time, particularly in applications involving pumps, valves, and hydraulic machinery.

Liquid Nitriding enhances a component's resistance to cavitation wear by creating a hard and wear-resistant surface layer. The nitride compounds formed during the process provide an added layer of protection against the erosive effects of cavitation, preventing surface damage and material loss. This benefit ensures the longevity and reliability of components used in environments where cavitation wear is a concern, such as marine applications, power generation, and industrial machinery subjected to fluctuating fluid pressures.

Extended Lifespan of Hydraulic Components

Hydraulic systems rely on precision components such as cylinders, pistons, and valves to operate efficiently. These components are exposed to high-pressure fluids, which can lead to wear and corrosion over time.

Liquid Nitriding enhances the durability and performance of hydraulic components by creating a hard and wear-resistant surface layer. The nitride compounds formed during the process provide excellent resistance to wear, corrosion, and fatigue, ensuring that these components can withstand the demanding conditions of hydraulic systems for an extended period. This benefit translates into reduced maintenance, longer service intervals, and increased reliability of hydraulic machinery, ultimately contributing to cost savings and improved operational efficiency in industries such as construction, agriculture, and manufacturing.

Stress Relieving Weldments

When metal components undergo welding processes, they can experience residual stresses, phase & micro-structure changes, hardening that may lead to distortion or even cracking, compromising their structural integrity. Some customers take advantage of the nitriding process temperature to stress relieve welds.

The Liquid Nitriding process temperature of 1055°F is close to the range that weldments are stress relieved at (starting at 1100°F). This provides stress-relief benefits by subjecting the welded components to controlled heating and diffusion during the nitriding process. This heat treatment helps alleviate the residual stresses that accumulate during welding, thereby reducing the risk of deformation, cracking, or stress-related failures. Stress-relieved weldments maintain their shape and mechanical properties, ensuring that they meet specified tolerances and performance requirements. This benefit is particularly crucial in industries like automotive and construction, where welded components need to maintain their structural integrity and reliability, even after exposure to welding-induced stresses.

Increased Stiffness

Stiffness, in materials engineering, refers to a material's resistance to deformation when subjected to an applied force. In the context of Liquid Nitriding, this benefit relates to the enhancement of a component's mechanical properties, particularly its rigidity and resistance to bending or flexing. A great, and very unusual example of a product we nitride for this purpose is rifle firearm box magazines, of which we nitride many. The OEM found that in addition to the many benefits of nitriding, the process also stiffens the feed lips. Maintaining feed lips geometry is critical to the successful feeding and chambering of cartridges. 

Liquid Nitriding achieves increased stiffness through several mechanisms:

  • Surface Hardening: During the nitrocarburizing process, a hardened surface layer is formed on the component's surface. This layer typically consists of nitride compounds, which are significantly harder than the base metal. This enhanced hardness contributes to increased stiffness, making the treated component less prone to deformation and deflection under load.
  • Improved Elastic Modulus: The formation of nitride compounds can alter the material's elastic modulus, which is a measure of its stiffness. In many cases, nitrided components exhibit a higher elastic modulus than untreated materials, further enhancing their stiffness.
  • Reduced Deformation: The hardened surface layer created by Liquid Nitriding provides increased resistance to plastic deformation, which means that the component is less likely to undergo permanent shape changes when subjected to mechanical stress.
  • Enhanced Fatigue Strength: Improved fatigue strength, another benefit of Liquid Nitriding, contributes to the increased stiffness of components. This means that the treated parts can withstand repeated loading cycles without experiencing excessive deformation or failure.

This increased stiffness is particularly advantageous in applications where dimensional stability and resistance to deformation are critical, such as firearm box magazines, precision machinery, gears, and automotive components. Liquid Nitriding not only enhances the stiffness of components but also contributes to their overall durability and longevity in demanding operational conditions.

Q vs QP vs QPQ Application Table

Nitride & Quench
(Standard process)
Nitride & Quench + Polish
Nitride & Quench +
Polish + Quench
Case Hardened Surface to 55HRC+1

Reduces Friction & Adhesion by up to 60%

Black Oxide (Quench) for Corrosion Resistance & Aesthetics.
Same as Q, plus a Polishing step which restores the original finish, and increases surface luster.
Same as QP, plus reimmersion into the oxidizing (Quench) salt bath to further enhance corrosion resistance.
Price & Delivery
Lowest cost & fastest delivery
Marginal increase in cost & delivery time
Highest cost & delivery time
Surface Roughness (RA)2
≤32µin (0.8µm)

Nitriding can increase RA up to ~32µin (0.8µm) total
≤16µin (0.4µm)

QP restores RA to ~8-16µin  (0.2-0.4µm)

RA can be restored to ~2µin (0.05µm) by hand polishing or other means.
Same as QP
Appearance / Aesthetics
Deep matte finish

Some material may be aesthetically affected by brown/red iron oxides (particularly stainless steels and cast iron)
Satin Luster

Very high quality & consistent appearance from part to part & batch to batch.

Polishing removes brown oxides and other surface contamination & visible defects.
Same as QP but with further handling and processing there is decreased part to part & batch to batch consistency of appearance.
Corrosion Resistance
(Compared to Raw / un-Nitrided Material)
Carbon, low-alloy & tool steels: Tremendous increase3

Martensitic stainless steels: Moderate increase

Nodular irons: Slight increase

Precipitation hardened stainless steels: Unchanged

Ferritic & Austenitic stainless steels: Decreased
Carbon, low-alloy & tool steels: Same as Q

Martensitic stainless steels: Same as Q

Nodular irons: Same as Q

Precipitation hardened stainless steels: Reduced compared to Q

Ferritic & Austenitic stainless steels: Further reduced compared to Q
Carbon, low-alloy & tool steels: Potentially better than Q & QP

Martensitic stainless steels: Likely better than Q

Nodular irons: Same as Q

Precipitation hardened stainless steels: Likely better than Q

Ferritic & Austenitic stainless steels: Significantly better than Q
Best Choice
Any material needing surface hardness, yet surface roughness does not need to be <32µin (0.8µm), and corrosion resistance & aesthetics are not critical.
Surface Roughness (RA) of <32µin (0.8µm) required. E.g.: seal surfaces, cylinder bores, etc. 

Components with high-spec aesthetic requirements. E.g.: Firearms, tools, etc.
Same as QP 

Stainless steels if corrosion resistance is critical  

Everything else if the additional cost is worth it.

1 55-60HRC for Carbon Steels, 60-70HRC for Low-alloy Steels, 70HRC+ for Stainless Steels
2 Nitriding is not expected to increase surface roughness (RA) where the starting roughness is >32µin (0.8µm)
3 Up to ~400hr ASTM B117 salt spray test