Heat Treatments

We have an experience of more than 50 years working with Heat Treatments, APRIM has state-of-the-art furnaces and a large team of professionals qualified in heat treatment of steel.

Case Hardening

Cementing gives us the advantage of having a very hard surface in a single piece of metal while preserving a resistant core. It is achieved by heating a metal in contact with another powder or paste.

Case Hardening

Induction Hardening

Induction Hardening consists of exposing the piece of steel to an alternating magnetic field, which allows heat to penetrate its surface.

Induction Hardening


Gas Nitriding at high pressure provides steels and iron castings with a high surface hardness together with tenacious diffusion and therefore, they are also focused on solving problems of friction, wear, fatigue, breaks, etc.

High Pressure Nitriding


Carbonitriding is a treatment that hardens a surface layer of steels by the simultaneous absorption of carbon and nitrogen

Gaseous Carbonitriding

Quenching and tempering

Heat treatment that increases the hardness and mechanical resistance of a steel. Possibility of applying a subsequent Temper.

Quenching and tempering


Specialists in heat treatment of steel


What are Heat Treatments ?

Heat treatments are procedures consisting of controlled temperature variations, by heating and cooling the materials to obtain changes in the structure of the pieces. The different heat treatments can increase hardness, increase resistance, decrease friction or facilitate machining; the application of the most suitable heat treatment has the objective of achieving controlled variations in the physical and mechanical properties of the parts, but without altering their chemical composition. The temperature of the furnaces to which they are subjected during the heat treatment processes will depend on the type of material, that is, on its concentration of carbon, nitrogen or other types of alloys.


The different types of heat treatments that APRIM puts at your disposal are the following:




  • Hardening

It consists of heating the metal evenly to the correct temperature followed by cooling with water, oil, air or in a refrigerated chamber. This produces a fine granular structure that increases tensile strength (tension) and decreases ductility.

It is a thermochemical surface enrichment treatment on steels that achieves structural changes in the surface of a piece of metal by increasing the concentration of carbon, thus providing great hardness.control of ovens for heat treatments

  • Surface hardening

Thermochemical treatment in which baths with cyanide, carbonate and sodium cyanate are used. Temperatures between 760 and 950 ° C apply. It allows to have metallic materials with high performance such as greater resistance to wear, preserving the ductility and toughness of the core.

Its purpose is to increase the hardness and resistance of the steel. To do this, the steel is heated to a temperature slightly higher than the higher critical Ac3 (between 900-950 ° C) and then cooled more or less rapidly (depending on the characteristics of the piece) in a medium such as water, oil, etc. .

Thermochemical process in which carbon and nitrogen are introduced into a surface layer, with hydrocarbons such as methane, ethane or propane; ammonia (NH3) and carbon monoxide (CO). Temperatures of 860 to 880 ° C are required in the process and subsequent quenching and tempering is necessary.

Process that increases the surface hardness to a high degree by incorporating nitrogen in the composition of the surface of the piece. It is achieved by heating the steel to temperatures between 400 and 525 ° C within a stream of ammonia gas plus nitrogen.

  • Nitrocarburization

It is a thermochemical diffusion process on the surface of the steel piece in which nitrogen, carbon, and oxygen atoms are diffused to a very small degree, forming a layer of compound on the surface and a diffusion layer. This process is done primarily to provide wear resistance to the surface layer and to improve fatigue resistance.

  • Annealing

It basically consists of heating to austenitizing temperature (800-925 ° C) followed by slow cooling. With this treatment, elasticity is increased, while hardness decreases. It also facilitates the machining of parts by homogenizing the structure, refining the grain and softening the material, eliminating the acrimony produced by cold work and internal stresses.

  • Stabilized

The stabilization process consists of heating the part to a temperature lower than its transformation point, followed by a slow and uniform cooling to eliminate stresses and avoid deformations in parts with complicated shapes or that must have very precise dimensional tolerances.

  • Stress relief

It is a treatment that manages to change the intensity and distribution of internal stresses on the surface of a piece of metal, increasing the concentration of carbon due to the environment or atmosphere to which it is subjected during heating and cooling.

Tempering is a type of heat treatment that is used to increase the hardness and mechanical resistance of a steel. Generally applied to metal parts or masses that have already been shaped in machining processes. Afterwards, a Tempering treatment is usually applied to improve the toughness of tempered steels.

  • Normalized

Its objective is to leave a material in a normal state, that is, absence of internal stresses and with a uniform carbon distribution. It is usually used as a pre-treatment for quenching and tempering.


  • The useful capacity of our ovens is 1,140 mm X 700 mm X 750 mm for all types of geometries and up to 1 Tn of load.
  • Our Tempering, Annealing and Stabilizing furnaces have a capacity of 1140 mm X 700 mm X 900 mm and up to 2 Tn of load.
  • Our programs are automated and allow monitoring through process charts.


specialists operating oven in controlled atmosphere



  • It is a Heat Treatment to harden, join or soften metals or other conductive materials.
  • Induction is a clean and non-polluting process that helps protect the environment.
  • Induction Hardening is a Heat Treatment that does NOT use fossil fuels.


  • Control by piece unit graph.
  • Quenching possibilities from small parts to large parts and internal diameter tempers.
  • Different types of frequencies and powers depending on the depth of the requested layer (high, medium and low frequency), having in our facilities 50kW, 100kW and 130kW generators at different HZ frequencies.
    • It allows to carry out the Heat Treatment of a certain part of the piece, obtaining layers from 0.5 mm to 12 mm deep (temper profile).
    • Management of applied power.
    • Management of applied power.
    • Control of cooling parameters.
    • Energy saving.
    • Control and location of temperature.part of the induction heat treatment process
  • DATA OF INTEREST: Maximum dimensions of the pieces to be inducted:

    • High Frequency Temper: Dimensions: 160mm Ø x 750mm Length.
    • Temper horizontally: Dimensions: 6000 mm length.
    • Tempering of wheels and crowns: Dimensions: 2000 mm diameter.
    • Medium frequency temper: Dimensions: 350 mm Ø X 1700 mm length.




Nitriding is a Thermochemical Thermal Treatment of surface enrichment with nitrogen and ammonia in the ferritic phase on steels. This is achieved by introducing the aforementioned elements into the material itself.


    • OF PROCESS TIME. The reduction in time can in some cases be as high as approximately 60% or 70%.
    • OF PROCESS QUALITY. The pieces come out clean, without scale. The shielding effect is eliminated – the gas gets into even the smallest holes – even if the parts are very small and complex or are “bulk”. The deformation is minimal, compared to other Heat Treatments.
    • OF ECONOMIC TYPE. Some of the alternative treatments -Tenifer, Sur Sulf, etc.- have added costs, as a result of their patents and their exclusivity. Furthermore, as the process time is shorter, it allows offering more competitive and interesting prices.


      • High hardness: being able to achieve values from 600 HV to 1100 HV depending on the material.
      • Dimensions of the cargo space: useful volume of L 800 mm X W 400 mm X H 400 mm.
      • Load capacity: 200 kg


    • Our Thermal Treatments area has a washing machine with electric immersion heating, equipped with an oil separator and drying of the parts.


    • Emission Spectrometer to analyze compositions of all types of steels, cast iron and stainless steels.controlled atmosphere furnace
    • Durometers, benchtop and portable, to measure surface hardness in all types of parts and materials, from 15 kg to 3000 kg.
    • Micro-durometers, for scanning micro-hardness in laboratory test tubes.
    • Crack detectors by electromagnetic system and demagnetizer.
    • Microscopes and MicroSPIto up to 2000x magnification for structure analysis.

APRIM’s Heat Treatment area works regularly for a wide variety of industrial sectors, among which we could highlight the automotive, aeronautical and agricultural sectors, among others. Also, our ovens can carry out heat treatment of a wide variety of materials.

We work together with our clients when it comes to detecting possible behaviors in certain materials and with the processes and conditions that they request: our objective is to avoid possible losses of productivity and competitiveness in our clients’ projects

We do not hesitate to put our knowledge and experience at your disposal, with very competitive prices and with the flexibility and agility of response that the market and its production systems require.



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