Process and composition of industrial gases forming atmospheres for heat treatment processes of ferrous parts and components and metal alloys using biomethane

Description

1 / 34 PROCESS AND COMPOSITION OF INDUSTRIAL GASES FORMING ATMOSPHERES FOR HEAT TREATMENT PROCESSES OF FERROUS PARTS AND COMPONENTS AND METAL ALLOYS USING BIOMETHANE FIELD OF THE INVENTION

[01] The present invention relates to a unique and optimized production process that aims to reduce CO2 emissions into the atmosphere, with a consequent reduction in environmental pollution from companies that perform heat treatments with protective atmospheres, to avoid decarburization of the surface of metal parts or that add other chemical elements to the surface in order to enhance the properties of metal alloys.

[02] This new composition of atmosphere-forming gases, notably with the insertion of biomethane gas and a new process design supported by new control systems for the furnaces of the gaseous atmospheres formed, generates less polluting processes and other advantages. It allows an evolution of the state of the art in relation to atmospheres previously optimized with the insertion of natural gas and the enormous technological efforts that lasted for decades to remove methanol from these atmosphere compositions of the heat treatment furnaces of metal alloys.

[03] This composition of state-of-the-art atmospheres using natural gas showed an evolution of industrial atmospheres for heat treatments of metal alloys, enabling the removal of methanol and the insertion of natural gas, but despite less emissive processes and products, they still use fossil fuels, which are pollutants in the heat treatment production cycles of Petition 870250073520, dated 08 / 20 / 2025, page 4 / 43 2 / 34 metals. The developed process and the composition of the developed atmosphere make the aforementioned process with biomethane gas, with differentiated process designs measured through integrated automation systems, even more aligned with global ecosystem conservation guidelines than the recently developed process with natural gas, being an important support in adapting factory facilities to the demanding international standards that address the subject.

[04] This developed process makes this new biomethane-optimized atmosphere even more productive, with lower pollutant emissions and the need to use a smaller volume of gases, due to the high potential of biomethane to release carbon into the atmosphere of the heat treatment furnace, with less risk of accidents, with full compliance with the required quality and with even shorter process times, making it even more advantageous in industrial manufacturing costs of processes and products and also with lower emissions in each cycle of heat treatments, meeting the determinations and guidelines of the United Nations Conference on Climate Change (COP28UAE) and the quality standards of the production market that were used to approve the product developed and treated with this atmosphere. BACKGROUND OF THE INVENTION

[05] Known as carbon dioxide, carbon dioxide (CO2) is a gaseous chemical compound essential for life on the planet. The presence of excess CO2 in the environment has a reverse effect, being extremely harmful to the health of the planet, capable of accentuating the greenhouse effect and increasing global warming. Petition 870250073520, dated 08 / 20 / 2025, page 5 / 43 3 / 34

[06] Unfortunately, the growth in the concentration of carbon dioxide (CO2) in the atmosphere has increased due to human activity and the record industrialization of the planet with the beginning of the industrial revolution. Since then, the average concentration of CO2 has been growing at an accelerated rate. According to a study published in WRI Insights, 89% of CO2 emissions come from the use of fossil fuels, especially for electricity and heat generation, transportation, manufacturing, and consumption.

[07] Sustainable production is that which seeks the best possible alternatives to reduce environmental and social impacts throughout the product's life cycle, that is, there are global concerns and actions to avoid the depletion of natural resources and the inability of the environment to absorb and sustain in a balanced way all the impacts of all world production.

[08] Following this line of thought, ESG – Environmental, Social and Governance – was born, corresponding to an organization's environmental (E), social (S) and corporate governance (G) practices. The term was coined in 2004 in a publication by the Global Compact in partnership with the World Bank, called Who Cares Wins. The term environmental refers to the environment as a whole.

[09] Our actions in the environment and in production environments or metal-mechanical component factories in general have significant impacts on the environment, with excessive consumption of energy and natural resources, excessive transport and storage of goods and the use of polluting products, coupled with rampant deforestation, the emission of gases harmful to the environment that contribute to the greenhouse effect and inadequate Petition 870250073520, dated 08 / 20 / 2025, page 6 / 43 4 / 34 Waste disposal, among other things, contributes to global warming and critical environmental problems.

[010] The strong demand for reducing greenhouse gas emissions, coupled with the growing safety requirements in metal heat treatment processes, in particular, and the need to reduce the operational costs of heat treatment processes, has led equipment and furnace manufacturers and heat treatment producers and / or service providers to seek new technologies for the development of cleaner, more sustainable and economical processes.

[011] The formation of atmospheres or the engineering of atmosphere formation for heat treatments in metal alloys involves orderly loading the parts into the heat treatment furnaces and injecting suitable gases under appropriate conditions, compositions, and times, monitoring their formation with advanced automation and control equipment. Process engineering for the formation of gaseous atmospheres for heat treatments of metal alloys is an important variable in the heat treatment process and requires absolute control to achieve the desired results. Its main objective is to preserve the surface characteristics and / or add properties to the metal components and alloys loaded into the furnaces to be treated.

[012] It is the responsibility of the heat treatment production process to deliver metal parts in the best possible condition, in accordance with the specifications in engineering designs. Often, these conditions are also specified in internal work procedures and international quality standards, as well as in national and international technical standards, linked to and managed by systems. Petition 870250073520, dated 08 / 20 / 2025, page 7 / 43 5 / 34 of internationally recognized quality standards, such as ISO standards, for example. The processes in these standards are defined in production orders in companies according to usual technologies, unfolding the guidelines of quality and environmental standards. The central objective is to obtain results in accordance with the engineering designs of metal-mechanical components facing the heat treatment that will be carried out on the metal components, their assemblies and metal alloys.

[013] Thus, the atmospheres and processes developed in this invention were based on conventional market production processes and the state of the art of gaseous atmosphere formation technologies for heat treatments of metal alloys.Today, some common heat treatments that are carried out on a global scale can be highlighted, such as: quenching and tempering, carburizing, carbonitriding, nitrocarburizing, normalizing, annealing, among other existing production processes that were observed and developed after numerous practical tests carried out and demonstrated in this invention.

[014] In a search conducted on the state of the art, some patent documents were identified that describe solutions applied to gas compositions for heat treatment, among which we can highlight the following documents:

[015] Document ES2715925T3 (Air Liquide. 2019) deals with a procedure for generating an atmosphere for the heat treatment of metal parts in a furnace, according to which the introduction, in at least one phase of the treatment cycle or in at least one area of ​​the heat treatment furnace, of a mixture, which is carried out therein, comprising gaseous CO2 and ethanol in the form of fine droplets or vapor. The Petition 870250073520, dated 08 / 20 / 2025, page 8 / 43 6 / 34 natural gas, methane gas, butane gas and other types of carbon-rich gas, deliver free carbon in the form of CO and / or CO2 to the heat treatment atmosphere system, with the aim of releasing carbon for a common heat treatment process in steels that will be heat treated by the process called carburizing, that is, enriching the surface or maintaining the neutrality of the carbon percentage in the atmosphere, as described in the aforementioned patent, in addition, the system of the patent adds another element to the atmosphere which is ethanol, with the purpose of also delivering carbon to the heat treatment system or facilitating this process.

[016] In the present invention and with the development of the new, less aggressive and polluting atmosphere, this ethanol element becomes unnecessary and is not used, therefore this new technology, with a new process and new atmospheric components, contributes to the reduction of the emission of polluting gases, such as CO2.

[017] Document EP2800723B1 (Air Liquide, 2014) defines a method for generating an atmosphere for the heat treatment of metal parts in a furnace, according to which: a CO generator is fed using a gaseous source of CO2 and a source of a gaseous hydrocarbon or a mixture of gaseous hydrocarbons, to produce CO; in at least one phase of the treatment cycle or in at least one zone of the heat treatment furnace, a mixture comprising the gaseous CO obtained from said generator and methanol in the form of fine droplets or vapor is introduced. Natural gas, methane gas, butane gas and other types of carbon-rich gas deliver free carbon to the heat treatment atmosphere system, in the form of CO and / or CO2, in order to release carbon for carburizing or Petition 870250073520, dated 08 / 20 / 2025, page 9 / 43 7 / 34 that is, surface enrichment or maintenance of the neutrality of the percentage of carbon in the atmosphere, as described, however, this patent mentions the use of a "gas generator" and the use of methanol in the gas recipe, this generator having the function of previously preparing the mixture of thermal treatment gases and the methanol also delivering free carbon to the production system.

[018] In the present invention, this new element methanol is unnecessary and is not used, contributing to the reduction of polluting gas emissions, such as CO2, and also does not use the aforementioned gas generator for the formation or delivery of carbon to the atmosphere. Thus, the invention uses only biomethane gas, derived from biogases, to deliver free carbon to the system or to the atmosphere to supply the surfaces of the parts to be heat-treated with carbon, without the need for further equipment to generate gas to feed the furnaces, reducing the costs of the atmosphere formed, the emissions from the heat treatment cycles, the need for maintenance, the industrial costs in general, along with increasing the safety of the process.

[019] Document CN208517476U (Suzhou Zhongmenzi, 2019) concerns a utility model relating to DX atmosphere heat treatment furnaces, including the furnace body, located within the furnace's internal DX atmosphere generator, the DX atmosphere generator includes the fuel element, the fuel element includes the radiant tube, the ignition burner component, and the cooling device that heats the DX gas in the radiant tube, the ignition burner component includes the burner, fuel gas piping, and radiant tube located in the preheating zone of the furnace body. Petition 870250073520, dated 08 / 20 / 2025, page 10 / 43 8 / 34 or heating zone and along the generation of the DX gas flow direction being divided into combustion zone, rectification section and current stabilization segment, the spontaneous combustion section of the rectification section gradually becomes smaller towards the current stabilization segment. The DX atmosphere generator also includes a nitrogen purge unit, a natural gas and air premixing unit and an anti-bomb unit.Natural gas, methane gas, butane gas, and other types of carbon-rich gases deliver free carbon to the heat treatment atmosphere system, in the form of CO and / or CO2, in order to release carbon for carburizing, i.e., enriching the surface or maintaining the neutrality of the carbon percentage in the atmosphere, as described. However, this patent mentions the use of a gas generator and the use of natural gas, this generator having the function of pre-preparing the mixture of heat treatment gases to deliver free carbon to the heat treatment system.

[020] The invention above uses only natural gas, methane and butane, all fossil fuels, to deliver free carbon to the system. When biomethane is used to compose a balanced and tested atmosphere, as claimed in the present invention, it is no longer necessary to use the external gas generator and therefore, the invention cited above still uses fossil fuels in its composition. This is combined with a complex gas system to deliver the gas mixture to the internal atmosphere of the heat treatment furnace and thus obtain free carbon in the atmosphere.

[021] Thus, the compound used in the process replaces, and / or eliminates, gases that are currently used in the atmosphere and that are responsible for the amount of CO2 (free carbon in the internal atmosphere of the furnace, Petition 870250073520, dated 08 / 20 / 2025, page 11 / 43 9 / 34 derived from fossil fuels) necessary to perform heat treatments. Therefore, this invention acts and contributes as a differentiating agent in obtaining a new carbon-free generating atmosphere for metallurgical heat treatment processes, since it uses biomethane gas in the optimized composition of developed or possible atmospheres to perform this function and no other type of fossil fuel gas, only nitrogen gas and atmospheric air properly balanced as a complement, making this atmosphere much less pollutant-producing.

[022] An important differentiation in relation to the state of the art is the possibility of decarbonizing the heat treatment process of alloys and metallic components, bringing enormous benefits to customers and users of the metallic parts treated by the heat treatment process of the invention, making the manufacture of these metallic components less polluting throughout their production chain, for example, of tested automotive, aviation and other components, which use the state-of-the-art patented processes found and used on a large scale today in the world market, without the advent of the invention of the balanced atmosphere with biomethane gas, which generated a new process design and new optimized controls in relation to patent BR102023027329-7A2 claimed by the same holder.

[023] Document BR102023027329-7 A2 (Grefortec, 2022) concerns a process for forming gaseous atmospheres for heat treatments of metal alloys using natural gas as a substitute for propane and methanol atmospheres, promoting significant decarbonization in the heat treatment process of metal alloys and increasing its efficiency. This invention patent demonstrates an atmosphere formation engineering process. Petition 870250073520, dated 08 / 20 / 2025, page 12 / 43 10 / 34 gaseous atmospheres already contain a smaller amount of fossil fuels in their composition, but still use natural gas as a carbon source, which is still of fossil origin. This is an important document in this milestone of the evolution of the technology for the formation, maintenance, and formulation of these atmospheres to generate less emissive, more productive production processes, and with products and processes of assured quality in the heat treatment of metal alloys.

[024] The researched state of the art showing the use of biomethane gas in heat treatment atmospheres for metal alloys is basically divided into biomethane gas refining and production plants, such as the most recent patents cited below:

[025] Document BR102017024793B1 (ER-BR Energias Renováveis ​​Ltda. 2020) concerns an integrated set of equipment and process for the treatment and refining of biogas with high levels of contaminants for the production of biomethane gas and vehicular fuel in small volumes up to 10 m3 / h, so that the refining unit produces small daily quantities of biomethane gas to fuel motor vehicles operating in the same location as the biogas, the source and origin of the biomethane, used and produced on rural properties and small wastewater treatment plants.

[026] In document EP4349453A1 (Air Liquide SA 2024) the invention relates to an installation for producing biomethane gas from organic waste feedstock comprising a biogas production system comprising at least one production vessel configured to contain the digestate or anaerobic digester and a biogas enhancement system comprising a device for increasing the biogas pressure and a membrane separation unit. Petition 870250073520, dated 08 / 20 / 2025, page 13 / 43 11 / 34

[027] No patent was found in the state of the art that demonstrated the use of biomethane gas in the formation of gaseous atmospheres for the heat treatment of metals, highlighting the technological disruptiveness of this patent.

[028] Thus, the present invention relates to a gas composition that contributes to environmental preservation, reduces operational and accident risks in the formation of atmospheres in heat treatment furnaces, reduces the need for transport and storage of polluting chemicals or fossil-derived gases for the formation of heat treatment furnace atmospheres, and also reduces operational costs and furnace process times. Biomethane is more capable of transferring carbon to the system due to its composition, while maintaining metallurgical characteristics and assured quality compared to current conventional heat treatment processes and the global state of the art with atmospheres that still use a greater number of fossil fuels in their compositions and processes. SUMMARY OF THE INVENTION

[029] A characteristic of the present invention is a process that provides the steps of preparing and assembling the heat treatment charge, prior preparation of the equipment (furnace), preparation of the process control instruments, preparation and execution of the heat treatment process,

[030] Quality inspection process, technical analysis and validation of specifications. Petition 870250073520, dated 08 / 20 / 2025, page 14 / 43 12 / 34

[031] A characteristic of the present invention is a composition that provides for the heat treatment of metal alloys in furnaces with a gaseous atmosphere by quenching: • biomethane: 0.10 to 1.25 m3 / hour; • Nitrogen: 0.10 to 1.50 m3 / hour and • Atmospheric air: 0.10 to 1.00 m3 / hour.

[032] A characteristic of the present invention is a composition that provides for heat treatments of cementation, normalization, annealing and other thermochemical processes, • biomethane: 0.10 to 1.50 m3 / hour; • Nitrogen: 0.10 to 1.50 m3 / hour; • Atmospheric air: 0.10 to 1.50 m3 / hour; • Methanol: 0.00 m3 / hour (discarded use).

[033] A characteristic of the present invention is a composition that provides a range of chemical compositions of gases and a novel composition, process and engineering for the formation of heat treatment atmospheres for the following metal heat treatment processes: • tempering / annealing; • cementation (carburization); • normalization / annealing; • boration; • ferritization / perlitization; • carbonitriding; • nitrocarburizing.

[034] A characteristic of the present invention is a composition that provides a range of compositions of the heat treatment atmosphere-forming gases for the following materials: • steels, Petition 870250073520, dated 08 / 20 / 2025, page 15 / 43 13 / 34 • Metal alloys and / or production processes: • Low carbon steels; medium carbon steels; high carbon steels; • alloy steels; • Stainless steels; • tool steels; • Gray cast iron; white or malleable cast iron; • nodular cast irons (including ADI); • PIM; MIM; Powder Metallurgy components • 3D printed metal parts.

[035] A characteristic of the present invention is a composition that provides the use of the gas composition defined with factory validation tests, intended for any and all ferrous or non-ferrous metallic products that use or require a protective atmosphere for the execution of heat treatment of metals.

[036] A characteristic of the present invention is a composition that uses biomethane gas to deliver free carbon to the system, eliminating the need for external gas generators to deliver the gas mixture to the furnace with the new atmosphere, making the atmosphere formation system simpler, less polluting, less costly, with lower accident risks and simpler installations and lower fixed maintenance costs and simpler operation.

[037] A characteristic of the present invention is a composition that provides a compound called a heat treatment gaseous atmosphere that eliminates gases that form the synthetic and fossil atmosphere currently used and that are responsible for the greater amount of carbon. Petition 870250073520, dated 08 / 20 / 2025, page 16 / 43 14 / 34 free in the internal atmosphere of the furnace required to perform the heat treatments.

[038] The present invention features a composition that acts as a differentiating agent in obtaining a new carbon-free generating atmosphere for metallurgical heat treatment processes, as it uses biomethane gas, derived from biogas, in meticulously balanced compositions to perform this task and no other type of fuel gas is needed, only nitrogen gas and atmospheric air to form the gaseous atmosphere necessary to perform heat treatments on metal parts or other components, strongly contributing to the decarbonization of the chain of heat treatment processes for metal alloys, as required by international customer standards that are included in the global environmental legal framework. BRIEF DESCRIPTION OF THE FIGURES

[039] Figure 1 shows the metallurgical structure found by the process currently used in the state of the art. This process uses natural gas to supply free carbon and form the internal atmosphere of the furnace and does not have biomethane gas in the composition of the gaseous atmosphere of the heat treatment furnaces for metal alloys and uses different engineering processes for the formation of gaseous atmospheres. Partial sample of a cemented part where we have the "teeth" with a cemented layer of approximately 1.4 mm thickness (darkened edge in the image on the side). The concept of cementation is to add carbon to the metal alloy, from the surface towards the core of the metal, increasing the percentage of carbon in the cemented region and, with this, increasing the resistance. Petition 870250073520, dated 08 / 20 / 2025, page 17 / 43 15 / 34 surface mechanical and / or hardness of the cemented part of the metal piece after treatment, maintaining the tough core.

[040] Figure 2 shows the metallurgical structure found in the composition applied in the process developed in the present invention, using biomethane gas. Partial sample of a cemented part where we have the “teeth” with a cemented layer of approximately 0.65 mm thickness (darkened edge in the image to the side). Even having a smaller cemented layer than the image above (previous), made with natural gas, this cemented layer using biomethane gas presented the same good characteristics and properties, according to the engineering design of the part, even paving the way for a reduction in process times.

[041] Figures 3 and 4 show the parts that were treated using the new gas recipe, in the charge preparation and assembly stage.

[042] Figures 5 and 6 show how the loads were assembled, to later be placed in the furnace, and also show how the parts were distributed in the parts baskets.

[043] Figure 7 shows the supervisory system that was developed exclusively for carrying out tests to monitor process engineering with regard to the use of new synthetic atmosphere-forming gas recipes used in heat treatment.

[044] Figure 8 shows the results of the cemented layers in tested components, in the heat treatment stage.

[045] Figure 9 shows the result obtained in all treated parts and in the test specimens as redundancy and supercontrol, all were satisfactory and fully met what was Petition 870250073520, dated 08 / 20 / 2025, page 18 / 43 16 / 34 specified in the part design. The photo shows a lightweight automotive part, LUVA3a / 4aVEL.

[046] Figure 10 shows the metallurgical structure of a metal part that was treated with usual atmospheres, without the use of biomethane gas.

[047] Figure 11 shows the metallurgical structure of a metal part that was treated with atmospheres using biomethane gas in its recipe. DESCRIPTION OF THE INVENTION

[048] The first step for a strategy to reduce emissions of gases harmful to the environment to be successful is to monitor CO2 emissions based on an understanding of the impact that a company's activities generate throughout its production process and also in its surrounding ecosystem.

[049] The present invention relates to the modification of the mixture (recipe) of artificial synthetic atmosphere-generating gases used in heat treatment processes, altering the current formulation recipes of this atmosphere with the use of the usual gases on the market, altering their control methods and their gaseous atmosphere formation engineering.

[050] Greenhouse gases are substances present in the Earth's atmosphere that trap the sun's heat, warming the planet. The main greenhouse gas is carbon dioxide (CO2), in addition to methane (CH4), nitrous oxide (N2O), and fluorinated gases (HFCs, PFCs, SF6). CO2 is emitted by human activities, such as the burning of fossil fuels inside and outside the industrial sector. The thermal treatment of metals is a relevant agent and process in this relationship with industrial and environmental pollution, due to the global volumes involved. Petition 870250073520, dated 08 / 20 / 2025, page 19 / 43 17 / 34 of treated metal-mechanical components and their operations still use fossil fuels. Therefore, the technology of this patent is relevant due to the need to work towards reducing emissions of gases harmful to the environment from the heat treatment of metal alloys worldwide. Heat-treated metal components of various metal alloys find wide application in the automotive, aviation, basic, agro-industrial, structural assembly, and shipbuilding industries; in short, wherever there are metal-mechanical components of metal alloys for industrial application, at least one heat treatment has been carried out in a large part of them.

[051] In this context, a new atmosphere was developed, with new gases, with new compositions (recipes) and tolerances, with new controls and monitoring technologies to allow the formation, adjustment and control of gas atmospheres formed at high temperatures in heat treatment furnaces, a risky process that, without monitoring such as that of the invention and the experiences of those involved in the preparation of this patent, would be impossible to test on this industrial scale as was done.This invention aims to generate a new, disruptive technology with clear inventive activity and industrial application, creating a cleaner atmosphere in heat treatment furnaces that process millions of tons of metal alloys worldwide annually, with lower emissions of pollutants and CO2 into the environment. This is because it involves the use of carbon-rich gases from clean sources such as biogas, thus contributing to the reduction of these gases originating from fossil fuels, which are significant emitters of CO2. Petition 870250073520, dated 08 / 20 / 2025, page 20 / 43 18 / 34 CO2 when used in industrial processes, such as heat treatments of metal alloys (especially ferrous ones).

[052] The production process according to the invention has a wide field of application, the components treated range from light (cars) and heavy (trucks, tractors and cranes) automotive products, civil construction (metals in general), development of various machines and equipment for the most varied sectors of society, as well as armaments, agricultural implements, aviation, aerospace, mechanical forming and cutting devices and tools, i.e., metal mechanics in general.

[053] The objective of the invention is to provide a technological alternative with the construction and development of furnace conditions to operate with a minimum of fossil fuels to obtain a cleaner, lower cost, and less risk-reducing heat treatment process for metal alloys, which is less polluting and meets the metal-mechanical technical requirements of the products to be heat treated, generating a reduction in the negative environmental impact of the generation of polluting gases such as CO2, that is, generating a “green production process for metal heat treatment atmospheres”.

[054] The invention relates to a new method of forming the chemical formulation (recipe) of industrial gas composition that makes up the internal atmosphere of a furnace (equipment) responsible for forming a neutral atmosphere or an atmosphere rich in free carbon for heat treating metal parts, comprising the following numbered and successive production steps in the heat treatment of metals of the most varied types and for the most varied industrial applications: Petition 870250073520, dated 08 / 20 / 2025, page 21 / 43 19 / 34 PREPARATION AND ASSEMBLY OF THE LOAD

[055] Figures 3 and 4 show the parts that were treated using the new gas recipe, showing parts made of Metallic Alloy: 19MnCr5G.

[056] The parts shown are automotive parts for a wide variety of applications in light vehicles (automobiles), such as: Planetary Gear, 1st Gear, Primary Shaft, 3rd / 4th Gear Sleeve, Gear, Reverse Gear, Primary Shaft, Secondary Shaft and Crown.

[057] Every part to be treated undergoes proper preparation. If it is a single piece or a set of pieces, this is called a load or batch or lot. This load is prepared using specific heat treatment baskets, which can be cast or welded. If cast, these baskets are for high-temperature resistance, usually made of cast alloys such as HK stainless steel. If welded, rolled bars of SAE 310 stainless steel, or similar, are used, which can withstand high working temperatures. In addition to the baskets, it is common to use devices and / or other instruments that provide the metal / part to be heat treated with physical integrity, support, fixation, organization, proper spacing between parts, and other factors relevant to the heat treatment of metals.These baskets and devices must respect dimensional and weight / load characteristics according to the equipment in which the basket will be inserted.

[058] This topic is relevant because the metallurgical process adopted and the invention require specific care, especially regarding the correct spacing between the metal parts arranged inside the baskets, since for some processes (carburizing / carbonization) the parts cannot be too close to each other or touch each other. Petition 870250073520, dated 08 / 20 / 2025, page 22 / 43 20 / 34 Furthermore, this spacing improves load homogeneity, results in better quality parts, improved effectiveness of furnace atmosphere gases, and better cooling after the production cycle is complete. IN THE PREVIOUS PREPARATION OF THE EQUIPMENT

[059] The invention utilizes equipment (furnaces) with special design and operating characteristics (pit furnaces or chamber furnaces or continuous furnaces, or other type of furnace, which allows the formation and control of an atmosphere inside), the most important characteristics being the following: • Control of timing, • Control of temperatures, • Control of heating and cooling rates, and • Control of the atmosphere surrounding the metal parts.

[060] The objective is to meet the metallurgical specifications contained in international standards with the most varied existing heat treatment processes, according to each specified process, for each project and for each component produced. The equipment is standardized and the production processes are also governed by automotive quality standards and also by standards from other areas that work with safety components, such as aviation, for example, giving the experiments carried out greater safety and high repeatability and reproducibility in the manufacture of items with critical characteristics and relevant topics of the ISO TS automotive standards that govern the heat treatments of metal alloys in general.

[061] These pieces of equipment (furnaces) must be sufficiently airtight and robust to withstand the high temperatures and pressures. Petition 870250073520, dated 08 / 20 / 2025, page 23 / 43 21 / 34 involved, must be periodically monitored, measured and calibrated according to specific standards (such as AIAG CQI-9), notably ensuring the quality of the resulting parts and reducing the cost of the process with the use of the process and the new atmospheres developed in this invention.

[062] A chamber furnace is used that is capable of performing heat treatment with the new recipe of gases forming the internal atmosphere of the furnace with biomethane gas, and the new recipes of processes and compositions, with lower emission of gases harmful to the environment. There are other furnace models that can be used by the invention, such as: pit furnaces, continuous furnaces, bell furnaces, box furnaces, among others. All instrumented and verified. In the preparation of equipment control instruments for carrying out production processes.

[063] The equipment involved in the heat treatments used to control the atmospheric characteristics formed with the new recipe including biomethane gas are:

[064] Regarding time, it is necessary to have a controller and recorder for the times adopted in the heat treatment process. These times can vary from seconds, minutes, hours and even days, depending on the thermal process involved, as an example we can mention: Timer or PLC Peripheral Control System.

[065] As for temperature, thermocouples (e.g. type K) and special digital temperature controllers or recorders are used to monitor temperatures, in addition to the use of a complementary supervisory system. Petition 870250073520, dated 08 / 20 / 2025, page 24 / 43 22 / 34

[066] Regarding speeds: speeds were used in these experiments at the Grefortec industrial plant as a source of available energy delivered by the furnace to the system to generate more or less heating of the parts to be treated and also of the appropriate cooling medium for removing this energy present (heat) from the metal parts moments before completing the heat treatment, all in accordance with the metallurgical treatment process adopted, where the speed and the heating and cooling rates are part of the metallurgical heat treatment processes, which can be altered to higher or lower working speeds, in the heating and / or cooling of the parts in the furnace.

[067] Regarding the atmosphere: it is necessary to have special rotameters that will provide the volume and quantity of gases for the formation of the free atmosphere inside the furnace, in addition, flow meters, pressure gauges and other measuring and control equipment are used for the formation of said atmosphere, as well as a supervisory monitoring system with the use of probes for measuring the carbon potential of the atmospheres, also confirmed, in a necessary redundancy, the amount of carbon in the atmosphere with the furnace atmosphere dew point meter.

[068] Regarding the overall evaluation of the data: it is necessary to have active and coordinated instruments, forming a complete supervisory support system capable of presenting the real behavior of the equipment at the instant the treatment takes place (in real time) in order to form and test atmospheres without the risk of explosions or process failures. It may be that, even for this reason, the atmospheres have been so little modified in their central composition by heat treatment engineers, who today have Petition 870250073520, dated 08 / 20 / 2025, page 25 / 43 23 / 34 also with new gases originating from cleaner sources such as biomethane.

[069] This supervisory system collects data from instruments added to the equipment, collecting thermal data for monitoring load behavior in service, using new gas-forming recipes from thermal treatments with biomethane gas and optimized balance. Below are some of these instruments added to the control for this formation and monitoring of safety and quality of performance tests of this new atmosphere and process with lower emissions of polluting gases or free of fossil fuel matrix: Dew Point Meter: The dew point meter is used to measure and record environmental values ​​under study (in this case, inside the heat treatment furnace) such as: • temperature, • relative humidity and • gas concentration. Additionally, the meter calculates the dew point, absolute humidity, and water vapor content. PROBE: To measure the carbon potential of the atmosphere inside the furnace. The purpose of the oxygen probe is to detect the oxygen concentration in the furnace. COMBUSTION ANALYZER: Used in boilers and furnaces, the combustion gas analyzer's function is to measure, control, and monitor the behavior of gases within the equipment and furnaces. Consequently, it helps to reduce fuel consumption and the emission of polluting gases. Petition 870250073520, dated 08 / 20 / 2025, page 26 / 43 24 / 34

[070] It should be noted that the invention has a strong disruptive impact on little-known techniques, generally treated as industrial secrets, for the formation of optimized and environmentally aligned gaseous atmospheres, aiming for zero CO2 emissions in heat treatment furnaces for metallic components such as steels, cast irons and other alloys. Therefore, emphasis was placed on the new and optimized controls necessary to test atmospheres with a low risk of accidents involving explosions and generating waste. IN THE HEAT TREATMENT PROCESS

[071] There is a need to alter the formulation of the industrial gases used by the invention in two large groups of basic heat treatment processes, which are:

[072] Tempering: This heat treatment process requires an internal furnace atmosphere with sufficient free carbon to preserve the surface chemical composition of the metal part, preventing decarburization of the surface or, conversely, the introduction of carbon into the surface of the part (carburization), an undesirable factor when only tempering is desired. To check for any alterations in the heat treatment atmospheres, measurements of the carbon potential are necessary at different stages of the heat treatment cycle, which is divided into heating, plateau, and cooling cycles, to understand and control the carbon content present in the metallic material and its respective thermal behavior. The composition of the gases used in this process of the invention was: • Biomethane: 0.10 to 1.50 m3 / hour. • Nitrogen: 0.10 to 3.00 m3 / hour. • Atmospheric air: 0.10 to 0.80 m3 / hour. Petition 870250073520, dated 08 / 20 / 2025, page 27 / 43 25 / 34

[073] Carburizing: This heat treatment process requires sufficient free carbon from the furnace's internal atmosphere to introduce carbon into the surface of the part (carburizing / carbonization). For the use of the invention's process, it was necessary to rethink the entire usual heat treatment process, as new data, control items, and information were added and / or altered to understand the statistical and safe behavior of the carbon potential present in these atmospheres. Furthermore, many tests and trials were performed, since the free carbon in the furnace's internal atmosphere must be sufficient to provide carbon in the system that will be introduced through the surface of the part towards its core, forming hardening layers called carburized layers.

[074] The process of the aforementioned invention adopts working temperature controls and variation of gas mixtures to engineer the formation of the most optimized atmospheres and clean matrices. In all tests already carried out with gas recipes containing biomethane gas and with this new atmosphere developed and tested, the results measured in all furnace automation and in the components evaluated via metallography were of compliant components with a safe and stable process, as the parts had their properties within the specifications of automotive quality standards, fully meeting all the metallurgical characteristics of the specific standards of each sector, and the furnaces operated as planned for most of the tests and adjustments of the tested atmosphere compositions. The results of the cemented layers in tested components are shown in Figure 8.

[075] Regarding the temperature of biomethane gas, since biomethane gas is a source of free carbon for the production system with a temperature of Petition 870250073520, dated 08 / 20 / 2025, page 28 / 43 26 / 34 working temperatures above 750°C are required for proper carbon cracking to occur, which is the separation of the chemical elements involved in the process (carbon, hydrogen, atmospheric oxygen and nitrogen).

[076] This working temperature can exceed 1,000°C, reaching up to 1,100°C, depending on the material (metal alloy) and the need for free carbon in the system and that meets the chemical composition of the material (metal alloy) being treated.

[077] In the part concerning the gas mixture, there is a need for adjustment according to the chemical composition of the material to be treated (metal alloy), now using predicted compositions of atmospheric air, biomethane gas and nitrogen, for the mixture, as well as adjustments regarding the constructive characteristics of the furnaces that will carry out the processes.

[078] Controlling the proper gas mixture involves pressure gauges, valves and rotameters for specific uses, flow meters and temperature controllers, which can be used manually (with the use of a “dew point meter”) or automatically (using special probes), or even using both together, making it redundant and important for automotive quality assurance that precise control of the internal atmosphere of the furnace chamber is maintained.

[079] Below are details of the practical tests carried out that were the basis for ensuring the projected theoretical results of the engineering project in the construction of atmospheres capable of various thermal treatments on the market and research with biomethane in balanced compositions with air and nitrogen and without fossil fuels in the composition, the following manufacturing recipe (process) was Petition 870250073520, dated 08 / 20 / 2025, page 29 / 43 27 / 34 adopted, tested and used for product and patent approval: Example of the Cementation Process. • Time to reach temperature: 56 min. (890°C) • Time to reach atmosphere: 56 min. (1.00°C) 890°C) • Austenitizing time: 240 min. (890°C) / Carburizing and min. (840°C) / Tempering • Total process time: 360 min. (890°C + 840°C) • Carbon percentage: 1.00%C (Carburizing) 0.80%C (Tempering) • Working oil temperature: 60°C • Maximum oil temperature: 78°C • Tempering: Temperature: 150°C | Time: 120 min.

[080] The objective of the initial tests was to verify whether biomethane gas would be able to deliver sufficient free carbon in the gas compositions tested and constructed to carry out the cementation process and whether the cemented layer formed, if it occurred, would have the same quality characteristics when compared to the use of other more usual and traditional gas recipes derived from fossil fuels.

[081] The results obtained in all treated parts and test specimens were satisfactory and fully met the specifications of the part design. This was verified by using techniques for analyzing cemented layers using microscopic metallography, hardness tests, microhardness tests, and the technique Petition 870250073520, dated 08 / 20 / 2025, page 30 / 43 28 / 34 of the tipping point assessment according to SAE J423 standard by the Methods of Measuring Case Depth, as shown in Figure 9.

[082] From this it can be said that biomethane gas performed its function in the tested and balanced atmospheres, and provided sufficient free carbon to favor and form the correct cemented layer.

[083] Opting to incorporate carbon from fossil sources through gases such as propane, butane, ethanol, methanol, and others, is the basis of the most common, oldest, and consolidated heat treatment processes, originating from the industrial era. This stemmed from less pressure for the preservation of the planet and the lack of control over pollutant gas emissions, standardizing the relationships between clients and suppliers since they did not demand accurate controls, or even control at all, over this heat treatment stage. This gave the heat treatment service provider, internal and captive sectors, from the most varied areas of engineering, the ability to comply with standards, broad ranges and limits for use, and large bands for pollutant gas emissions in the production chain.The market, understanding the importance of reducing emissions of polluting and harmful gases into the environment, has formed new concepts, determined new parameters, and specified new needs for environmental non-pollution. This invention, using biomethane gas, breaks a strong global paradigm in the formation of optimized and sustainable industrial gas atmospheres for heat treatment processes of metal parts.

[084] Thus, in order to have the process under control, it is necessary to generate data and information and to have the technical knowledge and intelligence to understand the behavior of the available carbon levels, the Petition 870250073520, dated 08 / 20 / 2025, page 31 / 43 29 / 34 chemical and energy kinetics, as well as the atomic diffusion of carbon molecules in the gas recipe, in the heat treatment atmosphere, in the part to be treated, and all this advanced metallurgical technology for forming atmospheres in heat treatment furnaces, with minimal use of gases from fossil fuels (or even mitigating or completely eliminating their use), thus making the internal atmosphere of heat treatment furnaces more useful, cleaner, and greener.

[085] Tests were needed to understand the mechanisms of atmosphere formation with precision and complete control of the carbon content present in the metallic material and its respective thermal and / or diffusional behavior.

[086] All necessary tests were carried out on both Grefortec's own and external / third-party customer metal components (parts and assemblies) and in heat treatment furnaces, both by Grefortec and by customers and partners. Examples include: • technical case studies; • PPAPs (Production Part Approval Process); • capability studies; AIAG CQI-9 test; • measurements of cemented layers; • Mechanical tests (Tension, Torsion and Compression); • Complete metallographic evaluation and complementary technical results.

[087] The new atmospheres developed were tested with a view to protecting the surface chemical composition present in the metal part, or adding new chemical elements to this surface in a controlled manner, and in accordance with engineering designs, to Petition 870250073520, dated 08 / 20 / 2025, pp. 32 / 43 30 / 34 Increase or improvement of the metal-mechanical characteristics of mechanical resistance to wear, surface oxidation, and tribological properties (friction) of heat-treated components. However, these processes, as currently used in companies, are polluting to the environment because they use many gases from fossil sources in the composition of the furnace atmospheres, generating excess CO2. These gases are responsible for generating the aforementioned atmosphere inside the furnaces, which is eventually exposed to the atmospheric air, polluting it. With the new formulation (recipe) of the gas atmosphere and the development of processes carried out with these new atmospheres, it is possible to mitigate the risks of accidents, explosions, and contamination of the atmosphere and the factory environment.

[088] The composition of the gases used in this process was: • Biomethane: 0.10 to 1.50 m3 / hour. • Nitrogen: 0.25 to 3.00 m3 / hour. • Atmospheric air: 0.20 to 1.00 m3 / hour.

[089] The new internal atmosphere of the heat treatment furnace as claimed in this patent seeks to reduce the amount of free CO2 emitted into the atmosphere after heat treatment by eliminating a special type of gas used in current formulations, which is methanol or even natural gas itself, more recently, without altering the metallurgical properties of the products that use this new formulation of the invention, making it possible to guarantee compliance with the current technical design specifications of each product, as well as to mitigate or even eliminate the use of other gases derived from fossil fuels, such as natural gas itself. Petition 870250073520, dated 08 / 20 / 2025, pages 33 / 43 31 / 34

[090] Usually the world market uses the following chemical composition / recipe of internal atmospheric gases for heat treatment, for the quenching process, for example: • Natural gas / propane / butane: 0.40 to 1.00 m³ / hour • Methanol: 3.50 to 4.50 m³ / hour • Nitrogen: 3.50 to 4.50 m³ / hour • Atmospheric air: 0.20 to 0.50 m³ / hour

[091] With some changes to the recipes, some users use other gases.

[092] The invention utilizes the following chemical composition / gas recipe for the same quenching heat treatment process: • Biomethane: 0.10 to 1.50 m³ / hour • Nitrogen: 0.25 to 3.00 m³ / hour • Atmospheric air: 0.10 to 1.00 m³ / hour

[093] In Figures 10 and 11 we can observe that in these new recipes that use biomethane gas as a free carbon supplier, and despite using a smaller amount of biomethane gas, no negative modifications occurred in the resulting metallurgical structure after the heat treatment process, in the heat treatment furnaces and in the metal alloys when using the atmosphere developed in the process of this purported invention, a relevant and highly positive fact as it confirms that when using the new recipes with biomethane gas, no undesirable variables and / or problems will be formed in relation to the test results and when compared to the processes currently performed.

[094] Figure 10 shows the metallurgical structure of a metal part that was treated with usual atmospheres (without the use of gas). Petition 870250073520, dated 08 / 20 / 2025, pp. 34 / 43 32 / 34 biomethane). Sample of a cemented part showing the metallurgical structure of the surface region (right, darker part) towards the core (left). In this case, the cemented layer was approximately 1.40 mm thick. The resulting metallurgical structure was tempered martensite, without the presence of retained austenite and hardening carbides.

[095] Each dark spot above refers to the indentation point on the sample and, in turn, refers to the hardness measurement test and cemented layer. The points are positioned according to the standard, exactly 0.10 mm apart from each other.

[096] Figure 11 shows the metallurgical structure of a metal part that was treated with atmospheres using biomethane gas in its recipe. Sample of a cemented part where we have the metallurgical structure of the surface region (left, dark part) towards the core (right, lighter part). In this case, the cemented layer was approximately 0.65 mm thick. The resulting metallurgical structure was tempered martensite, without the presence of retained austenite and undesirable hardening carbides. Within specifications.

[097] However, in addition to the tempering process, this new gas mixture (or recipe) can also be used in other metallurgical heat treatment processes such as carburizing (carbonization), normalizing, annealing and other thermal heat treatment processes that require internal atmospheric control in the furnace chamber, with or without free carbon.

[098] The process followed all the rules and is consolidated by mechanical tests, metallurgical tests, statistical data and Petition 870250073520, dated 08 / 20 / 2025, pages 35 / 43 33 / 34 reports requested by clients for the evaluation of heat-treated products in various types of industrial sectors.

[099] Therefore, with the optimization of the synthetic atmosphere formation process, along with process adjustments, it was possible to eliminate commonly used gases (such as methanol), eliminate unnecessary additional equipment such as costly and expensive artificial atmosphere generators, and enable the use of carbon-rich gases from clean sources such as biomethane, instead of other gases that can be discarded or no longer used, but are also carbon-rich and widely used in the heat treatment market, such as liquefied petroleum gas, natural gas, butane, propane, and ethanol plus nitrogen and air. Natural gas represents a noticeable evolution in these atmospheres, but its use is still incipient in the market, to obtain components with clean surfaces, without oxidation and / or carbon loss on the surface.

[0100] In this way, clean possibilities for constructing green atmospheres surrounding the metal part were developed, without altering its metal-mechanical characteristics, however, in a more economical and less polluting way. The process used differs from the state of the art notably by some process variables, such as the elimination of polluting fossil gases and an atmosphere formation process with a new formulation of volumes, gas addition temperature, time and addition volumes.

[0101] The recipe (mixture or composition) of heat treatment gases claims the composition range of heat treatment atmosphere-forming gases for the following metal heat treatment processes: quenching / tempering; carburizing Petition 870250073520, dated 08 / 20 / 2025, pages 36 / 43 34 / 34 (carburizing); normalizing; annealing; carbon itriding; nitrocarburizing; boriding; ferritizing and perlitizing.

[0102] The recipe (mixture or composition) of heat treatment gases claims the composition range of heat treatment atmosphere-forming gases for the following materials, steels, metal alloys and / or production processes: low carbon steels; alloy steels; gray cast irons; medium carbon steels; stainless steels; white cast irons; high carbon steels; tool steels; malleable cast irons; PIM; MIM; nodular cast irons; 3D printed metal parts.

[0103] The use of the recipe (mixture or composition) of gases claimed in this invention, for the formation of the protective atmosphere for heat treatment, for any and all ferrous or non-ferrous metallic products that use or require a protective atmosphere, rich or not in relation to free carbon, with regard to the heat treatment of metals. Petition 870250073520, dated 08 / 20 / 2025, pages 37 / 43

Claims

1 / 3 CLAIMS:

1. PROCESS, describe the following steps: • Preparation and assembly of the heat treatment load; • Prior preparation of the equipment (furnace); • Preparation of process control instruments; • Heat treatment processes (various); • Quality inspection and technical analysis processes; • Validation of specifications; The preparation of the control instruments for the equipment involved in the heat treatments, used to control the atmospheric characteristics formed, is characterized by: • Time control; • Temperature control; • Working speed control; • Atmosphere control; • General control and evaluation of data through a supervisory system.

2. PROCESS, according to claim 1, characterized in that the supervisory system is able to display the actual behavior of the equipment at the instant the treatment is taking place (in real time).

3. PROCESS, according to claim 1, characterized by the supervisory system using the following instruments for training and monitoring: • Dew point meter, measuring and recording environmental values: temperature, relative humidity and gas concentration; Petition 870250063806, dated 07 / 24 / 2025, page 38 / 50 2 / 3 • Probe: verifies the carbon potential, detecting the oxygen concentration in the furnace; • Combustion analyzer: promotes the measurement, control and monitoring of gas behavior inside the furnace.

4. GAS COMPOSITION, for heat treatment by quenching according to the process of claim 1, characterized by the use of: • biomethane: 0.10 to 1.50 m3 / hour; • nitrogen: 0.10 to 3.00 m3 / hour; • atmospheric air: 0.10 to 1.00 m3 / hour.

5. GAS COMPOSITION, according to the process claimed in claim 1, for heat treatment by carburizing, normalizing, annealing and other thermal processes, characterized by the use of: • biomethane: 0.10 to 1.50 m3 / hour; • nitrogen: 0.10 to 3.50 m3 / hour; • atmospheric air: 0.10 to 1.50 m3 / hour; • methanol: 0.00 m3 / hour (zero, without the use of methanol).

6. GAS COMPOSITION, according to claims 1, 4 and 5, characterized by the range of gas compositions of the heat treatment atmosphere for the following metal heat treatment processes: quenching / tempering; carburizing; normalizing; annealing; boriding; carbonitriding; nitrocarburizing; ferritizing and pearlitizing.

7. GAS COMPOSITION, according to claims 1, 4 and 5, characterized by the range of composition of the gases forming the heat treatment atmosphere for the following materials: Petition 870250063806, dated 07 / 24 / 2025, page 39 / 50 3 / 3 steels, metal alloys and / or production processes: low carbon steels; alloy steels; gray cast irons; medium carbon steels; stainless steels; white cast irons; high carbon steels; tool steels; malleable cast irons; PIM; MIM; nodular cast irons; 3D printed metal parts.

8. GAS COMPOSITION, according to claims 1, 4 and 5, characterized by the use of the gas composition, is intended for any and all ferrous or non-ferrous metallic products that use or require a protective atmosphere in relation to the heat treatment of metals.

9. GAS COMPOSITION (RECIPES), according to claims 1, 4 and 5, characterized by the use of biomethane gas in the gas composition recipe. Petition 870250063806, dated 07 / 24 / 2025, pp. 40 / 50

Images