Metal workpieces often undergo numerous processes to obtain substantial changes in their properties. One of these processes is the heat treatment process.

Heat treatment is a term used to describe activities that can alter the physical properties of a metal workpiece. This specific process typically involves heating or cooling in introducing changes to the involved part or component. Some properties that are affected by the heat treatment process include hardness, ductility, strength, toughness, and resistance to elements.

One great thing about the heat treatment process is that it can be done in numerous ways. It can even be done in various locations, ensuring that a workpiece can obtain its needed changes.

Issues with Heat-Treating Metal Workpieces

Before its processing, a metal workpiece is often exposed to various surrounding elements such as oxygen, carbon dioxide, and moisture. And with prolonged exposure to these elements, the metal workpiece may obtain changes and reactions, especially if it is processed with intense heat.

Now, to minimise undesirable reactions, professionals would often eliminate the source of the reactive elements from the heat-treating environment. One way of doing this is to replace the air in the heat-treating chamber with nitrogen, argon, or other gas combinations. Another way would be the exposure of the metal workpiece in a non-reactive molten salt bath. These processes may deter most of the undesirable reactions from the elements, but the workpiece would still contain low levels of impurities.

Vacuum Heat Treatment is the Key Solution

Vacuum heat treatment, fortunately, can remove most of the reactive elements from the heat-treating environment or heat-treating chamber. With the help of a vacuum pumping system, it can get rid of most air elements inside the heat-treating chamber that cause undesirable reactions and discolouration to the workpiece. Sometimes, an oil diffusion pump is installed alongside the pump system so that it can further eliminate elements and allow more sensitive metal workpieces to be heat treated.

The furnaces used for the vacuum heat treatment, however, can only be effective if they are maintained regularly. Without proper maintenance, they might develop some leaks, which can only lead to contamination during the heat treatment process.

The Processes of Vacuum Heat Treatment

Vacuum heat treatment starts with the positioning of the workpieces in a special chamber. With a vacuum pumping system and other related components, the elements inside the chamber will be removed and replaced with argon gas or other similar elements. Once these steps are done, the chamber will be subsequently heated up to as much as 1,300 degrees Celsius before lowering it for some time. The entire cycle of the vacuum heat treatment may take three hours to one day, depending on the needed material.

A fully maintained vacuum heat treatment furnace can easily produce workpieces with boosted strength and improved thermal efficiency. It can likewise avoid oxidation, decarburisation, and carburisation.

To know more about this process, you can call us at Alpha Detroit Heat Treatment.

Sources:

Benefits of vacuum heat treatment. Jones Metal Products. (2020, June 11). https://www.jmpforming.com/blog/vacuum-heat-treating/benefits-of-vacuum-heat-treatment.htm.

MetalTek International. (2021, June 2). Heat Treatment | Metal Processing. MetalTek. https://www.metaltek.com/capabilities/heat-treatment/

VAC AERO International. (2019, May 15). Why Heat Treat in a Vacuum?Vacaero. https://vacaero.com/information-resources/vac-aero-training/650-why-heat-treat-in-a-vacuum.html

To date, many heat treatment processes are being done to various metals and alloys for them to acquire property alterations and improvements. Once a material undergoes a heat treatment process, its physical and structural properties are expected to improve, allowing it to be processed further.

One heat treatment process that is common among metals and alloys is annealing. It is a process wherein the physical and sometimes chemical properties of a material undergo vital changes. Most of the time, this process allows the material to obtain increased ductility and reduced hardness, ensuring that it can be workable for other processes and procedures.

For copper, the process of bright annealing is typically conducted due to the benefits it can bring.

A Quick Overview of Bright Annealing

But before knowing the benefits of bright annealing, one must know how it works first. Bright annealing is normally carried out by annealing the material in a controlled-atmosphere furnace. The furnace being utilised by the process may possess certain sizes, temperatures, and cooling rates, ensuring that it can easily carry out the bright annealing process without any problems.

The bright annealing of copper and its alloys intends to protect them from oxidation. Hence, the furnace atmosphere system should possess less partial pressure than that necessary to generate the oxide. Oxygen reduction can likewise be achieved by exposing the atmosphere to an active gas like hydrogen. Additionally, utilising a non-flammable atmosphere as well as diluting any flammable component below its flammable limit must be done to avoid oxidation-related issues. Ultimately, oxidation problems and issues can be prevented through maximising zoning technology.

Aside from preventing oxidation, the furnace atmosphere system should be able to remove unwanted processing lubricants. This specific function can be done through physical flushing or exposing the lubricant through an atmosphere component.

Bright Annealing Copper and Its Alloys

One thing about copper is that it is difficult to oxidise. Hence, it is common for copper materials to be annealed with exogas or steam. However, the use of exogas in the annealing process will only generate carbon dioxide and soot. Annealing with steam, alternatively, can be costly. One non-toxic alternative to these two elements is the use of high-purity nitrogen and a small addition of hydrogen. 

For tough pitch copper, it is therefore recommended to be annealed in atmospheres that contain hydrogen of around 2%, preventing any instances of embrittlement. Annealing the copper with lower-purity nitrogen is also possible and can generate great results. The only problem with the use of hydrogen is that it can take some time. Without any intervention, the gas mixture may interact with the annealing process and just ruin the workpiece. To make things more efficient, it would be better for the gas mixture to pass over a catalyst before introducing it into the furnace.

Copper-based alloys that contain aluminium, beryllium, and zinc can also be annealed in a protective atmosphere system that consists of an exothermically generated gas. They can, however, utilise nitrogen/hydrogen mixtures to prevent toxicity and soot.

To know more about bright annealing, feel free to call us at Alpha Detroit Heat Treatment.

To date, a wide array of alloys can be utilised to create reliable parts and components. One of the alloys that are being maximised by many industries is cast iron.

Cast iron is an alloy of iron that is comprised of more than 2% carbon as well as varying amounts of manganese, silicon, sulphur, and phosphorus. The presence of these elements allows this specific alloy to possess great fluidity, low melting point, exemplary pouring characteristics, excellent machinability, and resistance to wear and deformation.

Most cast iron parts and components are used by the automotive, construction, and electronics industries. The formation of these products is possible through different heat treatment techniques. To know more about them, here is some information on various heat treatment techniques of cast irons.

Stress Relieving

Stress relieving is a heat treatment technique that subjects the cast iron to a constant temperature below its critical temperature before exposing it to controlled cooling. As the temperature gets higher, the mechanical properties of the cast iron typically change. Once the desired mechanical properties are achieved, the cast iron is then cooled. For most castings, a furnace cooling to 260°C can be done. Cooling to 95°C, alternatively, is a must for those that possess intricate shapes. This specific technique is applied to cast iron to effectively minimise residual stresses and dimensional changes.

Annealing

Another heat treatment technique that can be applied to cast iron is annealing. It is a heat treatment technique that changes the microstructure of the cast iron, therefore changing its electrical or mechanical characteristics. When applied to cast iron alloy, annealing can easily reduce its hardness, increase its ductility, and eliminate internal stresses on its structure. Annealing is typically done by heating the cast iron for a specific amount of time before letting it cool slowly to room temperature. Various types of cast iron can go through different heating and cooling cycles to achieve distinct purposes.

Quenching and Tempering

Both quenching and tempering are typically applied on cast irons to improve their ductility and relieve internal stresses. But to yield great results, various parameters should be selected and controlled. Selecting and controlling the parameters such as the temperature can then prevent the cast irons from distorting, warping, burning, or quench cracking. Before performing these techniques, the heating of the cast irons must be done gradually to avoid inducing thermal stresses. The parts that were soaked must then be quenched. Tempering is subsequently done at a temperature range of 120 to 595°C.

When processing specific types of cast iron, different heat treatment techniques can be done. For example, high-alloy white iron castings can be processed through stress relief heat treatment and tempering. Grey cast irons and ductile cast irons, alternatively, can benefit from stress relief heat treatment and annealing at varying temperatures.

To know more about heat treatment techniques of cast irons, you can contact us at Alpha Detroit Heat Treatment. We provide a wide range of services for all your heat treatment needs.

Source:

Herring, D. H. (2020, March 19). Heat Treatment of Cast Irons. 2018–12-12 | Industrial Heating. https://www.industrialheating.com/articles/94644-heat-treatment-of-cast-irons

A lot of processes can be maximised to generate metal products. Some processes are intended to change the properties of the metal products, while others are meant to alter their surfaces. There are even processes that add an adequate protective coating to the metal products.

One process that can be done to metal products is flame hardening. The flame hardening process is generally designed to harden a metal product while making it more malleable.

The Whole Process of Flame Hardening

Basically, the process of flame hardening involves the heating of a metal’s surface area very quickly through a high-temperature flame. The high-temperature flame typically comes from the combustion of a fuel gas with air or oxygen. Once the heating process is done, the involved metal workpiece is quenched or cooled in water or oil. The cooling process hardens the metal surface while maintaining the soft state of the core, making the metal product malleable and workable.

Throughout the flame hardening process, the metal workpiece can gain no change in composition. Hence, it must contain ample carbon content so that its intended surface hardness can be achieved. The depth of the hardened surface area hugely depends on the flame head design, heating duration, hardenability of the steel, quenching medium, and the quenching method itself.

Flame Hardening Notable Advantages

The process of flame hardening is carried out by industries due to its associated advantages.

One of the advantages of flame hardening is that it can provide localised hardening effects to the metal workpieces. The process can likewise provide controllable hardening depth. These advantages can make the surface of metal products hard and wear-resistant, with significant improvements over their fatigue strength. Another advantage of flame hardening is that it can minimise heat treatment distortion, making the metal products more resistant to surrounding elements.

As for the flame hardening itself, some advantages that the industries can obtain from the said process include minimised operational costs, decreased processing steps, and reduced processing time.

Remarkable Uses of Flame Hardening

Flame hardening can be used for low, medium, and high carbon steel. The results of the process with low and medium carbon steel products, however, would depend on their required surface hardness and core qualities. High carbon steel products, alternatively, can be processed if careful control is carried out. Other materials that can be processed with flame hardening are cast ironsand alloy steels.

Aside from their compatibility with certain types of metals, flame hardening can be applied to very large parts. It can likewise be maximised in processing workpieces that require heat treatment on small areas. If certain industries want to obtain metal parts with various shapes, then flame hardening can also be conducted to meet their requirements.

Some products that can maximise flame hardening are rolls, shafts, sheaves, rope drums, slew rings, dies, moulds, gears, sprockets, machine ways, and rails.

If you want to know more about flame hardening, you can contact us at Alpha Detroit Heat Treatment.

Depending on the needs of specific industries, metal materials can be processed in a lot of ways. One of the processes that can be applied to metal materials is induction hardening.

Induction hardening is the process of hardening the surface of metal materials. During this process, a metal workpiece is typically placed inside a copper coil, which carries a substantial level of alternating current. The alternating current can then generate heat at and near the surface of the workpiece. The temperate of this process often goes above the transformation temperature of the workpiece. After the heating process, the metal workpiece will then be quenched, changing its structure effectively.

Benefits of Induction Hardening

Through the process of induction hardening, metal workpieces are expected to obtain some benefits.

One of the benefits of induction hardening is that it can increase the wear resistance of metal products. With increased wear resistance, metal products are expected to last for a long time, despite using them at various applications. Another benefit of induction hardening is that it can increase the fatigue strength of the materials. The residual compressive stress that is generated by the process allows workpieces to have a hardened structure near their surface, protecting the core from possible damages and issues.

Aside from increased wear resistance and fatigue strength, induction hardening can also grant workpieces the chance to have an adjusted hardness level after conducting the said process. Lowering the hardness of the materials while decreasing their brittleness is possible through tempering.

One more benefit of induction hardening is that it allows industries to utilise low-cost steel materials. These materials are often machinable due to their minimal carbon content. They likewise have a low risk of cracking and other negative effects. These features make the process cheaper compared to others.

Induction Hardening Applications

Given the benefits of induction hardening, it can truly generate excellent products out of various metal materials. It can even be used to enhance the mechanical properties of various ferrous components, making the process very useful for repairing field failures or warranty claims. It can likewise generate a lot of products since it does not require holding time.

Some of the materials that can be used for induction hardening include alloy steel, carbon steel, powder metal, cast iron, and martensitic stainless steel. Some products that can be created out of induction hardening are gears, axles, shafts, cam lobes, stampings, and spindles.

To know more about induction hardening, feel free to call us at Alpha Detroit Heat Treatment. We provide a wide range of services as well as suggest the most appropriate process for all your heat treatment requirements. We pride ourselves on providing quality service and reliability.