Before metal parts can become strong and reliable, they must be heat treated first. Heat treatment subjects metal workpieces to heat below their melting temperatures. Subsequently, the heated materials are cooled controllably, making sure that they attain the desired mechanical properties of specific industries or users.
Tons of heat treatment processes can be carried out to alter the properties and qualities of metal parts. One of these processes is nitriding.
Nitriding is a heat treatment process that disperses nitrogen elements into metal surfaces, providing them with a case-hardened surface. Many metals can be subjected to nitriding. Some of them are titanium, molybdenum, aluminium, and low-alloy steel. To date, nitriding can be classified into two: hard nitriding and soft nitriding.
Hard Nitriding
The conventional way of nitriding is known as hard nitriding. This process refers to the placement of a workpiece in a furnace gas containing nitrogen or ammonia. The temperature, gas flow rate, ammonia concentration ratio, and other elements are then regulated to a specific level in time, ensuring that the nitrogen can infiltrate into the workpiece’s surface. After a specific period of time, the workpiece is expected to develop a surface nitride phase, making it more resistant to fatigue and wear.
Hard nitriding is often conducted at temperatures of between 480 and 540 degrees Celsius. These temperature levels are necessary to sustain the hardness and other qualities of the workpiece’s core. They are likewise significant in ensuring the hardness of the nitriding layer. As for the time, a workpiece is expected to undergo the nitriding process for around 15 to 70 hours, making sure that it obtains the required depth of a specific application.
Workpieces that undergo hard nitriding can expect higher hardness and wear resistance, better fatigue strength, and higher seizure and corrosion resistance. This process is best for workpieces made from steels that contain chromium, molybdenum, titanium, aluminium and other alloy elements, stainless steel, and die steel.
Soft Nitriding
Soft nitriding, also known as nitrocarburizing or cyanidation, is the process of subjecting workpieces to not only nitrogen but also carbon. It makes the process work similarly to a low-temperature carbonitriding, which is then based on nitriding. This process can be grouped into two: gas soft nitriding and liquid soft nitriding. Gas soft nitriding is a nitriding process that adds low-temperature carbon and nitrogen into the workpiece. Liquid soft nitriding, alternatively, maximises a cyanide salt mixture in a bath in processing a workpiece.
The temperatures used for gas soft nitriding may range between 560 and 560 degrees Celsius, with the whole process lasting around 2 to 3 hours. Liquid soft nitriding, alternatively, may be done between 540 and 590 degrees Celsius.
What is great about soft nitriding, in general, is it can infiltrate workpieces in a short time. It can also provide good toughness and minimal brittleness to the involved metals. So, with metals that possess small load and shallow infiltration layer requirements, soft nitriding would be the best option to maximise. Most steel grades and cast iron can take advantage of this process.
To know more about these nitriding options, you can contact us at Alpha Detroit Heat Treatment.
One of the most utilised materials in the world right now is metal. Metals generally boast a wide array of useful mechanical properties that enticed industries to use them in creating many products.
Some mechanical properties that most metals boast include high melting points, high thermal and electrical conductivity, high density, excellent malleability, and respectable ductility. Thanks to these properties, the construction, manufacturing, shipbuilding, automotive, energy, mining, and aerospace industries can produce components and products that can be functional and long-lasting.
One area of metal components and products, however, that should be enhanced further is their outermost surface. This specific part of metal components and products often undergoes direct impact. Without carrying out any finishing process, the underneath metal may gradually become damaged.
The Process of Case Hardening
To protect metal components and products from attaining abrasions and other damages, industries can rely on the case hardening process.
Case hardening is the process of increasing the hardness of a metal surface by adding new elements to its exterior part. Once a metal workpiece undergoes case hardening, it will attain a very thin metal layer that is harder and more durable than the metal underneath the said layer. Case hardening is often carried out as the final process of newly fabricated metals, especially those that possess a low carbon content since it reduces formability and machinability.
Case Hardening Major Benefits
Metals that undergo case hardening can effectively attain a substantial increase in strength and durability. Since their core metal materials are already enclosed by thick cases, they can effectively be utilised in applications that are often exposed to impact. Case hardening can also ensure that the metal parts and components will not wear easier compared to those without any of this process. Even the impact resistance of metals is expected to increase due to case hardening.
As for manufacturers, they can also take advantage of the case hardening process itself since it is more efficient than other finishing processes. Compared to others, case hardening does not require a lot of energy and time, helping them save tons of resources. Case hardening is likewise dependable as it can provide metals with their needed resistance to elements that other processes cannot provide.
Applications of Case Hardening
Different types of metals can undergo case hardening. These metals include low carbon steel, high carbon steel, cast iron, high strength low alloy steel, tool steel, and stainless steel. Case hardening is often maximised in products such as gears, fasteners, rods, pins, and camshafts. Valves, bearings, engine blades, pistons, and gearboxes can also undergo case hardening.
For more information about case hardening, you can contact us at Alpha Detroit Heat Treatment.
Induction hardening is one of the surface hardening processes that manufacturers often maximise. This process entails the hardening of the metal part surface quickly and selectively.
Several manufacturers opt for induction hardening as it can provide tons of advantages to a wide array of metal parts and products such as increased wear resistance, increased strength and fatigue life, and minimised distortion. Workpieces that have undergone induction hardening can also be tempered right after, allowing manufacturers to adjust their hardness level.
Process Details of Induction Hardening
When conducting induction hardening, manufacturers would place the workpieces inside a copper coil to heat them above their transformation temperature. They would then apply an alternating current to the coil, which induces an alternating magnetic field within the workpiece. The outer surface of the workpiece is subsequently expected to attain a temperature above the transformation range. This step is later followed by quenching, which is carried out by a quench that is water-based with the addition of polymer.
Resolving Induction Hardening Issues
While induction hardening is often done by professionals, the process can still be filled with issues due to a wide array of reasons. Here are some of the most common induction hardening issues and some ways to resolve or avoid them.
These are only some of the problems associated with induction hardening. To know more about them, you can contact us at Alpha Detroit Heat Treatment.
Various construction companies rely heavily on metal parts and products to make their projects successful. Metal architectural pieces, after all, are durable, versatile, and long-lasting.
But raw metal architectural pieces may not be robust enough in withstanding weather and other outdoor elements. And so, companies would only opt for architectural pieces that have been subjected to various heat treatment processes. One heat treatment process that can enhance the qualities of small and large architectural pieces is oil quenching.
An Overview of the Quenching Process
Heat treatment is comprised of various steps. And one of the most crucial steps in this process is quenching. Quenching is the rapid cooling of workpieces in water, air, or oil after subjecting them to high temperatures. As they cool down, the involved parts may attain certain properties needed by industries.
As mentioned, quenching can be done through water, air, or oil. While all these quenching mediums have their respective benefits and limitations, most industries prefer oil as their primary quenching medium as it provides more benefits to the parts compared to others.
Three Main Stages of Oil Quenching
Oil quenching is done in multiple stages. The first stage is the vapour stage, which is the formation of a vapour blanket around the submerged part. A vapour forms around the part since it is hotter than the quenchant, the quenching medium used in cooling the workpiece.
The second stage is the boiling stage, which is the boiling of the quenchant. During this stage, the submerged parts cool the fastest since the vapour blanket has already dissipated. Its dissipation allows the quenchant to contact the parts flawlessly, removing most of the heat through boiling.
Oil quenching ends in the convective stage. This stage allows convention and conduction to remove heat away from the parts. Convection is the movement of a liquid due to the tendency of hotter and less dense material to rise, while colder and denser material to sink. Conduction, alternatively, is the tendency of heat dissipating through a substance on which temperature differences exist in the liquid. Oil tends to be disturbed strongly during quenches, forcing this medium to flow upward through the workload.
Primary Advantages of Oil Quenching
What makes oil quenching advantageous for parts and products is it can transfer heat more quickly than other quenching mediums without causing cracks and distortion. Another great advantage of oil quenching is it can be modified freely. The temperature, viscosity, and other chemical properties of the quenching medium can be altered to provide varying outcomes to the heat-treated parts. Oil quenching can likewise accommodate different types of metals, making the process more versatile than others.
Oil quenching can utilise either fast oils or hot oils. Fast oils work best with parts out of low-carbon steel and low-hardenability alloys. Hot oils, alternatively, can process high-hardenability alloys effectively.
The versatility and adjustability of oil quenching make it ideal for large architectural pieces. To know more about architectural blackening, you can contact us at Alpha Detroit Heat Treatment.
Many industries require a wide range of products to ensure that they remain functional. One notable material that is used in creating these products is metal.
Metal products have been beneficial to many industries since they are durable and strong. They can also be versatile, allowing manufacturers to alter their properties through casting, welding, forging, soldering, and others. Metal products can likewise resist heat and other elements that can be destructive to products made from other materials.
To date, many processes can be conducted to make metal products machinable and workable. One of these processes is stress relieving.
The Stress Relieving Process
Stress relieving is the process of heating metal workpieces to a predetermined temperature just below their transformation temperature. Subsequently, the heated metal workpieces are subjected to cooling in the furnace or the air. The purpose of this process is to relieve any crystal dislocations or stresses of metal workpieces that have undergone machining, forming, straightening, rolling, and other processes.
This specific process can be done during the manufacturing process of metal workpieces. However, it can also be conducted throughout their life. Metal workpieces that require tight tolerances should undergo this process before their finish machining. Stress relieving can also be carried out before heat treating metal workpieces to effectively minimise distortion. Ultimately, metal workpieces designed for tooling can undergo stress relieving as part of their maintenance or upkeep.
Benefits of Stress Relieving
The working principles of stress relieving can conveniently provide benefits to metal workpieces. Some of the benefits of stress relieving are as follows:
Stress Relieving Applications
Tons of metals can undergo stress relieving so they can attain the previously stated benefits. Some of these metals are steel, copper, and brass.
To make stress relieving successful, hardened and tempered parts must be heated at around 50°C below the temperature previously used for their tempering. When stress relieving before nitrocarburizing, the process must be done at temperatures greater than 600°C. To know more about stress relieving applications and other necessary information, you can contact us at Alpha Detroit Heat Treatment.