Industries such as automotive, construction, and others have been utilising welding as it can significantly help them gain access to essential materials and carry out more processes. Welding, in general, is a process of joining two parts together by subjecting them under high heat without using a separate binder material. With this process, the mentioned industries can easily create modern assemblies and finish projects like skyscrapers, vehicles, aeroplanes, and many more.
Welding has helped industries form and construct components and structures that cannot be processed by other material binding processes. In fact, almost 70% of the products that are manufactured today are made through the welding process. Given its importance, industries ensure that it will be carried out optimally without causing any problems and issues.
The Significance of Stress Relief
One way to maintain and produce high-quality weldments is through stress relief. Stress relief is a form of post-weld heat treatment that is intended to eliminate residual stresses, lessen distortion, and recover dimensional tolerance. Without performing the necessary stress relief treatment, the weldments can easily obtain stress-corrosion cracking near welds and in some areas that have been cold-strained during the welding process, which then affects the overall production of structures and components.
You see, distortion among weldments and the surrounding bare metal normally occurs whenever they are subjected under rapid and uneven heating and cooling. Once the molten weld metal cools down, their structure contracts at a rate that is different from the base metal around them. The different cooling rates between these parts, especially if they are restrained, will then result in the presence of residual stresses. If they are not restrained, however, both parts will obtain some noticeable distortion.
The presence of welding stresses to materials can increase their susceptibility to brittle fracture and reduce their dimensional stability. They can also cause deformation of the structure and make their form factor and appearance to become out of shape.
Ways to Minimise Welding Stress
Fortunately, there are various ways of minimising welding stress. For one, the welded structures are exposed to vibrations so they can effectively relieve up to 25% of residual stress. Distortion can also be reduced with the use of vibratory stress relief treatment, all without changing the mechanical properties of the weldment. Another way of minimising welding stress is through thermal treatment. This specific treatment is done by heating the parent metal uniformly until it reaches the appropriate temperature. Once the temperature has been reached, the material will then be subjected to uniform cooling.
Peening is also one way of minimising welding stress. This process elongates the outer portion of the weld and is controlled through a pneumatic chisel with a blunt round edge. With preening, it can easily reduce the internal stress of the weldments. It must, however, be done optimally to avoid hardening the weld metal or bending and cracking the weld. Minimising and countering residual stresses can likewise be done through thermomechanical stress relief treatment. This treatment utilises uses thermal expansion in countering residual stresses and other possible issues.
If you want to know more about the process and benefits of stress relief, feel free to contact us at Alpha Detroit Heat Treatment. Our expertise allows us to suggest the most appropriate process for your heat treatment requirements.
A lot of metal parts and components normally require additional processes for them to achieve wear-resistant surface, improved core strength, and other dependable properties. These enhancements allow them to be useable for specific applications and conditions.
Achieving these enhancements can be done in two ways. First, metal parts and components can be subjected under the process of altering the chemical composition of their surface. Some processes that can be utilised for this type of enhancement include carburising, nitriding, cyaniding, and carbonitriding. Another way of achieving the aforementioned enhancements is through the hardening of their surface layer only, which can be done by either flame hardening or induction hardening.
General Overview of Flame Hardening
One process that can be done to strengthen the surface layer of metal parts and components is flame hardening. It is a fairly common surface hardening process that utilises high-temperature flame in heating the surface layer of materials. Through this process, metal parts and components are expected to obtain surfaces that are tough and resistant to wear and corrosion.
Generally, there are two flame hardening techniques that can be utilised for metal parts and components.
Steels that have a carbon content of 0.4 to 0.7% can be processed by flame hardening. Other materials that can also be processed by this process are cast iron and cast steel products. Materials that have sensitive materials can undergo flame hardening, given that emulsions with an oil-like quenching behaviour will be used instead of water.
Flame Hardening Working Principles
As previously stated, flame hardening utilises high-temperature flame in performing the hardening process. Metals under this surface hardening process are normally heated to their austenitizing temperature, allowing their surfaces to change without affecting their respective cores. As these metal materials reach their austenitizing temperatures, they are often quenched immediately. The quenching process allows them to develop much harder and more corrosion-resistant surfaces.
Crucial factors that can determine the results of the flame hardening would normally include the heat of the flame, the duration of the heating, the speed and temperature of the quenching process, and the entire composition of the material or workpiece.
Useful Benefits of Flame Hardening
The flame hardening process can be beneficial for manufacturers and businesses since it can give higher hardness for increased longevity, provide more efficient productivity, reduce downtime and maintenance costs, and decrease distortion, processing time, and the need for machining and grinding. Some products that can be subjected under flame hardening include rolls, shafts, sheaves, rope drums, slew rings, machine ways, rails, dies, moulds, gears, and sprockets.
To know more about the flame hardening process, you can talk to us at Alpha Detroit Heat Treatment.
Induction hardening is a type of heat-treating process that typically subjects a metal part under induction heating and quenching. After conducting this specific process, the metal part is intended to undergo a martensitic formation, allowing it to obtain features and properties that it does not possess before.
The process of induction heating starts by placing a metal part near a copper coil that has a significant level of alternating current. Through eddy current and hysteresis losses, the said coil can generate heat that is directed at or near the surface of the metal part. Subsequently, the metal part is directed or submerged under a water-based quench, which then initiates its aforementioned martensitic formation.
Induction hardening can bring numerous benefits to the processing of different metal parts. The same process, however, also share some disadvantages that manufacturers may encounter along the way.
Advantages of Induction Hardening
Disadvantages of Induction Hardening
For more information about induction hardening, you can call us at Alpha Detroit Heat Treatment.
To get the desired properties of metal materials, metallurgists would normally place them under heat treatment. Heat treatment is a group of industrial and metalworking processes that are used in changing and modifying the properties of a metal or any other material. The processes involved in heat treatment are constantly enhanced by different metallurgists to obtain improved results and achieve cost-efficiency.
Some Effects of Heat Treatment Processes
Heat treatment processes bring numerous effects to metal materials that undergo them. For one, some processes can make metal materials soft, while others can boost their overall hardness. Alternatively, the electrical and heat conductivity of numerous metal materials may also improve due to specific heat treatment processes. Even the chemical properties of these metals can be altered once they are placed under numerous heat treatment procedures. Stresses due to earlier heat treatment processes may likewise be alleviated and relieved once they are placed under other heat treatment processes.
Understanding the Technological Process
Understanding the technological process of heat treatment is key to the successful alteration and modification of metal materials. Most of the heat treatment processes are carried out by three essential steps: heating, heat preservation or holding, and cooling. These steps are usually interlinked. However, the inclusion of some of these steps would still vary based on the metal that is intended to be processed.
The effects of heat treatment processes may vary according to the composition of the metal and its overall condition. Steps and elements involved in a specific heat treatment process can also affect the outcome of a metal being processed and treated.
Air from our environment has various elements that can easily react with metals and cause undesirable results. Under room temperature, the moisture, oxygen, carbon dioxide, and hydrogen that are present in the atmosphere can each cause small but varying reactions with metals. Most of the time, however, these reactions can accelerate drastically if the metals are exposed to heat or a hot environment.
One instance where metals would be subjected under heat would be their fabrication process. The colour of a polished metal that is held over a heat source can ultimately turn to blue or black as it reacts to the elements present in the atmosphere. Without any intervening processes, some types of metals would truly have worse reactions and severe property changes than the mentioned example.
Basic Principles of Vacuum Heat Treatment
Fortunately, more and more metal fabrication companies have been applying the processes of vacuum heat treatment for their works. Vacuum heat treatment is comprised of a series of processes that can prevent metals from interacting directly with reactive elements. Some of the undesirable results that vacuum heat treatment can avoid include discolouration, scale, and contamination.
To effectively remove the reactive elements, the metal product is placed in a tightly sealed heat-treating chamber. The vacuum pumping system on this chamber is guaranteed to remove most of the air that would affect the overall quality and integrity of the metal material. At the same time, in this very same chamber, the metal is heated to a suitable temperature for it to possess the desired properties. Inert gases are then used for the cooling process of the processed metal material.
Advantages of Vacuum Heat Treatment
The advantages brought by vacuum heat treatment are abundant. One great advantage of this process is that it ensures the absence of oxidation, decarbonisation, and other presence of carbon inside the metal material. The absence of these processes and elements will then allow the workpiece to be formed without unnecessary scaling or discolouration. Additionally, the very same workpiece would emerge ready for further processing and forming, all without the need to clean it again.
As for the properties of the metal material, vacuum heat treatment can significantly improve its plasticity, toughness, and fatigue strength. Improvements over the thermal efficiency of metal materials are likewise expected right after all necessary vacuum heat treatment processes are done.
Common Vacuum Heat Treating Services
Some of the most common services that are conducted for vacuum heat treatment are the following:
Other vacuum heat treating services that can be used for metal materials are normalising, solution heat treatment, and aging treatment.