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.