Heat treatment is used as a secondary machining step following CNC machining
Your job isn't over after you complete CNC cutting a part. These basic components may have ugly surfaces, be insufficiently strong, or be only one component that must be combined with others to produce a full product. After all, how frequently do you use a gadget composed of distinct parts?
The point is that post-processing activities are required for a variety of applications, and we'll walk you through some factors so you can select the best secondary operation for your project.
In this three-part series, we'll look at heat treatment procedures, coatings, and hardware installation alternatives and considerations. Any or all of these may be necessary to convert your machined product to a customer-ready state. Part I of this essay covers heat treatment, while Parts II and III look at surface preparation and hardware installation.
In this three-part series, we'll look at heat treatment procedures, coatings, and hardware installation alternatives and considerations. Any or all of these may be required to transition your item from the machined state to the customer-ready condition. The topic of heat treatment is covered in this article.
Is heat treatment performed before or after processing?
After machining, heat treatment is the first operation to consider, and it is also feasible to consider milling pre-treated materials. Why should one approach be used over another? The sequence in which the heat treatment and machining metals are chosen can have an impact on the material qualities, machining process, and component tolerances.
When you employ heat-treated materials, it affects your machining since tougher materials take longer to process and equipment wear out faster, increasing machining expenses. It is also possible to cut through the hardened layer of the material and undermine the purpose of utilizing hardened metal in the first place, depending on the type of heat treatment used and the depth below the affected surface of the material. It's also possible that the machining process creates enough heat to raise the workpiece's hardness. Certain materials, such as stainless steel, are particularly prone to work hardening during machining, and special precautions must be taken to avoid this.
However, there are several advantages to using a warmed metal. Your parts may be held to tighter tolerances using hardened metals, and procuring materials is easier because preheat-treated metals are widely accessible. Furthermore, deferring heat treatment until after machining adds another time-consuming step to the production process.
Heat treatment after machining, on the other hand, provides you more control over the machining process. There are many different forms of heat treatment, and you may employ any of them to get the desired material qualities. Heat treatment after machining guarantees uniform heat treatment on the part's surface. Because heat treatment may only influence the material to a limited depth in preheated materials, machining may remove hardened material in certain locations but not others.
As previously stated, post-processing heat treatment raises costs and lengthens lead time since it necessitates extra outsourced procedures. Heat treatment can also cause items to warp or distort, which can compromise the tight tolerances achieved during machining.
Heat treatment
Heat treatment often alters the material characteristics of the metal. Typically, this entails boosting the metal's strength and hardness so that it can endure more harsh uses. Certain heat treatment methods, such as annealing, might, on the other hand, diminish the hardness of the metal. Let's have a look at the various heat treatment options.
Hardening
Metal is hardened by the process of hardening. When hit, a metal with a higher hardness is less likely to dent or mark. Heat treatment also enhances the metal's tensile strength, which is the force with which the material fails and breaks. The material's increased strength makes it more appropriate for specific applications.
To harden a metal, the workpiece is heated to a temperature that is higher than the metal's critical temperature, or the temperature at which its crystal structure and physical characteristics change. The metal is maintained at this temperature for a short period of time before being quenched in water, brine, or oil to cool. The quenching fluid is determined by the metal's alloy. Because each quench fluid has a different cooling rate, the choice is based on how quickly it cools the metal.
Case hardening
Case hardening is a sort of hardening that solely affects the material's exterior surface. This is often done after machining to generate a strong outer layer.
Precipitation hardening
Precipitation hardening is a method for hardening certain metals using specified alloying components. Copper, aluminum, phosphorous, and titanium are among these elements. When a solid metal is heated over a lengthy period of time, these elements precipitate or form solid particles. This has an effect on the grain structure, improving the material's strength.
Annealing
As previously stated, annealing is used to soften metal, reduce tension, and enhance the ductility of the material. This technique softens the metal and makes it simpler to deal with.
To anneal a metal, it is gently heated to a specified temperature (above the critical temperature of the material), kept at that temperature, and then slowly cooled. This delayed cooling is achieved by burying the metal in insulating material or maintaining it in the furnace as the furnace and metal cool.
Large Slab Machining Stress Relief
Stress relief is similar to annealing in that the material is heated to a specific temperature and then progressively cooled. In the event of stress alleviation, however, this temperature is lower than the critical temperature. The substance is then cooled by air.
This procedure eliminates stress from cold working or shearing without affecting the physical qualities of the metal appreciably. While the physical attributes remain unchanged, alleviating this stress aids in the prevention of dimensional changes (or warping or other deformation) during further processing or usage of the part.
Tempered
Tempering a metal involves heating it to a temperature below the critical temperature and then cooling it in air. This is nearly identical to stress relief, however the end temperature is not as high. Tempering enhances toughness while keeping the majority of the hardness obtained during the hardening process.
Final thoughts
Metal heat treatment is frequently required to produce the correct physical qualities for a given application. While heat treating the material before milling might save total production time, it also adds time and expense to the machining process. Simultaneously, machined heat-treated components make machining the material easier but add an extra step to the manufacturing process.
Do you have any specific questions about the Machining services? Contact Yogie! Our sales engineers will work with you from start to finish to ensure that your project is completed to your requirements.
Also, Yogie is a professional manufacturer for Mining equipment, CNC Machine tools, and Machinery parts for over 20years.
