It is essential to note that the forging manufacturing process is completely different from the casting one (see difference between forging and casting), where the molten material is poured into a mold. Another significant difference to the other manufacturing methods as casting and machining is that forging improves the mechanical properties of the material by refining its grain structure and making it tougher and stronger. In terms of temperature, forging can be divided in hot foging and cold forging. Among them, hot forging is the most widely used process for forged steel parts. So people may ask what is hot forging? what are the differences between hot forging and cold forging?
Hot forging is the forging process that metals are plastically deformed above their recrystallization temperature, which allows the material to retain its deformed shape as it cools.
Like its name “hot forging”, the hot forging process is performed at very high temperature (up to 1150 °C for steel). This temperature is necessary in order to avoid strain hardening of the metal during deformation.
This process usually involves heating the steel billets (to the above its recrystallization point) after which it is pressed under dies – depending on the requirements, this die would be heat treated so that the hardness can withstand the violent hitting. Because the billet is hot, it ‘moves around’ easily and allows steel forging manufacturers to create more elaborate shapes than with cold forging.
After the hot forging process ends, parts must be cooled rapidly to “set” the metal in its new shape. Care must be taken in the cooling process, however, too fast cooling of hot forged parts can result in warping. Usually we just place the hot forged products cooling under room temperature.
The hot forging process produces very little material scrap, making it one of the most efficient metal forming methods.
Flash is always existed during hot die forging process. And it is necessary to produce complex 3D geometries with very different local cross-sections and secondary design elements. The flash acts as a brake on the material flow and slows the flow of excess material. Thus, high internal pressure is built up in the die, which forces the remaining material into the die cavities.
Hot die forgings are usually manufactured in multiple steps for complex shapes, and multi-pairs of forgings dies are required to form final shapes. Besides, machining might be operated after forging, if hot die forging process can not meet the dimensions and tolerances.
The Benefits of Hot Forging
Hot forging is selected when large amounts of plastic deformation are needed to form the part. Lots of advantages of hot forging can be seen:
- An increased ductility.
- Because of the decrease in yield strength, it takes less energy (or force) to work with the material.
- During hot forging and subsequent deformation, pores can reduce (in size) or close completely.
- Because the elevated temperatures increase diffusion it is possible, in turn, to reduce or remove chemical inhomogeneity.
- In hot forging steel, the weak and ductile FCC (face-centered cubic) austenite is deformed instead of the strong BCC (body-centered cubic) ferrite – which would deform at lower forging temperatures.
The main difference between hot forging and cold forging may be concluded that, the cold forging manufacturing process increases the strength of a metal through strain hardening at a room temperature. However, the hot forging manufacturing process keeps materials from strain hardening at high temperature, which results in optimum yield strength, low hardness and high ductility.
The decision on hot forging or cold forging should be based on the structure and application of the desired component, also the quantity can be considered when selecting a forging process.
Why Hot Forging China?
Economically speaking, the reason producing hot forgings in China is so cost effective stems due to the value of our currency and the cost of labor. The American Dollar is currently equal to 6.68 Chinese Yuan .
You can understand why the labor costs are cheap when you know the Chinese factory worker is getting paid an average of $2 USD an hour compared to over $23 USD in America. The cost of living is also much cheaper in China and to exemplify that I often compare the prices of necessities of life in both countries.
When you’re looking to produce hot forging products like flail hammer blades, labor is your main cost outside of raw material. The cost of labor in China is always going to be cheaper than in America. But in 2017, the raw material of round bars is keep raising, this affected the price heavily, and forging companies in China have to increase the price according to updated material cost.
Hot Forging Capabilities of CFS Forge in China
As the representative of hot forging company in China, CFS Forge can make all kinds of hot steel forgings. We aim to provide best quality products in good prices. Our capabilities are:
- All the forged steel parts are produced in our company in hot forging process with closed dies. With forging equipments up to 2,500 tons, our company can forge products over 30kg.
- Our hot forging service can create custom parts that match your design specifications. The strength and durability of hot forged parts makes them ideal for more rugged applications, include automotive, agriculture,aerospace, construction equipment, and so on.
- Heat treatment service is offered here in CFS Forge. Common heat treatment methods for hot forgings are: normalization, quenching & tempering, carburizing treatment, etc.
- Equiped with full sets of machining equipments, we can do machining as precise as possible.
Surface coatings like powder coating, paiting, hot dip galvalization, etc. are also avaialble in our factory.
To guarantee the quality of hot steel forging in China, it is quite important to source a reliable hot forging company? Fly Forge is the right supplier for all the hot forging requirements in closed die forging process. Contact us right away!