Hot Forging VS Cold Forging

 The Hot Forging Manufacturing Process

The hot forging manufacturing process is performed at extreme high temperature (up to 1150 °C for steel, 360 to 520 °C for al-alloys, 700 to 800 °C for cu-alloys). This temperature is necessary in order to avoid strain hardening of the metal during deformation. Stamping is the most widespread hot forging manufacturing process, where the material is squeezed in a press, between a tool and a die surface.

Advantages of Hot Forging

The high temperature during hot forging enables the highest possible level of material deformation and the access to complex 3D geometries. Hot forged components possess increased ductility which makes them desirable for many configurations. Also, as a technique hot forging is more flexible than cold forging, since customized parts can be manufactured.

The excellent surface quality allows a wide range of finishing work as polishing, coating or painting, tailored to customers’ specific need. Hot forging materials are available all over the world which has a positive impact on their final price.

Disadvantages of Hot Forging

The properties of hot forged metals are obtained by subsequent heat treatment, where the material has been quenched to 1000° C and then returned to 500 ° C. This requires additional cost, which can be avoided if using cold forging (except in some cases as softening, annealing or relaxation).

Less precise dimensional tolerance is another possible disadvantage of hot forged components compared to the cold forged ones. The cooling process should be also performed under special conditions; otherwise there is a risk of warping. Also, the grain structure of forged metals may vary and there is always a possibility of reactions between the atmosphere and the workpiece.

The Cold Forging Manufacturing Process The cold forging manufacturing process is performed at room temperature. The workpiece is squeezed between two dies until it has assumed their shape. To deliver a finished, ready to fit component, the technique includes rolling, drawing, pressing, spinning, extruding and heading. Cold forging extrusion is one of the most common manufacturing techniques, widely used in the production of automotive components.

Advantages of Cold Forging

Manufacturers may prefer cold over hot forging process; since cold forged parts require very little or no finishing work. Since all bars are annealed before being forged, there is no need for a secondary heat treatment prior to machining. Another significant advantage is the material savings achieved through near net shapes. The initial weight of the workpiece equals the final weight of the cold forged component.  Cold forged parts offer a good level of attainable dimensional accuracy and excellent surface quality.

The economic advantages combined with high production rates and long die life are more than enough to convince many manufacturers that cold forging is the best option for them.

Disadvantages of Cold Forging

Depending on the manufacturer’s requirements, some of the cold forging characteristics may turn out disadvantages; e.g. only simple shapes in high volumes can be shaped. The achievable deformation levels and shaping grade are much more limited compared to stamping. Therefore, if the customer is searching for a specific customized component, cold forging won’t be the best alternative.

A second more significant disadvantage is that cold forged metals are less ductile, which makes them inappropriate for certain configurations. Also, because of the grain structure that gives the material its strength, residual stress may occur.

It is important to mention that cold forging extrusion for example requires also a heat treatment to eliminate possible cracks, creeks hardening or rafters.

As a consequence of the above statements, cold forging cannot be used on every steel grade, particularly on those with low ductility or sensitivity to strain hardening. For instance, low alloy steel with carbon content higher than 0,05% is not appropriate for cold forging.

The Main Difference Between Hot and Cold forging

The cold forging manufacturing process increases the strength of a metal through strain hardening at a room temperature. On the contrary the hot forging manufacturing process keeps materials from strain hardening at high temperature, which results in optimum yield strength, low hardness and high ductility.

Finally, a manufacturer would choose one process over the other because of economic and not quality reasons. The decision is based on the required functions of the desired component, the industry and if it’s a mass production or a low volume of customized parts.

Setforge provides cold, warm and hot forging or combination of different processes to address various customer demands, both performed in excellent conditions with state-of-the-art machinery for perfect results. We work close with our customers to understand their specific needs and find the best possible solution.

Anbao Group is a experienced manufacturer of flanges, die castings,sand castings,carbon steel castings,alloy steel castings,304/316 stainless steel castings,duplex 2205 stainless steel castings,precision investment castings,custom forging and custom precision machining which means we can handle all your needs.We are professional casting parts OEM/ODM manufacture and supplier in china.