Forging VS Casting

July 24, 2009

Forging VS Casting

There are a variety of methods to produce a given part. Each has its own set of advantages and

disadvantages. Some of the important factors affecting the selection of a process include the


– Quantity of the material required

– Design of the part

– Tolerances required

– Metal specification

– Surface finish required

– Tooling costs

– Economics of machining versus process costs

– Delivery requirements


Forging is a manufacturing process where metal is shaped by plastic deformation under great pressure into high strength parts.

Fundamentals of forging

Forging or cold forming are metalforming process. There is no melting and consequent solidification involved. Plastic deformation produces an increase in the number of dislocations resulting in a higher state of internal stress. Indeed, strain hardening is attributed to the interactions and other barriers (such as grain boundaries). Simultaneously, the shape of primary crystals )dendrites) changes after plastic working of the metal. Dendrites are stretched in the direction of metal flow and thus fform fibers of increased strength along the direction of flow.

we may distinguish how working from cold working. Hot working is performed above the recrystallization temperature; cold-working is performaed below it. In hot working strain hardening and distorted grain structure are very rapidly eliminated by the formation of new strain free grains as the result of recrystallization. Rapid diffustion at hot working temperatures aids in homogenizing the preform. Initial porosity can also be signficantly reduced, eventually completely healed.

Matallurgical phenomena such as strain hardening and recrystallization are important because those changes in structure result in an increase in ductility and toughness over the cast state.


The casting process consists of pouring or injecting molten metal into a mould contraining a cavity with the desired shape of the casting. Metal casting processes can be classfied either by the type of mold or by the pressure used to fill the mould with liquid metal.

Fundamentals of Casting

Casting is a solidification process. Therefore, the microstructure can be finely tuned, such as grain structure, phase transformations and precipitation. Howerver, defects such as shrinkage porosity, cracks and segregation are also intimately linked to solidification. These defects can lead to lower mechanical properties. A subsequent heat treatment is often required to reduce residual stresses and optimize mechanical properties.

About China Castings
sand casting, investment casting, CNC machining and other castings from Chinese foundry

Leave a Reply

Your email address will not be published. Required fields are marked *

error: Alert: Thanks for your interesting, but Article is protected ! You can click the Top Right email!