Forging vs Casting
Forging and Casting already become the two main metal forming processes for all kinds of industries. Today, we would like to discuss the differences between forging and casting in below:
Forging is processing way that putting pressure on metal blank by forging machinery, making it produce plastic deformation, in order to obtain certain mechanical properties,a certain shape and size of forgings. Forging can eliminate the as-cast osteoporosis of the metal, welded holes,and generally mechanical properties of forging is better than that of the same material of the casting. So for those important components that require to undertake high mechanical load, or working in serious conditions, in addition to simple shape rolling plate,or welding parts are available, all will consider forging process.
According to its forming methods, forging can be divided into:
1)Open die forging: Use impact or pressure to make metal deformed on the up and down irons (anvil blocks) to obtain the required forgings, there are mainly two different kinds of working way, manual forging and mechanical forging.
2)Closed die forging: Metal blank is shaped by compression deformed in the bore of the forging dies,this process can be divided into die forging, cold heading, rotary forging, extrusion, etc.According to the deformation temperature, forging can be divided into hot forging (processing temperature above the recrystallization temperature of billet metal), warm forging (below the recrystallization temperature) and cold forging (room temperature). Forging materials are mainly carbon steel and alloy steel, followed by aluminum, magnesium, titanium, copper and its alloy etc. Normally the original state of material is a bar.
Casting is a metal forming process that melting the metal into certain requirements of the liquid and then pouring it into the mold, after cooling solidification, we can get desired shape and sizes. Production cost of blanks produced by casting is low. For complex shape, especially the parts with complex inner cavity, casting can show its economical efficiency more; At the same time, it has a wide adaptability,and has better comprehensive mechanical properties. But materials that needed in casting production and equipments (such as metallurgical furnace, sand mixing machine, molding machine, core making machine, shakeout machine, shot blasting machine, etc.) will produce dust,harmful gas and noise. Thus it will do harm to environmental.
|Definition||A manufacturing process which makes use of compressing forces to enhance rigidity||A manufacturing process in which molten metal material is poured into molds to create the desired shape|
|Forming way||Press heated metal bars on upper and lower dies to desired shape||Pouring of molten metal into a mold for cooling|
|Performace||High strength with longer working life||Worse performance|
|Metallurgical defects||Avoid||Can occur|
|Types||Open die forging,closed die hot forging,cold heading,ect||Investment casting,sand casting|
How to Distinguish Forging Parts or Casting Parts?
Metal after forging processing can improve its organizational structure and mechanical properties. Products, which were originally designed in casting, after forging process, due to metal deformation and recrystallization, make original bulky dendrite and columnar grain to fine & uniform grain organization. So forging improves the plasticity and mechanical properties of the metal.
In general, the mechanical properties of castings is lower than that of forging with the same material. In addition, the metal forging process can guarantee the continuity of fibrous tissue, keep fibrous tissue and forging appearance consistent. This can guarantee the parts with good mechanical properties and long service life of products. No matter it is hot forging or cold forging, casting is incomparable.
Methods for distinguishing forgings and castings:
1. Forgings look smoother and more delicate than castings.
2. The sound that hits forgings is crisp and the casting is a bit dull.