∙ Process of Forging
∙ Forging 工伤申请
∙ Types of Forging
o Hammer Forging (Flat Die)
o Press Forging
o Die Forging
∙ Forging equipment
死性不改歌词
o Smith Forging Hammer
o Board Drop Hammer
o Forging Press
o Mechanical Forging Press
o Hydraulic Forging Press
∙ Heat Treatments
o Preheating
o Annealing
o Normalizing
o Hardening
∙ 女孩背影图片LISTS OF FORGING MANUFACTURERS
o Forging and Forming Resources
范冰冰孩子o Forging Industry Association
o Forging Equipment英语a级真题 – Johnson Forging Equipment Company
天气怎么写o Forging Equipment – SIFCO Indurtries, Inc. - Forge Group
o Forging Equipment – Delta forging Services, Inc
Process: Forging is a metal forming process ud to produce large quantities of identical parts, as in the manufacture of automobiles, and to improve the mechanical properties of
the metal being forged, as in aerospace parts or military equipment. The design of forged parts is limited when undercuts or cored ctions are required. All cavities must be comparatively straight and largest at the mouth, so that the forging die may be withdrawn. The products of forging may be tiny or massive and can be made of steel (automobile axles), brass (water valves), tungsten (rocket nozzles), aluminum (aircraft structural members), or any other metal. More than two thirds of forging in the United States is concentrated in four general areas: 30 percent in the aerospace industry, 20 percent in automotive and truck manufacture, 10 percent in off-highway vehicles, and 10 percent in military equipment. This process is also ud for coining, but with slow continuous pushes.
The forging metal forming process has been practiced since the Bronze Age. Hammering metal by hand can be dated back over 4000 years ago. The purpo, as it still is today, was to change the shape and/or properties of metal into uful tools. Steel was hammered into shape and ud mostly for carpentry and farming tools. An ax made easy work of cutting down trees and metal knives were much more efficient than stone cu
tting tools. Hunters ud metal-pointed spears and arrows to catch prey. Blacksmiths ud a forge and anvil to create many uful instruments such as horshoes, nails, wagon tires, and chains.
Militaries ud forged weapons to equip their armies, resulting in many territories being won and lost with the u and strength of the weapons. Today, forging is ud to create various and sundry things. The operation requires no cutting or shearing, and is merely a reshaping operation that does not change the volume of the material.
Forging: Forging changes the size and shape, but not the volume, of a part. The change is made by force applied to the material so that it stretches beyond the yield point. The force must be strong enough to make the material deform. It must not be so strong, however, that it destroys the material. The yield point is reached when the material will reform into a new shape. The point at which the material would be destroyed is called the fracture point.
In forging, a block of metal is deformed under impact or pressure to form the desired sha
pe. Cold forging, in which the metal is not heated, is generally limited to relatively soft metals. Most metals are hot forged; for example, steel is forged at temperatures between 2,100oF and 2,300oF (1,150oC to 1,260oC). The temperatures cau deformation, in which the grains of the metal elongate and assume a fibrous structure of incread strength along the direction of flow. (See Figure)
Figure - Flow lines in a forged part
Normally this results in metallurgical soundness and improved mechanical properties. Str
ength, toughness, and general durability depend upon the way the grain is placed. Forgings are somewhat stronger and more ductile along the grain structure than across it. The feature of greatest importance is that along the grain structure there is a greater ability to resist shock, wear, and impact than across the grain. Material properties also depend on the heat-treating process after forging. Slow cooling in air may normalize workpieces, or they can be quenched in oil and then tempered or reheated to achieve the desired mechanical properties and to relieve any internal stress. Good forging practice makes it possible to control the flow pattern resulting in maximum strength of the material and the least chances of fatigue failure. The characteristics of forging, as well as fewer flaws and hidden defects, make it more desirable than some other operations (i.e. casting) for products that will undergo high stress.
In forging, the dimensional tolerances that can be held vary bad on the size of the workpiece. The process is capable of producing shapes of 0.5 to >50.0 cm in thickness and 10 to <100 cm in diameter. The tolerances vary from 1/32 in. for small parts to ¼ in. for large forgings. Tolerances of 0.010 in. have been held in some precision forgings, but
the cost associated with such precision is only justified in exceptional cas, such as some aircraft work.
Types of forging:
Forging is divided into three main methods: hammer, press, and rolled types. 时当
(1) Hammer Forging (Flat Die): Preferred method for individual forgings. The shaping of a metal, or other material, by an instantaneous application of pressure to a relatively small area. A hammer or ram, delivering intermittent blows to the ction to be forged, applies this pressure. The hammer is dropped from its maximum height, usually raid by steam or air pressure. Hammer forging can produce a wide variety of shapes and sizes and, if sufficiently reduced, can create a high degree of grain refinement at the same time. The disadvantage to this process is that finish machining is often required, as clo dimensional tolerances cannot be obtained.
