Forged Pipe Fitting semifinished Various specifications can be
Forging forging the forging weight
1. Forging allowance: forgings precision and surface quality are
poor, so the parts in the forging surface are left
forging margin to ensure that the parts can have a reasonable
margin for mechanical processing, while Forging in
the forging due to the structure of parts and forging process, you
must simplify the shape of forging, thereby
increasing the part of the dressing metal.
2. Burning weight: Forging billet In the process of heating and
forging, the surface oxidation and burning part of the
weight of the metal, the first heat to take the metal weight of 2
to 3%, after each heating to take the metal weight of
1.5 to 2% , Stainless steel, alloy steel due to more alloying
elements, plasticity decreased, deformation resistance
increases, the number of heating more, burning will be greater.
3. The weight of the part of the metal that is washed away or cut
off for forging. Such as the middle of the opening
of the cover plate or tube plate in the forging of the middle of
the material washed away, repair the end of the
forging of the material head, for large forgings must be used to
cast steel ingot for the blank, but also consider the
cut off the steel cap Mouth and tail metal .
The precision forging process has been applied to the production of
precision forging a lot of technology.
According to the different forming temperature can be divided into
hot forging, cold forging, precision precision forging, composite
precision forging, isothermal precision forging and so on.
1.1 Hot forging process forging temperature in the recrystallization
temperature above the precision forging
process known as hot forging. Hot precision forging material
deformation resistance is low, good plasticity, easy
to shape more complex parts, but due to strong oxidation, the
workpiece surface quality and dimensional accuracy is low. Hot
forging for the commonly used method for the closed die forging.
1.2 Cold forging process cold forging is carried out at room
temperature forging process. Cold forging process has the following
characteristics: the workpiece shape and size easier to control, to
avoid the high temperature error; workpiece strength and high
precision, good surface quality. Cold forging forming process
towel, poor plastic parts, deformation resistance, the requirements
of the mold and equipment, and difficult to shape the complex parts
of the structure.
1.3 Temperature forging process temperature precision forging in
the recrystallization temperature below a suitable temperature for
the precision forging process. Warm forging precision forming
technology not only break through the cold forging deformation
resistance, the shape of the parts can not be too complicated, need
to increase the intermediate heat treatment and surface treatment
steps of the limitations, but also to overcome the hot forging due
to strong oxidation and reduce the surface quality and size
Accuracy of the problem. It also has the advantages of cold forging
and hot forging, to overcome the shortcomings of the two.
1.4 Composite precision forging process With the increasingly
sophisticated forging parts and precision requirements to improve
the simple cold, warm, hot forging process has been unable to meet
the requirements. Composite precision forging process will be cold,
overflow, hot forging process to complete a workpiece forging, can
play a cold, warm, hot forging the advantages of abandoning the
cold, warm, hot forging shortcomings.
1.5 Isothermal forging process isothermal forging is the billet in
the trend towards a constant temperature forging forming.
Isothermal die forging is often used in the aerospace industry in
the titanium alloy, aluminum alloy, magnesium alloy and other
difficult deformation of precision forming materials, in recent
years also used in automotive and machinery industry, non-ferrous
metal precision forming. Isothermal forging is mainly used in
forging temperature narrow metal materials, especially for the
deformation temperature is very sensitive to titanium alloy.