1, the purpose that when the preform of purpose mould spare parts that mould spare parts forgings prepares, forgings has two: (1) wins proper geometrical form; (2) improves the constituent function of material and treatment performance. The common structural member in the mould (like fixed head, pull makings board to wait) give priority to with the first purpose, and main working part (wait like punch, sunken model) criterion two purposes hold concurrently. Obtain the means of appearance of module preform geometry through forginging, its flexibility is extremely strong. Can satisfy the requirement of module preform norms and size diversity basically, have economic data, shorten the advantage such as man-hour. To the main part in the mould, wait for the requirement of the respect as a result of its heat treatment, quality and service life, toward contact need improves the performance of raw material through forginging. If make the organization of material compact, even through forginging, make its anisotropy not apparent etc. At this moment forginging is change geometry appearance not only, more important is the method that should notice to forging. If use fore-and-aft Dui,unplug, transverse Dui unplugs, 3 unplug to Dui and diagonal forgings etc. 2, the raw material of the affirmatory principle forging stock of dimension of the makings below forging stock is round steel commonly, diameter of logical choice round steel and issueing makings length certainly is to forging the important segment in semifinished product process. Its decide the principle can induce as follows: (1) bulk is equal, namely the bulk of forging semifinished product is added forging the metal in the process burns caustic rate to should be equal to raw material (round steel) next makings bulk. (2) metal burns caustic to lead δ to forging namely the loss that wait leads the oxidation skin of the generation when heating, decarburized layer. Take δ =0 commonly. 05 ～ 0.
10. Fire second grow in quantity, forging rough degree big, material takes big cost when decarbonization liability is big. (3) raw material grows diameter to compare (L/D) cannot too big, take L/D=1 commonly.
5 ～ 2.
5, the biggest do not exceed 3. L/D is too big, criterion forging forgings the likelihood in the process happens bend, the blemish such as interlining. (The raw material diameter after 4) is calculated must undertake by the norms of national level the circle is rectified, and had better be factory storeroom in existent or the norms that supplies on the market. 3, the computational method of dimension of the makings below forging stock can reach according to above principle formula of the following computation and method: Above all, by the principle (1) can get forge of V base =V (1+ δ ) in % type, v forge is the module bulk after forginging, namely the bulk after the over all dimension of mould spare parts increases mental allowance. V base is next makings bulk of raw material. CNC Milling
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