CN102867131B - The computing method of tension in a kind of cast metal sleeve of centrifuge cross section - Google Patents

Abstract

The invention belongs to centrifugal casting technique field, be specifically related to the computing method of tension in a kind of cast metal sleeve of centrifuge cross section, the tensile stress sigma that in described cast metal sleeve of centrifuge cross section, tensile stress sigma is produced metal jacket casing cross section by the centrifugal force produced because of metal jacket casing quality ₁with the tensile stress sigma that the centrifugal force produced because of quality of molten metal produces metal jacket casing cross section ₂be formed by stacking, i.e. σ=σ ₁+ σ ₂, wherein: σ ₁=ρ _coverr _outward ²ω ², the invention has the beneficial effects as follows the computing method established to tension total on metal jacket casing cross section under centrifugal action, for the design of cast metal sleeve of centrifuge provides method, break away from the full Design Mode by rule of thumb of metal jacket casing; The security incident quantitative test that these computing method are also broken for cast metal sleeve of centrifuge is laid a good foundation.

Description

The computing method of tension in a kind of cast metal sleeve of centrifuge cross section

Technical field

The invention belongs to centrifugal casting technique field, be specifically related to the computing method of tension in a kind of cast metal sleeve of centrifuge cross section.

Background technology

Casting mold structure for hydro-extractor is formed by base plate, cover plate and metal jacket casing three incorporating aspects usually, and wherein metal jacket casing the most easily damages thus causes the parts of security incident, therefore tackles it when designing and carry out force analysis and calculating.But up to the present, not yet there are the computing method of tension in ripe centrifugal casting mould metal jacket casing cross section, can only estimate according to the design experiences of casting mold metal jacket casing in the past, so often cause very large deviation, estimate that excessive (namely conservative property is excessive) may cause the waste of mold material and cost to increase on the one hand, then exceed the capacity of equipment of hydro-extractor time serious and cause centrifugal casting scheme to implement; Estimate that (namely security is not enough) less than normal may bring potential safety hazard on the other hand, the security incident that metal jacket casing breaks can occur time serious.

Summary of the invention

Technical matters to be solved by this invention is to provide the computing method of tension in a kind of cross section of cast metal sleeve of centrifuge accurately and reliably, can be used as the foundation of design cast metal sleeve of centrifuge, on this basis, for the Security Checking of existing cast metal sleeve of centrifuge provides precondition.

For solving the problems of the technologies described above, technical scheme of the present invention is:

The computing method of tension in a kind of cast metal sleeve of centrifuge cross section, under the condition of metal jacket casing uniform rotation, when molten metal pours into casting mold, the tensile stress sigma that in described cast metal sleeve of centrifuge cross section, tensile stress sigma is produced metal jacket casing cross section by the centrifugal force produced because of metal jacket casing sole mass ₁with the tensile stress sigma that the centrifugal force produced because of quality of molten metal produces metal jacket casing cross section ₂be formed by stacking, i.e. σ=σ ₁+ σ ₂, wherein

In formula:

ρ _cover---the density of metal jacket casing, ㎏ ∕ m ³; ρ _liquid---the density ， ㎏ ∕ m of molten metal ³;

N---the rotating speed of metal jacket casing, r/min; R ₀---metal jacket casing inner circle radius, m;

R _outward---metal jacket casing exradius, m; r ₀---foundry goods inner circle radius, m.

The invention has the beneficial effects as follows the computing method established to tension total on metal jacket casing cross section under centrifugal action; For the design of cast metal sleeve of centrifuge provides method, break away from the full Design Mode by rule of thumb of metal jacket casing; The security incident quantitative test that these computing method are also broken for cast metal sleeve of centrifuge is laid a good foundation.

Accompanying drawing explanation

Fig. 1 is vertical centrifugal machine casting mold wiring layout in the computing method of tension in first embodiment of the invention cast metal sleeve of centrifuge cross section;

Fig. 2 is horizontal centrifugal machine casting mold wiring layout in the computing method of tension in first embodiment of the invention cast metal sleeve of centrifuge cross section.

Embodiment

Below in conjunction with the drawings and specific embodiments, technical scheme of the present invention is further described in detail.

First embodiment: a kind of large-scale worktable worm gear, casting dimension is cylindrical Ф 1880mm ∕ inner circle Ф 1674mm × height 120mm, and the trade mark is ZCuSn10P1, ρ _liquid=8760kg ∕ m ³, casting quality is 560kg, adopts the casting of large-scale vertical hydro-extractor.As shown in Figure 1, casting mold structure comprises base plate 3, cover plate 1 and metal copper sheathing 2, and metal jacket casing 2 is of a size of cylindrical Ф 2200mm ∕ inner circle Ф 1880mm × highly for 130mm, casting mold centrifuge speed n=325r ∕ min, metal jacket casing material be spheroidal-graphite cast iron QT450-10, ρ _cover=7300 ㎏ ∕ m ³, the tensile stress sigma that metal jacket casing 2 cross section is subject to is:

$={\left(\frac{\mathrm{\π}\×325}{30}\right)}^2\×[7300\×{1.1}^2+\frac{8760\×0.940({0.940}^2-{0.837}^2)}{2\×(1.100-0.940)}]$

$=1158.31\×(8833+4709.85)=10231352+5455466$

$=15686818\left(\mathrm{Pa}\right)=15.7\left(\mathrm{MPa}\right)$

Second embodiment: a kind of low alloy steel (chromium molybdenum steel) axle sleeve, the trade mark is ZG35CrMo, and casting dimension is cylindrical Ф 458mm ∕ inner circle Ф 351mm × length 1400mm, ρ _liquid=7000 ㎏ ∕ m ³, casting quality is 745kg, adopts the casting of large-size horizontal hydro-extractor.As shown in Figure 2, casting mold structure comprises cover plate 1, base plate 3 and metal copper sheathing 2, and metal jacket casing 2 is of a size of cylindrical Ф 590mm ∕ inner circle Ф 458mm × length 1700mm, and mold quality is 1550kg.Casting mold centrifugal rotational speed n=760r ∕ min, casting mold material be carbon cast steel ZG230-450, ρ _cover=7800 ㎏ ∕ m ³, the tensile stress sigma that metal jacket casing 2 cross section is subject to is:

$={\left(\frac{\mathrm{\π}\×760}{30}\right)}^2\×[7800\×{0.295}^2+\frac{7000\×0.229\×({0.229}^2-{0.1755}^2)}{2\×(0.295-0.229)}]$

$=6334.08\×(678.8+262.8)=4299573.5\left(\mathrm{Pa}\right)+1664596.2\left(\mathrm{Pa}\right)$

$=5964170\left(\mathrm{Pa}\right)=5.96\left(\mathrm{MPa}\right)$

The present embodiment and the first embodiment are compared known, when casting quality is more or less the same, tension in vertical centrifugal casting mold metal jacket casing cross section is more much bigger than the tension in horizontal centrifugal casting mold metal jacket casing cross section, therefore, vertical centrifugal casting mold metal jacket casing is the key object of Security Checking.

The computing method of the above embodiment of the present invention can accurately calculate to the tension on metal jacket casing cross section under centrifugal action, for the design of cast metal sleeve of centrifuge provides foundation, have broken away from the full Design Mode by rule of thumb of metal jacket casing; The security incident quantitative test that these computing method are also broken for cast metal sleeve of centrifuge is laid a good foundation.

It should be noted last that, above embodiment is only in order to illustrate technical scheme of the present invention and unrestricted, although with reference to preferred embodiment to invention has been detailed description, those of ordinary skill in the art is to be understood that, can modify to technical scheme of the present invention or equivalent replacement, and not departing from the spirit and scope of technical solution of the present invention, it all should be encompassed in the middle of right of the present invention.

Claims (1)

1. the computing method of tension in cast metal sleeve of centrifuge cross section, is characterized in that, the tensile stress sigma that in described cast metal sleeve of centrifuge cross section, tensile stress sigma is produced metal jacket casing cross section by the centrifugal force produced because of metal jacket casing quality ₁with the tensile stress sigma that the centrifugal force produced because of quality of molten metal produces metal jacket casing cross section ₂be formed by stacking, i.e. σ=σ ₁+ σ ₂, wherein

In formula:

ρ _cover---the density of metal jacket casing, ㎏ ∕ m ³;

ρ _liquid---the density ， ㎏ ∕ m of molten metal ³;

N---the rotating speed of metal jacket casing, r/min;

R ₀---metal jacket casing inner circle radius, m;

R ₀---foundry goods inner circle radius, m;

R _outward---metal jacket casing exradius, m.