CN104923755A - Arc-radiation method for eliminating bulging defect of flat nodular cast iron - Google Patents

Abstract

The invention discloses an arc-radiation method for eliminating the bulging defect of flat nodular cast iron. The method is implemented through the steps of, firstly, performing linear fitting on parameters of flat nodular cast iron profiles in different specifications; secondly, processing graphite shrouds according to the parameters of the flat nodular cast iron profiles in different specifications in the first step; thirdly, processing dummy bar heads according to the graphite shrouds in the second step; fourthly, during horizontal continuous iron casting, completing production of the profiles according to the graphite shrouds in the second step and the dummy bar heads in the third step. The arc-radiation method for eliminating the bulging defect of the flat nodular cast iron effectively solves the bulging defect of the flat nodular cast iron without reducing the production efficiency.

Description

Eliminate the anti-circular measure of flat spheroidal graphite cast-iron section bar bulge defect

Technical field

The invention belongs to cast iron horizontal continuous caster technical field, be specifically related to a kind of anti-circular measure eliminating flat spheroidal graphite cast-iron section bar bulge defect.

Background technology

Cast iron horizontal continuous caster adopts special production line, by horizontal continuous-casting method, produces the technological package of cast iron profile material.Cast iron profile material production at home only has the history of more than two decades with application.During this, while production capacity and demand expand rapidly, production technology is also in continuous improve.Nowadays, domestic have family of professional production enterprise more than ten, define the ability producing tens thousand of tons of cast iron profile materials per year, the cast iron profile material (as Ductile iron bar, gray iron section bar, alloy cast iron section bar etc.) of all kinds can be produced, the section bar produced can be multiple prismatic shape (as circular, square, rectangle, hexagon, semicircle, quincunx etc.), and the length of section bar is changeable according to the demand of user.The cast iron profile material produced by horizontal continuous casting process has a series of feature more excellent than common foundry goods, as: there is no the casting flaws such as shrinkage cavity and porosity, sand holes, pore; Crystal grain is tiny, dense structure; There are better mechanics, mechanical performance etc.Cast iron profile material has become the important engineering material of machine industry, and its application still expands in continuation.

In cast iron profile material, have the flat type material of a class square-section, it is except being suitable for being processed into except the part with its shape approximation, in making hydraulic part, have very important application.But find in production, such section bar is easy to produce " bulge defect ", that is: the flat horizontal surface generation bulging of section bar and protruding, makes the more satisfactory state of the shape and size of section bar create notable difference, this phenomenon, particularly outstanding in spheroidal graphite cast-iron section bar.

Summary of the invention

The object of this invention is to provide a kind of anti-circular measure eliminating flat spheroidal graphite cast-iron section bar bulge defect, solve the bulge deformation problem being difficult to when prior art produces rectangle spheroidal graphite cast-iron avoid.

The technical solution adopted in the present invention is, eliminates the anti-circular measure of flat spheroidal graphite cast-iron section bar bulge defect, specifically implements according to following steps:

Step 1: linear fit is carried out to the parameter of the flat spheroidal graphite cast-iron section bar of different size;

Step 2: according to the parameter processing graphite cover of the flat spheroidal graphite cast-iron section bar of different size in step 1;

Step 3: according to the graphite cannula processing dummy bar head in step 2;

Step 4: the dummy bar head that the graphite cannula obtained according to step 2 in cast iron horizontal continuous caster and step 3 obtain completes the production of section bar.

Feature of the present invention is also:

Carry out linear regression fit to the parameter of the flat spheroidal graphite cast-iron section bar of different size in step 1, regression forecasting equation is:

c＝-0.046a-5.62d+0.052ad+7.002，

Wherein, d=a/b is the ratio of width to height of section bar,

A is the nominal width of flat spheroidal graphite cast-iron section bar,

B is the nominal height of flat spheroidal graphite cast-iron section bar,

C=s-b is the bulge amount of flat spheroidal graphite cast-iron section bar,

S is the bulge height average of the flat spheroidal graphite cast-iron section bar of often kind of specification,

Bulge height is the distance of the peak that sticks out of flat spheroidal graphite cast-iron section bar to lower surface.

According to step 2 processing graphite cover, design parameter is:

The shrinkage factor of getting spheroidal graphite cast-iron is 1%,

The width of graphite cannula cavity

The height of graphite cannula cavity

The maximum normal distance of the upper surface sunken arcs distance upper surface of graphite cannula cavity

The radius R corresponding to upper surface sunken arcs of graphite cannula cavity ₁meet:

${R_1}^2={H_1}^2+{\left(\frac{a_1-e_1\×2}{2}\right)}^2,$

Wherein,

H ₁＝R ₁-h ₁，

E ₁the length of wherein one end of the non-recessed portion of the upper surface for graphite cannula cavity.

Process dummy bar head according to step 3, design parameter is:

The width a of dummy bar head ₂=a ₁-1,

The height b of dummy bar head ₂=b ₁-0.5,

Radius R corresponding to dummy bar head upper surface sunken arcs ₂=R ₁,

Dummy bar head upper surface sunken arcs is apart from the maximum normal distance h of upper surface ₂=h ₁,

E ₂the length of wherein one end of the non-recessed portion of the upper surface for dummy bar head, e ₂=e ₁-0.5.

The invention has the beneficial effects as follows: under the prerequisite ensureing production efficiency, effective elimination bulge defect, not only makes the technical merit of cast iron horizontal continuous caster be further enhanced, and the producer can also be made to increase economic efficiency, help user to obtain more preferably section bar, decrease the allowance of section bar.

Accompanying drawing explanation

Fig. 1 is the shape appearance figure in kind of the bulge defect of flat spheroidal graphite cast-iron section bar;

Fig. 2 is the schematic cross-section of the bulge defect of flat spheroidal graphite cast-iron section bar;

Fig. 3 is graphite cannula cross sectional representation;

Fig. 4 is the schematic diagram of graphite cannula cross section of the present invention and sunken arcs position relationship;

Fig. 5 dummy bar head cross sectional representation;

Fig. 6 is the section bar pictorial diagram adopting the inventive method to produce.

Detailed description of the invention

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

The present invention eliminates the anti-circular measure of flat spheroidal graphite cast-iron section bar bulge defect, specifically implements according to following steps:

Step 1: linear fit is carried out to the parameter of the flat spheroidal graphite cast-iron section bar of different size

Be illustrated in figure 1 the shape appearance figure in kind of the bulge defect of flat spheroidal graphite cast-iron section bar, can find out that bulge is exactly that section bar middle part on flat direction raises up.The thick difference of the thickness of slab wide central protuberance and edge, bulge amount, weighs bulge deformation degree according to this.

Be illustrated in figure 2 the schematic cross-section of the bulge defect of flat spheroidal graphite cast-iron section bar, in figure, a is the nominal width of flat spheroidal graphite cast-iron section bar, and b is the nominal height of flat spheroidal graphite cast-iron section bar.For the spheroidal graphite cast-iron section bar of existing different size in production, the peak sticked out with vernier caliper measurement section bar is to the distance (i.e. bulge height) of lower surface, and the spheroidal graphite cast-iron section bar of often kind of specification all measures five, and measured value is denoted as s respectively ₁, s ₂, s ₃, s ₄, s ₅.Get s ₁, s ₂, s ₃, s ₄, s ₅mean value be bulge height average s, deduct the nominal height b in section bar cross section with bulge height average s, just obtain the bulge amount c=s-b of section bar, obtain the ratio of width to height d=a/b in section bar cross section.Disposal data, obtains table 1:

The parameter list of table 1 all size section bar

Data in table 1 are carried out regression fit, obtain following regression forecasting equation:

c＝-0.046a-5.62d+0.052ad+7.002。

Step 2: processing graphite cover

As Fig. 3 (a) is depicted as the cross sectional representation of existing graphite cannula, Fig. 3 (b) is depicted as the schematic diagram of graphite cannula cross section in the present invention, comparison diagram 3 (a) is known with Fig. 3 (b), when processing the graphite cannula of crystallizer, need the shape being become by the graphite cannula pocket machining of script rectangle its excess-three limit recessed, top constant.According to size (nominal width a, nominal height b) and the regression forecasting equation of section bar to be produced, draw the bulge amount c of section bar, then determine the width a of graphite cannula cavity ₁, height b ₁and the upper surface sunken arcs of graphite cannula cavity is apart from the maximum normal distance h of upper surface ₁, concrete steps are:

In the production process of section bar, molten iron injects casting ladle by melting furnace, then injects holding furnace by casting ladle, injects a certain amount of molten iron at set intervals to holding furnace.In this case, the molten iron temperature in holding furnace is not constant, and the temperature of molten iron reduced, until add the molten iron of next casting ladle gradually along with the time.When the molten iron temperature in holding furnace is higher, freezing rate is comparatively slow, and go out the strand layer after crystallizer thinner, the degree causing section bar top to raise up is larger; When the molten iron temperature in holding furnace is lower, freezing rate is very fast, and go out the strand layer after crystallizer thicker, the degree that section bar top raises up weakens to some extent.Therefore, from crystallizer out after the degree of section bar top epirelief be different, there is situation recessed on the contrary, Wo Menqu to prevent section bar:

Figure 4 shows that the schematic diagram of graphite cannula cross section of the present invention and sunken arcs position relationship, the shrinkage factor of getting spheroidal graphite cast-iron is 1%, because nominal width a, the nominal height b of section bar to be produced are known, so:

The width of graphite cannula cavity

The height of graphite cannula cavity

By the width a of graphite cannula cavity ₁, graphite cannula cavity upper surface sunken arcs apart from the maximum normal distance h of upper surface ₁, the radius R corresponding to upper surface sunken arcs of graphite cannula cavity is drawn according to Pythagorean theorem ₁meet:

${R_1}^2={H_1}^2+{\left(\frac{a_1-e_1\×2}{2}\right)}^2$

Wherein,

H ₁＝R ₁-h ₁，

E ₁the length of wherein one end of the non-recessed portion of the upper surface for graphite cannula cavity.

Step 3: processing dummy bar head

Usual dummy device combines by two sections, and a section of entering in crystallizer die cavity is called dummy bar head, and another section is called dummy bar.During processing dummy device, first rectangle dummy bar head (cross section is as Suo Shi Fig. 5 (a)) is processed, then the dummy bar head of rectangle is processed into further the shape (cross section is as Suo Shi Fig. 5 (b)) that its excess-three limit recessed, top is constant, the cross dimension of dummy bar head is determined according to section bar cross section, and design parameter is:

The width a of dummy bar head ₂=a ₁-1,

The height b of dummy bar head ₂=b ₁-0.5,

Radius R corresponding to dummy bar head upper surface sunken arcs ₂=R ₁,

Dummy bar head upper surface sunken arcs is apart from the maximum normal distance h of upper surface ₂=h ₁,

E ₂the length of wherein one end of the non-recessed portion of the upper surface for dummy bar head, e ₂=e ₁-0.5.

Step 4: according to the size of section bar to be produced, the parameter of the graphite cannula cavity obtained by step 2, the parameter of the dummy bar head obtained by step 3, make corresponding crystallizer graphite cannula and dummy bar head device, in cast iron horizontal continuous caster, complete the production of section bar, eliminated the section bar of bulge defect.

Embodiment

The width a=180mm of spheroidal graphite cast-iron section bar to be processed, height b=50mm.

Step 1: linear fit

Data in table 1 are carried out regression fit, obtain following regression forecasting equation:

c＝-0.046a-5.62d+0.052ad+7.002

Step 2: processing graphite cover

Known section bar width a=180mm, height b=50mm, draw according to regression forecasting equation: c=12.18mm, $h_1=\frac{2}{3}c=8\mathrm{mm}.$

Again according to formula $a_1=\frac{a}{1-1\%},b_1=\frac{b}{1-1\%},{R_1}^2={H_1}^2+{\left(\frac{a_1-e_1\×2}{2}\right)}^2,$ H ₁=R ₁-h ₁, e ₁=10mm, draws:

a ₁＝182mm，b ₁＝50.5mm，R ₁＝414mm，H ₁＝396mm。

Step 3: processing dummy bar head

Because a ₂=a ₁-1, b ₂=b ₁-1, R ₂=R ₁, H ₂=H ₁, h ₂=h ₁, e ₂=e ₁-0.5, draw:

a ₂＝181mm，b ₂＝50mm，R ₂＝414mm，H ₂＝396mm，h ₂＝8mm，e ₂＝9.5mm。

According to the above-mentioned data calculated, processing novel graphite cannula and dummy device, and applied aborning, produce material object as shown in Figure 6, experimental result shows that the anti-circular measure that the present invention eliminates flat spheroidal graphite cast-iron section bar bulge defect effectively can solve bulge defect under the prerequisite not reducing production efficiency.

Claims (4)

1. eliminate the anti-circular measure of flat spheroidal graphite cast-iron section bar bulge defect, it is characterized in that, specifically implement according to following steps:

Step 1: linear fit is carried out to the parameter of the flat spheroidal graphite cast-iron section bar of different size;

Step 2: according to the parameter processing graphite cover of the flat spheroidal graphite cast-iron section bar of different size in step 1;

Step 3: according to the graphite cannula processing dummy bar head in step 2;

Step 4: the dummy bar head that the graphite cannula obtained according to step 2 in cast iron horizontal continuous caster and step 3 obtain completes the production of section bar.

2. the anti-circular measure of elimination flat spheroidal graphite cast-iron section bar bulge defect according to claim 1, it is characterized in that, carry out linear regression fit to the parameter of the flat spheroidal graphite cast-iron section bar of different size in described step 1, regression forecasting equation is:

c＝-0.046a-5.62d+0.052ad+7.002，

Wherein, d=a/b is the ratio of width to height of section bar,

A is the nominal width of flat spheroidal graphite cast-iron section bar,

B is the nominal height of flat spheroidal graphite cast-iron section bar,

C=s-b is the bulge amount of flat spheroidal graphite cast-iron section bar,

S is the bulge height average of the flat spheroidal graphite cast-iron section bar of often kind of specification,

Bulge height is the distance of the peak that sticks out of flat spheroidal graphite cast-iron section bar to lower surface.

3. the anti-circular measure of elimination flat spheroidal graphite cast-iron section bar bulge defect according to claim 2, it is characterized in that, according to described step 2 processing graphite cover, design parameter is:

The shrinkage factor of getting spheroidal graphite cast-iron is 1%,

The width of graphite cannula cavity

The height of graphite cannula cavity

The maximum normal distance of the upper surface sunken arcs distance upper surface of graphite cannula cavity

The radius R corresponding to upper surface sunken arcs of graphite cannula cavity ₁meet:

${R_1}^2={H_1}^2+{\left(\frac{a_1-e_1\×2}{2}\right)}^2,$

Wherein,

H ₁＝R ₁-h ₁，

E ₁the length of wherein one end of the non-recessed portion of the upper surface for graphite cannula cavity.

4. the anti-circular measure of elimination flat spheroidal graphite cast-iron section bar bulge defect according to claim 3, it is characterized in that, process dummy bar head according to described step 3, design parameter is:

The width a of dummy bar head ₂=a ₁-1,

The height b of dummy bar head ₂=b ₁-0.5,

Radius R corresponding to dummy bar head upper surface sunken arcs ₂=R ₁,

Dummy bar head upper surface sunken arcs is apart from the maximum normal distance h of upper surface ₂=h ₁,

E ₂the length of wherein one end of the non-recessed portion of the upper surface for dummy bar head, e ₂=e ₁-0.5.