HU204103B - Treating material for improving the quality of cast iron melt and process for using same - Google Patents

Abstract

The mixt. of 0.06-2mm granules is added to molten iron in quantities of 0.15-0.4% at approx. 1400 deg.C (%w/w). The mixt. contains 30-40C, 30-40 Si, 5-7 Ca, 3-4 Ba, 1-2.5 Al, 5 CaF2, 5.5 Ca-Al synthetic slag, and/or up to 1% Mg and 1% rare earth metals.

Description

The treatment agent of the present invention is used to treat the cast iron melt by adding 0.150.40% by weight of a treatment agent of type a), b) or c) to the cast iron melt heated to 1380-1450 ± 10 ° C.

HU 204 103 B

Scope of the description: 9 pages, without figure

EN 204 103 Β inoculants or modifiers are commercially available but can be used only because they have different effects on time, temperature and mass of material to be cast. One class of conventionally used inoculants is that it contains the active compound in the form of a metal compound (CaSi, CaSiBa, CaSiBaMg, FeSi, etc.). The other group is characterized in that it consists of a mechanically prepared mixture of modifying reagents. These materials are usually added in an amount of 0.3-0.51% prior to casting into the pouring pan. The inoculum or modifier forms crystalline germs in the melt and promotes graphite crystallization and perlite core formation at all points in the casting.

In daily practice, in many cases, even though inoculation or modification is carried out correctly, crystallization anomalies still occur, the greater the difference in mass between the castings from the same pan and the longer the time between treatment and casting.

In view of the disadvantages of the above treatments, our aim was to develop a treatment composition that improves the quality of various types of cast iron castings, such as crystallization, compactness, moldability, surface quality.

The present invention is based on the discovery that the effectiveness of complex modifying reagents containing silicon, calcium, barium, magnesium and aluminum in the form of a compound and mechanically produced inoculation mixtures can be substantially increased if the known and listed elements also contains calcium aluminate synthetic slag.

The treatment agent of the present invention, comprising carbon, a multi-component complex alloy and a rare earth silicide, is characterized by having a particle size of 0.06 to 2.0 mm

(a) 30 to 40% by weight of carbon,

30-40% by weight of silicon,

5-7% by weight of calcium,

3-4% by weight of barium,

1-2.5% by weight of aluminum,

5.0% by weight of calcium fluoride,

5.5% by weight of calcium aluminate synthetic slag or

(b) in addition to the components specified in (a), 0,40,8% by weight of magnesium and at least 0,6% by weight of rare-earth metals, or

(c) containing, in addition to the components indicated in (a), 0,61.6% by weight of magnesium and at least 1,0% by weight of rare-earth metals.

According to the process of the invention, the cast iron melt treatment is carried out by heating the base iron to 1380-1450 ± 10 'C, and then 0.15-0.40% by weight of the iron melt has a particle size of 0.062.0 mm.

The present invention relates to a self-melting compound, a composite and a composite of composite alloys of composite alloys of composite alloys containing silicon, calcium, magnesium, aluminum, barium, carbon, rare-earth silicide, folate and calcium aluminate, applies to their use.

It is generally known that castings of different wall thicknesses will have varying hardness due to the unequal settling rate during cooling after casting. Therefore, in the case of castings with variable wall thickness, parts with faster cooling - e.g. sharp, at corners, and at thinner wall thicknesses - the hardening occurs according to the Fe-Fe ₃ Cmetastable System and has a carbide-ledeburitic texture, where hardness can exceed 300 Brinell. However, thicker cross-sections, which are slower to cool, can only have a hardness of 150-200 Brinell hardness. The heterogeneous structure of the fabrics, which causes varying hardness, significantly increases the post-casting tension, the tendency for hot and cold fractures in the castings. Hard edges erode the machinability of the castings, significantly increasing the wear of the machining tool 25. In general, reducing the variable hardness of casting parts is metallurgy. 30

It has long been known that various cauldron additives can be used to control the crystallization processes, the shape distribution of the excellent graphite, and thereby also the strength properties. Modification or inoculation has been known and practiced in the foundry for nearly 100 years, but consciously to regulate crystallization processes, tissue structure, graphite shape and distribution, inoculation alone is an operation 40 in which small amounts of inoculum are added. prior to casting into the liquid metal, thereby temporarily inducing physico-chemical changes in the peak state of the melt that are different from those occurring when the same alloys are added separately.

A characteristic feature of the inoculation or modification is that the supercooling rate of the crystallising cast iron changes, as a result:

-feminine cell number, 50

- uniformly distributed, less branched graphite,

- decreases the tendency to bleach,

- improves the strength of cast iron and the production safety required by the standard. 55

With regard to vaccination and modification in recent years, numerous theories have been elaborated, and none of them can correctly explain the mechanism of action of the modification or vaccination. This is in part the reason for its numerous compositions 60

HU 204103 Β

(a) 30 to 40% by weight of carbon,

30-40% by weight of silicon,

5-7% by weight of calcium,

3-4% by weight of barium,

1-2.5% by weight of aluminum,

5.0% by weight of calcium fluoride,

5.5% by weight of calcium aluminate synthetic slag or

(b) in addition to the components specified in (a), 0,40,8% by weight of magnesium and at least 0,6% by weight of rare-earth metals, or

c) addition of a component containing 0.61.6% by weight of magnesium and at least 1.0% by weight of rare earth in addition to the components indicated in a).

Synthetic calcium aluminate slag in the treatment composition of the present invention deoxidizes, desulfurizes the melt, and facilitates coagulation of oxides and other inclusions with calcium fluoride and penetrates the slag. This significantly improves the mechanical properties of the casting.

A further advantage of using the therapeutic agents of the invention is that

- increases relaxation time and thus safety of hits,

- neutralize the deleterious effects of trace elements which interfere with normal crystallization and thus promote the stable crystallization of the FeFe ₃ C diagram,

- reduce the excessive eutectic swelling and expansion force accompanying crystallization during crystallization, thereby reducing the tendency of cast iron porosity and improving casting density,

- they are effectively deoxidized and desulphurised, thereby favorably altering the surface tension and improving the filling capacity,

- reduce the reactivity of the oxide silicate slag formed on the cast iron melt surface, thereby reducing the chemical burn rate, thus improving the surface quality of the casting.

Depending on the magnesium and rare earth content, the treatment agent of the present invention is suitable for producing reliable, highly reproducible, less sensitive to changes in production conditions, sheet, transition and spheroidal graphite castings.

The chemical and granulometric compositions of the present invention for the production of cast iron of various grades are shown in Tables 1 and 2.

Table 1

Chemical composition of the treatment family

Material name the type Complex family of substance type b type c c ^a ) 30-40% 30-40% 30-40% Si ^b > 30-40% 30-40% 30-40% C °) 5-7% 5-7% 5-7% Ba ^d > 3-4% 3-4% 3-4% al 1-2.5% 1-2.5% ' 1-2.5% mg min.0,4-0,8% min.0,6-1,5% Rare Earth min. 0.6% min. 1.0% CaF ₂ 5.0% 5.0% 5.0% Calcium aluminate synthetic slag 5.0% 5.0% 5.0%

All percentages are by weight.

a) Containing 95% of the total carbon content as charcoal meal and 5% as hardwood charcoal

b) CaSiBaAl complex alloy containing 75% to 75% FeSi, optionally containing Mg, and 44 to 46% containing FeSi 45

c) CaSiBaAl complex alloy containing 30% Ca, optionally containing Mg and 70% CaSi

d) The CaSiBaAl complex optionally contains Ba in the form of a CaSiBaAl complex alloy.

Hü 204 103 Β

Table 2

Granulometric composition of treatments

particle size mm The remaining sieve quantity (%) minimum maximum 2.0-1.0 10 15 1.0 to 0.63 30 5Q 0.63 to 0.3 35 25 0.3 to 0.2 10 5 0.2 to 0.1 10 5 0.1 to 0.06 5 0 Below 0.06 - - Altogether 100 100

In a complex treatment device according to the invention.

Example 1

The composition of the tested cast iron before and after treatment is shown in Table 3. For comparison purposes, results from inoculation of the same iron with FeSi 75 under the same conditions are also shown.

Treatment of cast iron melt in both cases

RJn and HB were determined using standard probes from 0 30x600 mm molded molded specimens. The test results are shown in Table 4.

Wall thickness sensitivity was determined on a step test, a casting voltage grid. The throughput ratios; 0 30mm, 010mm. Tables 5 and 6 contain the test results.

Table 7 shows the results of the graphite and tissue structure qualification of the cast samples.

Example 2

Further examples of the use of the type a treatment agent of the invention are shown in Table 8.

Table 3

Chemical composition of the investigated cast iron

denomination c% CK.% Ski% Mn% S% P% Neither% O2% * H 2% basic Iron AIapvas + 0.3% 3.42 .462 1.85 0.54 0.11 0.088 0,934 ³ 3,410- 3.0 ¹⁰ FeSi75 AIapvas + 0.3% 3.36 0.471 2.12 0.54 0.10 0.088 0.936 ³ 3,510- 2,810- ³ 2,610- ³ Escaloy AIapvas + 0.3% 3.35 0.472 2.10 0.54 0.089 0.088 0,935 3,110 " ³ material handling 3.43 .595 2.07 0.54 0.078 0,087 .956 ³ 2,610- ³ 2,310-

* Analyzed by LECO Total% by weight

Table 4

Mechanical properties and calculated quality indices of cast iron tested

denomination HB rm Degree of maturity RG Relatívkeménység RH basic Iron Iron Base + 0.31% 197 210N / mm ² 84.18 1,035 FeSi75 Iron Base + 0.31% 194 221N / mm ² 89.18 0.994 Escaloy Iron Base + 0.31% 198 220N / mm ² . 88.48 1,017 Material handling 207 229N / mm ^z 129.26 RG- (measured) / 1020-825S _c ] x 100 RH- [HB _{m (Irish} / 100 + 0.43R _m ) .9056

HU 204 103 Β

Table 5

The test has a tendency to cast iron and to have wall thickness sensitivity

denomination the depth of the white crust mm 3.5 7.0 hardness of the step test mm 28 56 basic Iron 11 305 249 227 209 160 Base + 0.31% FeSi75 3.5 269 238 223 200 170 Base Head + 0.31% Escaloy 1.0 236 228 216 208 197 Base iron + 0.31% complex treatment 1.0 234 226 216 207 196

Table 6

Residual tension and cold rupture tendency of tested cast iron on symmetrical stress grid (in cast state)

denomination HB * 30mm-en measured km N / mm2 KH Residual casting voltage N / mm2 Hiderepedési susceptibility basic Iron 197 217 1.1225 92,142,44 Base Iron + 0,3t% FeSi75 194,221 1.0053 84.9 37.06 Iron Base + 0.31% Escaloy 193,220 1,017 72.7 33.04 Iron Base + 0.31% complex treatment agent 207,302 .9005 64.3 21.29

Table 7

Qualification of graphite and fabric structure of the studied cast iron

denomination Graphite fabric Structures Base 40t% Ga2 Gm45 Ge2 + Iron Base + 0.31% FeSi75 80t% Ga2Gm45 / 90Fe2 + Base Iron + 0,3t% Escaloy 90t% Ga2Gm45 / 90FeZ + 8t% GaZ, Gm25, Ge6 2t% Ga2, Gm25, GeG Iron Base + 0.31% complex treatment agent 100t% GalGm90Gel P, F30, Ffl0, FO2, Foe2, F650 P, F O, Pf0.5 / l, Fo2, Foe 2, E 400 P, F30, Pf0,5 / l, FO2, Foe2, E400 P, F O, Pf 1.0, Fo2, Foe 2, E 250 Table 8 Quantity of diluent to be added in the manufacture of cast iron sections of various grades denomination Chemical composition of cast iron to be treated C% 3.5 mm 7.0 mm 14.0 mm 28.0 mm wall thickness 56.0 mm Mn% P% s% To be administered type A material handling Ö.V150 H. B. 145-190 3.45 - 3.65 3.0 - 2.7 - 2.3 - 3.1 2.8 2.6 0.450.60 0.15 0.10 0.15%

HU 204103 Β

Continuation of Table 5

The amount of curing agent to be added in the manufacture of cast iron sections of various grades

denomination Chemical composition of cast iron to be treated 56.0 mm mh% P% s% To be administered type A material handling % C 3.5mm 7.0mm wall thickness 14.0 mm 28.0 mm Ö.v.200 HE. 175-210 3.25-3.35 2,35- 2.25 1,95- 1,80- 0,60- 2.45 2.35 2.10 2.00 0.70 0.15 0.10 0.20% Ö.v.250 HE. 180-225 3.15-3.25 1,90- 1,65- 1.45 0,70- 2.10 1.80 1.60 0.80 0.10 0.10 0.25-0.30% Ö.v.300 HE.190-230 3.10-3.20 1,70- 1,50- 1.30 0,80- 1.80 1.60 1.50 0.90 0.10 0.10 0.30 to 0.35% Ö.v.350 HE.190-230 3.05-3.15 1.60 1,55- 1,25- 0,80- 1.70 1.65 1.35 0.90 0.10 0.10 0.35 to 0.40%

All SS mass mean SS

The melting point treatment temperature is 1380 ° C to 1420 ° C 10 ° C; lower temperature is higher, higher temperature is lower

Applicable to C-containing iron melt.

Example 3

In this example, the use of a type b curing agent according to the invention in the manufacture of ferritic transition graphite cast iron is described.

Melting and melt retention were performed in a medium frequency rectangular induction oven.

The insert contains 30% by weight of D-1 type Sorel iron, by weight of the LR6IA1 type Soviet iron, and contains by weight CIO grade steel waste and by weight recycled graphite cast iron waste.

The Si content was adjusted by addition of FeSi 75

After melting, the melt was superheated to 1470 ° C, then after 10 minutes of heating, cooled to 1450 ° C and treated at this temperature with magnesium.

Before casting with magnesium, the composition of the cast iron:

C% = 3,4tömeg

Ski-1.28% by weight

Mh = 0,25tömeg%

S% = 0,02tömeg

P = 0.04%

The magnesium treatment was carried out with 1.8% (5% Mg) MgFeSi alloy in the furnace. Following the treatment, FeSiZr alloy was also added to the furnace. Then, at different times, one test was cast. Drainage was performed at 1400-1410 ° C, casting was performed at 1380 ± 10 ° C.

In molds made from furan resin molding compounds, standard (MSZ 8277-69) specimens were cast:

(a) Of untreated metal (base iron)

b) 0.3% by weight of FeSi 75 treated metal during taping

c) 0.3% by weight of metal treated with a treatment composition according to the invention, of type b (Table 1).

From the cast iron dipsticks, standard specimens were developed to determine the tensile strength and elongation values as well as the deformation of the graphite. The values measured for base iron and treated iron are summarized in Table 9.

HU 204103 Β

Table 9

AFeSi 75 and type h of the composition according to the invention (Table 1) on the tensile strength, elongation and deformation of the graphite cast iron as a function of time after magnesium treatment

After the treatment with magnesium elapsed time, minute rm N / mm2 basic Iron A10 % graphite form Base iron + 0.3% by weight Base iron + 0.3% wt / wt treatment agent rm N / mm2 FeSi 75 A10 % graphite form rm N / mm2 A10 % graphite form 3 470 6.5 temporary 435 7.2 temporary 480 7.3 temporary 6 455 6.1 temporary 432 7.0 temporary 470 7.1 temporary 9 428 5.2 temporary 420 6.3 temporary 460 6.5 temporary 12 380 4.1 temporary 380 5.8 temporary 435 6.0 temporary 15 330 2.2 temporary 338 4.0 temporary 400 4.5 temporary 17 280 0.6 laminar 305 2.3 temporary 380 4.1 temporary 18 236 - laminar 282 - laminar 320 1.9 temporary 21 230 - laminar 242 - laminar 320 1.9 temporary 24 - - 230 - laminar 275 0.7 laminar

The measured data clearly demonstrate that iron treated with tap water of type b according to the invention significantly enhances the safety of transient graphite cast iron production compared to untreated and FeSi 75 treated samples. In the example shown, the use of 0.3% by weight of the composition type b (Table 1) of the present invention can significantly extend the "hardening time" of the transition graphite cast iron melt, resulting in improved tensile strength and elongation.

Example 4

The example illustrates the use of a type c curing agent according to the invention in the production of spheroidal cast iron. The purpose of the application of the curing agent was to "extend the finish time and improve the strength values.

Melting and melt retention were performed in a medium frequency crucible induction oven.

The insert: 20% by weight Soréi D-1 pig iron, by weight, Soviet LR6IA1 pig iron, by weight, contained recycled spheroidal iron cast iron by weight, containing CIO grade steel waste.

After melting, the melt was superheated to 1470 ° C, then, after 10 minutes of heating, cooled to 1450 ° C and treated with magnesium at this temperature.

Before casting with magnesium, the composition of the cast iron is:

C% = 3,62tömeg

Si = l% 14tömeg

Mh = 0,18tömeg%

S = 0.01% by weight

P% = 0,04tömeg

The magnesium treatment was carried out with 1.8% (5% Mg) MgFeSi alloy in the furnace. Samples were cast at different times after treatment. Tapping was performed at 1380-1410 ° C and casting was performed at 1380 ± 10 ° C. For the casting of the samples, for comparison purposes, one was treated with tap and cast during treatment, the other with 0.3 wt% FeSi 75, and the third with tap c, according to the invention (Table 1).

In addition to the determination of tensile strength and elongation, the deformation of graphite was also examined under a microscope on standard specimens formed from molds made from furan resin molding compounds.

The results of the tests are shown in Table 10.

Ηϋ 204103 Β

Table 10

The effect of AFeSi 75 and c-type composition of the invention (Table 1) on the tensile strength, elongation and graphite deformation of the transition graph as a function of time after magnesium treatment

Amagnesium Base Iron Alapvas + 0.3% by weight Base Iron + 0.3% by weight FeSi75 Type H Treatment Agent

elapsed time, rm A10 graphite rm A10 graphite rm A10 graphite minute N / mm2 % form N / mm2 % form N / mm2 % form 3 510 17 sphere 485 18.2 sphere 540 18 sphere 6 508 16.5 sphere 480 17.3 sphere 535 18 sphere 9 480 15.5 sphere 478 16.1 sphere 535 17.5 sphere 12 450 12 sphere 461 12.3 sphere 500 16 sphere 15 390 7.2 temporary 396 7.8 temporary 475 13.1 sphere 18 300 3.1 temporary 325 3.6 temporary 430 9.3 sphere 21 230 0.6 laminar 267 1.2 laminar 370 6.2 temporary 24 220 0.4 laminar 242 0.7 laminar 310 3.1 temporary 27 - - - - 256 0.8 laminar

From the measurement data it can be seen that the application of the composition according to the invention gave the best strength values. After 15 minutes of treatment with magnesium, cast untreated and FeSi 75-treated probes were already transient graphitic, even during taping, the iron treated with the composition of the invention was spherical graphitic, with the use of the caking agent (Table 1). time ”was significantly prolonged, only the casts cast in the 21st minute were transient graphitic. This is particularly advantageous in the case of thin-walled low-mass castings compared to the prior art.

Example 5

This example illustrates the use of the b and c type curing agents of the present invention in the production of black alloy.

The aim is to improve the strength properties by modifying the morphology of the setting.

The insert was 25% by weight of CIO steel scrap% by weight of type 05IB2 domestic iron iron by weight recycled black malleable waste.

Melting and melt retention were performed in a medium frequency crucible induction oven.

After melting, the melt was overheated to 1490 ° C, and after 10 minutes of heating, it was cooled to 1460 ° C and then started to cast.

Before casting, the composition of the melt was as follows:

C% = 2,72tömeg

Si-1.31% by weight

Mh »0.41% by weight

P 0,08tömeg%

S 0,14tömeg%

In the molds made from the molten metal furan resin molding compound, standard specimens (MSZ 8282-66) were cast. The casting temperature was set so that it fell within the normal casting temperature range of the black temper iron.

We cast test specimens:

(a) Of untreated metal

(b) 0.003% by weight of B (in the form of FeB ₂ ) and 0.02% by weight of Al, during tapping

c) 0.4 wt.% of metal treated with a treatment composition of the type b according to the invention (Table 1) during taping

d) 0.4% by weight of metal treated with a c-treatment composition of the invention (Table 1) during taping.

The casting temperature of the specimens was 1450 ± 10 ° C.

After cleaning, standard specimens were heat treated according to the following program:

carbide decomposition: at 1050 'C for 20 hours Cooling: from 1050' C to 820 'C at 80' C / h. 820 ° C to 690'C 7'C / hour

From 620 'C to 20' C at 300 'Qora.

The strength of the heat-treated specimens is given in the table of 50 ketals.

Table 11

Changes in tensile strength and elongation of black tempered iron as a result of various treatments

Headdress' Base iron + 0.003% B + 0.02% Al Base iron + 0.4 wt% H type treatment agent Base iron + 0.4 wt% IH type treatment agent Ε ^ ΝΛηηώ 327 365 378 409 A _in % 5.68 7.97 9.78 12.3

HU 204103 Β

As a result of the treatment compositions of the present invention, the favorable changes in the curing morphology resulted in an increase in the tensile strength and elongation of the black mallow compared to the basal and B and Al treated probes.

Claims (4)

1. A treatment agent for improving the quality of cast iron melt comprising carbon, multi-constituent complex alloy and rare-earth metal silicon, having a particle size of 0.06 to 2.0 mm a) 30 to 40% by weight of carbon, 30-40% by weight of silicon, 5-7% by weight of calcium, 3-4% barium, 1-2.5% by weight of aluminum, 5.0% by weight of calcium fluoride, You are 5.5% calcium aluminate synthetic slag (b) in addition to the components specified in (a), 0,40,8% by weight of magnesium and at least 0,6% by weight of rare earth; c) contains, in addition to the components specified in a), 0.61.6% by weight of magnesium and at least 1.0% by weight of rare earth. 2. A process for treating cast iron melt, wherein the base mat is heated to 1380-1450 ± 10 ° C, characterized in that the iron melt has a particle size of 0.15-0.40% by weight of 0.06-2.0 mm. a) 30 to 40% by weight of carbon, 30-40% by weight of silicon, 5-7% by weight of calcium, 3-4 tomeg% barium, 1-2.5% by weight of aluminum, 5.0% by weight of calcium fluoride, 5.5% by weight of a treatment material containing calcium aluminate synthetic slag, or (b) 0,40,8% by weight of magnesium and at least 0,6% by weight of rare earth metal, in addition to the components specified in (a); (c) in addition to the components specified in (a), 0,6— \ t 1.6% by weight of magnesium and at least 1.0% by weight of rare earth metal type c are added. Method according to claim 2, characterized in that a treatment material of the type a or b is used in an amount of 0.15-0.30% by weight for the production of sheet-iron cast iron. 4. A process according to claim 2, wherein the high strength, transition and spheroidal cast iron is produced in an amount of 0.30 to 0.35% by weight of the c treatment material.