CS272704B1 - Silicon modifying agent - Google Patents

Abstract

The invention concerns a silicon modifying agent based of metals of rare earth for the production of cast-iron with wormed graphite, which contains 35 to 37 % by weight Si, 34 to 37 % by weight metals of rare earth of which 17 to 19 % by weight is Ce, 1.3 to 3.0 % by weight is Al, 0.30 to 0.45 % by weight Ca, the residue is 22.55 to 29.4 % by weight Fe, with granulating composition of 3 to 5 mm. To achieve an 80 to 95 % share of wormed graphite in the structure of the cast-iron a quantity of 0.30 to 0.55 % by weight of the modifying agent is added.

Description

The present invention relates to a rare earth silicon modifying additive to obtain cast iron and worm-like graphite.

Worm-like graphite cast iron, which is one of the quality types of cast iron, can also be obtained by using modifiers based on globulization and antiglobulization post-absorption elements or by using a modifier containing 98 wt. rare earth metals (pure rare earth metals). A major disadvantage of a modifier containing pure rare earth metals is that they contain a relatively high percentage of deficient elements such as Ce, La, and the like. Pr and so on.

The above-mentioned drawbacks are remedied to a large extent by the silicon modifying additive according to the invention, which comprises 35 to 37 wt. % Si, 34 to 37 wt. rare earth metals, of which 17 to 19 wt. _From 1.3 to 3 wt. Al, 0.30 to 0.45 wt% Ca, the remainder 22.55 to 29.4 wt%, Fe, granulation composition 3-5 mm.

The main benefit of the silicon modifier is a more economical method of obtaining worm-like graphite cast iron compared to the use of pure rare earth metals.

The amount of modifier for obtaining worm-like graphite in cast iron depends primarily on the sulfur content of the melt. At a sulfur content of the starting melt of 0.018 to 0.024 wt. 0.30 to 0.55% by weight is required to obtain an 80 to 95% fraction of worm-like graphite in the iron structure. a silicon modifying additive according to the invention.

The optimum effect of imparting the silicon modifying additive according to the invention is in its low consumption and in a considerable high after-effect, 20 min. after zamodifikovani.

The silicon modifying additive according to the invention is produced in an autoclave pressure vessel at an overpressure of p = 0.6 MPa. To produce the silicon modification additive, 30 kg of FeSi 75 (lump) (see Table 1) was fused in an electric induction furnace. At 1,250 ° C, 2.5 kg of Al and 10.5 kg of rare earth metals were added to the molten FeSi 75 (see Table 1). Rare earth metals were added to the melting furnace from an inlet-modified size basket of the autoclave pressure vessel. At 1,470 ° C (as measured by an optical pyrometer without correction), molten and treated FeSi 75 was cast into a heated siphon pan which was then placed in the autoclave space. container. 11.5 kg of rare earth metals were placed in the modification basket in the autoclave pressure vessel lid (see Table 1). After insertion of the siphon pan with liquid treated FeSi 75, the autoclave pressure vessel was pressurized to p = 0.6 MPa. After pressurization, the modification basket was inserted into molten and treated FeSi 75 in a siphon pan. After a reaction of 1.5 to 2.0 minutes, the modification basket was ejected from the siphon pan. 2 of the autoclave pressure vessel, the necessary pressure was discharged and the modifier thus produced was cast in the form of compact cylindrical bodies into bentonite molds. After cooling, the modifying bodies are blasted.

The waxy graphite lxatine is obtained using the pouring method when pouring the melt from the melting furnace into the ladle using 0.30 to 0.55 wt. % of the rare earth silicon modification additive according to the invention and the subsequent graft grafting 0.5 to 0.7 wt. FeSi 75 (see Table 1).

The use of the silicon modification additive according to the invention guarantees the production of worm-like graphite cast iron having a tensile strength Rm = 360 to 450 MPa, an impact strength KG = 29 to 35 O.cm-2 and a Brinell HB hardness of 180 to 210.

CS 272704 Bl

Table 1 Chemical composition _of raw materials in vsád.zkových silicon modifying q

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II «|| CO 1 J> II S ll UJ}! r IN LO Λ cn cn I I ΤΓ II ca II about h-q 11 s · » I II about II tm H II tn 0) II r » about II I he I • 11 4 P II about G M II in x! 0) 1! about fs II 1 ·% T II about II II 4 II WHAT Ή B0 II τ- II I l ABOUT II about E_i ff q II 03 ra 1 -rj- ca 1 0¾ 1 I XJ about 11 about about II "> 3 II II • , p II <4 h II ca s I about II ε ABOUT • ti II 'ca II ra II • ΓΛ ø> II M ABOUT F about 'd WHAT II ω ·> T II II ε about g II II • II Η about about fs II ca » T Γ rh II ε about N II Ό II ϋ II • ABOUT q II κ LPi • H * = 2 II what l 1 g II a * - » ABOUT X} II ABOUT II • about • I-i II Μ CJ in- q co II ca Λ • n cn II ε OJ about ε II • H II OJ > N CO in- WHAT II ο 03 O Λ r II II ABOUT H 11 ...... 1 n 1 & » II II about q II i q ϋ • rl II N > II O Ή Ό ABOUT II 'ca ε 'ca H II N <D ra 3 II tn · í> ie r * ra II II • rl >> xí R-4 and, • ro II what !> o «? É ~ í CD > II II II CD fs í§ É?

CS 272704 Bl

Example 1

Chemical composition melt: 3.49 wt% C, 1.95 wt% Si, 0.22 wt%, Mn, 0.013 wt%. P, 0.022 wt. S, 0.085 wt. Cr. 0.062% wt. Ni, 0.094 wt%, Cu, 0.009 wt%; Al modified at 1,450 ° C in the ladle by the pouring method when pouring from the melting furnace into the ladle by the silicon modifying additive of the invention having a composition of: 35.1 wt. Si, 2.9 wt. Al, 0.36 wt. Ca, 35.9 wt. rare earth metals, of which 17.85% wt. Ce, the remainder 25.74 wt%, Fe, at an added amount of 0.35 wt%. % graft grafted 0.7% wt. FeSi 75 at a granulation composition of 3 mm.

Metallographic evaluation (according to CSN 42 04 61): 90% III, 10% VI - Fe 80

Mechanical properties: Rm β 446 MPa, KG = 29.3 3.cm HB = 202.

Example 2

Melt of chemical composition: 3.52 wt. C, 1.98 wt%, Si, 0.28 wt% Mn,

0.014 wt. P.0, -021 wt.%, S, 0.14 wt. Cr, 0.094% wt. Ni, 0.12 wt. Cu,

0.007 wt. Al modified at 1460 ° C in a ladle by the pouring method when pouring from a melting furnace into a ladle with a silicon modifying additive according to the invention having a composition of 36.2 wt.%, Si, 1.35 wt. Al, 0.41 wt. Ca, 36.2 wt. rare earth metals, of which 17.4 wt. % Ce, 25.84 wt. Fe, at an added amount of 0.50% w / w, graphitized grafted with 0.7% w / w. FeSi 75 at a granulation composition of 3 mm.

Metallographic evaluation (according to CSN 42 04 61): 85% III, 15% VI - Fe 85.

Mechanical properties: Rm = 44S MPa, KG »31.2 3.cm, HB = 199.

Claims (1)

OBJECT OF THE INVENTION A rare earth silicon modifying additive comprising 35 to 37 wt. % Si, 34 to 37 wt. rare earth metals, of which 17 to 19 wt. Ce, 1.3 to 3.0 wt. Al, 0.30 to 0.45 wt. Ca, residue 22.55 to 29.4 wt. Fe, a granulation composition of 3 to 5 mm.