SU1294862A1 - Cast iron - Google Patents

Abstract

The invention relates to cast iron and can be used for the manufacture of thin-walled critical castings such as blocks and cylinder heads, crankcases and others. The purpose of the invention is to reduce the tendency of iron to chill, linear shrinkage and residual pressure while improving machinability. Cast iron contains, wt%: C 2.9-3.6; Si 1.2-1.7; MP 0.03-0.30; Cr 0.03-0.08; Ti 0.03-0.08; Zr 0, p2-0.1 0; C 0.2-1.5; Fe rest. Properties of cast iron: chill on the wedge sample 2.5-3.0; linear shrinkage of 1.1-1.2%; the area of the destroyed section of the central rib of the shrinkable grille 250-300 is the depth of drilling at a spindle speed of 350 minutes, the force on the spindle is 490 N, the drill bit from P6M5, 10-10 mm, angle 2 × 118 & is 4.5-5.0 mm. 1 tab. with b cl GS UD 4; :: 00 SG N5

Description

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The invention relates to metallurgy, in particular to cast iron, used in automotive engineering for the manufacture of thin-walled responsible castings, such as blocks and cylinder heads, crankcases and others. The purpose of the invention is to reduce the tendency of pig iron to chill, linear shrinkage and residual stresses during and improvement. machinability.

The invention is illustrated by the examples presented in the table.

The cast iron was smelted in an IS1-004 induction furnace on a wire consisting of metallized pellets and ferroalloys. The liquid metal was modified with silicocyrconium with a granule size of 3-5 mm, its input into the pouring ladle under the stream of cast iron. The known cast iron was modified by metallic magnesium in a crucible furnace. The copper content was regulated by the introduction of copper cathode into the mixture. From each variant of cast iron at a temperature of metal of 1420-1400 C, samples for chill (wedge) and mechanical properties with a diameter of 30 mm and a length of 340 mm were cast using a thermocouple immersion. The cast iron compositions are given in the table.

 The machinability is determined by acceleration when drilling square bars with a side of 30 mm according to the Kesner method, which allows to obtain comparative characteristics of the workability of the metal under investigation and consisting in processing the test material with a drill at a constant spindle rotation frequency and constant force on it.

The machinability was characterized by the depth of penetration of the drill (average of 10 measurements) into the material for a selected time interval (15 s)

. The tests were carried out on a vertical drilling machine at a spindle speed of 350 minutes and an effort on a spindle of 490 N, which was created by the load. Processing was carried out with a drill of 0 10 mm made of steel RBMZ, the normal form of sharpening (2 × 118 °).

The propensity to btbelu was investigated using wedge samples. The magnitude of the residual linear stresses was determined by the cross-sectional area of the central rib of the shrinkable grille, which was destroyed during filing. The magnitude of the linear shrinkage was determined on a Bolshakov instrument.

Experimental castings for defining these characteristics were shrinkable grids with dimensions of 300x200 mm and a cross-sectional area of a central rib of 350 mm and test bars of 30x75x25 mm (for Bolshakov device).

The central rib of the shrink grids was incised by the noscite before a through-crack was formed. Measuring the depth of cutting by:} it was estimated to estimate the area of destruction of the cross section and indirectly the magnitude of residual stresses.

Obtained in re: $ ultata research data are shown in the table.

When the content and zirconium less

carbon, silicon of the lower limit, g

titanium and copper more than the upper limit

0

deterioration of handling stress

With concentration and zirconium more

| Shaemost iron, depth and level of | are magnified. carbon, silicon of the upper limit.

and titanium and copper; 1 strength lower.:. cast iron.

The introduction of copper into cast iron reduces the amount of eutectic carbides (a decrease in the thickness and turbulence of graphite

machinability),; ts from the effect of the oral composition, its effect is related

formation (improvement that is fundamentally different from copper in the cast iron

bleached), change

with hardening effect on the metal base of cast iron.

Analysis of the data in the table shows

compared with

limestone offers "damn cast iron has

optimal set

technological partnerships. The use of this cast iron for the purpose of: the preparation of complex hull otliyok will allow semi-mechanical and

45

Chit significant effect.

Claims (1)

Formula of economic acquisition Cast iron containing carbon, silicon, manganese, xpoji, titanium, zirconium and iron, about t and iron, in that. with the aim of And y and u with: lower tendency of pig iron to chill, linear shrinkage and residual stresses while improving machinability, it additionally contains copper n; and the following ingredient ratio is Carbon. Silicon at, 0.03-0.30 0.03-0.08 0.03-0.08 Zheleao - osglpnoe. Editor N. Lazarenko Compiled by A. Osmantsev Tehred I.Popovich Proofreader A. Tsko Order 565/29 Circulation 605 VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 0.02-0.10 0.2-1.5 Else Subscription