SU1617013A1 - Method of producing cast-iron articles - Google Patents

Abstract

FIELD OF THE INVENTION The invention relates to agricultural machinery, in particular, to methods for producing self-sharpening plowshares from high-strength cast iron. The purpose of the invention is to increase the reliability of the plowshare by reducing warping and improving mechanical properties. The method consists in pre-annealing the castings to obtain a ferritic structure and hardening the blade edge with sections by heating with an electric arc while simultaneously cooling at a speed of 600-700 ° C / s. The application of the method makes it possible to speed up the process, increase the hardness and plasticity of the hardened layer, as well as reduce the boom deflection and improve the quality of tillage. 2 silt, 1 tab.

Description

From 6; 1 applies to agricultural} timing machine engineering 1, in particular to methods of making self-sharpening chisels of high-strength cast iron.

The purpose of the invention is to increase the reliability of the plowshare by reducing warping and improving mechanical properties,

The method involves annealing the casting, after which the edge of the blade on the back side of the plowshare is subjected to hardening of the core by heating the electric arc while simultaneously cooling at a speed of 600-700 s / Co

Thus, the non-reinforced areas that have a ferritic structure, without being affected by heat, will be the relaxers of the internal stresses that arise and, consequently, decrease

warping the blade edge with the cutting edge, and a high cooling rate will allow to obtain in the ashes of hardened areas more crushed quasi-eutectic doped with Nd, Pr, GLa, Zr, which are part of the base metal. Grinding and more uniform distribution of perlite in the cementite base will reduce the fragility of the structural conglomerate and, consequently, increase m microhardness

In the initial period of operation of the plowshare, its non-reinforced sections B wear out faster than the strengthened sections A and for this reason the blade takes on a pointed gear shape.

FIG. 1 shows the arrangement of the reinforcement portions A on the dark side of the Blade at interval B; on

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ig.2 - plowshare from the front side after some wear

The prewash method is carried out

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As cast materials for making plowshares, pig iron with sulfur content up to 0, U // o, odified with cerilmantane ligaura, containing as a partner of U10 th components neodymium, praseodymium, iobium, zirconium

After the casting of the plowshares, I have 19 and 1 structure of finely dispersed perylite-like perlite and ferrite as edges into the district. graphite inclusions of spherical shape, subjected to annealing in the following mode: on. . , - L, -. .l. f tt iTV - G1

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warming up to 750 + 10 ° C .; Exposure 6 h | cooling with a furnace or in the air, and after annealing, the ploughshare material gives a HE of 140–160 units and a impact strength of 2.8–3.0 kg / cm. current IbU-- ZOOA) using a non-melting carbon dioxide electrode (diameter 8-10 №s) o

In the process of -strengthening (from the beginning to the end of it), an intact Strength-. va) the plowshare side must be in contact with the surface of the coolant circulating in a 35-loop closed cycle and providing a speed of 600-700 ° C / s.

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As a result of the dissolution of carbon in the ferrite base and a high rate of: cladding, uniform stretching occurs on the depth of 1 mm g on the depth of the formation of a fine 45 ledeburite (quasi-vertical). Mikrsg- hardness of the bleached layer of 1030 units. The depth of the bleached layer is S 1 spacing within the limits of and from / to TJo and depends on the strength of the TOK and the speed of the electrode moving relative to the blade surface. This method eliminates the penetration of the base metal and through the chipping,

a constant layer of constant thickness on a very oncom section of the plowshare (up to 3 mm)

The results of tests of plowshares, molded by the known and proposed methods, are presented in the table - ./ As can be seen from the data in the table, the optimal cooling rate for achieving this goal is 600-700 C / Co

The cooling rate is regulated by the linear energy of the arc, which depends on the current and voltage, the boundary values of which are listed in the table

A further increase in the cooling rate (above 700V./c) leads to a decrease in the microhardness of the hardened sections, since no doping of quasi-eutectic does not occur. The cooling rate of less boo c / c makes it impossible to increase the microhardness of the structure of the hardened layer

The present invention makes it possible to increase the microhardness by a factor of 1 to 2, and the internal ploughshare tension to be reduced by a factor of 7 to 8. At the same time, it makes it possible to speed up the hardening process by a factor of 2.5–3 (since the hardening of the composite layer lasts 4–5 min and 1.5–2 min in sections); reduce the efficiency of plowing and improve the quality of tillage (due to the serrated shape of the blade edge acquired during the operation); raise the replacement manufacturer; ia ::; otnogo unit by 17% and reduce the specific fuel consumption per hectare of plowing to 7% ..

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acquisitions

The method of making cast iron products,. predominantly plowshares, B1clustering the casting of the workpiece, annealing to obtain an effective structure, on the back side of the blade: zlek-g; —Carnel arc and cooling, characterized in that warping and improvement of mechanical properties, heating is carried out in local areas, and cooling - from a speed of 600-700 ° C / s „

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Claims (1)

Claim A method of manufacturing cast iron products. mainly plowshares, including casting a workpiece, annealing to obtain a ferrite structure, heating the surface of the back side of the blade with an electric arc and cooling, characterized in that, in order to increase the reliability of the share by reducing warpage and improve mechanical properties, heating is carried out in local areas, and cooling - at a rate ^of 600-700 C / s " Speed Tension- Force Plates Micro- Arrow cooling (U) current nost hard deflection denia IN (1), A (<?),% Dost (f) mm ^a C / s ----------1 1 f '' 1 a; about 1 and 1 eleven Known method 400 65 180 1,04 640 4.6 500 65 . 200 1.12 780 3.8 Proposed the way 600 65 290 1.21 800 0.2 650 65 270 1.43 970 0.49 Beyond value 800 65 230 1.9 760 0.96