RU2336971C2 - Method of electroslag facing with grainy filler - Google Patents

Abstract

FIELD: technological processes; metallurgy.

SUBSTANCE: after assembly pf part with iron chill alloying plate is installed along the wall of the latter from the side of part working surface. Consumable or nonconsumable electrode is used in melt of slag bath with supply of unalloyed or low-alloyed grainy filler into it, which serves as a binder for alloying elements of plate in the process of facing. Grainy material is supplied into clearance between electrode and plate. Alloying plate is used that contains multi-component materials and that was produced by casting or pressing of powder charge with binder. As grainy filler cast-iron pellets or chips are used.

EFFECT: higher quality of faced metal and reduction of facing prime cost.

2 cl, 2 ex

Description

The invention relates to electroslag surfacing (ESH) with a granular filler material and can be used to produce cast, bimetallic and restore worn parts.

A known method of manufacturing and restoration of parts, including fixing parts and chill molds, the use of a consumable or non-consumable electrode in the melt of the slag bath with the filing of a granular filler material (Kuskov Yu.M. et al. Electroslag surfacing / Ed. By A.F. Pimenov. - M .: LLC “Science and Technology.” - 2001, p. 67-74).

The disadvantage of this method is the high complexity of manufacturing a filler material from highly alloyed materials.

As the closest analogue, the method of manufacturing and restoring parts by electroslag surfacing, including assembling the chill mold and the part, using a consumable or non-consumable electrode in the melt of the slag bath with the filing of a granular filler material there (Kuskov Yu.M., Ksenzyk G.V. Use of a granular filler material, was chosen in electroslag surfacing (Review) // Modern methods of surfacing and their application, - Kiev: IES, 1982. - S.62-70.).

The disadvantage of this method is the high complexity of the manufacture of filler material from highly alloyed materials, their uneven distribution in the volume of the slag bath, as well as their irrational use due to the fact that the entire volume of the casting part is alloyed, and not its working part. In addition, if two or more types of granular filler materials having different fractional composition are used, this leads to their delamination in the dispenser, which sharply reduces the quality of surfacing. In this case, it is necessary to use two or more dispensers, which significantly complicates the surfacing process, increases its complexity, and also increases the likelihood of a decrease in surfacing quality due to the difficulty of synchronizing the operation of several dispensers.

The technical problem to which the invention is directed is to improve the quality of the deposited metal and reduce the cost of ESH due to the directed and economical alloying of mainly the working surface of the part and the use of unalloyed or low-alloy granular filler material that performs only the role of a metal - a binder for alloying elements.

The specified technical problem is solved in that in the method of electroslag surfacing with a granular filler material, which includes assembling the part with a chill mold, using a consumable or non-consumable electrode in the melt of the slag bath with the filing of a granular filler material, in contrast to the prototype, after assembling the part with the chill mold along the wall of the latter, from the side of the working surface of the part, an alloying plate is installed, unalloyed or low-alloyed filler material is used, which during surfacing olnyaet role binder for the alloying elements of the plate, while it is fed into the gap between the electrode and plate.

As an alloying plate, multicomponent materials obtained by molding or pressing a powder mixture with a binder are used, and cast iron shot or shavings are used as a granular filler material.

The installation of the alloying plate from the side of the working surface of the part provides directional alloying of this particular surface, which ensures, on the one hand, obtaining high performance properties of the part, and on the other, saving alloying elements. At the same time, unalloyed or low-alloy low-cost and non-deficient materials that act as a metal — bundles for alloying elements contained in an alloying plate — are used as a granular filler material. As alloying plates, cast hard alloys of the stellite type can be used, including stellite-like, for example, Sormait, and high carbide fame or high alloy steels. However, the widest possibilities for directional alloying and varying the composition of the deposited metal are provided by the technology of manufacturing alloying plates by mixing with a binder and pressing various powder components, such as ferroalloys, powders of metals, alloys, minerals, etc. All this provides an increase in the quality and lower cost of ESH .

Examples of the method.

Example 1. Conducting the manufacture of castings ESH using granular filler material and an alloying plate. As an alloying plate, a sormite cast plate is used, and cast iron shavings (SCH21-40) are used as a granular filler material. Surfacing is carried out with a non-consumable tungsten electrode of the EVI-1 brand.

A copper water-cooled chill mold is mounted on a steel substrate in the form of a rectangular plate, a thin layer of sand is poured (to prevent fusion of the surfacing with the substrate), and an alloy plate is fixed along the chill wall, from the side of the intended working surface of the part. Then the flux (AN-348) is filled up and a slag bath is induced by a non-consumable tungsten electrode, after which pig-iron shavings are fed between the electrode and the plate from the dispenser and the ESH process is carried out. In this case, the electrode during the surfacing process is raised at a speed equal to the rate of rise of the slag bath. After surfacing, the casting (25 × 30 × 40 mm) is easily separated from the substrate.

An analysis of the chemical composition showed that the number of alloying elements transferred from the molten alloying plate to the casting gradually decreases from its working surface into the interior of the material. The abrasion resistance test according to GOST 23.208-79 showed that the wear resistance of the casting working surface is 2.5 times higher than non-working.

Example 2. Carry out the restoration of beat hammer mills ESH using granular filler material and an alloying plate. Pre-worn beats are cut on a vertical band saw to obtain a flat end surface, the same weight and size. Powders ПХ23Н18, tungsten and ferromanganese are used for the manufacture of alloying plates. Based on the required chemical composition of the surfacing (established experimentally in the process of laboratory research), the required number of the above alloying components is calculated and weighed, dry mixed, and then a binder (liquid glass) is introduced. The obtained viscous flow mass is pressed in a special mold and dried in an oven at a temperature of 300 ° C for one hour.

A worn beater is fixed vertically in a special installation for ESH, and a copper water-cooled chill mold is installed on top. An alloy plate is installed along the chill wall from the side of the beat surface, then a consumable electrode is introduced (steel strip 110 × 20 mm from ordinary mild steel), the flux is filled up and the ESH process is carried out. In the process of surfacing using a dispenser between the electrode and the alloying plate serves a predetermined amount of cast iron shot brand CHDL.

An analysis of the chemical composition of the recovered beats showed that the working part of the beater with a thickness of about 15 mm is alloyed cast iron, smoothly turning into steel. Moreover, the largest number of alloying elements (about 70%) is located in this part, which ensures its high wear resistance.

Production tests of reconditioned beats deposited by known and proposed methods have shown that the wear resistance of the latter is 1.5-2 times higher, and the cost is 1.3-1.5 times lower.

Thus, the proposed method for the manufacture and restoration of ESH components with a granular filler material using alloying plates, in comparison with known methods, provides an increase in the quality of the deposited metal and a reduction in the cost of ESH

Claims (2)

1. The method of restoring parts by electroslag surfacing, including assembling the part with a chill mold, using a consumable or non-consumable electrode in the melt of the slag bath with the filing of a granular filler material, characterized in that after assembling the part with a chill mold along the wall of the latter, an alloying alloy is installed plate, use unalloyed or low-alloy granular filler material, which in the process of surfacing serves as a bond for alloying elements of pl slime, while it is fed into the gap between the electrode and plate. 2. The method according to claim 1, characterized in that they use an alloying plate containing multicomponent materials obtained by molding or pressing a powder mixture with a binder, and cast iron shot or shavings are used as the granular filler material.