SU1588483A1 - Composition for surface alloying of castings - Google Patents

Abstract

The invention relates to foundry. The purpose of the invention is to increase the corrosion resistance of the alloyed layer. The composition includes, wt.%: Ferroniobiyantaln 40-60

borax 1-3

bentonite 23-33 and 8% polyvinyl butyral solution the rest. With the introduction of ferroniobium tantalum, the surface layer of the casting is alloyed with niobium and tantalum. This makes it possible to increase the durability of the doped layer under high temperature gas corrosion. The use of the composition reduces the consumption of cast products by increasing their operational durability. 1 tab.

Description

The invention relates to a foundry, namely, compositions for alloying the surface of castings in a mold.

The purpose of the invention is to increase the corrosion resistance of the alloyed layer.

The composition for surface alloying of castings contains, in wt.%:

Ferroniobium tantalum 40-60

Bura1-3

Bentonite23-33

8% Solution

polyvinyl butyral

in solvent 646

The introduction of ferroniobiobantalum makes it possible to alloy the surface of the casting with niobium and tantalum. The complex surface alloying with niobium and tantalum provides an increase in the corrosion resistance of the casting. Borax interacts with ferroniobium tantalum with the formation of complex compounds of niobium and tantalum. Which diffuse to the surface of the casting and disintegrate with the release of atomic niobium and tantalum. The latter are dissolved in the surface layer of the casting. The introduction of bentonite in large quantities provides a high sedimentation stability of the composition, which is a suspension with heavy particles of ferroniobium tantalum suspended in it.

Example. The composition is prepared from powdered ferroniobio tantalum. containing 10-40% niobium and tantalum with a total amount of 50-65%. 30-35% silicon and iron - the rest, bentonite and borax with a particle size of not more than 50-60 microns. The dry components of the formulation are mixed with an 8% solution of polyvinyl butyral in solvent 646 until a homogeneous suspension is obtained. The resulting composition is applied to the surface of a mold or rod with a thickness of 3-5 mm. The mold is poured with steel ZOH2N2L and castings with a wall thickness of 60 mm are obtained. The quality of the doped layer is assessed by the distribution of niobium and tantalum in over W

ate

00

with

00

CJ

Nost layer and corrosion resistance of the alloyed layer. The corrosion resistance of the doped S5G layer is determined in accordance with GOST 6130-71 by the sample mass loss at holding it. At 900 ° C for 10 h.

Variants of compositions and quality parameters of the alloyed casting layer are given in the table.

The introduction of fefroniobio-tantal to the composition ensures that the surface of the castings is alloyed with niobium and tantalum to a depth of 2 and 0.8 mm, respectively. A variation of containing (niobium and tantalum in the ferroniobiyantantal in the range of 10–15 to 40% with a total amount of 50–65% does not lead to a significant change in the total depth of the doped layer. On castings, less (40 mm) or more (100 mm the thickness of the doped layer decreases accordingly by 0.1-0.2 mm or increases by 0.05-0.1 mm. When making castings from carbon steel or gray iron, the depth of the doped layer decreases by 5-20 or L5-30% .

The application of the invention allows to increase the resistance of castings with high-temperature gas corrosion 2-2.5 times. The economic effect resulting from this is due to a decrease in the consumption of cast products.

Claims (1)

Invention Formula The composition for surface alloying of castings mainly of iron-based alloys, including powder of the alloying material, activator of the delivery of the alloying element to the surface of the casting, suspension stabilizer and binder, differing in that. that, in order to increase the corrosion resistance of the doped layer, it contains ferroniobio tantalum as an alloying material, borax activator, bentonite and stabilizer, and a binder-8% solution of polyvinyl butyral in solvent 646 at the following ratio, wt.%: Ferroniobium tantalum 40-60 Bura1-3 Bentonite- 23-33 8% Solution polyvinyl butyral in solvent 646 “With cm (d) about cm i. h-w-h-h- | oh oh oh oh oh go about sh about. IU i S (O le co o h- h О5 t- tP 1 "O Yu Yu to About ee se C) sz se оо со со со со со о о о о о о о cm cm cm CN sh t And 52 f with hh-OT) hh-hh chg cho Yu You t-O) "- see" - CN CN "- with about I r (U m ABOUT) with Ltd s about as t about with S 0) oh ffl s (Q. O. oo with so with oo cm cm cm cm Qi m with tol -: -; about. 2 "er m 1 s ii ID about. 0O 1sh D S AZ S Si I Ltd and S