SU543479A1 - The composition of cored wire - Google Patents

Description

The invention relates to the hardening of a rock cutting tool with wear-resistant coatings, for example, for reinforcing the teeth of the bits of drill bits. Drilling dopota work in conditions of intensive abrasive wear and active shock loads. The main purpose of surfacing teeth of bits is to increase their abrasive and impact resistance. At present, all teeth of the bit are reinforced with a hard alloy - relit. However, the test bits show the feasibility of reinforcing only the back of the cones. As a result of analysis of the state of the drill bits, it was found that the cause of the durability of the tested bits was the presence on the lateral edges of the crown teeth of a fragile reinforced layer with a large number of macroinhomogeneities and defects that reduce the performance of the reinforced layer. When drilling hard rocks a tooth of a roller bit is subjected to impact loads, abrasive wear and repeated heating in an oximeter. Therefore, materials suitable for hardening tamps and cutting tools, working under the conditions of significant cyclically varying temperatures, impacts and specific pressures, are the most suitable for surfacing the knitting teeth of roller cone bits. Known charge for surfacing 1J, coa aa our following components, wt. %: Ferro-tungsten 25-32.5 10-13 Ferrochrome 2-2.7 Ferroboral 12-16 Ferrovanadium 2-5 Ferrotitanium 2-4 14-18 Fluorspar 18-22 Marble Also known cored wire 2, containing the following components, ec. %: Ferromanganese 0.2–0.5 Foppocpe shi1.6–2.3 Chromium (at vias rochrome) 5.5–8.5

Ferro Tungs S-8.3

Ferrovanadium 1-3

Ferromolybdenum 0.6-1.5

Kremneftor isty

sodium 1,2,2,2

Nickel 0.4-4

Steel sheathErest

However, the layer deposited by known compositions has a low resistance to abrasive wear,

In order to increase wear resistance and quality of the deposited metal, working under conditions of abrasive wear, dynamic loads and thermal cycling, the mixture also contains ferro and graphite in the following ratio of wire components, weight. %:

Ferromanganese1-1,5

Chrom14,5-15

Ferro tungsten17-18

Ferrovanadium 3,8-4,5

Ferrobor1,6-2

Graphite2-2.5

Fluorosilicate

sodium 1-2

Low carbon

steel sheathEverything.

The specified composition of flux-cored wire is optimal when applied to the overlaying of the crown teeth of drill bits and n6ecne4K30iei chemical composition of the deposited layer in the following boundaries, weight. %: Carbon1 -1.3

Chrome13-15

Manganese 0.8-1.2

Tungsten14-16

Vanadium1,8-2

Silicon0,2-0,6

Bor0,1

IronErest

The exclusion of silicon from the charge is due to the fact that during cementation silicon reduces the rate of diffusion of carbon. This makes it difficult or completely eliminates surface carbons: imitation of the deposited layer, which is unacceptable, because the bits and pieces of the bits after surfacing cause the cementation and hardening,

The action of silicon as a deoxidizing agent is completely replaced by manganese, which

also has a high deoxidizing ability.

In the proposed composition of the charge, nickel is absent and the manganese content of nickel is increased. Nickel is replaced by manganese due to its lower cost, since the effect of marccc and nickel is similar. The increase in the content of manganese in the weld layer and, consequently, of the ferromanganese in the charge is higher.

This leads to grain growth during heating, which adversely affects the properties of the deposited layer: brittleness increases and resistance to shock loads decreases.

The presence of ferroboron in the charge leads to an increase in the abrasive resistance of the layer due to the formation of the boride and carbide boron phases. An increase in the boron content in the deposited layer over the above one leads to a significant decrease in impact resistance due to the appearance of brittle carboborides and borides located along the grain boundaries; austenite.

To preserve the degree of austenite doping and increase the amount of carbides, and, accordingly, the wear resistance, the amount of chromium, ferro-tungsten and graphite was additionally introduced into the mixture.

The introduction of an additional amount of chromium and ferro-tungsten will increase the resistance of the deposited layer to the action of multiple cyclic heating and cooling.

The increase in ferrovanadium in the charge provides the doping of the layer with vanadium, which has a greater carbide-forming ability than chromium and tungsten. The formation of vanadium carbides leads to an increase in the resistance of the layer to the effect of the abrasive wear resistance of the layer. Above all, vanadium, which has a dewyness and degassing ability, prevents the formation of pores in the weld layer.

An increase in the content of ferrovanadium in the charge above the specified limits leads to a further increase in wear resistance, however, the impact resistance decreases and there appear hot cracks in the weld metal.

Reinforced (weld) layer, obtained by the proposed cored wire, in comparison with the known, has greater abrasive wear resistance, resistance to cyclic shock loads and to cyclic heating and cooling.

Claims (1)

Invention Formula The composition of the flux-cored wire consisting of a low-carbon steel sheath and a powdery mixture containing ferromanganese, chromium, ferro-tungsten, ferrovanadium, sodium silicofluoride, o t l i- 56 H yu shchi and with the fact that, with the aim of raising graphite2-2 5 durability and quality of Krikshefurity Lennoto Meta.tt, working in conditions of sodium1 2 abrasive atatos, dynamic loads of low carbon and thermocyclic action, the charge is up to | steel sheathEverything else It contains ferroboron and graphite in addition. The sources of information accepted in the following ratio of components are components in the examination of: WA wire. weight%: 1. USSR author's certificate Ferromanganese1.0-1.5№ 365228, M .. Kl. At 23 to 35/360 of .5-15101971 g. (Equivalent). Ferro tungsten17-182. USSR author's certificate Ferrovanadium 3.8-4.5. No. 319173, M .. KlG H 23 K 35/368 from Ferrobor1,6- 21970 g. (Prototype). 543479