SU812486A1 - Powdered wire composition - Google Patents

Description

(54) COMPOSITION OF POWDER WIRE

The invention relates to the field of welding materials, in particular, flux-cored wires, intended for the seam welding of dissimilar steels and the separation layer of bimetals used in chemical engineering.

Known composition 1 of the welding wire, consisting of a shell made of an alloy based on nickel, the shell and the powdered charge, which includes the following ingredients, weight. %:

Hrom24-30

Manganese

nitrated 0,3-1,5

Fluoropolymers0.3-0.6

Iron powder18-24

Zirconia 3.6-6

Aluminum-vanadium-molybdenum-titanium

ligature 3-6

Low silicon

non-oxidizing flux3,6-3,4

Rare earths 0.03-0.3

Alloy shell on

Nickel Based Else

However, such wire does not guarantee

getting resistant to the formation of them

And cold cracks schv when welding separation layer of bimetals, especially with highly corrosive steels XI7Н13МЗТ and ОХ23Х28МЗДЗТ and so on. A layer and dissimilar. compounds of these steels with low carbon materials. In addition, the production of such wire is difficult due to the complex composition of the mixture.

Also known is flux-cored wire 2, designed for welding a separation layer of bimetals and dissimilar joints and providing a rather high corrosion resistance of the weld metal of the following composition, weight. %:

Chrom30-35

Manganese 3-5

Aluminum1-2

five

Molybdenum 5-8

Gas and slag-forming components (marble -f + fluorspar) 9-14

Niobium 0.8-1.2

Nickel shellEverything else

However, this wire does not provide for welding bimetals with a high-alloyed sustained-wall cladding layer.

sufficiently high resistance against the formation of hot and cold cracks.

The purpose of the invention is to develop such a composition of flux-cored wire, which, being simple in production, would allow to obtain resistant to the formation of hot and cold cracks when welding the bimetal separating layer (including high-corrosion resistant steels, for example similar) and dissimilar compounds of these steels with low carbon.

The goal is achieved by the fact that the sheath of the cored wire is made of nickel, for example electrolytic, and the powdered powder additionally contains calcium and nitrated chromium in the following ratio of incoming components, wt. %:

8.5-11.5

Chromium nitrated

22-26

Chromium

17-24

Manganese

9-11

Molybdenum

4-5

Aluminum

0,009-0,012

Calcium 2.5-3.1

Yttrium

Gas and slag-forming

7-11

components Else

Nickel shell

Let us consider the influence of the ingredients included in the mixture of the claimed wire on the properties of the metal of the schv.

The gas and slag-forming components used marble and fluoride mat, which form the desired slag and gas phases during welding. A suitable (optimal) concentration of these elements is 4-6% and 3-5%, respectively. Bbi6j) aHHbie the limits of the content of marble and fluorspar are valid for the proposed wire with any ratio of components in its charge. Another system for alloying the charge will require some clarification of the content of the elements in question.

Molybdenum is introduced into the wire to increase the resistance of welds to the formation of cracks and improve the resistance to corrosive wear of the high-alloyed facing seam. Repeated experiments show that a decrease in the charge of molybdenum wire below 9% does not allow to obtain welds with no hot cracks (the critical deformation rate is less than 2.4 mm / min). A further (over 11%) increase in the concentration of this ingredient has little effect on the subsequent technological strength of the weld metal. In this connection, molybdenum is introduced into the charge in the range of 9-11 / o.

Doping with chromium is carried out to prevent a decrease in the chromium concentration in the facing groove and thereby achieve the required corrosion resistance of the latter. The selected limits of chromium content in binder: the lower 22% and the upper 26% - contribute to ensuring the specified corrosion resistance. The introduction of nitrated chromium into the mixture, on the one hand, improves the corrosion resistance of welded joints, and on the other, significantly improves the mechanical properties of the weld metal by increasing the austenite stability and improving the resistance to hot cracking. At any ratio of components included in the charge of the wire components, the optimum manifestation of nitrided chromium is observed when the content is between 8.5 and 11.5%. Aluminum is introduced into the charge of the wire to prevent pores in the weld metal and grinding its structure. When its content is less than 4%, the deposited metal shows a tendency to the formation of pores, most pronounced in single-layer welding of small cracks. An increase in the concentration of aluminum versus 5%, although leading to a further refinement of the structure, however, adversely affects the ductility of joints. For this reason, aluminum is taken in the range of 4-5%.

To increase the stability of austenite, resistance to the formation of pores and cracks in the weld, 1-7-24% manganese was introduced into the wire. This concentration is optimal for any ratio of charge components within the specified limits, since its increase in excess of 24% can cause a decrease in the viscosity of the weld metal due to the formation of an excessive amount of the J-phase, and a decrease below 17% reduces the impact strength and plasticity due to the presence of zones with low-plastic products of nos lymph transformations.

Thus, these components to a certain extent contribute to the improvement of the mechanical, welding-technological properties and structure of the weld. However, introducing them only into the powder mixture does not allow one to achieve the goal, since the specified weld characteristics do not provide acceptable resistance to cold and hot cracks when welding dissimilar joints and a bimetal separating layer with austenitic high-alloyed cladding layer.

Claims (2)

This task is solved by co-doping the mixture with calcium and yttrium, which contribute to an abrupt change in the properties of the deposited metal, which consists in a sharp increase in the resistance to cold and hot cracks (assessed by the critical strain rate). The specified effect of calcium and yttrium on the properties of the weld metal occurs s only if they are introduced into the mixture together and is explained by the development of adsorption effects in the border areas of actual austenitic grain, increasing the stability of austeitium, changing the effective crystallization range, etc. For quantifying the joint the effects of yttrium and calcium on the properties of the proposed wire were subjected to tests a series of compositions of its charge containing (by calculation) 0.002 successively; 0,006; 0,009; 0.011; 0.012; 0.015% calcium and 1.8; 2.4; 2.6; 2.5; 2.9; 3.1; 3.3% yttrium with a concentration of other components within the specified limits and an electrolytic nickel shell constituting the remaining additional part up to 100%. Experimental results showed that welds made of wire with 0.011% calcium and 2.9% yttrium have the best properties. The introduction of calcium below 0.009% of calcium and 2.4% of yttrium into batch has little effect on the resistance of the weld metal to hot and cold cracks, and exceeding them above 0.012% and 3.1%, respectively, has little to no further improvement in the quality indicators under consideration. In this connection, the lower limit of the content of calcium and yttrium in the wire should be limited to 0.009 and 2.5%, and the upper limit to 0.012 and 3.1%. The offered wire provides high quality of seams when welding a bimetal separating layer with austenitic high-alloyed cladding layer and dissimilar joints, and can find wide application in the manufacture of especially responsible welded chemical equipment. The economic effect from the introduction of the proposed wire in comparison with the known materials is 2.3-3.1 p. per 1 kg of weld metal, which is achieved by increasing by 15–20% the productivity of welding, reducing by 10–15% from waste and improving the quality of welded joints. The invention Composition of flux-cored wire for making a separation layer when welding bimetals, mainly with a high-alloyed austenitic cladding layer, and dissimilar compounds consisting of a nickel sheath and a mixture containing chromium, manganese, molybdenum, aluminum, yttrium, gas and slag-forming components, different the fact that, in order to increase the resistance to hot and cold cracks of the weld metal, the mixture additionally contains chromium nitrated and calcium in the following ratio of wire components ki, weight %: Chromium-22-26 Manganese17-24 Molybdenum9-11 Aluminum4-5 Yttrium.2.5-3.1 Gas and Slag Forming Components7-11 Nitrided chromium8.5-11.5 Kaliny0.009-0.012 Nickel ShellEverything else Information sources, taken into account during the examination 1. USSR author's certificate No. 596404, cl. B 23 K 5/368, 01.06.76. 2. USSR author's certificate for application number 2699237, cl. At 23 K 35/368, 12/18/78.