SU686206A1 - Fusing composition - Google Patents

Description

The invention relates to the machine-building industry and can be used to restore worn-out parts of machines by means of automatic surfacing of layers using powder materials. A composition for surfacing, dragging, weight,%, is known: Carbon 0.5-20 Aluminum 1-9 Fluorspar 5-15 Magnesium 0 , 5-4 Calcium1-7 Rare-earth metals0,1-2 Silicon4-20 Bor O, 001-01 Iron Remaining 1. Such a composition is intended for surfacing cast iron parts such as engine shafts. However, when surfacing with a known powder composition of steel crankshafts for machines of the type ZIL-130, SMD-BO, GAZ-51 along the deposited layer, uneven fine-grained pearlite structure, uneven hardness is obtained, which causes uneven wear of the deposited shaft. In addition, due to the presence of a strong carbidopa element - boron, carbide inclusions are formed along the fillets of the welded necks of steel crankshafts, which chill off, which always complicates the workability of the necks and, in the course of operation of the shafts, causes tears in the areas of the crankshaft necks with liners, in order to obtain a high-quality deposited layer on steel crankshafts with high physicomechanical properties, with a uniform fine perlitic structure, the same solid Stu and without primary carbides composition additionally comprises nickel with the following ratio of components, wt%: 10-25 carbon 4-15 Silicon Aluminum 1-9 0.5-5 0.5-7 Calcium Magnesium Rare Earth. 0.1-3 Metals 0.01-1, O Nickel Fluorspar 0.5-3 Iron Else.

With the additional introduction of nickel (0.01-1.0%) in the composition for surfacing, a high-quality layer of the deposited necks of steel crankshafts is provided. Nickel contributes to the grinding of the pearlite base of surfacing, leveling the hardness along the deposited layer and prevents the formation of ledeburitic carbides (along the fillet of the shaft necks). Nickel also has a beneficial effect. elimination of scaling by means of a layer of steel shafts and on it, its resistance to shock loads.

Nickel in the composition for surfacing also contributes to a decrease in hardness in the corners (fillets) of the weld necks, eliminating chill. The effect of nickel is particularly effective together with small additives of rare-earth metal and calcium modifying elements (0.5–7%),

If the composition of the powder contains less than 0.01% nickel, its effect on the alignment of the structure and on the elimination of chill in the shaft fillet is reduced. When more than 1% nickel is deposited in the composition, the properties and structure of the deposited layer change slightly. Therefore, in order to save nickel, its content in the powder in the amount of 1% is quite enough to equalize the microstructure of the physicomechanical properties of the weld layer and eliminate chill.

The introduction of calcium, magnesium, and rare-earth metals in the composition for the deposition makes it possible to obtain a spherical shape of graphite in the weld layer and to improve the physical and mechanical properties of the alloy.

Aluminum in the composition of the powder contributes to the improvement of the process of surfacing (deoxidizes the liquid metal in the deposited layer, eliminates the formation of shrinkage porosity and cracks),

The presence of carbon (10–25%) and silicon (4–15%) powder for surfacing together with nickel helps to obtain a fused layer without inclusions of structurally free carbides, which cause scuffs on the crankshaft necks during operation.

Fluorspar in the composition of the powder for surfacing performs the role of a flux that protects the modifying elements from oxidation and contributes to the liquefaction and floating of non-metallic inclusions.

The proposed surfacing composition is made in powder form. This is due to the type of surfacing, in which the powder in a certain amount is fed to the wire fed automatically to weld the parts. Due to the electromagnetic field arising around the wire, a uniform powder sheath is created around its perimeter. As the wire melts, the sheath of the powder melts evenly.

The surfacing powder is made from ground alloys of complex modifiers containing magnesium, calcium, rare earth metals, aluminum, nickel, carbon, silicon, iron, followed by the addition of graphite, fluorspar or by mechanical mixing of an alloy of a complex modifier containing calcium, magnesium, rare earth metals , silicon, iron, with aluminum powder, nickel and, if necessary, magnesium or silicocalcium.

The table lists examples of formulations.

10 15 9 0.5 3.5 3.0 0.01 0.5

2.5 0.5 1.5 0.5

15 10

 The composition of the powder for surfacing corresponds to the prototype.

These powder compositions weld the worn out necks of the steel crankshafts of the ZIL-130 engines,

The results of the study of the microstructure of hardness and quality of the deposited layer showed that during the deposition

- The rest

1.5

Also

The steel crankshaft with compositions of 2.3 deposited layer was dense without porosity, chipped, had no non-metallic inclusions, captured. The hardness of the deposited layer along And across the weld is uniform (269277 HB). The structural-free carbides in the deposited layer were removed.

including fillet necks, absent When surfacing the necks of steel shafts of composition 4 (according to aut. No. 500945), there is chill in the deposited layer in the places of the fillets, the structure reveals up to 5-8% cementite not the same. Hardness along and across the seam ranges from 255 to 320 HB.

The use of the proposed composition for the surfacing of steel crankshafts allows to obtain a quality layer with a uniform fine structure, the same hardness along the surfacing, without inclusions of primary carbides, which contributes to improving the wear resistance and service life of the weld steel crankshafts.

Claims (1)

Invention Formula Composition for surfacing containing carbon, silicon, aluminum, magnesium. Calcium, rare earth metals, fluorspar, iron, are distinguished by the fact that, in order to improve the quality of the weld metal and enhance the physicomechanical properties of the weld metal by means of an even finely dispersed pearlitic structure with the same hardness and the absence of primary carby. The composition additionally contains nickel in the following ratio of components, wt%: Carbon 10-25 Silicon4-15 Aluminum1-9 Magnesium, 5-5 s Calcium 0.5-7 Rare-earth metals 0.1-3 Fluorspar 0.5-3 Nickel 0.01-1 0 Iron Else. Sources of information taken into account in the examination 1, USSR Author's Certificate 500945, class B 23 K 35/30, 1974.