CN105252172A - Preparation method for sintered flux used for nickel base strip electrode submerged arc surfacing - Google Patents

Abstract

Disclosed is a preparation method for a sintered flux used for nickel base strip electrode submerged arc surfacing. The sintered flux contains fluorite, marble, alpha-aluminum oxide, zircon sand, sodium fluoride, pure potash water glass and alloy powder. A nickel base band is an EQNiCrMo-3 welding strip. The fluorite, the marble, the alpha-aluminum oxide, the zircon sand, the sodium fluoride and the alloy powder are subjected to dry mixing together and stirred evenly. Afterwards the pure potash water glass is added for wet mixing pelletizing and wet-mixed pellets are stirred evenly. The wet-mixed pellets are put into a drying oven for low temperature drying, and the temperature of low temperature drying is controlled to be 300 DEG C. Then the wet-mixed pellets are moved into a high temperature sintering furnace for high temperature sintering, and the temperature of high temperature sintering is controlled to be 650 DEG C-700 DEG C. After high temperature sintering, the sintered flux is obtained after 20-100 mesh screening. The sintered flux has a good welding technological property and is matched with the corresponding welding strip for welding. The chemical components of a surfacing layer meet requirements. The result of an intergranular corrosion test is good. No cracks are generated when a bending test is conducted after corrosion. The use requirements are met.

Description

The preparation method of a kind of nickel-base strip pole sintered flux for submerged arc welding

Technical field

The invention belongs to technical field of welding materials, refer more particularly to the preparation method of a kind of nickel-base strip pole sintered flux for submerged arc welding.

Background technology

Along with the progress of Chinese society and the raising of industrialized level, the condition of work that the large pressurized vessel be on active service in the fields such as petrochemical industry, Coal Chemical Industry and nuclear power faces is also more and more harsh, it is also proposed higher requirement to the corrosion resistance of its inwall.Lower common bearing device is required to corrosive nature, general one or more layers stainless steel layer of wall built-up welding within it that passes through just can meet its anti-corrosion requirement, but requires that higher, that operating temperature is higher bearing device stainless steel anticorrosion layer can not meet instructions for use for those to corrosive nature.And nickel-base alloy has more excellent decay resistance and elevated temperature strength compared with stainless steel, require in corrosive nature, instead of stainless steel in the higher device of service temperature.

It is high that strip surfacing has deposition efficiency, welding bead beautiful appearance, and cladding layer chemical composition is even etc., and advantage is used widely in pressure vessel industries.Existing strip surfacing method has two kinds, is respectively submerged arc overlay welding and ESW.Compared with submerged arc overlay welding, ESW fusion penetration is more shallow, dilution rate is low, easily there is slag inclusion, incomplete fusion defect, and due to heat input be usually greater than submerged arc overlay welding, cause molten bath life period at high temperature longer, the probability that aggravation fire check is formed, easily produce under built up welding clad crack, on large thick-wall pressure vessel during built-up welding nickel-base alloy, the effect of welding stress and different heat expansion coefficient can be accelerated crackle further and sprout.Therefore the welding quality of submerged arc overlay welding has more reliability than ESW usually.

But also there are some technological difficulties in nickel-base alloy band pole sintered flux for submerged arc welding, is mainly manifested in:

1) nickel-base alloy has the features such as fusing point is low, poor fluidity, poor thermal conductivity, is easy to occur weld seam dry slag, welding bead does not flush, the defect such as fire check under welding bead in welding process;

2) elements such as Nb, Ta in nickel-base alloy are easy to react to the oxidative components in solder flux generate corresponding oxide, make weld seam take off slag and become difficulty;

3) in solder flux, S, P difficulty controls, and can increase overlay cladding tearing tendency when S, P content overproof;

4), when the oxidisability of slag is too high, the alloying element in easy scaling loss nickel-base alloy, has a negative impact to its corrosion among crystalline grains;

5) the composition fluctuation of nickel-base alloy medium trace element also has important effect to its decay resistance.

Chinese patent CN102990251A discloses a kind of welding flux for electroslag surfacing, the overall fusing point of solder flux is adjusted by the melt flux adding proper proportion, realize the stable welding in the less situation of heat input, but this solder flux is only applicable to the ESW of nickel-base alloy.

Summary of the invention

For the problems referred to above, the invention provides the preparation method of a kind of nickel-base strip pole sintered flux for submerged arc welding, the nickel-base strip pole sintered flux for submerged arc welding prepared has that oxidisability is low, fusing point is low, welding usability is good, weld seam decay resistance is good.

For achieving the above object, the present invention adopts following technical scheme:

The preparation method of a kind of nickel-base strip pole sintered flux for submerged arc welding, containing fluorite, marble, Alpha-alumina, zircon sand, sodium fluoride, pure KP1 and alloy powder in this sintered flux, wherein fluorite, marble and Alpha-alumina form basic slag system, nickel-base strip is EQNiCrMo-3 welding, EQNiCrMo-3 welding and this sintered flux together use, and feature of the present invention is:

Sintered flux proportioning all is by weight: 38 ~ 48 parts, fluorite, 1 ~ 5 part, marble, Alpha-alumina 28 ~ 34 parts, zircon sand 1 ~ 4 part, sodium fluoride 1 ~ 3 part, pure KP1 17 ~ 21 parts, alloy powder 1 ~ 2 part;

Above-mentioned fluorite CaF ₂wt% content requirement be: CaF ₂>=97.0, SiO ₂≤ 1.00, S≤0.010, P≤0.010, requires fluorite CaF ₂granularity be 80 orders;

Above-mentioned marble CaCO ₃wt% content requirement be: CaCO ₃>=99, S≤0.010, P≤0.010, requires marble CaCO ₃granularity be 60 orders;

Above-mentioned Alpha-alumina Al ₂o ₃wt% content requirement be: Al ₂o ₃>=99, S≤0.030, P≤0.030, require Alpha-alumina Al ₂o ₃granularity be 80 orders;

Above-mentioned zircon sand ZrSiO ₄wt% content requirement be: ZrO ₂>=60, SiO ₂>=32, S≤0.050, P≤0.010, requires zircon sand ZrSiO ₄granularity be 80 orders;

The purity requirement of above-mentioned sodium fluoride NaF is: NaF >=99.0, requires that the granularity of sodium fluoride NaF is 60 orders;

The wt% content requirement of above-mentioned pure KP1 is: K ₂o>=12.6, SiO ₂>=26.2, S≤0.010, P≤0.010, requires that the modulus of pure KP1 equals 3.2, and Baume degrees when 20 DEG C equals 37 ~ 40 ° of Be ';

Above-mentioned alloy powder is made up of nickel powder and chromium powder, nickel powder: chromium powder=1:1;

According to said ratio fluorite, marble, Alpha-alumina, zircon sand, sodium fluoride and alloy powder be dry mixed and stir, add pure KP1 afterwards carry out wet mixing granulation and stir, drying oven is put in described wet mixing granulation and carries out low temperature drying, the temperature of low temperature drying controls at 300 DEG C, and then move in high temperature sintering furnace and carry out high temperature sintering, the temperature of high temperature sintering controls, at 650 ~ 700 DEG C, to sieve and can prepare sintered flux after high temperature sintering through 20 ~ 100 orders.

Owing to adopting technical scheme described above, the present invention produces following good effect:

1) sintered flux of the present invention has that granulation is good, uniform granularity, yield rate are high, and solder flux production technology is excellent.

2) sintered flux of the present invention and the together welding of EQNiCrMo-3 welding, within the scope of certain welding parameter, its welding process is stablized, and the weld seam removability of slag is good, and welding bead shaping surface is attractive in appearance, and edge wetting effect is good, scrap (bridge) place transitions smooth.

3) sintered flux of the present invention and the together welding of EQNiCrMo-3 welding, surfacing layer metal chemical composition stability, the constituent contents such as C, Si, S, P control at reduced levels.

4) sintered flux of the present invention and the together welding of EQNiCrMo-3 welding, overlay cladding has good intergranular corrosion resistance performance, and bending flawless produces.

Detailed description of the invention

The present invention is the preparation method of a kind of nickel-base strip pole sintered flux for submerged arc welding.

Containing fluorite, marble, Alpha-alumina, zircon sand, sodium fluoride, alloy powder and pure KP1 in sintered flux of the present invention.Sintered flux of the present invention and EQNiCrMo-3 welding together use.

In sintered flux, the Main Function of each component is summarized as follows:

Fluorite CaF ₂main as slag former, be the main component of slag.CaF ₂fusing point low, slag surface tension force can be reduced, improve slag fluidity, appropriate CaF ₂the viscosity of slag can be guaranteed rightly, improve the shaping of weld seam.CaF ₂the fluorine gas decomposing generation in high temperature environments can reduce the hydrogen dividing potential drop of arc zone, reduces weld seam diffusible hydrogen content.CaF ₂the too low meeting of content causes viscosity coefficient of dross to increase and easily produces the defects such as undercut, CaF ₂during too high levels its molten slag excess liquidity, appearance of weld is obviously deteriorated.CaF in the present invention ₂weight portion control 38 ~ 48 parts of its best results.

Alpha-alumina Al ₂o ₃main as slag former, Al ₂o ₃fusing point high, oxidisability is low, can change the fusing point of solder flux, viscosity and mobility, and can not the alloying element in weld seam be oxidized in a large number and cause dry slag.Al ₂o ₃with CaF ₂the desulphurizing ability of solder flux can be improved when coexisting.The Al of certain content ₂o ₃can also refinement face of weld crystallization streakline, improve appearance of weld.Al appropriate in solder flux ₂o ₃can obviously improve its removability of slag, too high levels causes slag to solidify prior to deposited metal, causes face of weld to produce impression and pore, and content is too low causes that viscosity coefficient of dross is too little, excess liquidity, and appearance of weld unsightly.Al in the present invention ₂o ₃weight portion control 28 ~ 34 parts of its best results.

Marble CaCO ₃be slag making main component, the basicity of solder flux can be improved, there is good desulfurization, dephosphorization and stabilising arc effect simultaneously.CaCO in the present invention ₃weight portion control 1 ~ 5 part of its best results.

Zircon sand ZrSiO ₄be mainly used in regulating viscosity coefficient of dross, improve the removability of slag.ZrSiO in the present invention ₄weight portion control 1 ~ 4 part of its best results.

Sodium fluoride NaF is a kind of low melting point fluoride, and shoddye effect is more obvious, adds the viscosity and mobility that also can regulate slag bath in right amount, improves weld edge angle of wetting.The sodium ion of low ionization potential can improve the stability of electric arc.The weight portion of NaF controls 1 ~ 3 part of its best results in the present invention.

Alloy powder mainly participates in deoxidation, improves the removability of slag, prevents face of weld oxidized.Simultaneously alloy powder add the scaling loss can supplementing alloying element in welding process, ensure the chemical composition of deposited metal, high temperature oxidation resisting and decay resistance.The weight portion of alloy powder controls 1 ~ 2 part of its best results in the present invention, and alloy powder is made up of nickel powder and chromium powder, nickel powder: chromium powder=1:1.

Sintered flux proportioning all is by weight: 38 ~ 48 parts, fluorite, 1 ~ 5 part, marble, Alpha-alumina 28 ~ 34 parts, zircon sand 1 ~ 4 part, sodium fluoride 1 ~ 3 part, pure KP1 17 ~ 21 parts, alloy powder 1 ~ 2 part.

According to technical scheme proportioning of the present invention, now enumerate five embodiments as following table.

Numbering	Embodiment 1	Embodiment 2	Embodiment 3	Embodiment 4	Embodiment 5
						Fluorite	44	42	38	43	48
Alpha-alumina	30	31	34	30	28
						Marble	5	3	1	2	3
Zircon sand	1	2	1	4	2
						Sodium fluoride	1	2	3	1	1
Alloy powder	1	1	2	2	1
						Pure KP1	18	19	21	18	17

According to upper table described proportioning fluorite, marble, Alpha-alumina, zircon sand, sodium fluoride and alloy powder be dry mixed and stir, add pure KP1 afterwards carry out wet mixing granulation and stir, drying oven is put in described wet mixing granulation and carries out low temperature drying, the temperature of low temperature drying controls at 300 DEG C, and then move in high temperature sintering furnace and carry out high temperature sintering, the temperature of high temperature sintering controls, at 650 ~ 700 DEG C, to sieve and can prepare sintered flux after high temperature sintering through 20 ~ 100 orders.

Above-mentioned 5 kinds of sintered fluxes together use with EQNiCrMo-3 welding respectively, and Mayari 15CrMoR steel plate carries out overlay welding experiment, and the thickness of 15CrMoR steel plate is 30mm, EQNiCrMo-3 welding specification is 60 × 0.5mm.Bead-welding technology reference parameter sees the following form.

The welding usability reference result of above-mentioned 5 kinds of sintered fluxes sees the following form.

Numbering	Welding stability	Appearance of weld	The removability of slag	Productivity
					Embodiment 1	▲	▲	■	●
Embodiment 2	●	●	●	●
					Embodiment 3	▲	■	●	●
Embodiment 4	▲	▲	■	●

Embodiment 5

●

■

▲

■

In upper table: ● represent good; ▲ represent general; ■ represents poor.

Cladding layer chemical composition the results are shown in following table.

Overlay cladding intercrystalline corrosion and bend test reference result see the following form.

Above-mentioned each table absolutely proves:

1) in raw material selection, select the raw material that the impurity contents such as S, P are lower as far as possible, comprise mineral, ferroalloy and waterglass, to reduce it to the transition in deposited metal, reduce the tendency of overlay cladding cracking.

2) consider from the physical property of slag, the proportioning of Reasonable adjustment fluorite, Alpha-alumina, marble and sodium fluoride, make slag have suitable fusing point, viscosity and surface tension, make overlay cladding have good mouldability.

3) ratio of deoxidation material in conservative control sintered flux, to control the oxidisability of sintered flux, while minimizing weld overlay alloy composition scaling loss, ensures that sintered flux has the good removability of slag.

4) a certain amount of zircon sand is added, due to ZrO ₂because phase variable volume can change a lot when from high temperature to low temperature, the slag detachability of sintered flux can be improved.

5) C, Si content in strict control deposited metal.Carbon and silicon dominate the pick-up behavior in deposited metal, and the generation of grain boundary carbide and Laves phase (rich Si) is the major reason that overlay cladding corrosion among crystalline grains declines, and therefore needs C, Si content strictly controlled in deposited metal.The test reference data of above-mentioned each table shows: C content is less than 0.03%, Si content and is less than 0.35%, can significantly improve its decay resistance.

To sum up, the sintered flux prepared by the present invention, its welding usability is good, and mate corresponding welding welding, cladding layer chemical composition meets the requirement of ASMEA5.14EQNiCrMo-3.Adopt ASTMG28A method Huey test result good, corrode laggard line bend test flawless and produce, meet instructions for use.

Claims (1)

1. the preparation method of a nickel-base strip pole sintered flux for submerged arc welding, containing fluorite, marble, Alpha-alumina, zircon sand, sodium fluoride, pure KP1 and alloy powder in this sintered flux, wherein fluorite, marble and Alpha-alumina form basic slag system, nickel-base strip is EQNiCrMo-3 welding, EQNiCrMo-3 welding and this sintered flux together use, and it is characterized in that:

Sintered flux proportioning all is by weight: 38 ~ 48 parts, fluorite, 1 ~ 5 part, marble, Alpha-alumina 28 ~ 34 parts, zircon sand 1 ~ 4 part, sodium fluoride 1 ~ 3 part, pure KP1 17 ~ 21 parts, alloy powder 1 ~ 2 part;

Above-mentioned fluorite CaF ₂wt% content requirement be: CaF ₂>=97.0, SiO ₂≤ 1.00, S≤0.010, P≤0.010, requires fluorite CaF ₂granularity be 80 orders;

Above-mentioned marble CaCO ₃wt% content requirement be: CaCO ₃>=99, S≤0.010, P≤0.010, requires marble CaCO ₃granularity be 60 orders;

Above-mentioned Alpha-alumina Al ₂o ₃wt% content requirement be: Al ₂o ₃>=99, S≤0.030, P≤0.030, require Alpha-alumina Al ₂o ₃granularity be 80 orders;

Above-mentioned zircon sand ZrSiO ₄wt% content requirement be: ZrO ₂>=60, SiO ₂>=32, S≤0.050, P≤0.010, requires zircon sand ZrSiO ₄granularity be 80 orders;

The purity requirement of above-mentioned sodium fluoride NaF is: NaF >=99.0, requires that the granularity of sodium fluoride NaF is 60 orders;

The wt% content requirement of above-mentioned pure KP1 is: K ₂o>=12.6, SiO ₂>=26.2, S≤0.010, P≤0.010, requires that the modulus of pure KP1 equals 3.2, and Baume degrees when 20 DEG C equals 37 ~ 40 ° of Be ';

Above-mentioned alloy powder is made up of nickel powder and chromium powder, nickel powder: chromium powder=1:1;

According to said ratio fluorite, marble, Alpha-alumina, zircon sand, sodium fluoride and alloy powder be dry mixed and stir, add pure KP1 afterwards carry out wet mixing granulation and stir, drying oven is put in described wet mixing granulation and carries out low temperature drying, the temperature of low temperature drying controls at 300 DEG C, and then move in high temperature sintering furnace and carry out high temperature sintering, the temperature of high temperature sintering controls, at 650 ~ 700 DEG C, to sieve and can prepare sintered flux after high temperature sintering through 20 ~ 100 orders.