JPS5823596A - Method for horizontal electroslag build-up welding by tubular wire - Google Patents

Abstract

PURPOSE:To secure an effective build-up welding layer from the first layer and obtain the high-hardness build-up layer without cracks, by setting components of an included flux, the ratio of the included flux to a tubular wire, the electric conductivity index of a slag making agent, etc. with proper ranges. CONSTITUTION:A lag making components in an included flux is >=10%, and the ratio of the included flux to the overall quantity of a tubular wire is 10-70%, and the content of slag making components calculated by the equation is Ki%, and the tubular wire contains 20-60% CaF2, 2-20% CaO or CaCO3, 5-30% SiO2, and 10-50% one or more of TiO2 and ZrO2. In expressions, Ei(%) is the sum of components (i) supplied from the tubular wire and the flux, and Ai (%) is the content of components (i) in the flux, and B (g) is the weight of the included flux, and C (g) is the weight of the tubular wire, and Di (%) is the content of component (i) in the included flux, and SIGMAEn (%) is the total sum of the slag making agent. An electric conductivity index indicated in expression is set within 2.5-5.5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a horizontal electroslag build-up welding method using tubular wire, in particular keeping the dilution rate low, ensuring an effective build-up layer from the first layer, and creating a hard build-up layer. The present invention relates to a horizontal electroslag welding method that can obtain the following properties without cracking.

In overlay welding, which involves welding dissimilar materials onto low-lying base materials, whether hard overlay or corrosion-resistant overlay, it is economical to keep the dilution rate low and secure an effective overlay layer as quickly as possible. Don't wait for arguments. Therefore, compared to the conventional submerged arc welding method using round wire, a submerged arc welding method using a strip electrode, which can keep the dilution rate much lower, was developed and has become the mainstream automatic welding method. It has not yet been possible to obtain an effective build-up layer for the first layer, so countermeasures have been taken, such as using a strip-shaped electrode with a high alloy content for the first layer.

Horizontal electroslag welding using a strip electrode was developed to improve these points, and the dilution rate was reduced to 10.
% or less, and it has become possible to secure an effective build-up layer from the first layer without using a strip electrode containing an excessive amount of alloy components.

In this way, current flows over a wide range in a wide strip electrode, and it is possible to flow a large current.
Electroslag phenomenon can be exhibited relatively easily.

However, when trying to apply the horizontal electroslag welding method using a wide strip electrode to the field of hardfacing, there are restrictions on the addition of alloys to the flux for horizontal electroslag welding, so it is difficult to add any alloys to prevent oxidative wear. In order to obtain a high-hardness build-up layer, it is necessary to add hardening elements to the strip-shaped electrode, and the rolling properties of the strip-shaped electrode deteriorate significantly, so it cannot be used as a factory product. However, in the field of corrosion-resistant overlay, the production of band-shaped electrodes that could produce overlays of any hardness was at most Hv 400. Various difficulties were often encountered when performing construction using the strip electrode method, such as overlay welding of narrow pipes.

In view of the above-mentioned problems, the present inventors have conducted a number of studies to improve the problems. As a result, the slag-forming agent component in the flux contained in the tubular wire, the ratio of the contained flux to the tubular wire, Agent Dendenden 24#
This is a completely new finding that horizontal electroslag welding can be easily performed and a build-up layer with high hardness can be obtained even when using a consumable electrode with a small cross-section such as a flux-cored wire, provided the index is within the appropriate range. The present invention was achieved by obtaining the following.

That is, the gist of the present invention is a method of horizontal electroslag overlay welding using tubular wire and 7lux, in which the slag-forming agent component in the flux contained in the tubular wire is 10% or more, and The ratio of the included flux to the total amount of wire is 1o to 'i'o5A, and the converted content ttKi of the slag-forming agent component in one or both of the flux and tubular wire is C! aF220-60%, CaO or C! a
0032~20%, 5i025~30%, one or two types of TiO2 or ZrO2 total 10~50%,
or further A-/-203+MfO or Mn
A horizontal electroslag overlay welding method using a tubular wire, which contains one or more types of O and a total of 20% or less of O, and has an electrical conductivity index F expressed by equation (2) of 2.5 to 5.5. It is in.

1 Ki = -X100 ... (1) ΣKn where Ei: Ai + 1.1 (-XDi) K1: Converted content of 1 component (%) El: 1 component supplied from tubular wire and flux Sum (%) A1: Content of one component in flux (%) B: Weight of embedded flux (2) C: Weight of tubular wire (2) Dl: Content of one component in embedded flux (%) ΣEn
: Total sum of slag forming agents (%) F=exp(1,9111,38Gx-5,690"x
)...(2) Gx = 0.0036CaO (wt%) 10, OO12EliO2 (wt%) + 0.0063Ti
02(wt%) +○,0041Z r 02(wt
%)+0.0098AtzOa (W t%) F: Electrical conductivity index The present invention will be described in detail below.

First of all, the reason why the slag forming agent component in the flux contained in the tubular wire is 10% or more and the ratio of the contained flux to the total amount of the tubular wire (hereinafter referred to as filling rate) is 10 to 70% is that If the slag component in the slag is less than 10% and the filling rate is less than 10%, the slag that produces an effect similar to that of a solid wire is generated substantially only from the flux and has a small cross-sectional area. In the case of horizontal electroslag welding using a round wire, which is much smaller than a strip electrode and cannot carry a large current, the slag bath depth is shallow, which causes the wire to penetrate too far, causing an arc and making it difficult to perform satisfactory electroslag welding. This is because.

Furthermore, even if an electroslag phenomenon occurs and welding is possible, most of the energy is consumed in melting the wire because the current flows through the thin wire in a concentrated manner at one point, which is necessary to melt the wire into an electroslag state. The melting of the flux and the formation of a slag bath are delayed, and if an attempt is made to form a slag bath sufficient to maintain the electroslag state,
If the wire has to be melted excessively and the welding amount is excessive and overlaps, and the next pass is welded, defects such as slag entrainment will occur, making it difficult to perform sound welding.

On the other hand, when the slag component in the flux is 10% or more and the flux filling rate is 10% or more, the components that form the slag bath are supplied as the wire melts, and the flux melts and In combination, a slag bath sufficient to maintain the electroslag welding phenomenon can be formed, and an appropriate amount of welding can be ensured, so that welding defects as described above do not occur and sound welding is possible. Further, if the flux filling rate exceeds 70z, the productivity of the tubular wire will drop significantly, which is not preferable.

The slag forming agent referred to here refers to oxides other than alloying agents and deoxidizers added in the form of metal powder 1 alloy powder, etc.

It is a general term for fluorides, carbonates, etc. In addition, in the case of the welding method of the present invention, the slag forming agent components are supplied from the flux shear wire and the flux, so each component can be added from either source, and when the slag boule is formed, it will have the desired components. It is good if it is. In the case of the welding method of the present invention, the melting ratio of wire and flux is approximately:
1.1, the required converted content is 1 as shown in equation (1).

K1: Converted content of one component (%) El: Sum of main components supplied from tubular wire and flux 6) A1: Content of one component in flux (light) B Weight of two included flux Cf) C: Weight of tubular wire (2) Dl: Content of one component in the included flux G) Σ]lCn: Total sum of slag-forming agents (%) Of the slag-forming agent components, Ca1F2 is the main component because of its electrical conductivity. This is because it is an essential component for maintaining a good □ and stable electroslag welding. By mixing 20% or more, continuous generation of shear arc can be suppressed. However, - CaF2 alone has too high electrical conductivity and poor welding workability, so it is necessary to add other ingredients to maintain electrical conductivity within an appropriate range.In order to maintain good surface welding workability, The electrical conductivity of a slag whose main component is 0CaF2, which requires an upper limit of 60X, is generally expressed by Equation (3) by Mr. Ogino.

K(Ω-”an')=exp(1,911-1,3
8Nx-5,a9Nfi)+0.39(t-1973)
・ ・ ・ ・ A3) N FNAZ203
+” N (! a O+O0'l 5 N Ej i
c+2+0.5()IT102+Nzro2)t:1
823-2053°k NAt, o3. NCaO, N1310z, NTi0z+
NZrO3 is A 1203 t c a Or S i
o2 HT ” 21Molar fraction of Zr02 However, equation (3) has a term that depends on temperature, so it is not suitable for horizontal electroslag bath welding, especially when there are large temperature changes such as small welding in a slag bath with a round wire. Therefore, as shown in the following formula, OF' = exp (1,91
1-4,38Gx-5,690”x) ・-・(IGx
==0.0036CaO(wt%)+0.001281
o2(wt%) + 0.00637 i o2(w
t96) + 0.0041Zr02 (wt%) + 0.0
098At*Os (wt%) P: Electrical conductivity index The coefficients of each component for calculating Gx in equation (2) are all values obtained by Mr. Ogino (Japan Institute of Metals Bulletin Vol. 18, 10, 1979) and changed the mot fraction display to weight % display to simplify calculations.

The relationship between electrical conductivity index F and penetration rate is shown in the town map.

In this case, fluorite 55h is used as the tubular wire.

An encapsulated flux containing 7% ferrosilicon, 14% metal manganese, and 24% chromium carbonate was encapsulated in an annealed copper band at a filling rate of 30 yb, and a wire diameter of 3.2 mm was used. Also, the flux is CaF2 20-6
Set to 0% range Ca0,8102°T i 02
By changing the blending ratio of At20s, various electrical conductivity indexes F can be obtained. If the electrical conductivity index F is small and approximately 1.8 or less, an arc will occur and normal submerged arc welding will fail. The penetration rate in the visible region is 30-40%, which is similar to normal arc welding. Next, there is a mixed region (arc + electroslag) in the range of F = 1.8 to 2.5, and the penetration rate also decreases rapidly as the proportion of electroslag phenomenon increases10
It will be around %. Next, when the value of F becomes 2.5 or more, it becomes a complete electroslag region, and the penetration rate becomes low and stable. In view of this phenomenon, it is necessary to set the F value to 2.5 or more in order to obtain a built-up layer with a low penetration rate by the welding method of the present invention, but if the F value is 5.5 or more, If this happens, the welding workability will deteriorate rapidly, so the electrical conductivity index F
must be in the range of 2.5 to 5.5.

Next, (!acO3 has a reducing atmosphere of CO2 gas generated by thermal decomposition due to welding Joule heat, which effectively shields the molten part from the atmosphere and prevents the intrusion of oxygen, hydrogen, nitrogen, etc.). Its decomposition product C
aO forms a strongly basic slag and can be expected to have a refining effect. In this case, electroslag welding is required, and the area around the weld is filled with molten slag, which does not necessarily produce a large amount of CO2.
It is not necessary to maintain the atmosphere with gas, but rather the effect of OaO on the slag refining action is required, so Ca
It is also possible to replace C03 with CaO. Also, Ca
Since O itself is a factor that influences the electrical conductivity index F of the slag, it can also be expected to have the effect of maintaining an appropriate electrical conductivity index in relation to other factors. If CaO or caco3 is less than 2 mm, the above effect cannot be expected and the yield of the alloy will be low. Moreover, if the content exceeds 20%, the slag becomes too basic and the viscosity of the slag increases too much, impairing welding workability, so the content should be limited to 2 to 20%.

If 5102 is added in an amount of 5% or more, the fluidity of the slag will improve and stable welding will be possible. However, if the amount exceeds 30%, 81 will be excessively included in the weld metal, so 5 to
The electrical conductivity index F should be controlled within a range of 30 degrees.

TlO2 and ZrO2 can maintain good fluidity of the slag, widen the bead width, and stabilize the transfer of droplets.
This is effective in stabilizing the melt pool, but TlO
If the total amount of one or both of ZrO□ and ZrO□ is less than 10%, the effect cannot be expected. However, if it exceeds 50%, the fluidity of the slag becomes too large and the bead shape tends to become disordered, so it is necessary to keep it below 50%, and the electrical conductivity index F must also be controlled within this range. Should.

Furthermore, one or more of A1O3, MfO, and MnO is added to the above-mentioned slag-forming agent.
It can be added for the purpose of increasing the viscosity of the slag and improving the peelability of the slag, but if it exceeds 20%, the slag viscosity will become excessive and the bead shape will become poor.
% or less.

Incidentally, the method for producing flux may be any one of melting method, sintering method, and baking method.

Also, considering the productivity of the wire, mild steel is suitable for the hoop material used for tubular wire, but when the purpose is to add alloying agents, ferritic stainless steel and austenitic stainless steel are also commonly used. used.

The effects of the present invention will be illustrated in more detail by way of examples below.

The base material of the example was 8M41B (thickness 20 mm) shown in Table 1 in all tests.
■) was used. The welding conditions are shown in Table 2. Table 1: Base materials used: Table 2: Welding conditions: Table 3: Tubular wire used; Table 4: Melt flux used.

For comparison, tubular wire W-1 having a filling rate outside the range of the method of the present invention and a ratio of slag forming agent to the included flux
Tests were conducted using wires No. 1, W-12, W-13, and solid wire W-14, but in all cases the wires penetrated too far and a healthy pead was not formed, so subsequent tests were discontinued.

Table 5 shows the results of welding tubular wires W-1 to W-10 and fluxes F-4 to F-8 in appropriate combinations.

Flux F-6 and wire W-4 shown as comparative examples
and W-9, and the combination of fluxes F-8 and W-4, the wire penetrates too much, arcing occurs, and sound horizontal electroslag welding is impossible.

Also, flux F-7 and wires W-1, W-5 and W-
The combination with S exhibits an electroslag welding phenomenon, but the welding phenomenon is unstable because the slag has too good electrical conductivity, and the bead shape deteriorates.

In comparison, the examples of the present invention exhibited stable welding workability and showed good results with no cracks occurring in the welded 1JiX.

As explained in detail above, the method of the present invention is excellent in that it enables horizontal electroslag welding using a round wire, which was previously difficult due to the shallow depth of the slag bath.

Note 1) % l CaF2 98.4% %16 c
o 99.3%%2 (!ao 55.4%
Arrow 17 F'e9B, Q% Yellow 3 At203 99
．． 3% → (-5Mt09), 9 Taroya 60 99.6% ≠8 J Engineering 8F813 (8142,3%) -%9,
T work day MMnE (Mn 99.9%) arrow 1ON199
．． 5%%n, Tl8 MOr(Or 99.8″A)%1
2 09.5%, 0r88.5% Arrow 13J Work Day FMoL (Mo62.1%) -%14J Work SF FV 2 (V 52.3%) Arrow 15 W 99
．． 1% 0.31%.

1/f18 The composition of the steel strip is 0 81 Mn Or NiO,020,2
21.7B 24.2512.27 Note 3) Wire diameter is 3.2mm

[Brief explanation of drawings]

The drawing is a graph showing the relationship between the electrical conductivity index F and the penetration rate. Applicant Nippon Seikatsu Co., Ltd.

Claims (2)

[Claims] (1) A method of horizontal electroslag welding using tubular wire and flux, in which the slag-forming agent component in the flux contained in the tubular wire is 10%.
In addition, the ratio of the included flux to the total amount of tubular wire is 10 to 70%, and either or both of the flux and tubular wire contains the converted sludge component calculated by formula (1). ~6
0%, CaO or 0aO032N20%, 810
15 to 30%, Ti (h 4 L< contains 10 to 50% in total of one or two types of ZrO2, and the electrical conductivity index expressed by the formula (2) is 2.5 to 5.5. A horizontal electroslag build-up welding method using tubular wire, which is characterized by Harmony of ingredients) A1: Contains 1 ingredient in 2 lux! (%) B: Weight of embedded flux IL'<9) C: Weight of tubular wire (f) Dl: Content of one component in embedded flux) ΣEn: Total amount of slag forming agent) 1=exp(1 ,911-1,38G!-5,690"
IC) ・-・(2)G)C:0.0036CaO(w
t%) + 0.0012810g (wt%) + 0.006
3TiO1 (wt%) 10.0041Zr02 (wt%
) + o, o O98A 1xoscvn:A )F
: Electrical conductivity index (2) A method of horizontal electroslag welding using tubular wire and flux, in which the slag forming agent component in the flux contained in the tubular wire is 1.0
% or more, and the ratio of the included flux to the total amount of tubular wire is 10 to 70%, or the converted content of the slag component calculated by formula (1) in one or both of the tubular wires. 1 and Ca'F22
0-60%, CaO or CaC! 032~20%,'8
1025 to 3.0%, and a total of 10 to 50% of one or both of TiO2 or ZrO2, and further At2032M
Contains one or more types of tO or MnO in a total of 20% or less, and has an electrical conductivity index y shown by formula (2) of 2.5 to 5.
．． 5. A horizontal electroslag overlay welding method using tubular wire. Ki= -X100 (1) ΣF
in Here, Ei = A soil + 1.1 (-XDi) K1: Converted content of 1 component) Ki, Qi'-7'5 Sum of soil components supplied by wire and flux (%) A1: In flux B: Weight of embedded flux (2) C: Weight of tubular wire (2) Dl: Content m (%) of one component in embedded flux ΣEn: Total sum of slag-forming agent (4) F = exp(1,911-1,38Gx-5,69G
2X)...(2) Here Gx=0.0036C! ao
(wt%) +0.0.0128102 (wt,%),
+O, OO63T i o2(wt76t+0.004
1Zr02(wt%)+o,oo9sAt203CWt
ratio) F: Electrical conductivity index