JPS62183994A - Wire for gas shielded arc welding of stainless steel - Google Patents

Abstract

PURPOSE:To improve weldability and the quality of a weld metal by specifying the contents of Si and S in a wire compsn. and limiting the contents of Al, Ca, and Mg. CONSTITUTION:The compsn. of the wire for welding is made to contain, weight %, <=0.15% C, <=1% Si, <=2.5% mn, 11-32% Cr, <=22.5% Ni, <=4% Mo, 0.004-0.015% S, is limited to <=0.01% O, >= (SiX0.03%) Al, <=0.005% Ca, <=0.005% Mg and is composed of the balance mainly Fe. N is further added at <=0.50% thereto according to need. A stable arc is obtd. in MIG welding and a good bead shape is obtd. if the wire for gas shielded arc welding of stainless steels having such compsn. is used. The generation of the slag in TIG welding is decreased and the strength and corrosion resistance of the deposited metal are improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a stainless steel gas-shielded arc welding wire, and particularly to a stainless steel welding material that has excellent weldability and can obtain high-quality weld metal. It is something.

[Conventional technology]

Stainless steel has excellent rust resistance, corrosion resistance, heat resistance, etc., and is widely used as a material for chemical machinery, heat-resistant parts, etc. Covered arc welding has been the most widely used welding method to date, but a method with high efficiency and high quality is required. Gas shielded arc welding is a method for this purpose. Gas-shielded arc welding includes consumable electrode methods such as MIG welding in which the wire itself serves as an electrode, and non-consumable electrode methods such as TIG welding in which a tungsten electrode is used. M
IG welding is widely used because the equipment is easy and it can perform not only semi-automatic welding but also automatic welding and is highly efficient, but the wire itself acts as an electrode and generates an arc.
The weld metal is transferred as droplets due to arc heat, but in general: 1) It is difficult to maintain a stable arc condition and it tends to become unstable.

2) The bead shape is poor and the bead tends to become convex.

3) Welding defects such as poor fusion are likely to occur.

There is a tendency that reliability is inferior.

Japanese Patent Application Laid-open No. 1983 (1983) on arc stability in MIG welding
JP-A-165589 discloses that as the B and AN contents in the wire increase, the arc instability region becomes wider. Al is added as a deoxidizer, and
If N is regulated, deoxidation will be insufficient and 0 will tend to increase.

Regarding the influence of zero in the wire on MIG welding workability, Japanese Patent Application Laid-Open No. 58-202993 discloses that zero contributes to improving welding arc stability and bead shape. However, when the amount of O in the wire increases, workability deteriorates in the wire manufacturing process. In particular, when rolling and wire drawing are carried out at high speeds, this tendency becomes noticeable, resulting in problems such as deterioration of workability, reduction in efficiency, and increase in cost. Further, it is extremely difficult to uniformly contain more than 0.01% of 0 in the wire in terms of the steel manufacturing process, and is not practical.

Furthermore, in JP-A-58-202993, Ca, Mg and rare earth elements (R) are added to the wire in RIG welding.
It has been disclosed that slag removal can be improved by adding an appropriate amount of EV), but TIG? The effect of slag on the 8th tangent has not been clarified so far.

TIG? In the 8-junction, an arc is generated using a non-consumable tungsten electrode, and a wire is inserted into a molten pool formed by the heat of the arc and melted to form weld metal. If slag does not occur on the weld metal surface, a stable arc condition is obtained and the weld metal spreads well. However, if slag that is difficult to peel off occurs on the weld metal surface, the arc is disturbed by the slag and the weld metal The spread of welding becomes worse, and welding defects such as poor fusion are more likely to occur. Another problem is that it is necessary to remove the slag using a grinder or the like.

[Problem that the invention seeks to solve]

The object of the present invention is to
In consumable electrode type gas shielded arc welding such as 6 contacts, it has excellent arc stability, good bead shape, and TI
In non-consumable electrode type gas shielded arc welding such as G welding, there is less generation of slag that disturbs the arc and causes welding defects such as poor fusion. It is an object of the present invention to provide a welding wire that can be applied, has a good yield in the wire manufacturing process, and is low in cost.

[Means for Solving the Problems] The present inventors have discovered that in such gas-shielded arc welding, a welded part with excellent arc stability, good bead shape, and few welding defects can be obtained, and in addition, wire manufacturing As a result of investigating welding wires with good yield and low cost in the process, we found that Al plays a large role in the stability of the arc in MIG welding, but the allowable amount of Al is not determined uniformly. We found that the permissible content of An changes depending on the Si content, and that S is significantly involved in improving the bead shape. By including Ca and Mg, the arc stability is excellent and the bead shape is also improved.In addition, Ca and Mg prevent the generation of slag that disturbs the arc during TIG welding and causes welding defects such as poor fusion. By regulating these elements, it is possible to prevent the generation of slag that disturbs the arc.Also, when there are too many zeros in the wire, workability deteriorates in the wire manufacturing process and efficiency decreases. However, by regulating 0, the workability is improved,
It has been found that efficiency can be improved. Furthermore, by adding an appropriate amount of N to such a composition, in consumable electrode type gas shielded arc welding such as MIG welding, excellent arc stability and good bead shape can be achieved, and non-consumable electrode type gas shielded arc welding such as TIG welding can be achieved. It has been found that during welding, almost no slag is generated, and the strength and corrosion resistance of the deposited metal are improved.

That is, the gist of the present invention is that C: 0.15% by weight
Below, 5il1% or less, Mn: 2.5% or less, Ni: 2
2.5% or less, (:r: l l ~32%, MOF
Less than 4%.

S: Contains 0.004-0.015%, 0:0
．． 01% or less, A1 5iX (1,03% or more F, Ca
: fl, 01) 5% or less, Mg: limited to 0.005% or less, or C: 0.15% or less, 5i11
% or less, Mn: 2.5% or less.

Ni: 22.5% or less, Cr: I1~32%, M
o: 4% or less, S: 0.004-0. (l l 5%
, and N: 0.5% or less, O: 0.01% or less, Ca: 0.005% or less, 1 Mα: 0.005%
The following describes a stainless steel gas-sealed l-arc welding wire characterized in that Al is limited to 5ix0.03% or less, and the remainder is mainly Fe.

The present invention will be explained in detail below.

[For production]

First, in the present invention, gas-shielded arc welding is "1'-re welding" performed in an atmosphere containing an inert gas such as ^r, Ile, or a small amount of active gas added thereto. Refers to MIG welding, IG welding, and plasma welding.

Next, the reasons for limiting the composition of the wire of the present invention will be described. First, C increases strength, but if it exceeds 0.15%, workability deteriorates in the wire manufacturing process, so 0.1%
5% or less.

Next, Si improves oxidation resistance and improves the full flow of weld metal. If it exceeds 1%, workability deteriorates in the wire manufacturing process, so it is set to 1% or less.

Mn is added as a deoxidizing and desulfurizing agent, but if it is too large, it deteriorates corrosion resistance and oxidation resistance, and also deteriorates workability in the wire manufacturing process, so it is limited to 2.5% or less.

Ni is an austenite-forming element that stabilizes austenite and improves corrosion resistance and toughness, but high Ni deteriorates workability in the wire manufacturing process.
．． 5% or less.

Cr is an essential component of stainless steel, forming a passive film and improving oxidation and corrosion resistance, but if it is less than 11%,
If the properties cannot be maintained sufficiently and Cr exceeds 32%, sigma phase precipitation tends to occur, resulting in poor workability in the wire manufacturing process, so it is set at 11 to 32%.

Mo strengthens the structure and improves corrosion resistance and creep strength, but if it exceeds 4%, it promotes the formation of sigma phase,
Since ductility decreases and workability deteriorates in the wire manufacturing process, the content is set to 4% or less.

S increases the conformability of the weld metal and improves the bead shape, but if it is less than 0.004%, the effect is small;
If it exceeds 0.015%, workability will deteriorate in the wire manufacturing process and efficiency will decrease, so 0.004 to 0.015%
shall be. If the amount of O in the wire increases, the workability will deteriorate in the wire manufacturing process and the yield will decrease, so 0.01
% or less.

Although Al is effective as a deoxidizing agent, it makes the arc unstable in MIG welding, and its range is correlated with the Si content. When Si is high, the allowable range of Al affecting arc stability becomes wider, but if it exceeds 5iX0.03%, the arc becomes unstable, so the upper limit is set to 5iX0.03%.
%. In TIG welding and plasma welding, slag that is difficult to peel off is generated widely on the weld metal surface, the arc is disturbed by the slag, the spread of the weld metal is poor, and welding defects such as poor fusion are more likely to occur.
, limited to oos% or less.

M is also limited to 0.005% or less in TIG welding and plasma welding, as slag is generated, the arc is disturbed by the slag, the spread of the weld metal is poor, and welding defects such as poor fusion are likely to occur. .

N improves the strength and corrosion resistance of weld metal, but 0
．． Even if it is added in excess of 5%, no significant effect will be obtained, and the processability will be poor in the wire manufacturing process.
．． 5% or less.

Here, referring to the method for manufacturing the wire of the present invention,
The ingot obtained by melting and casting in a vacuum or atmospheric atmosphere is hot-forged, then hot-rolled into a coil, which is then cold-drawn to a specified diameter. be. Note that hot forging and hot rolling are performed by heating to about 1000 to 1200°C, and in the cold wire drawing process, if necessary,
The hardness of the wire can be adjusted by annealing at about 'C.

Hereinafter, the effects of the present invention will be described in more detail with reference to Examples.

〔Example〕

Table 1 shows the chemical composition of the test welding wire.

Table 2 shows the chemical components of the base materials used.

Table 3 shows the welding workability test results. The welding workability test was conducted for MIG welding and TIG welding. The combinations of the test welding wires and the base materials used are as shown in Table 3, and the base materials used in each case were plate thickness 6, width 75, and length 40.
It had a dimension of 0 m and was used by setting it in a restraint jig.

Table 4 shows MIG welding and TIG welding conditions. In each case, approximately 350 beads were welded using a straight rod and the welding workability was evaluated.

Table 5 shows the evaluation of wire workability in the wire manufacturing process.

From the above, A1-A21 of the present invention has excellent arc stability and good bead shape in consumable electrode type gas shielded arc welding such as MIG welding, and has excellent arc stability and good bead shape in non-consumable electrode type gas shielded arc welding such as TIG welding. It generates less slag, which can disturb the arc and cause welding defects such as poor fusion, and can be applied to consumable electrode methods, non-consumable electrode methods, or both, and has good wire processability in the wire manufacturing process. It is clear that this is a low cost welding wire.

On the other hand, comparison wire B1 has C exceeding 0.15%, B2 has Si exceeding 1%, and B3 has Mn exceeding 2%.
．． In B4, Ni exceeds 22.5%, in B5, Cr exceeds 32%, in B6, Mo exceeds 4%, and in B7, N exceeds 0.5%. In B8, S exceeds 0.015%, and in BIO, 0 exceeds 0.01%, and both have poor wire workability in the wire manufacturing process.

B9 had an S content of less than 0.004%, and the bead shape was poor in MIG welding. Bll is 309 series, B1
4 is 410 series, B15 is duplex stainless steel thread, both are Ai! was more than 5iX0.03%, and the arc was unstable in MIG welding, resulting in bead defects. B12 has Ca exceeding 0.005%, and B1
3 has Mg exceeding 0.005% and Isusere is also TI
In G welding, slag that is difficult to peel off was widely generated on the bead surface, and the arc was disturbed.

〔Effect of the invention〕

As is clear from the above examples, the wire of the present invention has MI
In consumable electrode type gas shielded arc welding such as G welding, it has excellent arc stability and good bead shape, and in non-consumable electrode type gas shielded arc welding such as TIG welding, it disturbs the arc and prevents welding defects such as poor fusion. It generates less slag, which can be a cause, and can be applied to consumable electrode method, non-consumable electrode method, or both.
In addition, it is a welding wire that has good wire processability in the wire manufacturing process and is low in cost, and its industrial effects are extremely significant.

Claims (1)

[Claims] 1. Contains, in weight percent, C0.15% or less, Si1% or less, Mn2.5% or less, Cr11-32%, Ni22.5% or less, Mo4% or lessS0.004-0.015%, and O0. A stainless steel gas-shielded arc welding wire characterized by being limited to 0.01% or less AlSi x 0.03% or less Ca 0.005% or less Mg 0.005% or less, with the remainder mainly consisting of Fe. 2.Contains C0.15% or less, Si1% or less, Mn2.5% or less, Cr11-32%, Ni22.5% or less, Mo4% or less, N0.50% or less, S0.004-0.015%, and O0.01. % or less AlSi x 0.03% or less Ca 0.005% or less Mg 0.005% or less, the remainder being mainly Fe.