JPS59209488A - Welding method of complete austenitic stainless steel - Google Patents

Abstract

PURPOSE:To prevent high-temp. cracking, etc. during welding of a titled stainless steel by using an Mg-contg. wire and applying specific AC excitation current to an excitation coil provided to the tip of a welding torch thereby oscillating and stirring a molten metal and forming finer crystal grains. CONSTITUTION:AC excitation current of 1-20Hz is passed to an excitation coil 7 wound around a magnetic conductor 6 at the tip of a torch which is a tungsten electrode 5 in TIG welding, etc. of a stainless steel lining plate 2 on a carbon steel 1 which is a base material. A voltage is impressed from a welding power source 8 between the electrode 5 and the plate 2 and DC welding current 9 is passed and at the same time a wire 11 is fed to form a molten metal. The current 9 flows radially from the electrode 5 to the molten metal and the plate 2. The molten metal is oscillated and stirred clockwise or counterclockwise by the Lorentz force generated when the excitation current is applied. Finer crystal grains of the molten metal 3 are thus formed and the complete austentic stainless steel is welded without high temp. crack.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of bath welding ferrite-free fully austenitic stainless steel.

In chemical-like equipment, chemical plants, nuclear-like equipment, etc.
In order to protect the corrosion resistance of high eaves and low temperature toughness, or to improve the rate to 7, welding metal strength of completely ausbunite stainless steel is required.

An example of a welded joint shape is shown in Fig. 1. FIG. 1(a) shows an example of a lining weld joint, and FIG. 1(b) shows an example of a butt welded lxr joint. In the figure, 1 is a base material of carbon steel, 2 is a stainless steel lining plate, 3 is a weld metal, and 4 is a stainless steel silver plate.

However, as shown in Figs. 2 and 3, the weld metal fake 3 is
As the amount of ferrite decreases, hot cracking D becomes more pronounced, and is most noticeable in fully austenitic stainless steels that do not contain any ferrite.

Methods to prevent this include reducing welding heat input or reducing impurity elements in the weld metal. However, these methods have drawbacks such as longer welding time and increased cost of welding materials. Therefore, the inventor of the present invention aimed to solve this problem (I
I inspected it thoroughly. As a result, it was found that stirring the weld at a frequency of 1 to 20 Hz flattens the bead shape, refines the crystal grains, prevents cracking, and prevents blowholes.

The present invention is based on this knowledge.
) Among the effects of stirring, high tij due to grain refinement
1. 1. Focus on the prevention of I'l in other ways.
: 14'fl fully austenitic thread stainless steel valley; high? 1i it l! Easy to use '1. '4'j:
fa″, with the aim of preventing it at low cost.
It is a ζ thing.

That is, according to the present invention, a completely austenitic stainless steel plate 1 is welded using a wire containing 3 to 7 tons of Mn, and a wire containing molten J? An alternating current excitation current of 1 to 20 Hz is applied to the coil provided at the tip of the torch, and the resulting elongation and Lorentz force caused by the welding current cause the melt fL"M?A"; The process of stirring the crystal grains by vibration to turn them into micro-a and 11 particles is referred to as ash υ11.

Hereinafter, I will explain the book-) [, Akira 111J to Winter> +Ki.

Figure 4 shows an example of applying the misfire method to TIG welding of stainless steel 'Ai' on the base metal 1 and lining plate 2. 5
1 ■ to the point of the torch,! , the excitation coil 7 wound around the body magnetically absent body is immersed, and the tungsten electrode 5 and the lining plate 2 are
A voltage is applied between the welding power source 8 and the welding current 9 as shown in FIG. 5, and the welding wire 11 is fed by the feeding roller 10 to form molten metal PA3'.

Further, in this method, an alternating current excitation current of 1 to 20 Hz as shown in FIG. 6 is caused to flow through the excitation coil 7 from an excitation power supply 12.

At this time, the welding current 9 is changed to tungsten 4 as shown by the solid arrow in both FIG. 7 (showing the case where the magnetizing current is positive) and FIG. 8 (showing the case where the magnetizing current is negative). The mud flows radially from the pipe 5 to the molten metal 3' and to the lining plate 2. When the trench excitation current is positive, a magnetic field is generated that goes from top to bottom as shown by the broken line in FIG. 7, and a stirring force that rotates to the left is generated due to the Lorentz force. Next, when the exciting current becomes negative, a magnetic field is generated from the bottom to the top, as shown in FIG. 8, and a clockwise stirring force is generated. Therefore, by repeating this at a frequency of 1 to 20 Hz, the molten metal 3' is stirred by vibration.

In this method, the frequency of the AC excitation current is set to 1 to 20 Hz. As shown in Figure 4 and 9, this 61) range reduces sieve temperature cracking during the Y valley removal process. In other words, Fig. 2 shows the magnetic lift frequency, gun yang (
The degree of temperature and the temperature of lTh in the welding metal are 1 to 1 (j indicates the yarn, from this 1 to 1).
In Hz, it can be seen that the larger the degree is, the more the temperature increases, the more the temperature increases.

As a wire JJ, there are 31 No. 4j including Mn 3 to 7 Shigechi; 1. Wire edible. In this case p, s.

Cuζ"j no, 1...1-11 light; ta illusion, 0.01
It is better to use 'jii,' or lower. In other words, Figure 10 shows the relationship between M n ', i; 1 and :Il're uncle in the bath, and from this figure it can be seen that I stirred (200G, 5Hz)
In this case, Mn"i3 to 7% containing 4" is H'H・3.
You can see that it is possible to lower the 2 shi reception to j 1 shi.

7, j:,! -・n1\dou1riki1-ini, (゛White throw-T
ri, 9fi: is positive, 1, 9-, j-chin (go1-4to's '11' is also acceptable. 1-8 is limited to TiG7Q contact)
] 0 rasma melt 4 times or %i I G #:'+Payment: It's good.

Next (・'Komoto Hikari's i, ・(b) 101 to 11;, 91 light.

In the 41st unit j, d = IO + 惺, Ll - 10T
The overnight bale method of the present invention was carried out with Il+T11t4-=20 rt, x.

In addition, bath welding was carried out using a comparatively soft force method that does not apply a comparatively soft excitation current. The welding protection f) - and r6 shrimp parts first
Shown in the table.

As shown in Table 1, according to the present invention, magnetic stirring makes the crystal grains finer, prevents high-temperature cracking, and makes the bead shape 4t), thereby preventing welding defects such as poor alignment. It has a remarkable effect on the skin.

[Brief explanation of drawings]

Figures 1 (a) and (b) are respectively nR cross-sectional views of the bath welding joint shape, No. 21 (1) is an i-no-f view of the bath weld joint where hot cracking has occurred, and No. 31 (d) is a ferrite crack diagram. Figure 1 shows the coefficient of I (14), Figure 4 is an explanatory diagram showing an example of the present seaming method, Figure 5 shows the welding current, and Figure 6 shows the excitation current. Figure 7 (a) shows the ox' [)L flow.
13"! <'Ni, the current in the case where the current is positive, 1ljji1ii lne1, the same figure (b) (zu2 the same table curved figure, the same figure 09 shows the bead shape Explanation 1 n 1.
Figure 8 (a) shows the excitation box; ′tun v when the flow is negative! 1JJ1 surface 1ne i, lit diagram (b) is the same (front view, same 1 1υ shows the bead shape and invention diagram, Figure 9 shows the direction of the A field, !, j wave and 47;, 1;' with Qresu, characteristic diagram showing 1ho, relationship between Mn JJ-t' and 3u number of 10th +fd spring-i attachment Figure 1 shows 1.
, '(j lining 4) L, 3...Weld metal AξS,
3'... Molten gold tin, 4... Stainless steel ζr1 plate,
5 ・Tungsten electricity for 4 nights, 6...2υ-sand body, 7.
... Excitation coil, 8... Welding source, 9... Welding current, lO... Feed roller, l... - bath welding wire, ear, no 2... Excitation source and (electric N i!Jj
10

Claims (1)

[Claims] Except for welding fully austenitic stainless steel, Mn
Using a wire containing 3 to 7 degrees, and applying an AC excitation current of 1 to 20 kHz to the excitation coil provided at the tip of the welding torch, the magnetic field generated thereby and the welding chamber υ1 were applied.
Due to the Lorentz force, #, il'! A method for welding fully austenitic stainless copper, characterized by vibrating and stirring gold [k]3 to reduce the total number of crystals.