JPS5834236B2 - Electron beam welding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in electron beam welding, and more particularly to a method for economically applying electron beam welding, which requires high equipment costs, to welding low-grade general structural steel materials.

The electron beam welding method uses high energy density to achieve deep penetration welding with a narrow repeat width, resulting in less welding distortion, and since welding is performed in a vacuum, there is almost no deterioration of the material, making it suitable for aerospace equipment. It is widely used for welding high-grade precision structures and their parts.

Recently, its characteristics have been utilized to apply it to general large structures such as ships, pressure vessels, and steel.

However, for applications in general large structures, low-grade general structural steel materials with low material costs are used in large quantities, so electron beam welding, which has high equipment costs, is used to achieve economic benefits. High-speed welding (2m/
At the same time, the accompanying welding defects include hot cracking, pores (CO gas generated by the reaction between the oxygen component contained in the weld metal and carbon in the steel, and the cooling rate of the molten metal is fast). (remains as a void inside the weld)
, problems such as abnormal bead shapes (undercuts) had to be solved.

The state of this welding defect is shown in FIGS. 1-3. In Figs. 1 to 3, 1 and 11 are materials to be welded, 2 is weld metal, and 3
4 indicates a hot crack, 4 indicates a pore, and 5 indicates an abnormal bead shape.

The present inventors have conducted intensive research to solve the above-mentioned problems when applying electron beam welding to low-grade general large structures.As a result, when electron beam welding low-grade general structural steel materials, Mn, A, / The present inventors have found that the above object can be achieved by welding under conditions such that the elements are simultaneously present in the molten zone during electron beam welding, and have completed the present invention.

Mn during electron beam welding in the method of the invention.

As a means for making the At element exist at the same time, M
n-A/, material (A7<20% or At>67%) or Fe-Mn-At material (Mn: 1.0-2.0%.

At
) Means of setting the welding groove as an insert material in advance (3) Means of spray coating the welding groove in advance, etc. can be applied.

In the method of the present invention, the Mn-At material containing At less than 20% or more than 67% is used because if it is outside this range, it will form an intermetallic compound (hard and brittle) and cannot be manufactured into a wire or foil. Yes, and Mn is 1.0 to 2.
Fe-Mn-At containing 0% and 1.0% or less of At
This material was chosen because if the composition was not within this range, the structure would be hard and brittle, making it impossible to roll or produce wire or foil.

In addition, in the FeMnAt material, the lower limit value of Mn is 1.0.
% because the less Mn there is, the less effective the deoxidizing effect will be.

These means will be explained in more detail below with reference to the drawings.

Fig. 4 shows a case in which when welding by irradiating the electron beam 6 to the ■-shaped opening where the base materials 1 and 11 to be welded are butted together, a means for feeding the wire or foil 8 toward the ■-shaped opening is adopted. This is a perspective view showing the case where the wire or foil 8 is supplied from behind the electron beam 6.

Needless to say, this supply can be made from in front of the electron beam 6.

Note that 2 indicates weld metal.

FIG. 5 is a perspective view of the cross section taken along the line A--A in FIG. 4, seen in the direction of the arrow, and 7 indicates the molten metal portion.

FIG. 6 shows that when Mn-At material or Fe-Mn-At material 9 is inserted into the ■-shaped butt part of the base materials 1 and 11 to be welded before welding, FIG. 7 shows the same < Mn -A, /, Material or Fe-Mn-A,/l; Material 10 is spray coated.

The electron beam 6 is partially omitted from the illustration.

Although the present invention can be implemented by the means listed above, MnA added to the molten metal part,
The Mn element in the steel or Fe-Mn-At# reacts with S in the steel to form MnS, which works to prevent high-temperature cracking by preventing the segregation of the low melting point compound FeS, and at the same time, Mn
Together with the At element, the element captures oxygen that is activated during high-temperature melting and deoxidizes it, thereby suppressing the generation of CO and preventing the formation of pores.
Since a filler such as n-A7 material is added, it has the effect of preventing the formation of abnormal bead shapes such as undercuts.

[Brief explanation of drawings]

Figures 1 to 3 are explanatory diagrams for explaining defects in the weld metal that occur when electron beam welding is simply performed on general low-grade structural steel materials. Figure 4 is an illustration of the supply of Mn and At elements by wire according to the present invention. Figure 5 is an explanatory diagram of the cross section taken along the line A-A in Figure 4 seen in the direction of the arrow, and Figures 6 and 7 show other embodiments of the present invention. It is an explanatory diagram.

Claims (1)

[Claims] 1 When welding low-grade general structural steel materials to electronic pieces, Mn- containing 20% or less or 67% or more of At in the welded part
A7 material or Fe-Mn-A containing 1.0 to 2.0% Mn and 1.0% or less At, /;
An electron beam welding method characterized by melting At element into molten metal.