JPS5926393B2 - Aluminum resistance welding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A method of obtaining a structure by joining aluminum (At) plates by resistance welding is applied to various industrial products such as aircraft, vehicles, and small structural products.

Resistance welding of At and At is extremely difficult compared to materials such as mild steel and stainless steel, due to the high electrical conductivity and thermal conductivity of At, and the tendency to form a strong oxide film on the surface of At. Therefore, the resistance welding machine itself must have a large current capacity. For this reason, the strength of the At-At joint has many variations and is also poor in reliability.
In order to solve this problem, ultrasonic welding methods have been developed, but they have drawbacks such as high equipment costs and complicated work, and have not become widely used. The present invention provides At
-Excluding the above-mentioned drawbacks of the At resistance welding method,
The purpose is to increase the strength of the welded part.
The gist is to facilitate the joining of Aι-A by interposing a stainless steel thin plate in advance at the At-At resistance welding part, so that the stainless steel and At react instantaneously during resistance welding. By applying the present invention, At-A
The strength of the t joint can be increased. If the present invention is applied to At-At joining, the current capacity of the welding machine can be reduced to less than a fraction, which helps to save energy.Moreover, the strength of the joint increases, and variations in strength are extremely reduced. Therefore, the reliability of the joint is significantly improved.

Further, the method according to the present invention can be used to prepare a stainless steel thin plate with At
Since it can be carried out through a simple process of inserting it between plates or applying stainless steel powder to the surface of At in advance, it is an extremely low-cost welding method compared to ultrasonic welding, etc. In addition, a high-strength joint can be obtained. Therefore, it can be widely applied to various industrial products.
Therefore, the industrial effect is extremely large. The effects of the present invention will be explained in more detail with reference to the following examples. Example 1 Figure 1 shows At-At and 50μ stainless steel (SU
S27) Aι-SUS joined by resistance welding via foil
27-A was welded under the same conditions as the welding current of 4000 A due to the relationship between the welding strength of the welded portion and the welding time.

As is clear from Figure 1, the bonding strength of 6At-At increases relatively rapidly until the bonding time is about 0.5 seconds. ．． After 05 seconds, the increase in bonding strength becomes extremely small. On the other hand, At-SUS27-A
The bonding strength of t is At-
Although it shows the same increasing tendency as At junction, it is about twice that of At-At junction. Moreover, when the bonding time is increased, At-
Although it is saturated with At, it increases further with At-SUS27-At. Although the detailed reason why the bonding strength of At-SUS27-At in which SUS27 foil is inserted is significantly higher than that of At-At bonding is not clear, the following effects are considered.

First, the reason why At--At resistance bonding is difficult compared to other metals is that At has a high electrical conductivity and high thermal conductivity. For this reason, electricity is not sufficiently concentrated at the point pressurized part for contacting the resistor, so At
f) There is not enough mellowness. On the other hand, At-A
If SUS27 foil is inserted between At.t. l. l) In the SUS27 portion where the electric conductivity and thermal conductivity are l to two orders of magnitude smaller, current is concentrated and sufficient shoe heat is generated.
At the same time, due to the insertion of SUS, the At-At contact point is doubled (the contact point of the butt joint is doubled at an extremely thin interval), and intensive heat generation occurs due to contact resistance. By dissolving the components of Fe, Cr, and Ni, At causes hardening or precipitation hardening, which increases the strength of the joint. SUS27 inserted between At-At
The thickness of the foil varies depending on conditions such as the thickness of At to be dissolved, the size of the electrode chip, and the current used, but in order to achieve the above purpose, 2 to 300μ is usually appropriate. It's the thickness.

Example 2 Similar to Example 1, austenitic stainless steel SUS28, 29, 32, 33, 35, 36, 39, 4
When resistance bonding was performed through the foil of 1, the same effect as that described in Example 1 was obtained.

Example 3 Similar to Example 1, SUS27 powder was applied to At to create resistance. When contact was carried out, the same effect as that produced in Example 1 was obtained.

As described above, if stainless steel foil is inserted in the resistance junction of At-At, a strength equivalent to that of At-At can be obtained with the current-carrying time and amount of current in the case of At-At. .

Therefore, in addition to the advantage of increased bonding strength, power can be saved, which has extremely large technical and economical effects.

[Brief explanation of drawings]

Figure 1 shows At-At and At-SUS271U series resistances. FIG. 3 is a diagram showing the relationship between bonding strength and bonding time.

Claims (1)

[Claims] 1. When welding aluminum by resistance welding, a resistance welding method for aluminum is characterized in that resistance welding is performed in advance through a thin stainless steel plate at the joint of two aluminum plates that require resistance welding.