JPS60103146A - Aluminum filler metal with low rolling crack sensitivity - Google Patents

Abstract

PURPOSE:To obtain Al filler metal with low rolling crack sensitivity by adding a specified rare earth element to an Al-Si alloy. CONSTITUTION:When various Al alloy bearings are manufactured, blanks for bearings are rolled and worked to manufacture bearings of desired shapes. At this time, the blanks are welded to each other before the rolling and working so as to improve the productivity in the rolling and working stages. When the welding is carried out, an Al alloy contg. 3-8wt% Si and 0.3-2wt% one or more kinds of rare earth elements such as La, Ce, Pr and Nd is used as filler metal. A rolled material of high quality as a blank for bearings is obtd. without causing rolling crack in the weld zone.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aluminum filler metal with low rolling crack susceptibility.

For example, aluminum alloy bearings are used in automobiles, ships,
Used in aircraft, industrial machinery, etc.

The alloys used in such bearings include:

There are Al-8n-Pb based alloys and At5n-Cu based alloys, etc., and these alloys can be melted and manufactured according to the needs of users.2. Bearing materials have been produced by casting, and then the bearing materials have been rolled one by one to manufacture bearings of desired shapes.

Although such a manufacturing method has the advantage of being able to quickly respond to user demands, it has the disadvantage of low productivity in the rolling process and increased manufacturing costs.

Therefore, the inventors investigated a method for improving the productivity in the rolling process without sacrificing the above-mentioned advantages, and found that it was possible to improve the productivity in the rolling process compared to the method. Based on such knowledge, the inventors more specifically manufactured bearing composites of various bearing alloys, and manufactured each using a known filler metal or a material having the same composition as the bearing composite. When welded and rolled, the welded part developed rolling cracks.
The intended purpose could not be achieved. Although it is not possible to explain exactly why rolling cracks occur in this weld, the composition of the weld changes as the alloy of the bearing and the filler metal melt together, making rolling cracks more likely to occur. This is probably due to the composition, or because microcracks occur in the welded part due to welding, and rolling cracks greatly develop from those areas during rolling.

Therefore, the inventors welded the bearing material, and even if the composition of the welded part changes or micro-cracks occur in the welded part, the inventors created a filler metal that is less likely to cause rolling cracks in the rolling process after welding. As a result of various studies to obtain Al-
The present invention was completed based on the knowledge that filler metals made by adding rare earth elements to 81 series alloys are less susceptible to rolling cracks. In other words, the present invention is a rolling crack sensitive material containing 3 to 8 inches by weight of Sl and 0.3 to 2 hours by weight of one or more rare earth elements, with the remainder being At and unavoidable impurities. It is a small aluminum filler metal.

The reason for adding each alloy component element in the present invention will be described below.

81 is intended to provide fluidity and filling properties and prevent cracking during welding.If the content is less than 3-3 by weight, the filling property will decrease and cracking during welding cannot be prevented, and rolling Rolling cracks occur during processing. If the weight exceeds 8φ, intermetallic compounds such as Al-8i-Fe will precipitate in the weld.

During rolling process (ζ cracks occur from that part.

Rare earth elements reduce the occurrence of cracks in welds.

It is used to prevent rolling cracks during rolling processing, and if its content is less than 0.6% by weight, the effect of addition will be small, and if it exceeds 2% by weight, the effect of addition will decrease again. Rolling cracks occur during rolling. Rare earth elements include some I4 elements belonging to group Ⅰ of the periodic table of elements, including Ls, Ce, Pr, Nd, etc.
These elements may be added alone or in a mixture of two or more of these elements. Also, so-called mitshu metal, which is commercially available as a mixture of these elements, is easily available and inexpensive, so it may be used as is.

The filler t (of the present invention) includes each of the above-mentioned elements as essential components, but the element 2 which is added in trace amounts to the filler metal alloy and mixed as an impurity, for example, about 0.8% The presence of Fe up to about 0.3% by weight, Cu up to about 0.3% by weight, Zn up to about 0.25% by weight, TI up to about 0.2% by weight, B, etc. is the rare earth element addition of the filler metal of the present invention. There is no problem because it does not interfere with the effects of preventing welding cracks and rolling cracks.

Welded with the filler metal of the present invention. For example, the above-mentioned bearing material may be a cast body, or it may be partially rolled, for example, to make the thickness uniform. The welded bearing material is then rolled to a desired thickness, and then the welded portion is cut off to form a bearing plate.

The welded part and the bearing material part can be easily distinguished because the brightness and roughness of the plates are different.

Examples of the filler metal of the present invention will be given below.

Table 1 shows the composition of the filler metals used.

Table 1 A/, -30% by weight 5n-1% by weight cu by conventional method.

A bearing material (dimensions: length 250+nm x width 250+++m x thickness 4) of A4-10 weight j 11 cm 8n-1 weight %P was prepared, and the filler material shown in Table 1 (dimensions: 1.6 m
mg1 wire, except for filler metal numbers 2 and 6, 6 on each side
．． Welded using a two-brained square rod) under the following conditions.

Rolling was performed and the presence or absence of rolling cracks in the welded area was investigated. The presence or absence of rolling cracks is visually inspected, and the length is 3w.
Cracks of P or higher were considered to be crack-initiated fabrics. The results are shown in Table 2.

Welding conditions Current (A) t70-190 Voltage (v) 25-26 Speed (pus/min) 600-800 Argon flow rate C11 minutes) 25 Rolling conditions Cold rolling. Approximately 10 pieces per bus with a board thickness of 4 fields
The thickness was reduced in 12% increments to a plate thickness of 0.8wn.

Table 2 Show that.

It can be seen that the number of orders received is small.

As mentioned above, the filler metal of the present invention has low sensitivity to rolling cracking, so for example, as described above, a large number of bearing materials can be welded and connected in a row, and these bearing materials can be continuously rolled. It is an aluminum filler material that has excellent effects such as improving productivity and lowering the manufacturing cost of bearings.

Patent applicant: Nippon Light Metal Co., Ltd.

Claims (1)

[Claims] An aluminum filler material having low rolling crack susceptibility, containing 3 to 8% by weight of Si and 0.3 to 2% by weight of one or more rare earth elements, and the balance being M and unavoidable impurities.