JPH0635052B2 - Soldering jig - Google Patents

Description

Detailed Description of the Invention

 Purpose of the invention

[Industrial applications]

The present invention relates to an improvement of a jig used in a soldering device.

[Prior art]

Along with the progress of technology utilizing semiconductors, the work of soldering ICs and other electronic components to circuit boards has increased.
The work is mostly automated and consists of holding the circuit board with the parts inserted in it with an appropriate jig, immersing it in a flux bath if necessary, preheating it, then immersing it in a molten solder bath and pulling it up. . Of course, this jig should not be easily wet with molten solder. At present, SUS304 stainless steel coated with Teflon is used as the jig material, but it gradually gets wet with long-term use, so the jig must be replaced after about 6 months of use. I won't. Although Ti is known as a material that is harder to be wetted by solder than stainless steel, it is not suitable for manufacturing a soldering jig because Ti is expensive and has poor workability. It has been found that ceramics are more difficult to get wet and have good resistance to wetting, that is, the property that they are hard to get wet can be sustained, but it is difficult to process them into complicated shapes, so if you dare to use ceramics, , Ti is more expensive.

[Problems to be Solved by the Invention]

An object of the present invention is to solve the above problems and to provide a soldering jig which is hard to get wet with solder and has improved wettability by using a metal material which is inexpensive and has good workability. . Structure of the invention

[Means for solving problems]

The soldering jig of the present invention is basically C: 1.0.
% Or less, Si: 5.0% or less, Mn: 2.0% or less, A
1: 0.6 to 7.0% and Cr: 7.0 to 30%, and a material having an alloy composition of which the balance is substantially Fe is molded and heated to a temperature of red heat or higher in an oxidizing atmosphere. And an oxide film rich in Al ₂ O ₃ is formed on the surface. As the material, in addition to the above basic alloy composition, Y and lanthanide REM (La, Ce, Pr, Nd, P
m, Sm, Eu, Gd, Tb, Dy, Ho, Er, T
m, Yb, Lu) one or more of the group consisting of: 0.0005 to 1.0% is the above A
It is a preferable material because it has an advantage that an oxide film rich in l ₂ O ₃ can be easily formed, and that the oxide film is strong and does not easily peel off from the substrate. Instead of Y and lanthanide REM, Mo: 1.5%
The following and / or W: 1.5% or less is added,
A similar effect can be expected. The effect of increasing the fixability of the resulting oxide film to the substrate is to use a material containing one or more of the group consisting of Ta, Nb, Ti, Zr and Hf: 0.002 to 25% added. Can also be obtained. When it is desired to increase the mechanical properties of the soldering jig, in particular, toughness, an alloy containing Ni: 3.0% or less and / or Co: 5.0% or less may be used as a material. It goes without saying that the above-mentioned optional additional elements may coexist with those belonging to two or more groups. In addition, as the material of the soldering jig of the present invention,
Unless it is against the purpose, it can be used even if it contains alloy components other than the above. Therefore, it is advantageous to select the material from existing commercial standard products in terms of availability and price. As an example, there is an iron-chromium alloy containing Al: 2.0 to 6.0% and Cr: 14 to 26% and supplied for a heating wire (the steel grade symbol for Daido special steel is FCH.
1, FCH2 and FCH51). Formation of an oxide film rich in Al ₂ O ₃ is 700 to
Temperature of 800 ° C or higher, preferably 1100 to 1200 ° C
The heating may be performed for about 0.5 to 2 hours.

[Action]

An Fe-based alloy containing Al: 1.0% or more, of course, produces Fe oxides when heated to a temperature of red heat or higher in an oxidizing atmosphere to form an oxide film. Preferentially, a large amount of Al ₂ O ₃ oxide is formed. This fact was confirmed by the fact that the M ₂ O ₃ type compound was overwhelming when the surface of the material after treatment was examined by X-ray diffraction, and that a large amount of Al was present when analyzed by EPMA. Was done. Further, the fact that this oxide film had a dense structure and was strongly attached to the matrix was observed by a scanning electron microscope photograph. If the Al content is less than 1.0%, this effect becomes weak. On the other hand, if the Al content is high, the material becomes brittle as is well known, which is not preferable. The limit is about 7%. The effect of Al ₂ O ₃ formation is sufficiently obtained within this limit. The presence of Cr promotes or promotes the formation of an Al ₂ O ₃ -rich oxide film as described above. This effect is 7
It is clearly obtained with the addition of more than%. Addition of more than 30% only lowers the workability of the material, increases the price, and saturates the effect, which is not a good idea. C should exist in an amount necessary to secure the strength of the jig. However, if the amount is large, the formation of a dense oxide film is affected, so 1.0% is made the upper limit. Si: 5.0% or less and Mn: 2.0% or less are both added as a deoxidizing agent, but if the respective upper limits are exceeded, Si makes the material mechanically brittle and makes processing difficult. Not only that, there is a risk of penetrating solder due to the generation of fine cracks, and Mn reduces the adhesion of the oxide film to the substrate. Addition of Y and lanthanide-based REM not only produces a dense oxide film as described above, but also enhances the adhesion to the substrate. This effect can be obtained by the addition of a very small amount of 0.0005%, and if 0.001% or more, a further favorable result is shown. However, when the amount is large, the hot workability tends to be deteriorated, which is also disadvantageous in terms of cost. Therefore, it is a good idea to limit the addition to within 1.0%. The group of Ta, Nb, Ti, Zr and Hf enhances the adhesion of the oxide film to the substrate, as described above.
The effect is obtained by adding 0.002% or more in total. There is no problem in physical properties even if the upper limit of 1.0% is exceeded,
The price will be high.

【Example】

Width 14mm x by machining from alloy with composition shown in the table
A plate with a thickness of 2 mm and a length of 200 mm was manufactured. Comparative Example 1 is a normal structural carbon steel, and 2 is SUS304 stainless steel. Each sample is 1200 ℃ in air
It was heated for 2 hours to form an oxide film. The following are typical soldering conditions: Solder used: 63% Sn-Pb (eutectic solder), melting point: 183 ° C Bath temperature: 250 ° C Cycle: (flux dipping + preheating) for about 20 seconds →
Soaking in solder bath Approx. 10 seconds ... Approx. 1000 cycles / 8 hours In order to realize test conditions close to this, a device for grabbing the test piece and immersing the lower half in the solder bath kept at 250 ° C for 10 seconds and pulling it up for 20 seconds Prepared. After 15,000 cycles, the state of solder adhesion was examined.
No solder adhesion was observed in any of the examples. On the other hand, in the comparative example, a large amount of solder adhesion was observed. EFFECTS OF THE INVENTION The soldering jig of the present invention is, so to speak, equivalent to a surface of a metal processed product coated with a ceramics containing Al ₂ O ₃ as a main component, and therefore the solder wettability is substantially zero. be able to. This coating is strong and does not come off even after many heat cycles, so it has excellent wetting resistance,
The jig can be used for a long time. Even when a decrease is observed, it can be easily regenerated by cleaning the surface of the jig by means such as pickling and heating. Existing materials that are easily available on the market are sufficient as the materials, and since the workability is generally not bad, the cost of the soldering jig is low, together with the fact that the heat treatment is easy.

Claims (5)

[Claims] 1. C: 1.0% or less, Si: 5.0% or less,
Mn: 2.0% or less, Al: 0.6 to 7.0% and C
r: An oxide film rich in Al ₂ O ₃ formed by molding a material having an alloy composition containing 7.0 to 30% and the balance being substantially Fe and heating it to a temperature of red heat or higher in an oxidizing atmosphere. A soldering jig formed by forming. 2. As a material, one or more selected from Y and lanthanide-based REM is further added to 0.0005.
Claim 1 using the thing containing ~ 1.0%
Item for soldering jig. 3. A soldering jig according to claim 1 or 2, wherein a material further containing Mo: 0.5% or less and / or W: 0.5% or less is used. Ingredient 4. A material further comprising Ta, Nb, Ti, Z
One or more selected from r and Hf: 0.0
The soldering jig according to any one of claims 1 to 3, wherein a jig containing 02 to 2.5% is used. 5. The solder according to any one of claims 1 to 4, wherein the material further contains Ni: 3.0% or less and / or Co: 5.0% or less. Fixture jig.