JPS60166177A - Fit welding between different kind metal - Google Patents

Abstract

PURPOSE:To avoid generation of stress cracking even when the space of fitted part is large by providing a projection of required shape at outer edge of fitted part of an article made of metal of higher melting point in fit welding articles made of metal of different kind. CONSTITUTION:A fitting hole 12 having a bearing surface 13 formed by a step of different diameter is provided in an article 11 out of articles 11, 21 made of metal of different kind, for instance SUS316, S20C. The article 21 is a fitting article and outer diameter of the fitting part 21a is made to have fitting space of 50-150mu in diameter space to the hole 12. A projection 14 of specified width and height (about 0.3-0.5mm. is proper for the both) is formed over whole circumference along outer edge of the hole 12 of article 11 of higher melting point. Outer edges of such articles 11, 12 are welded, for instance, by electron beam welding (EBW) over whole circumference as shown in the figure. The projection 14 is molten and flows into the fitting space and joins with material of already molten article 21 to form an alloy and stabilizes interfacial condition of the weld zone 30 in material quality.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a welding method for fitting and welding a fitting article made of a metal different from the above-mentioned article into a fitting hole of a metal article.

[Technical background of the invention and its problems]

A specific example of this type of fit welding using a conventional welding method is shown in Figure 1. In Fig. 1, (1) is the pressure transmitter main body, (
2) is the sensor envelope, (3) is the welded part, (41 line pressure sensitive diaphragm, (5) is the pin that takes out the output to the outside,
The sensor envelope (2) is fitted into the fitting hole FllK, which has a seat surface formed by steps of different diameters of the pressure transmitter main body (1), and the outer edge of the fitting hole 01 and the sensor envelope ( The outer edge of 2) is continuously welded all around.

The pressure transmitter body (1) is generally made of corrosion-resistant metal, e.g.
US 316 is used9, while the sensor envelope (
For 2), due to problems in manufacturing the sensor, a material having a coefficient of thermal expansion relatively close to that of glass, for example, 8200 with Keckel plating) is used. In addition, the gap between the fitting part of the pressure transmitter body (1) and the sensor envelope (2) is set at 50 to 1 mm in terms of dimensional control and cost for machining and plating.
Approximately 50 μm exists. (See Figure 2) In this way, when two items made of different metals are fitted together and there is a large gap between the fitting parts, welding (electron beam welding, abbreviated as EBW) involves the problem described in F. There is.

(1) Different types of gold M (for example, SUS 316 and 8200) have different melting points (SUS 316 is about 15006
0.8200 is approximately 1300°C), so the proportion of metal that can be melted is different.

[2] When the gap between the fitting parts is closed and the molten main metal cools and solidifies, excessive stress is generated in the center of the weld (3) and cracks occur, as shown in Figure 3. do.

The above-mentioned phenomenon occurs in a pressure transmitter where the pressure transmitter main body (1) and the sensor outer l#I-I device (2) must be tightly connected at the fitting part. However, if the gap at the fitting part is 30 μm or less, the problem of stress cracking as described above will disappear, but processing and plating control will be stricter. , Direct + M, 1!! There is a problem that the construction cost VC will be returned.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for fitting and welding dissimilar metal bodies in which stress cracking does not occur even when the fitting gap is large.

[Summary of the invention]

The present invention provides a method for fitting a fitting article made of metal, which has an outer diameter smaller than the fitting hole by a required gap and is different from the article, into a fitting hole provided in a metal article. However, when the outer edge of the fitting hole of the article and the outer edge of the fitted article are continuous all around, the one having a higher melting point of the article and the fitted article M,
Realizes a fit welding method between dissimilar metal bodies, characterized in that welding is performed after a protrusion having a required width and height and protruding along the entire circumference along the outer edge is formed in advance. achieved the intended purpose.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 4 to 6 are diagrams for explaining an embodiment of the fit welding method for dissimilar metal bodies according to the present invention. Figure 4 shows the state of the welded part before welding, and αυ is S U S
316M, and is provided with a fitting hole a having a seating surface Q31 formed by steps of different diameters. on the other hand,(
2υ is an 820ON fitting article, and its fitting part (ZXa)
is 50 to 150 μm in diameter gap for fitting hole a21vc
The outer diameter is made to have a fitting gap of 8 degrees. And, the melting point of the material is still SUS 316% 0υ
A protrusion (L4) that breaks the predetermined width and simplicity is formed along the entire circumference YC along the outer edge of the fitting hole α. The width and taste of this protrusion a4) are both 0.3~
Experiments have shown that approximately 0.5 ynm is appropriate.

As shown in FIG. 5, the article αJ) and the fitted article (2υ) formed as described above are defined as , for example, by electron beam welding (1BW)K.

During welding, the protrusion (14
) melts at about 1500°C and flows into the fitting gap, while the fitted article (
Combine with 2υ's 8200 material to create an alloy. At this time, the penetration rate of 5U8316 and 5200 is as follows:
Due to the difference in melting point between KSU8316 and 8200, when 41 is not formed, 5200, which has a lower melting point, has an extra front, but it can be made almost the same, and the state of the weld interface can be changed depending on the material. can be made stable. In addition, even if the welded part solidifies and further shrinks due to cooling, the material of the protrusion I will fill the gap in the fitting part, as shown in Fig. No large stress occurs.

The shape of the protrusion I is shown in Fig. 7 fa) and (b).
, As shown in (c), the cross-sectional shape is square, rectangular,
The shape is not particularly limited as long as it meets the purpose of the present invention, such as a trapezoid.

Among them, as shown in Fig. 7 (cl), if the head of the cutting tool is used to form the protrusion (14), the machine 7+
The 111 steps are easy and the number of steps can be reduced.

Further, from the viewpoint of welding and processing, it is appropriate that the dimensions of the protrusion (14) are approximately 0.3 to 0.5 mm in both width and height, but dimensions outside the above-mentioned ranges may also be used.

〔Effect of the invention〕

As described in detail above, according to the present invention, when fitting and welding articles made of dissimilar metals, the outer edge of the fitting part of the article made of Kintori whose melting point is / & By forming in advance a protrusion having the required width and height and protruding along the entire circumference along the outer edge, and then welding it for 5K, the following effects were obtained. is obtained.

[1] The material metal of an article made of a metal with a lower melting point, where the protrusion made of the metal with a higher melting point is melted at that melting point and flows into the fitting gap, and is already melted at the lower melting point. When combined with the alloy to form an alloy, the penetration rate of the two can be made almost equal, and the interface of the welded part can be made materially stable.

[2] The material of the protrusion fills the gap between the mating parts, so even if the weld solidifies and contracts, stress that will cause cracks will not occur, and it is necessary to create a liquid-tight seal at the mating part. It is possible to obtain a stable sealing function over time, such as in cases where there is a problem.

[3] Even if the fitting gap between the fitting hole and the fitting object is set to a value that is not too strict in terms of machining and plating dimension control, stable and reliable welding as described above can be performed. , it is possible to reduce manufacturing costs.

[Brief explanation of drawings]

Figures 1 to 3 are diagrams for explaining a specific example of fit welding between dissimilar metal articles by a conventional welding method. Figure 1 shows a pressure transmitter made by SUS 316 and a pressure transmitter made by A cross-sectional view showing the case where the sensor envelope is fit-welded, the second
The figure is an enlarged sectional view of the welded part in Fig. 1, Fig. 3 is an explanatory diagram showing defects in the welded part in Fig. 1, and Figs. Figure 4 is a cross-sectional view showing the state of the welded part before welding, and Figure 5 is a cross-sectional view showing the welded part of Figure 4 in the welded state. Figure 86 is an explanatory view showing the action of the protrusion during welding in Figure 5, Figures 7(a) and (b). (c) is a sectional view of a main part showing various modifications of the shape of the protrusion. 11... Metal article with a higher melting point 12... Fitting hole 13... Seat surface 14 formed by steps of different diameters... Projection 21... Metal with a lower melting point Fitted article 21a made by...
・Fitting part 30... Welding part agent Patent attorney Inoue - Male Figure 1 Figure 2 Figure 3 Figure 4 Figure/3 Figure 5 Figure 6 Figure 7

Claims (2)

[Claims] (1) Fit a fitting article made of a metal different from the article and having an outer diameter smaller than the fitting hole by the required gap into the fitting hole provided in the article made of gold and N. When the outer edge of the fitting hole of the article and the outer edge of the fitted article are continuously welded around the entire circumference, the melting point of the article or the fitted article is lowered by the required amount. A method for fitting and welding dissimilar metal bodies, characterized in that welding is performed after previously forming a protrusion having a width and a radius and protruding over the entire circumference along the outer edge. (2) The fitting welding method between dissimilar metal bodies according to claim 1, wherein the protrusion has a width and height of 0.3 to 0.5 mm.