JPS6281273A - Butt welding method for nickel or nickel alloy clad steel plate - Google Patents

Abstract

PURPOSE:To increase the quality of a weld zone and to make a work efficient by performing the welding of the base metal part close to the cladding face by reducing the welding metal quantity and by performing TIG one layer welding of the groove part of the concave curved face which expands its width at the prescribed penetration rate on the mating metal part. CONSTITUTION:The base metal 8 composed of a carbon steel or low alloy steel provides the groove 10 with 30-50 deg. groove angle theta at the place close to an adhesive boundary surface 9 and the mating metal 7 of Ni or Ni alloy provides the groove 11 of the concave curved face 11a which expands its width from the tip 10a of the groove 10. The welding is performed by subjecting the groove 10 to submerged arc welding with the welding material equivalent to the base metal 8 first, then by subjecting the groove 11 to TIG one layer welding at less than 5% penetration rate by the prescribed Ni wire. The base metal 8 is finished with the submerged arc welding of the back face after back chipping. The quality of the clad steel welding zone and work efficiency can thus be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for butt welding nickel or nickel alloy clad steel plates.

(Prior art) Nickel or nickel alloy clad steel plates are produced by bonding nickel or nickel alloy as a composite material to one or both sides of a steel plate as a base material by rolling compression bonding, explosion bonding, overlay welding, etc. The material nickel or nickel alloy provides corrosion resistance, and the base steel plate provides strength and toughness. For this reason, in the butt joint of nickel or nickel alloy clad steel plates, welding has been devised so that performance equivalent to that of the composite material part and the base metal part, respectively, can be obtained.

The conventionally employed @ contact method will be explained.

First, the base material side of the steel material is welded using a welding material equivalent to the base material, then the composite material side is welded using a welding material equivalent to the composite material,
3 in the groove using slight arc welding method or MIG welding method
The 1- to 4-layer cuts have been made.

This is 11! ! This is because in welding, the bath weld metal is diluted with iron from the base metal, making it impossible to obtain chemical components equivalent to the composite material. In addition, in order to secure a large amount of welding with single layer welding,
This is because it is necessary to increase the melting current and voltage, which also tends to increase the dilution rate.

(Problem to be solved this time) Although the thickness of the composite material of nickel or nickel alloy clad steel plate is generally 2°C to 100°C, there are three to four layers on the composite material side as described above. Because of the thick overlay required, a large number of man-hours were required to grind each layer using a grinder and weld the next layer.

(Means and effects for solving the problems) The present invention provides a method for butt welding nickel or nickel alloy clad steel plates by determining the groove shape on the composite material side and using TIG welding to achieve a penetration rate of 5 or less in one layer. The present invention provides a welding method for performing welding, and its configuration is as follows.

In butt welding of nickel or nickel alloy clad steel plates where the base material is carbon steel or low alloy steel and the composite material is nickel or nickel alloy, the bonding interface between the composite material and the base material starts from the middle part of the base material. The groove angle of the groove on the base metal side to a point close to is set to 30 degrees to 50 degrees, and a groove on the composite material side is provided with a concave curved surface that widens from the tip of the groove to the surface of the composite material, Overlay welding is performed on the base metal side using a welding material with a chemical composition equivalent to that of the base metal, and -S welding is performed on the composite material side using a welding material with a chemical composition equivalent to that of the composite material using the TIG welding method with a penetration rate of 5 or less. This is a method for butt welding nickel or nickel alloy clad steel plates.

Therefore, the groove on the base metal side should be welded with a relatively small groove angle of 30 degrees to 50 degrees to reduce the amount of weld metal. It is welded along the curved surface and further bath-welded using the TIG welding method with a penetration rate of 5 inches or less.

(Example) An example of the butt bath welding method for nickel or nickel alloy clad steel plates according to the present invention will be described with reference to the drawings.

As an embodiment of the present invention, a schematic diagram for explaining the principle of an automatic TIGf welding method adopted to ensure a penetration rate of 5 cm or less is shown in FIG.

1 is a water-cooled tungsten electrode, which is used as a cathode. 2 is a shield nozzle, and a shield gas passage 2
A shielding gas such as argon or helium is supplied from a to the tip of the shield nozzle 2. 3 is a welding wire for build-up, 4 is an arc, 5 is a weld metal, and 6 is a material to be welded that becomes an anode. Arrow A indicates the direction of lateral movement of the torch, and is approximately perpendicular to the direction in which the torch is fed.

In the commonly used TIG welding method, the water-cooled tungsten electrode 1 is used as an anode, and the overlay welding wire 3 is intermittently supplied to perform linear welding.

In the present invention, in order to ensure a penetration rate of 5 or less in the T-G welding method, we provide a feed rate equivalent to the welding wire for overlay-3EMIG welding method, and use water-cooled tungsten to an extremely low level.
The arc heat generated from the welding material 6 to the welding material 6 is concentrated on the overlay welding wire 3, and the shielding gas flow rate is set at about 2 s.
The shielding range is expanded by increasing I to ~28 l/, and welding is performed by increasing the arc voltage. Furthermore, in order to suppress the heating of the base metal due to arc heat as much as possible and perform build-up welding within the predetermined groove described later, a torch and wire feed (not shown) are moved in the direction indicated by the arrow, which is approximately perpendicular to the torch feed direction. The guide is moved laterally so that the arc 4 or the material to be welded 6 is not concentrated at one point.

By adopting the TIG welding method as described above, it is possible to ensure a penetration rate of 5 cm or less, and a large amount of weld metal 5 can be secured without melting the welded material 6 by arc heat. The chemical composition of the weld metal can be made almost the same as that of the welding wire 3 for overlay.

Next, in the method of butt welding nickel or nickel alloy clad steel plates according to the present invention, an example of the groove shape applied to ensure a penetration rate of 5% or less will be explained based on FIG. 2. .

7 is a composite material made of nickel or a nickel alloy, 8 is a base material made of carbon steel or low alloy steel, and 9 is an adhesive interface between the composite material 7 and the base material 8. Then, the groove angle θ is adjusted from 30A to 161 from the intermediate part of the base material 8 to a location close to the bonding interface 9, preferably from about 1 to 20 A to 161 inward of the contact field [9].
A composite material side groove is formed with a V-shaped base material side groove 10 having a 50-sided shape, and has biconcave curved surfaces 11a and lla that gradually widen from the tips 10a and 10a to the surface of the composite material 7. It is set at 11%. The composite material side groove 11 is a biconcave curved surface 11a,
The reason why Ila is formed up to the base metal 8 side is to make the welding surface more uniform and prevent poor fusion near the adhesive interface 9, and the groove angle σ% on the base metal side is 30 degrees to 50 degrees. The reason for making it relatively small is to suppress the amount of welded metal on the base material 8 side as much as possible.

Next, specific examples of embodiments according to the present invention will be described.

JISH2104N2 Nickel + Cobalt: 99.8
A composite material with a thickness of 3.5IlII was made using ASTMA
Butt welding was performed on a nickel-clad steel plate made of 387Gr12 and having a thickness of 141 m as a base material.

As shown in FIG. 2, the groove extends from a point 7 m deep from the adhesive interface 9 toward the base metal 8 side to a point near LOIII on the inside of the interface 9, with a groove angle θ of 30 degrees on the base metal side. First lO and
The tip 10a of the groove is a double-arc concave curved surface 11a with a radius of about 7 m from the tip 10a to the surface of the composite material 7.

11a, and a groove 11 on the composite material side.

For such a groove, first, the tip 10a of the groove on the base material side is
The base metal 8 up to 10a is submerged arc welded using a welding material equivalent to the base metal. nokel f
Using g welding wire 8, automatic TIG welding was carried out under the following f6 welding conditions to ensure a penetration rate of 5% or less.

Welding conditions: After welding the outer side of base metal 8 by 1'1, submerged arc bath welding was performed using a welding material equivalent to base metal 8.

The welded part was inspected by radiation JJJ rays, the welded part was cut, and the cross section was inspected at 400 times with an optical copying tool, but there were no defects such as poor fusion or cracks, and the penetration rate was approximately 445 cm. It had been.

In addition, the chemical composition of the weld metal surface of the composite material side groove was as shown in the following table.

As is known from the values in the table, the composition of the weld metal was found to be sufficiently satisfactory, no defects were observed in the side bending test of the welded part, and even in the tensile test other than the welded part. It is known that the welded part has a sufficiently high joint efficiency.

In addition, when the welding method of the present invention is applied to the inner longitudinal welding of a plate-wound welded pipe made of nickel-coated clad steel plate, there are no performance problems such as the chemical composition or mechanical properties of the weld metal. Ivy.

In addition, in a double-sided nickel or nickel alloy clad steel plate, the starting points of the base metal side grooves 10 are butted against each other to form the base metal side grooves 10 and the composite side grooves 11 symmetrically, so that both sides can be fused according to the present invention. ¥! Just apply the contact method.

(Effects of the Invention) As understood from the above explanation, according to the method of welding clad steel plates according to the present invention, melting of iron from the base metal into the weld metal is suppressed by further welding, and the welding of iron from the base metal is suppressed. The components can be made equivalent to those of the composite material, and a good joint can be obtained without the occurrence of fusion failure8 near the bonding interface between the dowel and the base metal, and it is possible to obtain a good joint without the need for conventional multilayer welding. The manufacturing cost was reduced by 8.0% due to the reduction in man-hours.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram illustrating the principle of the automatic TIG welding method used in the present invention, and Fig. 2 is a cross section showing the groove of a nickel or nickel alloy clad steel plate used in an embodiment of the present invention. It is a diagram. 1: Water-cooled tungsten , 9:
Tangent* boundary surface, lO: base metal 11i11 groove, 10a: tip (of groove on base metal side), 1: light on composite side, 11a: concave curved surface agent patent attorney front 1) profit 2 Fig. 1 Figure 2

Claims (1)

[Claims] In butt welding of nickel or nickel alloy clad steel plates where the base material is carbon steel or low alloy steel and the composite material is nickel or nickel alloy, the bonding interface between the composite material and the base material starts from the middle part of the base material. The groove angle of the groove on the base metal side to a point close to is set to 30 degrees to 50 degrees, and a groove on the composite material side is provided with a concave curved surface that widens from the tip of the groove to the surface of the composite material, Overlay welding is performed up to the tip of the groove on the base metal side using a welding material with a chemical composition equivalent to that of the base metal, and on the composite side, using a welding material with a chemical composition equivalent to that of the composite material, the penetration rate is 5 using the TIG welding method. A method for butt welding nickel or nickel alloy clad steel plates, characterized by welding in one layer at a temperature of less than %.