JPH08108281A - Method for welding rail by gas shielded arc welding method - Google Patents

Abstract

PURPOSE: To reduce the welding work time, and to improve the performance of the rail joint by setting the composition of the wire and the conditions for the welding performance to the prescribed values when the rail is welded by the gas shielded arc welding method where the solid wire for welding is used. CONSTITUTION: The rail consisting of the steel containing 0.50-0.75wt.% C is welded by the gas shielded arc welding method. The solid wire to be used in the welding has the composition consisting of, by weight, to the total weight of the wire, <=0.25% C, 0.05-1.50% Si, 0.50-2.50% Mn, 0.80-4.00% Cr, 0.05-2.00% Mo, <=0.015% P, <=0.015% S, and the balance Fe with inevitable impurities. For example, in the case of the diameter of the wire of 1.2mm, the welding conditions are the welding current of 180-250A, and the welding voltage of 26-31V. The interpass temperature is controlled to 400-700 deg.C at the rail top part 4, the build-up method is two or more passes for each layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for welding rails used in railways and the like, and more particularly to a gas shielded arc welding to which a gas shielded arc welding method can be applied and a high quality weld metal can be obtained. The method of welding a rail by the method.

[0002]

2. Description of the Related Art Conventionally, gas welding, flash welding, thermite welding, or enclosed arc welding using a covered arc welding rod has been used for welding the rails. Among them, the enclosed arc welding is widely used because it does not require rail movement and pressurizing process as compared with gas welding and flash welding, and has better joint performance than thermite welding. Welding method. However, the conventional enclosed arc welding using a covered arc welding rod requires a great deal of time for welding work, and it has been desired to shorten the welding time particularly in the case of time-limited rail replacement.

On the other hand, the gas shielded arc welding method using a solid wire has excellent weldability and enables highly efficient welding. However, the rail base material is designed to have a high carbon content and high hardness in order to obtain wear resistance and strength. Further, as a welding material, a welding wire having a high carbon content has been developed, as in Japanese Patent Publication No. 4-51275 or Japanese Patent Publication No. 4-51277.
As described above, in the welding of a material having a high carbon content, a hot crack is likely to occur in the deposited metal, which is remarkable particularly in the gas shield arc welding method in which the penetration is deep. In general,
In butt welding of a rail base material having a high carbon (C) content, solidification cracking easily occurs in the deposited metal.

Further, the rail welding is welding in a narrow groove as shown in FIG. 2, and the degree of freedom of the aim of the wire and the carrying rod is extremely small, and there is a risk of defective fusion from the bottom to the crown. Is high.

[0005]

[Problems to be Solved by the Invention] Under these circumstances,
As a welding method for rails, one that requires a short welding work time is desired, and as a welding material, excellent crack resistance,
A rail having required wear resistance and strength is demanded, and further, welding conditions are required to be capable of preventing solidification cracking of the deposited metal and less likely to cause defects. However, the conventional welding method is
It was not possible to satisfy such a demand.

The present invention has been made in view of the above problems, and pays attention to the high weldability of the gas shielded arc welding method using a solid wire for welding in order to shorten the welding work time. It is an object of the present invention to provide a rail welding method by gas shielded arc welding, which can obtain excellent joint performance as a rail by the gas shielded arc welding method by appropriately determining the composition of solid wire and welding work conditions. .

[0007]

The welding method of rails by the gas shielded arc welding method according to the present invention is C; 0.5.
In a rail welding method for welding a rail made of a steel material containing 0 to 0.75% by weight by a gas shield arc welding method, C; 0.
25% by weight or less, Si; 0.05 to 1.50% by weight, M
n; 0.50 to 2.50% by weight, Cr; 0.80 to 4.
00% by weight, Mo: 0.05 to 2.00% by weight, P: 0.015% by weight or less, S: 0.015% by weight
Regulated below, using a solid wire with the balance being Fe and inevitable impurities, when the wire diameter is 1.2 mm, welding current: 180-250 A, welding voltage: 26-3
Welding current: 260 when 1 V and wire diameter is 1.4 mm
~ 310A, welding voltage; 27-33V, wire diameter 1.
When it is 6 mm, the welding current is 320 to 380 A, the welding voltage is 29 to 35 V, and the welding condition is
At the rail top, the temperature between passes is 400 ° C to 700 ° C.
It is characterized in that the temperature is controlled at 0 ° C. and the laminating method is 2 passes or more per layer.

If necessary, Ni: 2.00 wt% or less may be added. Further, Ti: 0.03 to 1.5
You may add 0 weight%.

[0009]

The reasons for limiting the C (carbon) content of the rails to be welded according to the present invention, the reasons for adding the components and the composition for the solid wire used in the present invention, and the reasons for welding will be described below.

(1) C content of rail: 0.50 to 0.
If the C content of the 75 wt% rail is less than 0.50 wt%, the minimum necessary wear resistance and strength of the rail cannot be obtained. When the C content exceeds 0.75% by weight, the C content in the weld metal excessively increases due to dilution, and the hot crack resistance of the weld metal deteriorates. Therefore, the C content of the rail is 0.50 to 0.75% by weight.

(2) Reasons for adding solid wire components and reasons for limiting composition C (carbon); 0.25% by weight or less C is added to improve the hardness of the deposited metal and wear resistance. The increase due to the dilution of the base material must be taken into consideration. If the C content of the solid wire exceeds 0.25% by weight, the C content of the weld metal will be unnecessarily high, including the increase due to the dilution of the rail base material, and the weld metal will be significantly hardened. High temperature crack resistance deteriorates. Therefore, the C content is 0.25 wt% or less.

Si: 0.05 to 1.50 wt% Si improves the conformability of the deposited metal and the blowhole resistance, and has a function of preventing welding defects such as poor fusion that are likely to occur in narrow groove welding. . In order to obtain such an effect, the Si content must be 0.05% by weight or more.

On the other hand, if Si is contained in an amount of more than 1.50% by weight, the weld metal becomes brittle and the hot crack resistance deteriorates. Therefore, the Si content is 0.05 to 1.50% by weight.
And

Mn: 0.50 to 2.50 wt% Mn has the action of improving the conformability of the deposited metal and the blowhole resistance, and preventing welding defects such as poor fusion that are likely to occur in narrow groove internal welding. . In order to obtain such an effect, Mn needs to be added in an amount of 0.50% by weight or more.

On the other hand, if Mn is added in excess of 2.50% by weight, the weld metal becomes brittle and the hot crack resistance deteriorates. Therefore, the Mn content is 0.50 to 2.50% by weight.
And

Ni: 2.00 wt% or less Ni improves the ductility of the deposited metal and may be added if necessary. When Ni is added, its content must be 2.00% by weight or less. If Ni is added in excess of this upper limit, the hot crack resistance deteriorates, the hardness decreases, and the wear resistance required for the rail cannot be obtained. Therefore, when Ni is added, the content is 2.00% by weight or less.

Cr: 0.80 to 4.00 wt% Cr has an effect of stabilizing the hardness of the deposited metal. In order to obtain such an effect, it is necessary that the Cr content be 0.80% by weight or more.

However, if the Cr content exceeds 4.00% by weight, the deposited metal is hardened and the hot crack resistance is deteriorated. Therefore, the Cr content is 0.80 to 4.00% by weight.
And

Mo: 0.05 to 2.00 wt% Mo prevents the decrease in hardness when each pass undergoes multiple heat cycles and the hardness is likely to decrease, as in narrow groove internal welding. Have an effect. Therefore, 0.05% by weight or more of Mo is added.

However, even if Mo is added in an amount of more than 2.00% by weight, the effect of improving the performance is not recognized. Therefore, the Mo content is set to 0.05 to 2.00% by weight.

P: 0.015% by weight or less When a large amount of P is contained in the solid wire, the hot crack resistance of the deposited metal is impaired. Therefore, the P content is regulated to 0.015% by weight or less.

S: 0.015 wt% or less Since the content of S also impairs the hot crack resistance of the deposited metal, the S content is regulated to 0.015 wt% or less in order to prevent this.

Ti: 0.03 to 1.50 wt% Ti may be added to the solid wire as a deoxidizing agent. If the groove spacing is narrow or the rail base metal is diluted to a large extent due to welding conditions, the C content of the weld metal increases and C combines with O (oxygen), resulting in blowholes caused by CO gas. However, in order to prevent this, it is preferable to add Ti as a deoxidizing agent to the solid wire. When adding this Ti, it is necessary to add 0.03% by weight or more in order to obtain the effect.

When the Ti content exceeds 1.50% by weight,
The amount of slag generated increases, and welding defects such as slag winding and defective fusion occur. Therefore, the Ti content is 0.0
3 to 1.50% by weight.

(3) Welding conditions Welding current: 180 to 250 when wire diameter is 1.2 mm
A, 260-310 A when the wire diameter is 1.4 mm,
When the ear diameter is 1.6 mm and the welding current of 320 to 380 A is lower than the lower limit value for each wire diameter, the penetration is too shallow and fusion failure occurs. On the other hand, when the welding current exceeds the upper limit value for each wire diameter, the base material is excessively diluted, and depending on the rail steel type, the amount of C in the weld metal excessively increases and the hot crack resistance deteriorates. Therefore, the welding current is 180 to 25 when the wire diameter is 1.2 mm.
0A, wire diameter 1.4mm, welding current: 260
~ 310A, when the wire diameter is 1.6mm, welding current;
Set to 320 to 380A.

Welding voltage: 2 when wire diameter is 1.2 mm
6-31V, 27-33 when the wire diameter is 1.4mm
If the welding voltage is 29 to 35 V when the wire diameter is 1.6 mm and the wire diameter is less than the lower limit value for each wire diameter, the bead shape becomes defective and the fusion becomes defective. However, if the welding voltage exceeds the upper limit value for each wire diameter, the arc becomes unstable and welding defects are likely to occur. For this reason,
When the wire diameter is 1.2 mm, the welding voltage is 2;
6-31V, wire diameter 1.4mm, welding voltage;
When the wire diameter is 27 to 33 V and the wire diameter is 1.6 mm, the welding voltage is set to 29 to 35 V and 26 to 31 V.

Lamination method at the crown and interlayer temperature In order to relax and disperse the shrinkage stress applied to the final solidified portion of the weld bead, the rail crown has two or more passes per layer. Thereby, high temperature cracking (solidification cracking of the deposited metal) can be prevented.
Also, by stacking two or more passes per layer,
It is also possible to prevent welding defects (poor fusion, etc.).

Further, in the present invention, the interpass temperature at the top of the rail head is controlled to 400 to 700.degree. If the inter-pass temperature is less than 400 ° C., the shrinkage stress applied to the deposited metal becomes large, and hot cracking tends to occur. Further, if the interpass temperature exceeds 700 ° C., the rail base material is excessively diluted, the C content of the deposited metal is increased, and hot cracking is likely to occur.

[0029]

EXAMPLES Examples of the present invention will be described below in comparison with comparative examples.

First Example Rails having the chemical compositions shown in Table 1 below were arranged with the dimensions shown in FIG. 2 and welded under the welding conditions shown in Table 2 below. The temperature between passes of the crown was measured at the position indicated by A in FIG. Tables 3, 4 and 5 below show the chemical compositions of the welding wires of Examples and Comparative Examples used at this time, the combined welding conditions, and the evaluation results of the rail joints. Hot cracking,
The evaluation of the presence or absence of fusion failure, blowhole, slag inclusion, etc. was judged by an X-ray transmission test.

[0031]

[Table 1]

[0032]

[Table 2] However, the column P indicates the method of stacking the top (pass) (per layer).

[0033]

[Table 3]

[0034]

[Table 4]

[0035]

[Table 5]

In Examples 1 to 18, since the wire composition and welding conditions are within the scope of the present invention, high temperature cracking,
No defects such as poor fusion, blowholes, and slag insertion occurred.

On the other hand, in Comparative Examples 1 to 22, the welding conditions or the wire composition were out of the scope of the present invention, so that hot cracking occurred, or fusion failure, blowholes and slag inclusion occurred. did.

Second Example Rails having the chemical composition shown in Table 1 were arranged with the dimensions shown in FIG. 2 and welded under the welding conditions shown in Table 6 below. Table 7 below shows the chemical composition of the welding wire used at this time. Table 8 below shows the evaluation of the rail welded joint. The X-ray transmission test was used to evaluate the presence or absence of high-temperature cracking, defective fusion blowholes, slag inclusions, and the like. The presence or absence of slag inclusion was evaluated by an X-ray transmission test.

[0039]

[Table 6]

[0040]

[Table 7]

[0041]

[Table 8]

Examples 19, 20, 21, and 22 satisfy the conditions specified in the present invention, and the comparative examples are out of the scope of the present invention. Therefore, as shown in Table 8, in Examples 19 and 20, high temperature cracking, poor fusion, blowholes and slag insertion did not occur. On the other hand, in Comparative Examples 23, 24, and 25.26, since the wire composition was out of the range of the present invention, welding defects such as poor fusion occurred.

[0043]

As described above, according to the present invention, by welding the rail by the gas shield arc welding method using the solid wire for welding, the welding work time can be shortened by taking advantage of its high weldability. At the same time, by appropriately setting the composition of this solid wire and welding conditions, excellent joint performance as a rail can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a rail.

FIG. 2 is a standard side view of a rail showing a groove with the rails butted against each other.

3 (a) and 3 (b) are a cross-sectional view and a side view of a rail showing a temperature measurement position between passes at a rail top portion.

[Explanation of symbols]

 1; bottom 2; abdomen 3; head 4; crown 5; money

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication C22C 38/22 E01B 29/42 (72) Inventor Matsugo Matsugo Fujikawa City, Kanagawa Prefecture 100 No. 1 stock company Kobe Steel Works Fujisawa Works (72) Inventor Toshiharu Maruyama Fujisawa City, Kanagawa Prefecture Miyamae character Urakawachi 100 No. 1 stock company Kobe Works Fujisawa Works (72) Inventor Ken Yamashita Fujisawa City, Kanagawa Prefecture Back of the character Kawachi 100 No. 1 Stock company Kobe Steel Works Fujisawa Works

Claims (3)

[Claims] 1. A rail welding method for welding a rail made of a steel material containing 0.50 to 0.75% by weight of C by a gas shield arc welding method, wherein C: 0. 25% by weight or less, Si;
05 to 1.50 wt%, Mn; 0.50 to 2.50 wt%, Cr; 0.80 to 4.00 wt%, Mo; 0.05
To 2.00% by weight, P: 0.015% by weight or less, S: 0.015% by weight or less, and the balance is Fe and inevitable impurities. When it is 0.2 mm, welding current: 180 to 250
A, welding voltage; 26 to 31 V, when wire diameter is 1.4 mm, welding current; 260 to 310 A, welding voltage; 27 to
When the voltage is 33V and the wire diameter is 1.6mm, the welding current is 32.
Welding is carried out under welding conditions of 0-380A, welding voltage; 29-35V, the interpass temperature is controlled at 400 ° C to 700 ° C at the rail top, and the laminating method is set to 2 or more passes per layer. A method for welding a rail by a gas shielded arc welding method, which is characterized in that 2. A rail welding method for welding a rail made of a steel material containing 0.50 to 0.75 wt% of C by a gas shield arc welding method, wherein C: 0. 25% by weight or less, Si;
05-1.50 wt%, Mn; 0.50-2.50 wt%, Ni; 2.00 wt% or less, Cr; 0.80-4.
00% by weight, Mo: 0.05 to 2.00% by weight, P: 0.015% by weight or less, S: 0.015% by weight
Regulated below, using a solid wire with the balance being Fe and inevitable impurities, when the wire diameter is 1.2 mm, welding current: 180-250 A, welding voltage: 26-3
Welding current: 260 when 1 V and wire diameter is 1.4 mm
~ 310A, welding voltage; 27-33V, wire diameter 1.
When it is 6 mm, the welding current is 320 to 380 A, the welding voltage is 29 to 35 V, and the welding condition is
At the rail top, the temperature between passes is 400 ° C to 700 ° C.
A rail welding method according to the gas shield arc welding method, characterized in that the temperature is controlled to ℃ and the laminating method is 2 passes or more per layer. 3. The solid wire further comprises Ti;
The method for welding a rail by the gas shielded arc welding method according to claim 1 or 2, wherein the rail contains 0.3 to 1.50% by weight.