Welding material for quickly welding and repairing defects of large-sized QT500-7 nodular cast iron parts and method

A welding material and rapid welding technology, which is applied in the direction of welding/cutting medium/material, welding medium, welding equipment, etc., can solve the problems such as difficult to deal with the defects of ductile iron castings, achieve the enhancement of weld crack resistance, reduce white spots and Effect of Crack Tendency

Inactive Publication Date: 2012-07-04
XIAN UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a welding material for fast welding and repairing defects of large-scale QT500

Method used

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  • Welding material for quickly welding and repairing defects of large-sized QT500-7 nodular cast iron parts and method
  • Welding material for quickly welding and repairing defects of large-sized QT500-7 nodular cast iron parts and method
  • Welding material for quickly welding and repairing defects of large-sized QT500-7 nodular cast iron parts and method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] First, the welding material for welding large QT500-7 ductile iron castings is prepared, which is composed of powders of the following components mixed uniformly by weight percentage:

[0049] Fe 2 o 3 30%, Al 27%, Na 2 CO 3 1.6%, Na 2 B 4 o 7 6%, CaF 2 6%, CaO 6%, SiO 2 1.0%, graphite 7.0%, 75Si-Fe 5.0%, 75Mn-Fe 1.0%, Ni 0.5%, Bi 0.2%, 60Si-Ca 1.2%, RE-Mg 0.5%, Q14 pig iron 7%, the total weight is 100%.

[0050] Then, using the above-mentioned prepared welding materials, implement according to the following steps:

[0051] Step 1. Grinding the defective part of the defective ductile iron casting 1 to process the groove 8, such as figure 1 ;

[0052] Step 2. Shape around the upper edge of the groove 8. Use molding sand or cement to build the embankment 2 along the upper periphery of the defect groove 8 to remove slag and prevent the overflow of molten metal. The upper edge of the embankment 2 needs to reserve the introduction groove of the ignition fuze 5...

Embodiment 2

[0060] First, the welding material for welding large QT500-7 ductile iron castings is prepared, which is composed of powders of the following components mixed uniformly by weight percentage:

[0061] Fe 2 o 3 33%, Al 28%, Na 2 CO 3 1.4%, Na 2 B 4 o 7 4%, CaF 2 4%, CaO 5%, SiO 2 0.5%, graphite 6.0%, 75Si-Fe 4.5%, 75Mn-Fe 1.5%, Ni 0.9%, Bi 0.1%, 60Si-Ca 1.5%, RE-Mg 0.6%, Q14 pig iron 9%, the total weight is 100%.

[0062] Then, using the above-mentioned prepared welding material, implement according to the specific steps in Example 1, and obtain the chemical composition (Wt%) of the deposited metal as: C 3.3, Si 2.67, Mn 0.50, S 0.018, P 0.045, and all The composition of the repaired QT500-7 ductile iron castings is basically the same, that is, the metallographic structure is the same. The mechanical properties of the weld metal are: tensile strength σ b It is 530MPa, the elongation δ is 6.8%, and the hardness HB is 247.

Embodiment 3

[0064] First, the welding material for welding large QT500-7 ductile iron castings is prepared, which is composed of powders of the following components mixed uniformly by weight percentage:

[0065] Fe 2 o 3 33%, Al 28%, Na 2 CO 3 1.5%, Na 2 B 4 o 7 4%, CaF 2 4%, CaO 5%, SiO 2 1.0%, graphite 7.0%, 75Si-Fe 5.0%, 75Mn-Fe 1.4%, Ni 1.0%, Bi 0.1%, 60Si-Ca 1.5%, RE-Mg 0.5%, Q14 pig iron 7%, the total weight is 100%.

[0066] Then, using the above-mentioned prepared welding material, implement according to the specific steps in Example 1, the chemical composition (Wt%) of the deposited metal obtained is: C 3.61, Si 2.74, Mn 0.50, S 0.019, P 0.046, and the The composition of the repaired QT500-7 ductile iron castings is basically the same, that is, the metallographic structure is the same. The mechanical properties of the weld metal are: tensile strength σ b It is 491MPa, the elongation δ is 7.6%, and the hardness HB is 216.

[0067] In the above embodiments, the chem...

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Abstract

The invention discloses a welding material for quickly welding and repairing defects of large-sized QT500-7 nodular cast iron parts, comprising powder components including, by weight percent, from 30 to 35% of Fe2O3, from 25 to 30% of Al, from 1.4 to 1.6% of Na2CO3, from 4 to 6% of Na2B4O7, from 4 to 6% of CaF2, from 5 to 8% of CaO, from 0.5 to 1.5% of SiO2, from 5.0 to 7.0% of graphite, from 4.0 to 5.0% of 75Si-Fe, from 1.0 to 2.0% of 75Mn-Fe, from 0.5 to 2% of Ni, from 0.1 to 0.3% of Bi, from 1.0 to 2.0% of 60Si-Ca, from 0.3 to 0.8% of RE-Mg and from 7 to 10% of Q14 pig iron which are uniformly mixed. The total weight percent of the powder components is 100%. The invention further discloses a method for quickly welding and repairing the defects of the large-sized QT500-7 nodular cast iron parts by the aid of the welding material. By the aid of the material and the method, the QT500-7 nodular cast iron parts can be quickly welded and repaired at room temperature, probability of chills and cracks can be effectively, and ingredients, structures and colors of weld joints are basically consistent to those of the nodular cast iron parts.

Description

technical field [0001] The invention belongs to the technical field of iron casting salvage engineering, and relates to a welding material for quickly welding and repairing defects of large-scale QT500-7 ductile iron castings, and also relates to a method for quickly welding and repairing defects of large-scale QT500-7 ductile iron castings by using the welding material . Background technique [0002] The casting process is complicated, and defects in ductile iron castings are inevitable. Due to the inherent solidification characteristics of cast iron, white spots and cracks in the welding repair area are very easy to occur during the welding process. Ductile iron castings such as machine tool beds, large gears and wind power devices have a high probability of defects, and the added value of welding repair is relatively large. Rescue and repair of defective ductile iron castings is an important measure for enterprises to increase capital and save energy, which is conducive t...

Claims

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Application Information

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IPC IPC(8): B23K35/34B23K23/00
Inventor 翟秋亚徐锦锋
Owner XIAN UNIV OF TECH
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