CN114434041A - Gas-shielded welding wire for improving weld performance of tube head of air cooler and welding method - Google Patents

Abstract

A gas shield welding wire for improving the welding performance of a tube head of an air cooler and a welding method are disclosed, wherein the gas shield welding wire comprises the following components in percentage by weight: mn: 0.3-0.5%, Si: 0.01-0.03%, S: 0.001-0.008%, P: 0.001-0.015, C: 0.001-0.1%, Cr: 0.001-0.1%, Ni: 0.001-0.1%, the sum of Cu, Al, Ti, Mo, Nb and V: < 0.03%, iron: 99.15-99.5; the sum of the weight of the components is 100 percent; the gas shielded welding wire welding tube head can eliminate the martensite structure of a welding line, the hardness is less than 200HB, the pull-out force of the welded tube head can also meet the GB151 specification, after the welding wire welding tube head is used, a heat treatment process is omitted, the labor intensity and the cost are reduced, the welding line can effectively resist sulfide stress corrosion, the product quality is ensured, and the service life of a product is ensured.

Description

Gas-shielded welding wire for improving weld performance of tube head of air cooler and welding method

Technical Field

The invention relates to the aspect of improving the welding seam performance of a tube head of an air cooler, in particular to a gas-shielded welding wire for improving the welding seam performance of the tube head of the air cooler and a welding method.

Background

The pipe head connecting part of the air cooler is the weakest area of the whole equipment, particularly the hydrogenation air cooler, and because of the existence of the medium hydrogen sulfide, stress corrosion easily occurs, so that the pipe head welding line is cracked and failed, equipment leaks, and potential safety hazards appear. The reason for analyzing the failure of the welding line of the tube head is that the welding line has martensite structure, so that the hardness of the welding line is improved, and simultaneously, the residual stress in the welding line finally causes sulfide stress corrosion cracking. At present, hydrogen-resistant welding wires HS09MnSHG-3 and HS08SHA welding wires produced by Harbin welding research institute are mainly adopted in the industry to weld the tube head of the hydrogenation air cooler, and after welding is finished, the hardness of the welding seam exceeds the standard, and heat treatment is needed to reduce the hardness of the welding seam of the tube head.

Because the heat-dissipating capacity of the heat exchange tube is stronger, a great deal of equipment and manpower are required to be invested when the heat treatment of the tube head meets the standard requirement, and the process control is very strict, so that the manufacturing cost of the air cooler is increased; although the content of sulfur and phosphorus in the hydrogen-resistant welding wire produced by the haar welding is low, the content of manganese and silicon in the welding wire is higher, the cooling speed is higher due to the structure of an air cooler after welding, a weld joint and a heat affected zone have a hardened martensite structure, if the heat treatment control after welding is improper, the martensite structure cannot be eliminated, the hardened structures such as martensite and the like are not easily generated during welding, the hardness can meet the requirement, the heat treatment process is omitted, the labor intensity and the cost are reduced, and the technical problem which is difficult to solve for a long time is solved.

In view of the above, a gas-shielded welding wire and a welding method for improving the welding performance of the tube head of the air cooler are developed.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, and provides a gas-shielded welding wire and a welding method for improving the welding seam performance of a tube head of an air cooler, which can eliminate the martensite structure of the welding seam, have the hardness of less than 200HB, ensure that the pull-out force of the welded tube head can meet the GB151 specification, avoid the heat treatment process after the tube head is welded by using the welding wire, reduce the labor intensity and the cost, effectively resist sulfide stress corrosion of the welding seam, ensure the product quality and ensure the service life of the product.

In order to achieve the purpose, the invention adopts the following technical scheme: a gas shield welding wire for improving the welding performance of a tube head of an air cooler and a welding method are disclosed, wherein the gas shield welding wire comprises the following components in percentage by weight:

mn: 0.3-0.5%, Si: 0.01-0.03%, S: 0.001-0.008%, P: 0.001-0.015, C: 0.001-0.1%, Cr: 0.001-0.1%, Ni: 0.001-0.1%, the sum of Cu, Al, Ti, Mo, Nb and V: < 0.03%, iron: 99.15 to 99.5; the sum of the weight of the components is 100 percent.

The welding method comprises the following steps: a first layer: current: 200-240A, voltage: 10-14V, welding speed: 35-45 s/turn, wire feed length: 260 ℃ and 300 mm/circle, and preheating, post-heating and heat treatment are not needed;

a second layer: current: 200-240A, voltage: 10-14V, welding speed: 35-45 s/turn, wire feed length: 520-580 mm/ring without preheating, post-heating and heat treatment;

and a third layer: current: 200-240A, voltage: 10-14V, welding speed: 35-45 s/turn, wire feed length: self-melting, no need of preheating, post-heating and heat treatment.

The invention has the beneficial effects that: the gas shielded welding wire welding tube head can eliminate the martensite structure of a welding line, the hardness is less than 200HB, the pull-out force of the welded tube head can also meet the GB151 specification, after the welding wire welding tube head is used, a heat treatment process is omitted, the labor intensity and the cost are reduced, the welding line can effectively resist sulfide stress corrosion, the product quality is ensured, and the service life of a product is ensured.

Detailed Description

The present invention will be described in further detail with reference to the following examples and embodiments:

example 1

The tube plate is made of Q345RHIC (delta 22), and the heat exchange tube is 10HSC (phi 25 multiplied by 2.5);

the gas shielded welding wire has the diameter: 0.8mm, and the gas shield welding wire comprises the following components in percentage by weight: c: 0.07 percent; si: 0.02 percent; mn: 0.45 percent; p: 0.014%; s: 0.006%; cr: 0.02 percent; ni: 0.03 percent; mo: 0.02 percent; cu: 0.01 percent; al: 0.001 percent; ti: 0.013 percent, the balance being iron, and the sum of the weight of the components is 100 percent;

a first layer: current: 220A, voltage: 13V, welding speed: 40 s/turn, wire feed length: 280 mm/circle, without preheating, post-heating and heat treatment;

a second layer: current: 220A, voltage: 13V, welding speed: 40 s/turn, wire feed length: 560 mm/circle, without preheating, post-heating and heat treatment;

and a third layer: current: 220A, voltage: 13V, welding speed: 40 s/turn, wire feed length: self-melting without preheating, post-heating and heat treatment;

after welding is finished, heat treatment is not carried out, and the hardness of the cross section of the welding seam of the pipe head is detected to be not more than 200 HB; the weld joint is detected as ferrite and bainite in a microscopic mode, and no martensite exists; and (3) detecting the pull-off force of the welding line of the tube head, wherein the tensile strength is not less than 420Mpa, the requirement is met, the length of the fusion line is 4.5-6.5mm, and the requirement of GB151 on the wall thickness of the tube is met.

Claims (2)

1. A gas shield welding wire and a welding method for improving the performance of a welding seam of a tube head of an air cooler are characterized in that: the gas shield welding wire comprises the following components in percentage by weight:

mn: 0.3-0.5%, Si: 0.01-0.03%, S: 0.001-0.008%, P: 0.001-0.015, C: 0.001-0.1%, Cr: 0.001-0.1%, Ni: 0.001-0.1%, the sum of Cu, Al, Ti, Mo, Nb and V: < 0.03%, iron: 99.15-99.5; the sum of the weight of the components is 100 percent.

2. The gas shield welding wire and the welding method for improving the weld performance of the tube head of the air cooler as claimed in claim 1, wherein the gas shield welding wire comprises the following components: the welding method comprises the following steps: a first layer: current: 200-240A, voltage: 10-14V, welding speed: 35-45 s/turn, wire feed length: 260 ℃ and 300 mm/circle, and preheating, post-heating and heat treatment are not needed;

a second layer: current: 200-240A, voltage: 10-14V, welding speed: 35-45 s/circle, wire feed length: 520-580 mm/ring without preheating, post-heating and heat treatment;

and a third layer: current: 200-240A, voltage: 10-14V, welding speed: 35-45 s/turn, wire feed length: self-melting, no need of preheating, post-heating and heat treatment.