welding type mainly divided into: 1, welding rod arc welding; 2, submerged arc welding ( Automatic welding) ; 3, co2 gas shielded welding ( Automatic or semi-automatic welding) ; 4, MIG/MAG welding ( Melting polar inert gas protection welding; 5, TIG welding ( Tungsten inert gas) welding ; Six, six kinds of welding plasma arc welding method, the principle and application of each way is different, because is not the focus of this article, so simple known are available, the following focus on welding ball valve welding technology processing:

welding welding ball valve is different from ordinary welding technology, because the body cavity with nonmetal sealing material rubber and ptfe plastic, not in the heat treatment after welding. Welded ball valve the thick wall of multi-layer welding process is repeated heating and cooling of the metal material, the process of its welded joint are usually designed to be thick wall narrow gap submerged arc welding, and the use of fully welded body most is that the thickness of the large tubular welded joint. So the body of the root of the welded joint crack stress concentration, residual stress, the organization of inferior become weak link in the body structure, the two kinds of processing mode is: 1. Is the heat treatment technology; 2. Is the joint treatment; The two way will produce a few times the normal working stress of stress concentration, also make the factory engineers are difficult to deal with.

so, how to solve the welding ball valve body welding joint the root of the gap of stress concentration, residual stress, organizational inferior become the biggest problem the Industrial Valves welding, springs all welded ball Industrial Valves factory here for everyone to summarize the main points of body welding technology as follows, the hope can help to understand the ball Industrial Valves welding technology for friends!

is presently as follows the body of the welding process is introduced.

1, the body of the technical requirements

( 1) After the seam welding body without deformation, including upper and lower shaft flange ( 45 steel) 。

( 2) The body cannot too wide and the temperature of heated area cannot be too high, otherwise it will damage the body sealing device.

( 3) Not a flash.

( 4) Compression of guarantee in more than 10 mpa.

2, weld structure

according to the above technical requirements, determine the weld is not penetration weld. So the weld joint form to guarantee the assembly and ensure no penetration. After test, finally determine the weld form.

3, the valve body material

because the body is ZG15 Ⅱ, so before the processing of the chemical constituents of the valve body test, the test results are consistent with the test results of during casting, comply with the design requirements.

4, the assembly

use hydraulic press modified flip fetal positioning, bolt, and around half part adjust tightness test, sphere between external and body to meet the design requirements.

5, welding process

considering the technical requirements of the body, finally chose the MAG CO2 welding machine.

choose ER50 - welding materials 6 ( Ø 1. 0) Welding wire.

according to the principle of welding materials such as strength, the selected ER50 - 6 ( Ø 1. 0) Wire satisfied ZG15 Ⅱ requirements.

protective gas using Ar + 82% and 18% CO2 gas mixture.

5。 Tack welding 1

because of cast steel and 45 steel hardening tendency is serious, so the location need to preheating before welding, the oxygen - Acetylene flame on weld flanked by 2 times the thickness range evenly heating to 75 ~ 100 ℃ ( To 45 steel side) , does not affect the sealing device shall prevail, with the far infrared thermometer to measure.

a 20 mm on both sides of weld surface before welding within the scope of the scale and rust with Angle grinder polishing metallic luster.

50 mm away from the edge on both sides of weld dozen anchor point 6, with a caliper measuring the distance between two points, in order to measure its shrinkage.

5。 2 back weld

because of considering the ZG15 Ⅱ rigidity of materials, the characteristics of low plasticity, so in choosing welding specification should take small welding parameters, that is, small welding heat input. On the premise of guarantee the quality of weld, as far as possible to improve the welding speed, reduce the fusion ratio, in the aspect of deformation to multilayer multichannel points 6 section of the symmetry of welding method; Pay attention to each layer welding anchor point is measured with a caliper, to control the shrinkage, until after welding. Except the first and the last line of each other between the hammering method for eliminating stress.

6, the last step

after completion of welding by suppressing test ( Air tight) After joint leakage, and sealing surface to meet the technical requirement, through X-ray flaw detection, the weld itself without porosity, slag inclusion, incomplete fusion, welding defects such as cracks, rotary valve core to meet the technical requirements.

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