Flange welding quality and process

Welding quality
As far as iron plate welding flanges are concerned, many customers question whether the quality of iron plate welding flanges is better than that of forged welding flanges. In fact, the quality of the iron plate welding flange and the quality of the forged welding flange are the same, but where can the iron plate welding flange not be guaranteed, that is, the material of the iron plate welding flange is the most unguaranteed, because in the general process, the density of the iron plate welding flange is no problem, but in the process of production, the blank of the iron plate welding flange is rarely tested, so after the production, the material of the iron plate welding flange that has not been tested cannot be guaranteed.
Welding process
equipment
required A set of manual electric welding equipment, a handle type angle grinder, an electric air hammer, a plane ruler.

1. Check and debug the equipment to ensure the normal operation of the equipment;

2. Prepare φ4.0J402 electrode and dry it at 300°C-350°C for one hour.
Welding process
1, assemble the conerate and the large flange according to the requirements of the drawing, and then divide the large flange into 8 equal parts.
2. Due to the thick flange and large groove, the welding adopts segmented symmetry and multi-layer welding.
Weld quality
requires that the strength of the weld is at least that of the base metal. The surface of the weld is smooth and smooth, and there are no defects such as burn-through, porosity, welding leakage, slag inclusion, undercut, and incomplete welding. The residual height is less than 2mm.

Precautions 1. When laying the bottom, J506 welding rod must be used for manual surfacing welding, and small current welding is used. Welding in strict accordance with the welding process.
2. After each welding position, the deformation of the flange plane should be clamped with a level.
3. Hammer the weld with an air hammer while welding to achieve the effect of relieving stress.
Flange gasket
A gasket is a ring made of material that can produce plastic deformation and has a certain strength. Most of the gaskets are cut from non-metallic plates, or made by professional factories according to the specified size, and their materials are asbestos rubber sheets, asbestos sheets, PTFE sheets, polyethylene sheets, etc.; There are also metal-clad gaskets made of thin metal plates (white iron sheets, stainless steel) wrapped in non-metallic materials such as asbestos; There is also a kind of winding gasket made of thin steel belt and asbestos belt, the most commonly used is the metal winding gasket made of stainless steel belt and graphite, according to the use of different environments, the winding belt can also be made of asbestos. Ordinary rubber gasket is suitable for occasions with temperatures lower than 120°C; Asbestos rubber gasket is suitable for water vapor temperature below 450 °C, oil temperature below 350 °C, pressure below 5MPa, for general corrosive media, the most commonly used is acid-resistant asbestos board. In high-pressure equipment and pipelines, lens type or other metal gaskets made of copper, aluminum, No. 10 steel, stainless steel or other shapes are used. The contact width between the high-pressure gasket and the sealing surface is very narrow (line contact), and the processing finish between the sealing surface and the gasket is high.
Welded flanges are used for low pressure small diameters, welded flanges are used for high pressure and low pressure large diameters, and the thickness of the flanges and the diameter and number of connecting bolts are different for different pressures.

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