What is the ceramic pad welding process

Ceramic backing ​When welding the basic welding arc on one side, a shrinkage hole will appear in the center of the back side of the folded arc. The main reason for the shrinkage hole is that the thermal conductivity of the ceramic liner is smaller than that of the base metal. The molten metal above the molten pool solidifies first due to good cooling conditions, and the molten metal below the molten pool solidifies later due to poor thermal conditions. Volume shrinkage occurs when the temperature drops during solidification. At this time, some other metals have hardened and cannot compensate for this shrinkage, thus forming shrinkage holes. In order to eliminate this shrinkage hole, the current decay method must be adopted first.

What is the ceramic pad welding process

1. Groove style

Groove styles for butt flat, vertical, cross and fillet welds

In order to achieve the purpose of effective welding, the installation gap should reach the lower limit as much as possible during the assembly process, so as to reduce the melting amount of the welding metal of the ceramic backing. The north area of ​​the groove surface is determined by the segmented construction process in principle, and it should be located on the side where welding is convenient as much as possible. In order to facilitate on-site processing, ensure the accuracy of the groove angle.

2. Welding Specifications for Ceramic Liners

The welding specifications of the ceramic liner welding double-sided forming process are relatively flexible, which is related to the technology and proficiency of the welder. When selecting welding specifications, please pay attention to the matching of welding current and voltage to ensure that the welding is well formed. Skilled welders can use higher amperage welding specifications to increase labor productivity. The welding current should not exceed 230A (wire diameter 1.2).

3. Operation essentials

CO2 single-sided welding is a very technical welding method. Factors affecting welding double-sided forming include equipment performance, climate, construction space environment, network voltage, personnel quality, etc., but more importantly, personnel quality. The quality of welders is reflected in the aspects of cognition (theoretical level), technical skills, proficiency, and work attitude. Therefore, even if the appropriate welding specification parameters are used, the correct operation method and technical essentials must be mastered in order to obtain satisfactory welding quality.

Ceramic Liner Welding Finishing Method

Common CO2 welders now have an adjustment handle that fills the arc foot attenuation specification. Before welding, adjust this handle to an appropriate attenuation value, press the button on the gun twice when the arc is turned off, the welding current and welding voltage will be automatically attenuated to a smaller value in the original parameters. Afterwards, after the molten metal fills the pit, the arc is introduced into the solidified weld. Release the button on the torch at this point and the arc will shut off without constriction. The plate of the hull structure is relatively thick, so when using CO2 single-side welding and double-side forming process, multi-layer and multi-welding are usually used. When using multi-layer welding, it is necessary to focus on mastering the operation techniques of basic welding and cover welding. Basic welding is the core of CO2 single-sided welding as it relates to the backside forming of the joint. There is a pad on the back of the joint to prevent the molten iron from escaping and to support the retreat, but with the correct operation method, the front and back of the weld can be well shaped. In particular, in order to prevent the back side of welding from drooping too much or slag drooping, the front side of welding should be prevented from forming a shape with a medium height and low sides, so as not to cause difficulties for subsequent welding.

For welding with large structural constraints (such as large closed welding), it is necessary to complete the welding of 2 or 3 layers of welding (depending on the thickness of the plate) at one time to ensure that the welding strength is sufficient. In order to prevent welding stress from causing longitudinal cracks in the weld, it cannot be placed for a long time after back welding. The welding of each layer should maintain the continuity of the welding arrangement, and it is not possible to weld a good section, resulting in defects such as damaged heads and welding types of each card code.

When welding the lid, the welding current, voltage, welding speed and other specification parameters should be adjusted to ensure that the welding shape is well formed, reduce the workload of supplementary welding and grinding, and improve welding productivity. The remaining amount of welding should be controlled at 3. For long welds, you can use step-by-step retreat, jump or split welding methods. When using split welding method, please use symmetrical welding as much as possible to reduce welding distortion. When welding low-alloy steel, cast steel and high-strength steel, necessary preheating measures should be taken. Specific requirements can follow the relevant welding process.