Welding method of stainless steel plate

Stainless steel plate welding is a specialized process that requires precision and adherence to specific methods to ensure the integrity and strength of the joint. Here's a detailed overview of the various welding methods and techniques used for stainless steel plates:

Types of Butt Joints

Butt joints are the most prevalent type of joint used in welding. They come in several forms, including:

I-shaped butt joints, which are un-beveled and suitable for plates up to 6mm thick. These joints are welded double-sided with a gap left between the plates.

V-shaped bevel joints, which are easy to prepare but may lead to post-weld deformation.

U-shaped bevel joints, which require less filler metal and result in less deformation but are more difficult to machine.

X-groove joints, which have a symmetrical weld cross-section and cause less deformation and stress compared to V-shaped grooves. They also require less filler metal than V-shaped grooves when the plate thickness is the same.

Double U-shaped groove joints, which are similar to U-shaped bevels but are used for more critical structures due to their complexity.

Arc Welding Techniques

Arc welding of stainless steel plates involves specific techniques to initiate and maintain the arc effectively:

Arc Initiation: There are two primary methods for starting the arc:

Scratching Method: This involves aligning the electrode with the workpiece, lightly scratching the surface about 20mm away from the arc, and then lifting the electrode to maintain an arc height of 2-4mm. It's easier to perform but may damage the weldment's surface and is typically used with alkaline electrodes.

Direct Strike Method: This method involves aligning the welding rod with the workpiece, tapping the electrode vertically onto the workpiece to initiate the arc, and then lifting it to a height of 2-4mm. It's more precise but requires skill and is often used with acid electrodes or in confined spaces.

Troubleshooting: If the electrode becomes stuck to the workpiece, it can be freed by gently moving it from side to side. If this doesn't work, the welder should immediately release the electrode and allow it to cool before twisting it off. If the electrode has a sheath at the end, it should be removed with gloved hands before restarting the arc.