Puddle Arc Welding

MMA Puddle Arc Welding is the process of joining carbon steel crane rails

Preparation

The rails to be joined together are aligned leaving a prescribed gap between their ends. Rails end shall be smooth and free from defects and grease. The rails are set with a slight camber at the joint to allow for weld contraction and copper moulds are placed around and under the joint.

Heat Treatment

Joints are pre-heated to prescribed temperature and confirmed using temperature indicators prior to welding.

Welding

A mild steel strip is placed at the bottom of the joint on top of the copper strip (this steel strip will form part of the weld).

Welding is carried out using low hydrogen electrodes. Electrodes are held perpendicularly and short rectangular movements are used with the tip of the electrode. Copper moulds are placed around the outer profile of the rail as welding is continued. This process is continued until weld metal is within 10mm of the rail running surface and is allowed to cool for 5 minutes. The weld is then de-slagged and welding is continued to the top of the running surface.

Following an appropriate cooling period, the railhead is ground to profile and the rail aligned and fastened.

This is only a process guide. If you require further details please contact us using our contact page.