Overview

Pipe manufacturers have a different set of requirements to those who use of pipe products, specifically:

1. The need to weld seam or spiral depending on the type of pipe, not required for seamless pipe.

2. The ability to demonstrate that magnetism levels are less than an acceptable maximum.

3. To ensure that the customer receives a quality low magnetism product that can be used with confidence.

Manufacture

For seamed pipe the basis of manufacture is to start with steel sheet or strip and bend it into a pipe shape that can be welded.  Magnetism issues occur here for several reasons:

1. Mechanical stresses.

2. Sheet manufacture, handling and storage will induce magnetism.

3. Induced low level magnetism in the sheet is concentrated in the seam joint after forming.

Magnetism in use

Magnetism can stop welding on pipelines causing expensive delays and difficulties with pipe manufacturers.  Although the pipe may have no magnetism on leaving the factory, NDT, storage and handling can induce magnetism and it is often difficult to attribute the cause.

Solutions

There are several possible solutions:

1. At the manufacturing stage dynamic demagnetizing using Zeromag can be used to ensure that the seam welding is not hampered by magnetism.

2. A pass through system can remove all the magnetism in the pipe at manufacture – though this does not necessarily solve the problem for the user.

3. Many users use Zeromag to remove magnetism at the joint to allow welding to proceed.

Experience

The team at Diverse have wide hands on experience in tackling pipe magnetism issues and have the equipment, analysis tools and know-how to solve magnetic arc blow problems.