Demagnetization Products

Demagnetizing kit for pipe and plate welders DKPW

Everything needed to overcome magnetic arc blow in one package. At its heart is the world leading Zeromag machine which measures and neutralizes magnetic fields which may be present in the weld preparation region of mating steel components. Zeromag is a portable machine that can be carried by one person to the site where it is needed.

The kit comprises:

• Zeromag ZM100A demagnetizer
• Air cooled magnetic probe
• Demagnetizing cable 50m
• Magmeter MF300H+ gaussmeter
• Demagnetizing and probe extension cables
• Storage and shipping cases

Other components of the kit include the MF300H+, the tool of choice for measuring in magnetism in weld preparations.  The ZM2PG air cooled probe which is built from stainless steel and is sufficiently robust that it can be used close to active welding in the weld prep.

A full cable set of demagnetizing cables and extension cables is provided. Finally, the whole kit is supplied in 2 robust packing cases for transport and storage.

The DKPW comes with simple and comprehensive instructions for use.  We provide telephone and email support as well as training packages either on-site or on-line.  DKPW is available for hire for short term projects.

Zeromag ZM100A Demagnetizer

Zeromag ZM100A is a demagnetising system for steel pipes and plates. Zeromag is used to reduce the magnetic field levels in welding joint preparations to levels which are low enough to enable welding to proceed. Its novel technology has been solving this problem for welders around the world for over 15 years.  The solution is fast (ready to weld in just a few seconds), deep penetrating (will easily handle 50mm thick wall size) and easy to use.

Zeromag is used to eliminate arc blow which can occur when the parts to be welded are magnetic – this shows up as high magnetic field levels in the joint preparation. This table lists the most common effects of magnetism on welding processes.

Even when weak magnetic fields are present in the steel, the effect of the reduction in face area in a V or J weld preparations serves to concentrate the magnetic flux. Consequently, the value in the joint preparation can easily be several hundred gauss and fields reaching 1000 gauss are possible.

Working with large pipes, Zeromag can reduce magnetic field levels to a few gauss even with residual field levels of over 1000 gauss.

With Zeromag, you are in control – you can see the magnetic field level in the weld area, control Zeromag either manually or automatically and see the magnetism shrink to zero.  You then know its clear to weld unimpeded.

Zeromag can be extended to provide joint or pipe end degaussing.

Ferrite Meter MF300Fm+

Industrial processing and chemical plants work at high temperatures and pressures, often with aggressive media; stainless steel is often the material of choice for these applications. If the ferrite content of the steel steel is too low, then welding of stainless material may crack at elevated temperature or with high stress or vibration. If the ferrite content is too high, the weld may be weaker and corrode.

To address the need to measure the amount of ferrite in a sample the Welding Research Council introduced the Ferrite Number (FN) as standardised value which related to the ferrite content of an equivalently magnetic weld metal. The volume percentage of ferrite is estimated using a piecewise linear model for typical steels. The relationship depends upon the type and origin of the stainless steel used and the measurement technique.

Ferrite meter MF300Fm+ measures the Ferrite number (FN) of austenitic and duplex stainless steel weld material.  There are 4 probe options: P46 with an active area of 4x6mm; P46R right angled probe; P10 that is sensitive to ferrite content in a 10 mm diameter; P10AC is an air cooled version of P10 for use with hot samples.  Depth sensitivity of approximately 1 mm. MF300Fm+ can be supplied with up to 5 probes as follows: P10 (1 or 2), P46, P46R and P10AC.

The instrument is calibrated using NIST secondary weld standards.  All 16 standards are used in the calibration giving an instrument with a measurement range from 0 to 115 FN.  Transfer standards are supplied with the instrument allowing performance to be verified at any time.

Features of MF300Fm+ Ferrite Meter

• NDT of the ferrite content in a range of 0.1 to 115FN equivalent to 0.1 to 83% Fe in austenitic & duplex steel.
• Robust and portable
• Standard or peak measurement of Ferrite Number
• Piecewise estimate of ferrite percentage
• Automatic zero on demand
• Supplied with 5 transfer standards allowing veracity of instrument to be checked
• Storage of 1000 measurements, downloaded to PC with RS232/USB option
• 10mm diameter (P10) and 4x6mm (P46) probe options
• Right angled probe for use where access is restricted (P46R)
• Use with high temperature samples (air-cooled probe option)
• Up to 5 probes per instrument
• Simple measurement with small sample area.
• Units selectable between WRC-FN and %Fe.
• Calibration with standards traceable to NIST standards
• Large character display mode
• Backlit display
• Supplied in carry case

Magnetic Finite Element Analysis (FEA)

We use magnetic finite element analysis in the design of its products.  The procedure is to make 3D drawings of the components and assemblies of the system and then import this into Comsol multi-physics.  This allows the magnetic fields to be assessed together with other related physics such as electrical currents, mechanical forces and stresses, temperature rise and electrostatic fields.

User applications have ranged from pipe arrangements with specific materials through to the analysis of the magnetic field generated by an aluminium smelting pot line.

We make this same capability available for assessment of customers’ deployment of our products in unusual applications.  In its consultancy role, We offer its customers this capability for assessment of and simulation of multi-physics in products and applications removed from our demagnetizing business.

Following the above procedure, the client needs to supply us with 2D/3D drawings of the system to be considered and we will undertake the analysis.  The final output can be simply numeric, graphical or complex 3D representation like the one shown in the picture.