Residual magnetism

Pay attention to residual magnetism: this is a real defect and a supply problem that makes your pieces unsuitable for your clients’ needs; it also makes them not in line with some international standards. Moreover, it can create difficulties in several industrial processing.

Induced magnetism in the production
of steel pipes and bars

Steel parts such as pipes and bars may become magnetized when exposed to magnetic fields. For example, the magnetization can take place after industrial processing; or during transport or permanence in the storage place; or with a manipulation made using particular tools.
This phenomenon also occurs after the most well-known nondestructive testing which generate magnetic fields.

Magnetism induced by manufacturing

Many industrial processing carried out on ferromagnetic metals cause an induced magnetization. Some of these are: clamping with magnetic chucks, bending, rubbing/abrasion/friction between pieces and tools.

Magnetic field induced by non-destructive testing

Magnetic particles inspection and eddy currents are used for steel pipes and bars control. Despite the demagnetization usually applied downstream of these processes, the piece can maintain a magnetic residue.

High residual magnetism at the end of the production cycle?

Despite the magnetization following nondestructive testing, sometimes the level of magnetic residue remains too high. In this case, your clients will unlikely accept the piece, as it does not comply their needs.

Why does magnetism still remain inside of the part? For various reasons: for example, the piece may have undergone manipulation after quality controls or it may have been accidentally exposed to further magnetic fields. Again, the magnetism may have remained due to the controls themselves.

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Eddy currents: the core of the piece remains magnetic

Despite the magnetization following nondestructive testing, sometimes the level of magnetic residue remains too high. In this case, your clients will unlikely accept the piece, as it does not comply their needs.

Why does magnetism still remain inside of the part? For various reasons: for example, the piece may have undergone manipulation after quality controls or it may have been accidentally exposed to further magnetic fields. Again, the magnetism may have remained due to the controls themselves..

Problems in processing steel pipes and bars?

If you find it difficult perform particular processes or you notice unpleasant flaws at the end of the operations, residual magnetism could be the cause. You have to eliminate it: magnetic or flawed pieces could have a considerable impact on the processing costs!

Steel welding, chrome plating, nickel plating and washing: the compromised processes

Magnetism impacts on different industrial processing making them difficult and, sometimes, impracticable.
If the piece is magnetic, you will not be able to weld properly due to the arc blow.
Residual magnetism significantly affects several surface deposits. First, chrome plating and nickel plating are particularly prone to defects due to residual magnetism. In particular, during the nickel plating process needle-shaped deposit may form, compromising the result of the processing.

Non-stainless steel: the best known among ferromagnetic metals

You’ll probably already know it, but most of the steels you work daily (except for stainless steel) are naturally ferromagnetic, which means, simplifying, that they are attracted to magnets.
This happens because steel is an alloy composed of carbon and iron; the latter is one of the main ferromagnetic substances.

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The residual magnetization is a non-conformity of your supply process!

A high magnetic residue is considered a defect and a supply problem: by not respecting the current production parameters and the regulations, it will be difficult to market your pieces in many sectors.
Make sure that the level of magnetization of pipes and bars is within the supply specifications and satisfies the technical specifications, for example:

  • EN 10228-1, applied to forged pieces, requires a maximum magnetism of 800 A / m (about 10 Gauss)
  • EN 1290 applies to welds controlled with Magnetic Particle Inspection and suggests 400 A / m (about 5 Gauss)
  • The VPI09, for railway structures controlled with Magnetic Particle Inspection, requires 400 A / m (about 5 Gauss)
  • According to the API 5L, regulation of the American Petroleum Institute that defines the standards of the pipes (Standard Line Pipe) for the gas, water and oil transport, the level of magnetism should be less than or equal to 3.0 mT (30 Gauss) and in any case it should not exceed 3.5 mT (35 Gauss)

The solution? Our low-frequency industrial demagnetizer

With our low-frequency industrial demagnetizer, you will significantly reduce residual magnetism. It has an intuitive touchscreen interface; the machine degauss the pieces reaching a deep level and makes them ready for processing and subsequent uses.

Functionality combines with efficiency: you can demagnetize industrial components, especially large diameter pipes and bars, in single or bundled pieces, optimizing your time and saving money!

Rimozione magnetizzazione indotta quadro tunnel quadro