Magnetic Locating Theory Overview

📙 Unlike metal detectors, which can detect a wide range of metal types, magnetic locators are specifically designed to detect the presence of ferrous metals.


Magnetometers work by detecting the ambient magnetic fields emanating from natural ferromagnetic minerals, such as Iron, austenitic stainless steels, cobalt and nickel.


These changes are then translated into audio and visual signals, which can guide the operator to the object's precise location.

Module Learning Outcome.

Find out the answers to the following questions.

  • What is the difference between magnetometer and metal detector? 
  • What materials can magnetometers detect?
  • What is the difference between Ferromagnetic and non-ferromagnetic?
  • What are some examples of Ferromagnetic utilities?

Video for this page. Overview of Magnetic Locating. (54 Seconds)

Listen to this page. Audio Summary Version for Overview of Magnetic Locating. (54 Seconds)

What is the difference between "Ferromagnetic" and "non-ferromagnetic"?

✅ Ferromagnetic Metals

  • Iron
  • Iron Alloys
  • Cobalt
  • Nickel

❌ Non-Ferromagnetic Metals

  • Aluminum
  • Copper
  • Titanium
  • Brass

💡 TIP: Steel

Can Steel pipes and targets be located with a magnetometer or magnetic locating? Most construction steel materials are non-ferrous austenite stainless steels, and cannot be located by magnetic locators. However Martensitic Steel are magnetic, however they are usually used for springs, medical tools, knives and rarely used for utility piping.

✅ Ferromagnetic Metal Examples

Cast Iron, Iron Pipes: Rusted old buried iron pipes

✅ Ferromagnetic Metal

  • Iron 

Rusted iron pipes can be abandoned, disconnected, located to be replaced. 

✅ Ferromagnetic Metal

  • Iron
Ductile Iron Water Pipes

100mm Damaged Iron Water Pipe

✅ Ferromagnetic Metal

  • Iron
iron pipe corrosion

Rusted Iron Pipes (metallic corrosion)

✅ Ferromagnetic Metal

  • Other Ferrous Objects

Some Rusted Drums, Car parts, pipe connectors/junctions, Valves, Septic pit lids, Underground storage tank lids are detectable.

✅ Ferromagnetic Metal

  • Nickel Alloy Heat Pipes

Nickel Alloy Pipes are not common but are used in a high temperature applications in high corrosion industrial factory settings. 

✅ Ferromagnetic Metal

  • Iron 
ductile iron pipe

New Ductile Iron water pipe, picture of 300mm x 5.5m (Available in 100mm-600mm x 5.5m in Australia)

✅ Ferromagnetic Metal

  • Cast Iron 

Cast Iron Manhole Cover

Cast Iron Manhole Cover

Cast Iron Manhole Cover

Cast Iron Manhole Cover

⚠️ TIP: Survey Markers, Magnetic Markers.

👇 The below images are ferrous markers that can be located with magnetic locating. Only specific Surveyor markers can be detected magnetically. Copper or brass survey markers cannot be detected by magnetic locators .

✅ Ferromagnetic Metal

  • Iron 
Surveys Property Marker

Surveys Property Marker

Underground Magnetic Markers for Surveys

Underground Magnetic Markers for Surveys

Click Here Next Section:Theory of Magnetic Locators & Magnetometers 
Click Here Previous Section:Magnetic Locators Overview

1.  📙 Overview of Magnetic Locating

2.  ⚛️ Theory of Magnetic & Magnetometers

3. Utility Locating Technology Comparison Questions and Answers.

4.  ✅ Applications of Magnetic Utility Locating

5.  ✔️Advantages of Magnetometers Locating

6. 🚫 Limitations of Magnetic Fields

7.  🏁 Conclusion of Magnetic Utility Locating

8.  📚🎓 Magnetic Utility Locating Quiz

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