Diverse Technologies MF300Fm+

Diverse Technologies MF300Fm+

The MF300Fm+ provides superior accuracy at a fraction of the cost

What Problem Does it Solve?

Industrial processing and chemical plants work at high temperatures and pressures, often with aggressive media, and stainless steel is often the material of choice for these applications. If the ferrite content of the steel is too low, then welding of stainless material may crack at elevated temperature or with high stress or vibration. Alternatively, if the ferrite content is too high, the weld may be weaker and corrode. The ferrite meter MF300Fm+ allows the user to assess the ferrite content of such welds.

The MF300Fm+ is the newest Ferrite Meter from Diverse and supersedes its predecessor, the MF300Fe+. It meets or exceeds all specifications of the MF300Fe+ and can now be used with up to 5 probes at a time.

P10 probe on weld


P46 probe on weld

Why Choose This Product?

The main advantages are: 

  • Cost. The MF300Fm+ is generally less expensive and more cost-effective than the competitors' products.
  • Ease of use. The Ferrite Meter MF300Fm+ does not have different probes for different FN ranges. It does not need to take many measurements nor require statistical analysis. 
  • Probe Size. Due to the probe size a reasonable volume of stainless steel is assessed and the result is the average FN over this volume (roughly 10mm diameter area by approximately 1mm depth) for P10 probe. 
  • Accuracy. Calibration against 16 secondary ferrite number standards ranging from 0.5FN to 111.9FN certified by the American National Instititute of Standards and Technology (NIST). 
  • Air Cooled Option. For measurement on hot samples the Ferrite Meter MF300Fe+ has an option for an air cooled probe P10AC. This is unique in allowing measurement of samples at higher temperatures. 
  • Sturdy. The ferrite probe is very robust and not prone to damage.

The only downside is that our probes require a flat area of  minimum 10mm diameter for the P10 probe or 4 x 6mm for the P46 probe. While competitors' instruments have a smaller assessment area, complex statistic and repeated measurements are required to get a meaningful result due to grain size issues, making the MF300Fm+ a better option for the majority of uses.

The Probe Choices Are:

  • Standard P10 (up to 2 probes)
  • Air cooled probe P10AC (1 probe)
  • Small area P46 (up to 2 probes)


The MF300Fm+ is the latest instrument from Diverse Technologies, and an upgraded version of its predecessor, the MF300Fe+. The MF300Fm+ measures the Ferrite number (FN) of austenitic and duplex stainless steel weld material, and can be operated with 3 probes simultaneously. The robust, slimline probe benefits from a novel magnetic system with excellent coupling to a measurement sample, that is sensitive to ferrite content in 10mm area to a depth of approximately 1mm. An air cooled version of the probe (must be specified at time of order) allows Ferrite measurements on hot samples as well.

The MF300Fm+ can store up to 1000 measurements including record number (0 - 999), measured ferrite number and recorded ID (4 characters, 0-9, A-Z and space). You can download or upload these measurements to a PC via RS232 or USB (optional).

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


  • Non-destructive test of the ferrite content in a range of 0.1 to 115FN equivalent to 0.1 to 80.5% Fe in austenitic and duplex steel.
  • Robust and portable
  • Standard or Peak measurement of Ferrite Number 
  • Estimate of ferrite percentage (using a FN to F% curve)
  • Automatic zero on demand
  • Choice of probes: 10mm diameter probe or 4x6 probe, up to 5 probes per instrument
  • Spring loaded sleeve (4mm x 6mm probe)
  • Supplied with 5 transfer standards, allowing veracity of instrument to be checked
  • Storage of 1000 measurements downloadable to PC with RS232/USB (optional)
  • Use with high temperature samples (air-cooled probe option)
  • Simple measurement with small sample area
  • Units selectable between WRC-FN and %Fe
  • Calibration to weld standards validated by NIST and TWI according to methods described in DIN EN ISO 8249 and ANSI/AWS A4.2.
  • Supplied with carrying case and full user manual.



Large Area Probe: P10

The P10 Large Area Probe is constructed with a 10mm diameter ring that is set proud at the tip. For measurement, this ring is brought into contact with a reasonably flat portion of the object under test and a reading can be taken. This has the advantages of averaging over a wide area removing any need for statistical analysis.



Large Area Probe: P10AC (Air-Cooled)

With an air flow adaptor and other internal and calibration changes, the P10AC Air Cooled Probe version allows for measuring of hot samples. Air flow is directed in the standard hose connector, over the sensor and magnetic components and is routed out of vent holes in the probe barrel.



Small Area Probe: P46

The P46 Small Area Probe (4 x 6 mm) retains the pencil style but senses over a much reduced area. It can be used to measure weld seams down to 4 mm width. It has a spring loaded sleeve to minimize probe tip wear. The probe has the advantage of small sensing area suitable for welds and pipes. The end of the probe should be flat against the sample under test.

Technical Specifications


  • Ferrite Number FN
  • Ferrite percentage F%

0 - 115 FN
0 - 80.5% (percent ferrite)


0.1 FN
0.1 F%

Standard: Accuracy (10°C - 30°C)

FN 0 - 10: ± 0.5 FN
FN 10 - 30: ± 5% of the reading
FN 30 - 100: ± 10% of the reading

Air Cooled: Accuracy (30°C - 300°C)

FN 0 - 10: ± 1 FN
FN 10 - 30: ± 10% of the reading
FN 30 - 100: ± 20% of the reading


  • Factory calibration to NIST standards
  • User calibration to supplied transfer standards
  • Up to 5 calibrations can be supplied (for 5 probes)
Transfer Standards

  • Five transfer standards
  • Range typically 3 FN to 115 FN

Automatic on demand


Average or peak


1000 records with 4 character records ID (characters available 0-9, A-Z and space)

PC Download and Upload

  • Optional RS232 and USB
  • Functions include download of record or part or entire database and upload of record IDs
Probe P46

  • Pencil style, 15 mm diameter length 130 mm
  • Sensing area 4 mm x 6 mm (24 mm^2)
  • Spring loaded sleeve
Probe P10

  • Pencil style, 15 mm diameter length 120 mm
  • Sensing area 10 mm diameter (~80 mm^2)
Operating Temperature

  • Standard 0°C - 40°C (P46 and P10)
  • Air cooled 0°C - 300°C (P10ac)
Air Cooled Operation

  • Air line supply regulated to 1 bar maximum
  • Oil filtered supply desirable
  • Air temperature: ambient (10°C - 30°C)


Weight in Case

1.25 kg

Case Dimensions

8.27" x 3.94" x 1.73" (210mm x 100mm x 45 mm)

Probes (interchangeable up to 5)

  • 4 mm x 6 mm probe MF300Fm+ P46
  • 10 mm probe MF300Fm+ P10
  • 10 mm probe with air cooling MF300Fm+ P10ac

Kit Includes

MF300Fm+ Instrument Kit

  • Diverse MF300Fm+ Ferrite Meter and Probe (or probes)
  • 5x Transfer Standards
  • Carrying Case
  • (optional) Serial / USB cable and software MF300+

Product Literature

Description Part # Saved Price Select Option Add to
MF300Fm+ P46, handheld ferrite meter with 1000 records, 4mm x 6mm probe, 5 transfer calibration standards and carry case FM-DT-MF300FM-P46 $3,995.00
MF300Fm+ P10, handheld ferrite meter with 1000 records,10mm diameter probe, 5 transfer calibration standards and carry case FM-DT-MF300FM-P10 $3,995.00
MF300Fm+ P10AC, handheld ferrite meter with 1000 records,10mm diameter air cooled probe, 5 transfer calibration standards and carry case FM-DT-MF300FM-P10AC $4,725.00
MF300+ser, 176 GBP, serial option (RS232 and USB) compatible with windows XP, Vista, 7 and 10 *MUST BE ORDERED WITH INSTRUMENT* FM-DT-MF300FE-S $250.00
Additional P10 Probe FM-DT-MF300-P10 $1,425.00
Additional P46 Probe FM-DT-MF300-P46 $1,425.00