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)
  • Right Angle Small area P46R 


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.




Right Angle Small Area Probe: P46R

The P46R Small Area Probe has the same 4mm x 6mm probe tip but is configured to provide sensing at right angles. The rectangular body provides for easy handling in difficult to reach positions such as the inside of pipes.

Technical Specifications

MF300FM+ Specifications

Performance Specifications
Units: Ferrite Number FN
Ferrite percentage F%
Range: 0 - 115 FN
0 - 80.5% (percent ferrite)
Resolution: 0.1 FN
0.1 F%
Standard Accuracy:
FN 0 - 10
FN 10 - 30
FN 30 - 100

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

± 1 FN
± 10% of the reading
± 20% of the reading
Calibration: Factory calibration to NIST Standards
User calibration to supplied transfer standards
Up to 5 calibrations can be supplied (for 5 probes)
Transfer Standards: 5 transfer standards
Range typically 3 FN to 115 FN
Zero: Automatic on demand
Modes: Average or Peak
Storage: 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
Operating Temperature: Standard: 0°C - 40°C (32°F - 104°F) (P46, P46R and P10)
Air cooled: 0°C - 300°C (32°F - 572°F) (P10AC) 
Humidity: Non-condensing
Weight in Case: 1.25 kg (2.75 lbs.)
Case Dimensions: 210 x 100 x 45mm (8.3" x 3.94" x 1.77")
Probe P46: Pencil style, 15mm diameter x 130mm length
Sensing area 4mm x 6mm (24 mm^2)
Spring loaded sleeve
Probe P46R: Miniature rectangular 20 x 30 x 75mm
Sensing at 90 degrees to probe body
Probe P10: Pencil style, 15mm diameter x 120mm length
Sensing area 10mm diameter (~80mm^2)
Probe P10AC - air cooled: Pencil style as Probe P10
Air line supply regulated to 1 bar maximum
Oil filtered supply desirable
Air temperature: ambient 0°C - 30°C (32°F - 86°F)

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+

Description Part # Saved Price Select Option Add to
Diverse Technologies MF300Fm+, Handheld Ferrite Meter with 1000 Records, Including P46 4mm x 6mm Probe, 5 Transfer Calibration Standards and Carry Case (MF300Fm+ replaces the MF300Fe+) FM-DT-MF300FM+P46 $4,315.00
Diverse Technologies MF300Fm+, Handheld Ferrite Meter with 1000 Records, Including P46R Small Body Right Angle Probe with 4mm x 6mm Tip, 5 Transfer Calibration Standards and Carry Case FM-DT-MF300Fm+P46R $4,315.00
Diverse Technologies MF300Fm+, Hand Held Ferrite Meter with 1000 Records, Including P10AC 10mm Diameter Air Cooled Probe, 5 Transfer Calibration Standards and Carry Case (MF300Fm+ replaces the MF300Fe+) FM-DT-MF300FM+P10AC $5,075.00
Diverse Technologies MF300Fm+, Hand Held Ferrite Meter with 1000 Records, Including P10 10mm Diameter Probe, 5 Transfer Calibration Standards and Carry Case (MF300Fm+ replaces the MF300Fe+) FM-DT-MF300FM+P10 $4,315.00
Diverse Technologies MF300+ser, 176 GBP, serial option (RS232 and USB) compatible with windows XP, Vista, 7 and 10 *MUST BE ORDERED WITH INSTRUMENT* FM-DT-MF300+SER $245.00
Diverse Technologies Additional P10 Probe FM-DT-MF300-P10 $1,365.00
Diverse Technologies Additional P46 Probe FM-DT-MF300-P46 $1,365.00
Diverse Technologies Additional P46R Probe FM-DT-MF300-P46R Request Pricing