MH320 Leeb Hardness Tester





Measuring range:


Resolution Accuracy:


Communication storage:

500 measurement series.(Relative to average times 32~1) USB

Working time:

About 150 hours(with default brightness)

Main unit weight:




Package dimensions:


Total weight:



  • Overview
  • Graphic
  • Technical
  • Configuration
  • Related


  • Overview
  • Graphic
  • Technical
  • Configuration
  • Related
  • Product Overview

         MH320 portable Leeb hardness tester is based on Leeb hardness measurement principle, it can be quickly and easily used for on-site testing hardness of metallic materials and support free conversion between Leeb, Brinell, Rockwell hardness and other scales. It uses 128 × 64 dot matrix LCD screen, rich information, intuitive, stable performance and integrated high-speed thermal printer, which enables printing with instant measurement results.It can be widely used in metal processing and manufacturing, special equipment, permanent component failure analysis, inspection and other fields. It is particularly suitable for large parts and non-removable part of the on-site hardness testing. It is to improve production efficiency and pass rate and is a wise choice to save the cost of production.


    Function & application

    l Die cavity of molds

    l Bearings and other parts

    l Failure analysis of pressure vessel, steam generator and other equipment

    l Heavy work piece

    l The installed machinery and permanently assembled parts.

    l Testing surface of a small hollow space

    l Requirements of formal original record for test results

    l Material identification in the warehouse of metallic materials

    Rapid testing in large range and multi-measuring areas for large-scale work piece


    Working Principle

    The energy quotient is quoted in the hardness unit HL and is calculated from comparing the impact and rebound velocities of the impact body. It rebounds faster from harder samples than from softer ones, resulting in a greater energy quotient which is defined as 1000×Vr/ Vi.

    HL=1000×Vr/ Vi


    HL— Leeb hardness value

    Vr — Rebound velocity of the impact body

           Vi — Impact velocity of the impact body

    Working Conditions

    l Working temperature-10℃~+50℃

    l Storage temperature-30℃~+60℃

    l Relative humidity: ≤90%;

    The surrounding environment should avoid of vibration, strong magnetic field, corrosive medium and heavy dust.


    Instrument Features

    l Based on the principle of Leeb hardness testing theory. It can measure the Leeb hardness of all metallic materials.

    l One main unit can match to 6 impact devices

    l Support Steel ,when using D/DC sensor to test steel,it can show HB directly.

    l Preset on up and low limit of hardness value lower limits, it will alarm automatically if it is out of range alarm,which is convenient for the user to do more testings.

    l Chinese-English converting, simple menu-driven operation, and convenient.

    l High brightness, easy to use in dimly lit environments and intense sunlight.

    l 500 groups (impact times 32 ~ 1) hardness measurements, each set of data includes single testing value, average value,

    measurement date / time, impact direction, frequency, material, hardness, and other information.

    l Integrated thermal printer with the instrument as a whole, and quiet operation, fast print speeds, you can print the test report  on-site.

    l Software calibration automatically

    l Built-in NI-MH ,it can work for not less than 150 hours; standby with automatic screen, automatic sleep, automatic shutdown and other power-saving features.

    l Real-time display the remaining battery power, charging progress is displayed while charging.

    l USB interface can do transmission measurements, the measured value storage management, statistical analysis of the measured value, the measured value of the print report and batch set the instrument parameters through the PC data  processing software, to meet the higher demand for quality assurance and management.

    l Small size, portable, highly integrated, stable and reliable performance, suitable for harsh environment field operations,  prevent from vibration, shock and electromagnetic interference.

    l Dimension:221mm×80mm×32mm


    Operating Method and Attentions

    1 Start-Up

    ----Insert the plug of the impact device into the socket of impact device on the instrument.

    ----Press the power keynow power is on. The instrument is in working mode.

    2 Loading

    Pushing the loading-tube downwards until contact is felt. Then allow it to slowly return to the starting position or using other method locking the impact body.


    3 Localization

    Press the impact device supporting ring firmly on the surface of the sample, the impact direction should be vertical to the testing surface.

    4 Testing

    ----Press the release button on the upside of the impact device to test. The sample and the impact device as well as the operator are all required to be stable now. The action direction should pass the axis of the impact device.

    ----Each measure area of the sample usually need 3 to 5 times of testing operation. The result data dispersion should not more than mean value±15HL.

    ----The distance between any two impact points or from the center of any impact point to the edge of testing sample should conform to the regulation of Table 4-1.

    ---- If want accurate conversion from the Leeb hardness value to other hardness value, contrastive test is needed to get conversion relations for the special material. Use inspection qualified Leeb hardness tester and corresponding hardness tester to test at the same sample respectively. For each hardness value, each measure homogeneously 5 points of Leeb hardness value in the surrounding of more than three indentations which need conversion hardness, using Leeb hardness arithmetic average value and corresponding hardness average value as correlative value respectively, make individual hardness contrastive curve. Contrastive curve at least should include three group of correlative data.

    Type of Impact Device

    Distance of center of the two indentations

    Distance of center of the indentation to sample edge

    Not less than (mm)

    Not less than (mm)



















    5 Read Measured Value

    After each impact operation, the LCD will display the current measured value, impact times plus one, the buzzer would alert a long howl if the measured value is not within the valid range. When reaching the presetting impact times, the buzzer will alert a long howl. After 2 seconds, the buzzer will alert a short howl, and display the mean measured value.

    6 Notification

    ---- Replacing the impact device must be done during Power off. Otherwise the main body could not identify the type of the impact device, and it may damage the circuit board of the main body.

    ----You could not save the current test value if the impact time is less than the presetting times value.

    ---- Only type D and type DC of impact device have the function of strength test option. You can not change the setting to strength testing when using other types of impact device. The setting would be set to hardness testing automatically after replacing the impact device whether the setting is hardness testing or not before.

    ---- Not all materials could convert to all hardness scale value. The hardness scale is reset to HL automatically after changing the material. So select material firstly before changing the hardness scale.

    Instrument Maintenance