MRC MH320 User manual

MH320 Leeb Hardness Tester
User’s Manual
3, Hagavish st. Israel 58817 Tel: [phone], Fax:
972 3 5594529 [email protected]
MRC.11.21

1
1 Overview.....................................................................................................................3
1.1 Advantages........................................................................................................................3
1.2 Main Application &Testing Range ...................................................................................3
1.2.1 Main Application ...........................................................................................................3
1.2.2 Testing Range.................................................................................................................3
1.3 Configuration....................................................................................................................4
1.4 Working Conditions ..........................................................................................................4
1.5 Safety Instructions ............................................................................................................4
2 Structure Feature &Testing Principle..........................................................................5
2.1 Structure Feature...............................................................................................................5
2.1.1 The Hardness Tester Appearance...................................................................................5
2.1.2 Parts of the Main body...................................................................................................5
2.1.3 D Type Impact Device ...................................................................................................6
2.1.4 Different Types of Impact Device..................................................................................6
2.2 Leeb Hardness Testing Principle.......................................................................................6
3 Technical Specifications .............................................................................................7
4 Preparation & Testing .................................................................................................8
4.1 Preparation & Inspection before Testing...........................................................................8
4.1.1Preparation of Sample Surface........................................................................................8
4.1.2 System Setting ...............................................................................................................8
4.1.3Presetting Testing condition............................................................................................9
4.2 Testing Program................................................................................................................9
4.2.1 Start-Up..........................................................................................................................9
4.2.2 Loading..........................................................................................................................9
4.2.3 Localization ...................................................................................................................9
4.2.4 Testing............................................................................................................................9
4.2.5 Read measured value ...................................................................................................10
4.2.6 Power Off.....................................................................................................................10
5 Advice ....................................................................................................................... 11
6 Operation in Details ..................................................................................................12
6.1 Power On ........................................................................................................................12
6.2 Power Off........................................................................................................................12
6.3 Testing.............................................................................................................................12
6.3.1 Instruction of the Main Display Interface....................................................................13
6.3.2 Testing Operation at the Main Display Interface .........................................................13
6.3.3 Key Operation at the Main Display Interface ..............................................................13
6.4 Menu Structure ...............................................................................................................14
6.5 Test Set............................................................................................................................15
6.5.1 Impact Direction Setting..............................................................................................15
6.5.2 Average Times Setting .................................................................................................15
6.5.3 Material Setting............................................................................................................16
6.5.4 Hardness Scale Setting.................................................................................................16
6.5.5 Tolerance Limit Setting................................................................................................17

2
6.5.6 Hardness/бb Setting .....................................................................................................17
6.6 Print Function .................................................................................................................17
6.6.1 Print Current ................................................................................................................17
6.6.2 Print Memory...............................................................................................................18
6.6.3 Print All Memory.........................................................................................................18
6.6.4 Paper Feeding ..............................................................................................................18
6.7. Memory Manager ..........................................................................................................18
6.7.1 View from No.1 Group/View from Ending Group ......................................................18
6.7.2 View from Selected No. Group....................................................................................19
6.7.3 Data Transfer ...............................................................................................................19
6.7.4 Delete by Group No.....................................................................................................19
6.7.5 Delete All Data.............................................................................................................19
6.7.6 Deletion Confirmation .................................................................................................19
6.8 Browsing Memory Data Groups.....................................................................................20
6.9 System Set ......................................................................................................................21
6.9.1 LCD Brightness Set .....................................................................................................22
6.9.2 Time Date Set ..............................................................................................................22
6.10 Software Information....................................................................................................22
6.11 System Calibration........................................................................................................23
6.12 EL Background Light ...................................................................................................23
6.13 Auto Power Off.............................................................................................................23
6.14 Paper Loading...............................................................................................................24
6.15 Battery Charge ..............................................................................................................24
6.16 Battery Replacement.....................................................................................................24
6.17 Connection of Data Transmission Cable.......................................................................25
7 Fault Analysis & Evacuation ....................................................................................25
8 Servicing & Maintenance .........................................................................................25
8.1 Impact Device Servicing.................................................................................................25
8.2 Normal Maintenance Program........................................................................................25
9 Calibration.................................................................................................................25
10 Notice of Transport and Storage Conditions...........................................................25
APPENDIX..................................................................................................................26
Table 1 ..................................................................................................................................26
Table 2 ..................................................................................................................................27
Table 3 ..................................................................................................................................28
Table 4 ..................................................................................................................................29

3
1 Overview
1.1 Advantages
Wide measuring range. Based on the principle of Leeb hardness testing theory. It
can measure the Leeb hardness of all metallic materials.
Large screen (128×64 dot matrix LCD), showing all functions and parameters.
Test at any angle, even upside down.
Direct display of hardness scales HRB, HRC, HV, HB, HS, HL.
Seven impact devices are available for special application. Automatically identify
the type of impact devices.
Large capacity memory could store 500 groups (Relative to average times 32～1)
information including single measured value, mean value, testing date, impact
direction, impact times, material and hardness scale etc.
Upper and lower limit can be preset. It will alarm automatically when the result
value exceeding the limit.
Battery information indicates the rest capacity of the battery and the charge
status.
User calibration function.
Software to connect with PC via USB port.
With EL background light.
Thermal printer integrated, convenient for in field printing.
NI-MH rechargeable battery as the power source. Charge circuit integrated inside
the instrument. Continuous working period of no less than 150 hours (EL off and
no printing).
Auto power off to save energy.
Outline dimensions：212mm×80mm×32mm.
1.2 Main Application &Testing Range
1.2.1 Main Application
Die cavity of molds
Bearings and other parts
Failure analysis of pressure vessel, steam generator and other equipment
Heavy work piece
The installed machinery and permanently assembled parts
Testing surface of a small hollow space
Material identification in the warehouse of metallic materials
Rapid testing in large range and multi-measuring areas for large-scale work piece
1.2.2 Testing Range
Testing range refer to Table 1 and Table 2 in the Appendix.

4
1.3 Configuration
Table 1-1
No.
Item
Quantity
Remarks
Standard
Configuration
1
Main Unit
1
2
D type impact device
1
With cable
3
Standard test block
1
4
Cleaning brush (I)
1
5
Small support ring
1
6
Battery Charger
1
9V 500mA
7
Paper for printing
1
8
Manual
1
9
Instrument case
1
10
DataPro software
1
11
Communication cable
1
Optional
Configuration
12
Cleaning brush (II)
1
For use with G
type impact device
13
Other type of impact
devices and support
rings
Refer to Table 3
and Table 4 in the
appendix.
14
15
1.4 Working Conditions
Working temperature：-10℃～＋50℃;
Storage temperature：-30℃～＋60℃;
Relative humidity: ≤90％;
The surrounding environment should avoid of vibration, strong magnetic field,
corrosive medium and heavy dust.
1.5 Safety Instructions
The instrument can only work with the specially designed battery pack and power
adapter (charger) supplied by MRC LTD. Working with others may result in
damage of the instrument, battery leakage, fire or even explosion.
Do not cast the battery pack into fire and do not short circuit, disassemble or heat
the battery pack, otherwise battery leakage, fire or even explosion may occur.
Do not open the cover of the paper compartment or come into contact with the
heating head of the printer by hand or any part of your body to avoid burns due to
high temperature when the printer is printing.

5
2 Structure Feature &Testing Principle
2.1 Structure Feature
2.1.1 The Hardness Tester Appearance
1. Main unit
2. Impact device
2.1.2 Parts of the Main body
1 Socket of impact device 2 Socket of USB 3 LOGO 4 Paper compartment
cover 5 LCD display 6 Keypad 7 Battery switch 8 Power jack 9 Serial
Number 10 Product label 11 Battery compartment cover
DEL SAVE
ESC
MENU
ENTER
MAT
DIR
FEED
PRT
1
MRC
2
MODEL: MH320
BATTERY: 6V NI-MH
HARDNESS TESTER
CAUTION:
1 Do not disassemble
3 Use only supplied AC-DC adapter
for charging
CHARGER: 9V DC
2 Do not dispose of in fire or water
SCALE
DEL SAVE
ESC
MENU
ENTER
MAT
DIR
FEED
PRT
11
10
9
8
7
6
5
4
3
2
1
OFF---ON
HL0108070811
MRC

6
2.1.3 D Type Impact Device
1 2 3 4 5 6 7
1 Release button 2 Loading tube 3 Guide tube 4 Coil unit
5 Connection cable 6 Impact body 7 Support ring
2.1.4 Different Types of Impact Device
DC DL C D+15 E G
2.2 Leeb Hardness Testing Principle
The basic principle is: use an impact body of certain weight impacts against the
testing surface under certain test force, then measure the impacting velocity and the
rebounding velocity of the impact body respectively when the spherically test tip is
located 1mm above the testing surface.
The calculation formula is as follows:
.תרדגומ הניא הינמיסה !האיגשAHL=1000×VB/ VA
Where, HL—— Leeb hardness value
VB—— Rebounding velocity of the impact body
VA —— Impacting velocity of the impact body

7
3 Technical Specifications
Error and repeatability of displayed value see Table 3-1.
Table 3-1
No.
Type of impact
device
Hardness value of Leeb
standard hardness block
Error of displayed
value
Repeatability
1 D 760±30HLD
530±40HLD
±6 HLD
±10 HLD
6 HLD
10 HLD
2 DC 760±30HLDC
530±40HLDC
±6 HLDC
±10 HLDC
6 HLD
10 HLD
3 DL 878±30HLDL
736±40HLDL ±12 HLDL 12 HLDL
4 D+15 766±30HLD+15
544±40HLD+15 ±12 HLD+15 12 HLD+15
5 G 590±40HLG
500±40HLG ±12 HLG 12 HLG
6 E 725±30HLE
508±40HLE ±12 HLE 12 HLE
7 C 822±30HLC
590±40HLC ±12 HLC 12 HLC
Measuring range：HLD（170～960）HLD
Measuring direction：360°
Hardness Scale：HL、HB、HRB、HRC、HRA、HV、HS
Display：dot matrix LCD，128×64 dots
Data memory：500 groups max.（relative to impact times 32～1）
Printing paper: width is （57.5±0.5）mm, diameter is 30mm
Battery pack: 6V NI-MH
Battery charger: 9V/500mA
Continuous working period：about 150 hours（With backlight off, no printing）
Communication interface：USB1.1

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4 Preparation & Testing
4.1 Preparation & Inspection before Testing
4.1.1Preparation of Sample Surface
Preparation for sample surface should conform to the relative requirement in the
Appendix Table 3.
In the preparation processing for sample surface, the hardness effect of being
heated or cold processing on the surface of sample should be avoided.
Too big roughness of the being measured surface could cause measure error. So,
the surface of the sample to be measured must appear metallic luster, smoothing
and polish, without oil stain.
Support of test sample. Support is no necessary for heavy sample.
Medium-weight parts must be set on the smoothing and stable plane. The sample
must set absolutely equability and without any wobble.
Curved surface: The best testing surface of sample is flat. When the curvature
radius R of the surface to be tested is smaller than 30mm (D, DC, D+15,C, E and
DL type of impact device) and smaller than 50mm (G type of impact device), the
small support ring or the shaped support rings should be chosen.
The sample should have enough thickness, minimum thickness of sample should
conform to Table 3.
For the sample with hardened layer on surface, the depth of hardened layer
should conform to Table 3.
Coupling. Light-weight sample must be firmly coupled with a heavy base plate.
Both coupled surface must be flat and smooth, and there is no redundant coupling
agent existing. The impact direction must be vertical to the coupled surface.
When the sample is a big plate, long rod or bending piece, it can be deformed and
become unstable, even though its weight and thickness is big enough, and
accordingly, the test value may not be accurate. So the sample should be
reinforced or supported at its back.
Magnetism of the sample itself should be avoided.
4.1.2 System Setting
See 6.9 for details.

9
4.1.3Presetting Testing condition
See 6.5 for details.
4.2 Testing Program
Verification of the tester is by using standard test block. The error and repeatability of
displayed value should be within the regulation of Appendix table 2.
4.2.1 Start-Up
Insert the plug of the impact device into the socket of impact device on the tester.
Press【 】key，now power is connected. The instrument is in testing condition.
4.2.2 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.
4.2.3 Localization
Press the impact device supporting ring on the surface of the sample firmly, the
impact direction should be vertical to the testing surface.
4.2.4 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 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,
Note：Use a calibrated hardness tester, test the standard test block downward
vertically for 5 times, the arithmetical average value compare with the value of
standard test block. If this value exceeds the standard value, could use the function
of software calibration to adjusting.