Rockwell Tester 200HRS-150 MFR User Guide

7/28/2019 Rockwell Tester 200HRS-150 MFR User Guide

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I. Introduction

1. General information

Hardness is an important parameter of mechanical properties for metallic and alloyed

materials. Usually it refers to the capacity of the material to resist against another harder

material of certain shape and size to be pressed into its surface without any residual

deformation by itself.

Rockwell hardness test is a test method which is the rapidest, most convenient and

economy among all the tests of mechanical properties. Besides high testing efficiency

and simple operation, it also features that the hardness values could be obtained directly,

which enables it to accomplish the testing which other tests fail.

The Model 200HRS-150 Digital Display Rockwell Hardness Tester is designed and

manufactured according to the state standard Metallic Rockwell Hardness Test

GB/T230.1-2004. It can be used for measuring Rockwell hardness of hard alloys,

quenched steel and unquenched steels in the laboratories of factories, research

institutions and colleges.

2. Principle of Test

Fig-1 Principle of Rockwell Hardness Test

Rockwell hardness test is to apply diamond cone indenter (see Fig-2) or steel ball

indenter (see Fig-3) to the specimen surface in two steps as shown in Fig-1, which shall

be retained for a certain period of time, and measure the residual indentation depth under

preliminary test force after the main test force is removed. The Rockwell hardness is

calculated by formula (1) as per the h value, the constant N and S (see Table 1).


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Rockwell hardness value = Nh/S Formula (1)

Table 1 Symbols and Descriptions

Symbols Descriptions Units

F0 Preliminary test force N

F1 Main test force N

F Total test force N

S Unit of given scale mm

N Hardness value of given scale

h Residual indentation depth under preliminary

test force after main test force is removed mm

HRA

HRCRockwell hardness = 100h/0.002

HRB Rockwell hardness = 130h/0.002

1----Indentation depth under preliminary test force F0;

2----Indentation depth under main test force F1;

3----Depth of elastic come-back after main test force F1 is removed;

4----Residual indentation depth h;

5----Specimen surface

6----Measurement datum;

7----Position of indenter.

Example: 59HRC indicates that Rockwell hardness is 59 measured by C scale.

* The above content is referred to the state standardMetallic Rockwell Hardness Test

GB/T230.1-2004

3. Range of Application

As per hardness range and size of the specimen, different indenters and loads can be

selected and the hardness values can be indicated by different scale such as A, B and C

scales for Rockwell hardness. The loads, indenters, values of the constant K and ranges

of application are shown in Table 2.

l Scale A is used to measure the metallic materials whose hardness exceed 67HRC,such as tungsten carbide, hard alloy, hard thin slabs and surface hardened parts. The


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range of measurement is 2085HRA.

l Scale B is used to measure the lower-hardness parts whose range of hardness shallbe 25100 HRB, such as non-ferrous metal and its alloy, annealed steel, etc. If the

hardness of specimen is smaller than 25HRB, the metal will begin to creep, creep

deformation will last a long time and the result will be inaccurate. If the hardness of

specimen is larger than 100HRB, error will happen since the steel ball indenter is

prone to deform and the depth of indentation is too small.

l Scale C is used for hardness test of specimen which is quenched or tempered, suchas carbide steel, tool steel and alloyed steel. The range of measurement shall be

2067 HRC. If the hardness of specimen is lower than 20HRC, the measurement is

incorrect since it is too deep for the diamond indenter to penetrate into the specimen

and the error will increase caused by the geometric shape of the indenter. If the

hardness of specimen is larger than 67HRC, the diamond is easy to damage due to

the large pressure produced by the sharp tip of the indenter.

Fig-2 Diamond cone indenter Fig-3 Steel ball indenter

Table 2 Usual scales for Rockwell Hardness

Test force (kgf) ConstantScale Indenter (mm)F0 F1 F N

Application examples

A Diamond cone indenter 10 50 60 100 Hard metal and alloy

BSteel ball indenter

(1.588mm)10 90 100 130

Non-ferrous and soft

metal

C Diamond cone indenter 10 140 150 100Structural and tool

steel


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4. Technical Parameters

Please refer to Table 3 and Fig-4 for main technical parameters.

Table 3 Main Technical Parameters

Itemcode Content

HeightH 729mm

WidthW 225mm

LengthL 522mm

Maximum height of specimen (with sleeve)B 140mm

Maximum height of specimen (without sleeve)B 210mm

Depth of throat (A) 165mm

Net weight 98Kg

Power supply 110 / 220V, 50Hz

Reference

ScalesRange of Harness Reading Allowance

20HRA~75 HRA 2 HRA

A

>75HRA~88 HRA 1.5 HRA

20HRB~45HRB 4HRB

>45HRB~80HRB 3HRBB

>80HRB~100 HRB 2 HRB

C 20HRC~70HRC 1.5HRC


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Fig-4 Schematic Diagram of Overall Dimensions

5. Descriptions of Mechanism Parts

This tester is composed of machine body (1), indenter (27), loading and unloading

mechanism (10, 19), measuring mechanism (8), specimen support mechanism (5) and so

on (See Fig-5).

The test forces are applied onto the main axis by the combination of weights and

lever, which is magnified. That is to say, the test forces are magnified by the larger lever

and pressed onto the surfaces of specimen. At the same time when the indenter is pressed

into the specimen, the vertical displacements of main axis are passed to the reading

device through measuring lever, showing the hardness value as a result.

l The machine body (1) is the shell of the tester, which accommodates othercomponents directly or indirectly. Except the worktable (5), screw rod (4) andelevating handle (2), all the other parts are fitted inside the shell.

l Total test forces are composed of main test forces and preliminary test forces. Thepreliminary test force is produced by the self weight of the larger lever (10) and main

shaft (7). The main test force is obtained with weight (19) hanging on the larger lever

via hoist ring (15) as per Lever Principle.

l The upper end face of the indenter (27) shall carry the total test force while its sharpend is pressed into the surface of the specimen.

l To select different weights and combine them in different group to obtain required


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total test forces including 588N/60Kgf, 980N/100Kgf and 1470N/150Kgf,

l Loading and unloading mechanism is composed of motor and roller wheel. Themotor drives the roller wheel so that the support rod could be elevated, which

realizes the loading and unloading.

l Test results could be read out from the front display (17) of measuring mechanism.l Specimen support mechanism is composed of worktable (5) and screw rod (4) to

carry the hardness block or the specimen to be tested.

Fig-5 Schematic Diagram of mechanical parts

1.Machine body 2. Elevating handle 3. Elevating hand wheel4. Screw rod sleeve (with screw rod inside) 5. Worktable 6. Specimen to be tested

7. Main shaft 8. Sensor 9. Smaller lever 10. Larger lever 11. Electric control

12. Upper cover 13. Compensation block 14. Location mark 15. Hoist ring

16. Screw 17. Front display 18. Rear shield 19. Weight

20. Weights changeover support 21. Loading and unloading mechanism 22. Motor

23. on/off switch 24. Foundation screw 25. Printer 26. Load changeover handle27. Indenter


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II. Package Opening, Transportation, installation and Commissioning

1. Preparation

l The tester should be placed indoors, dry and clean and free from corrosive gases.l The tester should be placed indoors, free from foreign mechanical vibration.l Ambient temperature should be kept between 10-30C.l The test stand should be of cement or metal, with certain strength and stiffness so as

to carry over the hardness tester and its accessories. The plane surface should be made

same as shown in Fig-6 (the dimensions in the following figure is for reference only),

with a 70mm hole for the screw rod to pass through. The levelness should be

controlled within 0.2/1000.

l Adequate space should be reserved around the tester for the sake of installation,maintenance and commissioning.

Fig-6 Schematic Diagram of Test Stand

2. Package opening

1) Remove the packing belt around the package box, as shown in Fig-7.2) Remove the wood screw fixing the packing box to the bottom seat and lift up the

packing box.

3) Find the document bag and inspect the contents inside, including the OperationManual, Packing List and Quality Certificate.

4) Loosen the nut on the package hook fastening the box of accessory by the spanner,take down the package hook and box of accessory. Sort out the objects inside the boxand verify whether all the parts contained in the packing list are available.


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5) Remove the dust-proof cover.6) Remove the four foundation bolts fastening the tester onto the bottom seat of package

box by the spanners.

7) Remove the printer bound on the tester.

Fig-7 Schematic Diagram of Box Opening

3. Cautions for transportation

l Dont try to move the tester by yourself, or it may lead to damage to the tester orpersonal injury since the tester is heavy. Only with two or more than 2 experienced

people can the tester be moved.l During transportation, the slant of the axial line between the indenter and the screw


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rod should not be over 15 against the vertical line.

l During the transportation, the contacts between the operators and the tester are limitedto the plane C, D, E and F. Never touch the planes other than the aforesaid and other

parts in order not to influence the accuracy (Fig-4)

l The tester should be handled with care to avoid any impact or collision.4. Installation and commissioning

Before the installation, please make ready the tools such as spanner, level meter and

larger flat anvil, etc.

1) Place the tester onto the prefabricated test stand in a way that the screw rod fallsthrough the hole reserved. Fetch out the 4 foundation bolts (24) from accessory box

and fit them into the threaded holes on the bottom of tester.

2) Loosen the screws on the upper cover and rear shield, and remove the upper cover andrear shield.

Fig-8 Removing the binding rope of larger lever

3) Remove the binding rope of larger lever (10), as shown in Fig-8.4) Remove the binding rope of smaller lever (9), as shown in Fig-9.5) Take out the weights from accessory box and mount them on the end of larger lever.


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Fig-9 Removing the binding rope

6) Turn the elevating handle anticlockwise to let the screw rod coming downwards, andthen remove the protective cushion block for the indenter (Fig-10). In case that the

screw rod does not come down and the handle rises up with the screw rod when the

handle is turned, the protection block could not be removed. This is because the screw

rod and its seating are bonded together during the transportation. The best way is to

turn the handle anticlockwise to life up the hand wheel 20mm, and then press with

force down the hand wheel, and then the screw rod and its seating would be

disengaged.

Fig-10 Removing protective cushion block of indenter


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7) Remove the protective sleeve, clean the antirust grease on the screw rod and elevatingscrew with kerosene, fill some lubricants into the contacts between screw rod and

elevating nut and put back the protective sleeve.

8) Fetch the anvil from the accessory box and put it on top of the screw rod. Adjust thelevelness with a level meter to be within 0.2/1000. If necessary, adjust the four

foundation screws at the bottom of the instrument to make the tester is in good

levelness.

9) Put back the upper cover and rear shield.10)Connect the ground wire and insert the power plug into the power socket.III. Normal Operation

Before operation, the kind of reference scale should be determined subject to

different specimen. Except otherwise specified, the following operation is based on

Reference Scale C, i.e. using diamond cone indenter and total test force 150Kgf.

1. Preparation prior to normal operation

To be well versed with the functions of front and rear panel.

l Front Panel

Fig-11 Schematic Diagram of Front Panel

1) RESET: resume to initial status

2) CLEAR: to zero the displacement value


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3) ESC: to cancel one event being carried on.

4) SCALE: This button is actuated only when the number of times is zero under

measurement status. Then by pressing this button, the Scale, test force and indenter

will be brightened, which means that current status is scale selection. Press UP or

DOWN arrow key to select required scale.

5) DEL.: If the measured hardness value is beyond the preset maximum or minimum

value, the system will give out beeping sound. Here, the measured value could be

deleted by pressing this button. If not pressing this button, lower down the screw rod

and the beeping will disappear, and the measured value is valid.

6) MAN.: When the tester is turned on, at this moment, by pressing and then releasing

this button, the tester will enter Manual force measurement status.

7) LOAD: After the tester enters manual force measurement status, let the screw rod rise

up, then the screen will display the displacement of the sensor. Pressing this button

and releasing it, the tester will enter into force measurement status, and start to load,

retain the load, unload and display the hardness value.

8) MENU: This button could be started only when the number of times is zero at

measurement status. The tester will enter the setup interface by pressing this button, 5

items in total.

To select corresponding item by pressing UP or DOWN key, press OK to enter

into Preset Menu and press ESC to return back to Measurement status.

a. At HARDNESS CONVERSION, the scales could be selected by LEFT or RIGHT

arrow key. Press OK for confirmation or press ESC to return.

b. DWELL TIME means to select the load retaining time between 2-99 seconds.

Press LEFT or RIGHT key to increase or decrease the load retaining time. By

holding the LEFT or RIGHT arrow key, the figures could be decreased or

increased rapidly and continuously. And then press OK for confirmation or ESC toreturn.

c. LIMITS: to set up lower limit and upper limit by pressing UP arrow key to

changeover the selection and pressing LEFT or RIGHT key to preset the figures.

By holding the LEFT or RIGHT arrow key, the figures could be decreased or

increased rapidly and continuously. And then press OK button for confirmation or

ESC to return.

d. PRINTER: to preset the printing status. The selections could be shifted by pressingUP or DOWN arrow key. Then press OK for confirmation or ESC to return.


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e. TEST NUMBER: to preset test numbers within 2 to 99 by pressing LEFT or

RIGHT key. By holding the LEFT or RIGHT arrow key, the figures could be

decreased or increased rapidly and continuously. And then press OK for

confirmation or ESC to return.

l Rear panel includes power switch, printer interface, fuse and power socket, as shownin Fig-12.

Fig-12 Schematic Diagram of Rear Panel

l Other preparations1) Presetting test forces: to turn the load changeover handle, as shown in Fig-13, the

wordings such as 1470N, 980N, 588N could be seen at the handle.

Fig-13 Presetting test forces

2) Fitting indenter (Fig-14)


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The steel ball indenter is mounted on main shaft before delivery. To re-mount the

other indenter, please operate as follows:

a. Fit the indenter into the hole of main shaft.b. Ensure the end face of indenter is pressed tightly against the end face of main shaft,

and then tighten the screw.

Fig-14 Fitting the indenter

3) Adjustment of retaining time of total test force: As per the state standard Metal

Rockwell Hardness Test GB/T230.1-2004, the retaining time of total test force

should be 42 S. As for low hardness materials, the retaining time could be extended.

The allowance is 2 S.

4) The specimen should meet the following requirements:

a. The specimen should be of certain sizes and thickness. Both the distance ofcenters of two adjacent indentations and distance between the center of

indentations and the edge of specimen should be more than 3mm. The minimum

thickness of specimen shall be more than 8 times of the depth of indentation. After

the test, no obvious deformation should be observed at the support surface of the

specimen. The minimum thickness is subject to the quality of materials and the

load applied. For details, please refer to Table 4.


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Table 4 Minimum Thickness

b. The surface to be tested should be flat plane. In case of curved plane, the testresults shall be corrected if the radius is small. The amount of correction of

cylindrical specimen is included in Table 5 and Table 6.

c. The surfaces of specimens should be fine polished or grinded, the roughness shallbe up to no less than . However, the processing should not change the

hardness, i.e., no hardening or tempering. The roughness of supporting surface

shall be no less than . The tested surface, the supporting surface and the

worktable should be kept clean. The specimen should be placed on the worktable

stably without any movement during the testing.

d. The specimens shall be placed to ensure that the test force is applied perpendicularto the surface to be measured. As for specimens with curved shape or other

abnormal shapes, corresponding anvil and proper position of measurement should

be selected. For example, V-shaped anvil should be used for cylindrical specimens.

Those with hollow cavity shall be alert of deformation caused by the applied test

force, otherwise the measured hardness values wont be correct.

5) To presetting of scales, printer, upper and lower limit, load retaining time and numbers

of test shall be predetermined as per specific requirement.

ScalesHardness

HR

Min.

thickness

mm

ScalesHardness

HR

Min.

Thickness

mm

70 0.7 80 1.0

80 0.5 90 0.8A

90 0.4

B

100 0.7

25 2.0 20 1.5

30 1.9 30 1.3

40 1.7 40 1.2

50 1.5 50 1.0

60 1.3 60 0.8

B

70 1.2

C

70 0.7


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2. Testing Procedures

1) Turn power on (Fig-12), the LCD display screen will light up.2) At the main menu as shown in Fig-15: When the test number is zero, press SCALE

key to enter the interface of scale selecting. Change the scales by pressing UP and

DOWN arrow Key.

Fig-15 Main Menu Fig-16 Setup interface

3) When the test number is zero, press MENU key to enter the setup interface (seeFig-16). The conversion scale, printer, upper and lower limit, load retaining time,

number of tests and language can be preset, as shown in Fig-17-18-19-20-21-22.

Fig-17 Scale Shift Fig-18 Load Retaining Time

Fig-19 Upper and Lower Limits Fig-20 Printer


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Fig-21 Number of tests Fig-22 Language Selection

Fig-23 Testing interface

4) Clean the top face of screw rod and the end faces of test anvil, then place the anvil into

the reserved holes of screw rod. The type of anvil shall be selected as per the

dimensions of specimen.

5) Clean the support surface clean and then put the specimen onto the anvil. Turn

clockwise the elevating handle slowly to let the screw rod rise up. As soon as theindenter touches the specimen, turn the handle even more slowly and stably, and the

light band on the screen will move from PRELOAD to OK, which means the

preliminary load 98N has been applied. Herein, stop turning the elevating handle at

once, (otherwise the light band will enter into the OVER and the system will give out

warning noise and the test shall be regarded invalid. In this case, turn the elevating

handle anticlockwise to let the screw rod descend until the light band disappears and

the indenter is not in touch with the surface of specimen). At the same time, the motor

will run to automatically apply the main test force, retain the test force and remove it.


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This is the start of automatic testing and the system will shift from LOAD, DWELL

and UNLOAD, and finally displays the hardness value and corresponding hardness

value of different scale. Fig-23 shows the measured hardness value at the fifth test.

The measured value is 62.2HRC and the repeatability is 0.2. In case that the total

number of tests is five, the result for the first test will be omitted. If upper and lower

limits are preset, the system will give out warning in case of beyond the range.

Hereby, it is to omit the test by pressing DELETE. At end of each test, if the printer is

preset to ON, the data will be printed out automatically.

6) Turn the elevating handle to let the screw rod descend so as to remove the preliminary

test force. Then the light band will disappear, which means the end of one test cycle.

The hardness value will be remained until the start of next test.

NOTE:

During the operation of step 5 and step 6, load changeover handle shall not be turned

to prevent from damaging the tester.

The first test after anyone of indenter, specimen or the anvil is changed shall be

regarded invalid.

IV. Maintenance

1. Cleaning and Lubrication

l Cover the tester in case of no use for a long time.l Fill with adequate machine oil into the contacts between screw rod and handle

regularly.

2. Calibration

Examine the accuracy of the tester with the standard hardness block delivered with

the tester.

l The tester should be calibrated regularly. The interval of calibration shall be less than12 months.

l Clean the anvil and standard hardness block. The test shall be carried out on theproper testing surface. It is not allowed to make test on the supporting surface.

l If the reading error is beyond expectation, besides the regular examination listed inTable 7, the support surface shall be inspected and remove the burrs if any with oil

stone.

l The hardness block shall be moved along the worktable rather than fetch it from oneplace to another.


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V. Hardness Value Correction

Since the measured value is reduced for convex specimen, the correction shall be

added. While for concave specimen, the correction shall be reduced. The correction to

other diameters or hardness values could be obtained by method of insertion.

Table 5 Correction for C and A scales of Cylindrical specimen

Diameter of cylindrical specimen (mm)

6.4 10 13 16 19 22 25 32 38

Specimen

HardnessCorrection

20 6.0 4.5 3.5 2.5 2.0 1.5 1.5 1.0 1.0

25 5.5 4.0 3.0 2.5 2.0 1.5 1.0 1.0 1.0

30 5.0 3.5 2.5 2.0 1.5 1.5 1.0 1.0 0.5

35 4.0 3.0 2.0 1.5 1.5 1.0 1.0 0.5 0.5

40 3.5 2.5 2.0 1.5 1.0 1.0 1.0 0.5 0.5

45 3.0 2.0 1.5 1.0 1.0 1.0 0.5 0.5 0.5

50 2.5 2.0 1.5 1.0 1.0 0.5 0.5 0.5 0.5

55 2.0 1.5 1.0 1.0 0.5 0.5 0.5 0.5 0

60 1.5 1.0 1.0 0.5 0.5 0.5 0.5 0 0

65 1.5 1.0 1.0 0.5 0.5 0.5 0.5 0 0

70 1.0 0.5 0.5 0.5 0.5 0.5 0.5 0 0

75 1.0 0.5 0.5 0.5 0.5 0.5 0 0 0

80 0.5 0.5 0.5 0.5 0.5 0 0 0 0

85 0.5 0.5 0.5 0 0 0 0 0 0

90 0.5 0 0 0 0 0 0 0 0


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Table 6 Correction for B scale of Cylindrical specimen

Diameter of cylindrical specimen (mm)

6.4 10 13 16 19 22 25

Specimen

HardnessCorrection

0 12.5 8.5 6.5 5.5 4.5 3.5 3.0

10 12.0 8.0 6.0 5.0 4.0 3.5 3.0

20 11.0 7.5 5.5 4.5 4.0 3.5 3.0

30 10.0 6.5 5.0 4.5 3.5 3.0 2.5

40 9.0 6.0 4.5 4.0 3.0 2.5 2.5

50 8.0 5.5 4.0 3.5 3.0 2.5 2.0

60 7.0 5.0 3.5 3.0 2.5 2.0 2.0

70 6.0 4.0 3.0 2.5 2.0 2.0 1.5

80 5.0 3.5 2.5 2.0 1.5 1.5 1.5

90 4.0 3.0 2.0 1.5 1.5 1.5 1.0

100 3.5 2.5 1.5 1.5 0 1.0 0.5

VI. Troubleshooting

In case of breakdown, the following may be of help to predict the breakdown and

recommend the methods of troubleshooting. If remains unsolved, please contact our

after-sales service department instead of dismantling the tester by yourself.


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Table 7 Guidance to troubleshooting

Troubles Reasons Method of troubleshooting

Lag of screw rod Rusty or chips Get rid of chips and fill with lubricants

Main test force

failed to apply

Weights not hanged

properlyAdjust the position of weight group

Test forceWhether the preset test forces conform to

the requirements of the selected scale

Distance of

indentations

Distance between the centers of two

adjacent indentations is not big enough.Whether the indenter conforms to the

requirements of the selected scale

Eliminate the space between indenter and

main shaft

Indenter

Replace the indenter if damaged

Examine whether there are impurities

between test anvil and indenterWhether or not the test anvil is suitable for

the specimenTest anvil

Examine whether the protective sleeve

props up the test anvil

Examine whether the test force is

perpendicular to the surface

Remove any burrs on the back of

specimen

Specimen

Thickness of specimen is too small

Mechanical vibration nearlySurroundings

Ambient temperature beyond 10-30C

Measured

hardness value

not precise

Others Calibrate with standard block

Documents

Rockwell Tester 200HRS-150 MFR User Guide