1.Introduction

1.1 performance and use

HVD-50AP Vickers hardness tester is a new type of hardness tester which use accurate mechanical and combine optical, electric with computer software programs. This kind of hardness tester changed the traditional hardness test method which use the weight of the weight to be the method of loading test force. It simplified the structure of hardness tester and improved overall accuracy of hardness tester. It is used to measure Vickers hardness or Knoop hardness. By inputting the length of diagonal into integration calculator, then user can calculate and get the hardness value. This kind of hardness tester measure the hardness according to GB and ISO standard.

The difference between Vickers indenter and Knoop indenter: The Vickers is square underside of the pyramid -shaped indenter and the Knoop is diamond-shaped underside of the pyramid -shaped indenter. In additional, test the Vickers hardness only need to measure the length of the two diagonal, however, the Knoop hardness just need measure the length of one diagonal.

The features & using scope of Vickers hardness tester:

l Compared with Brinell, Rockwell hardness tester, the Vickers hardness tester used more widely. It can test the hardness from the most soft material to the most hard material.

l Adopted the square underside of the pyramid -shaped indenter, test the same specimen with different test force can get similar hardness. So, the option of test force more flexible.

l Since the indentation is clear, more easy to measure the length of the diagonal. Test data more accuracy.

1.2 Model difference

HVD-50MP Vickers hardness tester Observation - Test - Measurement operated by manual (Manual Turret).

HVD-50AP Vickers hardness tester Observation - Test - Measurement automatically by stepping motor (Auto Turret).

1.3 Test description

Vickers hardness measurement is a judgment for the permanent indentation size of the material. Figure 1-1

1.4 Equipment appearance

The appearance of Vickers hardness tester(Figure 1-2)

Figure 1-2 the appearance of the hardness tester

1. Optical path (CCD camera use)   2. Digital Micrometer eyepiece 10X    

3. 10× objective                   4. Indenter        5. Working table         

6. Elevated lead screw              7. Hand wheel     8. LCD screen

9. Membrane keyboard             10. Horizontal adjustment screw   

11. Conversion optical path knob      12. 20X objective   

13. Standard hardness block          14. Power switch      

15.RS232 interface                  16. power socket      

17. Reset switch                     18. Printer      19. Turret

1.5 Principles of Vickers hardness

Using the test force to press the square diamond indenter into the surface of the specimen. Holding some time, then unload the test force and measuring the diagonal length of the indenter in the surface of specimen. Figure 1-3

Figure 1-3 Vickers hardness test principle

Vickers hardness value =test force ÷the superficial area of the indentation. The indentation is considered to have a square base surface and the same indenter angle with the ideal shape.

Vickers hardness value can be calculated by the following formula:

      HV=0.102F/S=0.102×2Fsin(α/2)/D2=0.1891F/D2

      In the formula：HV---Vickers hardness value

F---test force，N

S--- superficial area，mm2

D---the average length of the two indentation diagonal，mm

α---indenter face angle=136°0′

if the unit of the test force is kgf，then the Vickers hardness value can be calculated by the following formula:

HV=F/S=2Fsin(α/2)/D2=1.854F/D2

1.6 Knoop hardness test principle

The difference between Knoop hardness measurement and Vickers hardness measurement is that the indenter is different and User need measure the length of two diagonal (D1, D2)in Vickers hardness measurement; user just need measure the length of one diagonal in Knoop hardness measurement. The Vickers indenter is square, but the Knoop indenter is rhombus. The Knoop indentation is rhombus. The ratio between two diagonal is 7:1.(Figure 1-4).

Figure 1-4 Knoop hardness test principle

The depth of indentation is very shallow. It is about 1/30 of the longer diagonal. Because of this feature, Knoop test is suitable to test the hardness of thin coasting, surface hardening layer, metal thin slice, decarburized layer, hard fragile metal. 

The Knoop indenter is very sensitive to the flatness and roughness of the surface of the specimen, the parallelism of the top and the bottom of the specimen.

Knoop hardness value can be calculated by the following formula:

HK=0.102F/S=0.102F/CD²=1.4509F/D²

In the formula：

HK----Knoop hardness value

F----test force, N

S----the area of the indentation, mm²

                  C----indenter constant（it can be calculated by the above formula（1）

D----the length of diagonal, mm

If test force unit is kgf，the knoop hardness value can be calculated by the following formula:

HK=F/S=F/CD²=14.229F/D²

2.Specifications:

1. Vickers Scale:

HV-50:HV1, HV2, HV3, HV5, HV10,HV20,HV30,HV50

2. Test force：
HV-50: (Kgf)       1     2     3      5     10   20   30   50

         (N)      9.8   19.6   29.4   49.0   98.1  196  294  490

3. Test force selection: select the test force on LCD screen

4. Load control：automatic（load/dwell/unload）

5. Dwell time：1-99sec（each step 1-second）

6. Test mode：HV/HK

7. Hardness value：measure manually, display automatically and auto-calculate

8. Test range: (8-3000)HV

9. Optical Systems

10. Max. height specimen： 200mm

11. Max. Throat depth：159mm（from the center）

12. Light intensity：There are 8 levels. User can adjust it .

13. Light source：          5V/3W LED

14. Power supply：           AC220V，60/50Hz

15. Power：        ≤80W

   16. Dimension：          560×186×635┨

   17. Weight：            43kg

3. Assemble and adjust hardness tester

3.1 Inspection before installation

Working table is sturdy, which can sustain the weight of the hardness tester and its accessories. In addition, the working table should horizontal.

Working table doesn’t affected by any mechanical vibrations.

It should have enough space between hardness tester and the wall, which is convenient to maintain in the future.

Power should locate in the 1m (3 ft.) far away from hardness tester, in addition, voltage need stable and uninterrupted.

The environment temperature of work room is 23±5℃.

The relative humidity of work room should less than 65%.

There is no corrosive thing in the work room.

3.2 Installation steps

3.2.1 Put the hardness tester on the work table.

3.2.2 Install four leveling screws (in the Accessory box) to the bottom of the hardness tester.

3.2.3 Install eyepiece to eyepiece tube.

3.2.4 Rotate the elevating wheel counter-clockwise, making the elevating screw rod to the appropriate position. Then put the test table ((in the Accessory box) into the hole of the of elevating screw rod, using screws to fix the test table.

Notice：   Before placing the test table, don’t rotate the elevating wheel clockwise, in order to prevent make the elevating screw rod elevate too high and make the screws and nut trip.

3.2.5 Put level instrument (in the Accessory box) on the test table, by horizontal adjustment screws to tune the tester level

3.2.6 Rotate the cap screws, using suction cup to open the cap, remove the desiccant.

3.2.7 Cover cap, tighten screws

3.2.8 Make sure the power switch is set in the “0” (closed), using the power line (in the Accessory box) to connect the hardness tester and power line.

Note: Before connect the power, you must check the whether the power setting match with power.

3.2.9 Press mark “I” which is on the power switch to turn on the hardness tester.

Note: The red reset switch is on the left of power socket(Figure 1-2 18）don’t press it casually. The purpose of the red replacement switch will be introduced in the latter chapter.

3.2.10 Test the standard harness blocks, you can see the test method in Appendix A: "Hardness tester checks."

Note：Your hardness tester equipped with one or two standard blocks

If the max-min of hardness is over the stated value in table A-1,indication value is over the stated value in table A-2,please contact local agency or call our after-sale service department.

3.2.11 Presses the mark "0" of the power to turn off the power.

3.2.12 Cover the instrument cover（in the accessory box）

4. The function of all the keys

Figure 4-1 shows the front panel of

HVD-50MP/HVD-50AP The upper half part of the figure is LCD. About the detail, this instruction manual will describe in the later chapters. The lower half part of figure 4-1 is keyboard. This chapter will instruct the function of each key in the keyboard.

Figure 4-1 the front panel of Vickers hardness tester

4.1 Display panel

4.1.1 Main panel（main menu）

    In figure 4-1,the panel which display on the LCD is main panel. From up to down, from left to right, the labels are hardness value, measuring scale, Vickers diagonal D1 and D1,test force, dwell time ,adjustment setting , print ,measurement times.

4.1.2 Sub-panel（submenu）

Press <SET UP> to enter the sub-panel, and press <ESC> back to main panel，figure 4-2. 

Figure 4-2 sub-panel (for reference)

Move  to <CONVERSION HARDNESS>, then press〈←〉or〈→〉to choice the hardness you needed.

Move to SEL FORCE , then press〈←〉or〈→〉to choice test force .

5. How to measure

This chapter shows how to operate the hardness. Knoop test and Vickers test are very similar, so this instruction manual just shows how to test Vickers hardness.

5.1 Select the measure scale

5.1.1 Press the mark “I” on the power switch, turn on hardness tester power, then the main panel will display on the LCD. Figure 5-1.

Figure 5-1 Main panel

5.1.2  Move to SEL FORCE, and selecting the test force you need through〈←〉or〈→〉 

5.1.3  If it is necessary, changing the dwell time.

5.2 Begin measuring

Note： <START> is used for starting a measurement after all the settings have been completed. Before measuring, system will display the main panel. User can click the button after the hardness tester completed the measurement.

Notice：

If there is no specimen on the test table, please do not begin to measuring，otherwise, the indenter will push down to test table , two parts will be damaged. Don’t use magneto metric test table and specimen fixture!

5.2  Put the specimen on the test table.

5.2.2 Turn 20× objective lens to working position.

5.2.3 Move the specimen to make it below the 20× objective. Rotate the elevated wheel clockwise, elevating the elevating screw rod until the specimen is 0.5┨ far from indenter.

5.2.4 Rotate the elevating wheel clockwise slowly and focus the optical system until you satisfied with the results of focus.

5.2.5 If essential, rotate the 10x objective lens to working position, observe and choice point to focus. Then return the 20x objective lens to working position for specific focus. The surface structure of the specimen should can be see clearly after focus well. 

Note : User should be careful when focusing and avoid collision between specimen, indenter and objective.

5.2.6 Rotating the indenter to working position and ready to measuring.

5.2.7 Click<START>,the system will began measuring and display a waiting message. Figure 5-2 show the process of measuring

                           Figure 5-2

5.2.8 After finishing the measurement, system will return to main panel. Figure 5-1. Now system is waiting for user to measure and enter the measuring diagonal indication.

5.3 Auto-test（only for HVD-50AP）

5.3.1 Put the specimen on the test table.

5.3.2 Turn 20× objective lens to working position.

5.3.3 Move the specimen to make it below the 20× objective. Rotate the elevated wheel clockwise, elevating the elevating screw rod until the specimen is 0.5┨ far from indenter.

5.3.4 Rotate the elevating wheel clockwise slowly and focus the optical system until you satisfied with the results of focus.

5.3.5 Rotating the 10x Objective lens to working position, observe and choice point to focus.

5.3.6 Return the 20x objective lens to working position for specific focus. The surface structure of the specimen should can be see clearly after focus well. 

Note：User should be careful when focusing and avoid collision between specimen, indenter and objective.

5.3.7  Click<START>,the indenter will return the working position and the system will began measuring and display a waiting message. See figure 5-2.

5.3.8 After finishing the measurement, 20x objective lens will return to working position. See figure 5-1. Now system will show waiting for user to measure and enter the measuring diagonal indication.

5.3.9 If skilled at the operation, you can omit the step 5.3.5 and 5.3.6.

5.3.10 Also can let the indenter return to working position after the operation 5.3.1-5.3.6, then operate follow 5.3.7.