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Indication of Hardness Value Dial
Max Height of Specimen 175MM
Indication of Hardness Value Dial display
Dwell time 0-60s
Distance of Indenter to outer wall 160mm
Initial testing force 10kgf (98.07N)
Testing force 60kgf (588N)   100kgf (980N)    150kgf (1471N)
Rockwell Scale HRA, HRB, HRC, HRD, HRE, HRF, HRG, HRH, HRK  
Hardness measuring range HRA: 20-88   HRB: 20-100  HRC: 20-70  HRD: 40-77 HRF: 60-100  HRG: 30-94  HRH: 80-100  HRK: 40-100
Power supply AC220V+5%, 50-60Hz
Overall Dimensions 520*240*700mm
Net weight About 55Kg

Standard accessories

Diamond Rockwell Indenter 1 PC

Diameter 1.5875mm Ball Indenter 1 PC

Hardness block (HRC High Low 2, HRB 1) 3

Large, Medium, “V” shaped Testing Table 1 each

Weights(A, B, C) 1 each

Plastic Dustproof cover 1

Manual 1 Product certificate 1


Introduction And Troubleshooting Analysis And Troubleshooting




HRD-150 electric Rockwell hardness tester is automatic to zero, the main test force is automatically loaded and unloaded, the lever is loaded, and the test process is automated.

This hardness tester is a practical semi-automatic hardness measuring instrument. In 1989, it won the National Quality Silver Award. It can be used to determine the Rockwell hardness values of ferrous metals, non-ferrous metals, non-metallic materials and products, and is widely used in factories, mines, research institutes and universities and colleges.



Main Features:

  1. Spindle system adopts a frictionless spindle structure, which is structurally strong, rigid, accurate, durable and reliable, and improves the accuracy of the initial test force.
  2. Indentation depth is measured using a unique automatic zero-specific table that eliminates the measurement error caused by manual zeroing.
  3. The application, maintenance, and removal of the total test force are automated, eliminating the errors caused by manual operations.
  4. Dial direct reading, HRA, HRB, HRC scale;
  5. Optional Rockwell's other scale;
  6. Accuracy meets GB/230.2,ISO 6508-2 and ASTM E18.


Technical Specifications And Parameters:

Measuring range: 20-88HRA, 20-100HRB, 20-70HRC

Test force: 588.4N(60kgf)980.7N(100kgf)1.471KN(150kgf)

Max.height of the specimen: 200 mm

Indenter center to machine wall distance: 135mm

Hardness resolution: 0.5HR

Working voltage: AC220V/50Hz

Dimensions: 500x250x700mm

Weight: 70kg




Standard list of the accessory box:







Large flat testing table





Small flat testing table





V type testing table





Diamond indenter





Φ1.588 ball indenter

ball indenter




Φ1.588 spare ball





Standard Rockwell hardness block





Standard Rockwell hardness block

35-55 HRC




Standard Rockwell hardness block

60-70 HRC




Standard Rockwell hardness block





Standard Rockwell hardness block






Through the above introduction, I believe that everyone has a more detailed understanding of HRD-150.

In the actual use process, you will encounter some faults. If you can't rule out these simple faults, you can only wait for the professional to come to the door for repair, which may affect our normal work. Let's take a look at it below.



Fault analysis and troubleshooting:

1. Pre-test force cannot be applied, that is, the hand feel is heavy when the pre-test force is applied, but the needle of the hardness indicator is not moved.

Cause: The rod in the head of the hardness indicator is caught by the upper and lower sleeves (the factor is not used for years).

Troubleshooting: Add some watch oil lubrication to the joint of the meter head and the upper and lower sleeves.

Quote: In this case, the reason why the hardness tester does not apply the pre-test force is caused by the increase of the friction of the metering rod and the bushing; sometimes the cause of the fault is due to the zeroing tip of the upper part of the measuring lever. Caused by improper position of the screw.

Another reason why the pre-test force cannot be applied does not occur in the head portion but in the screw portion. Since the guide rod at the bottom of the screw rod slides out from the guide groove, the guide rod abuts against the guide groove plate when the table is raised, so that the hardness block or the test piece on the work table cannot touch the indenter, thereby failing to add the pre-test force. .

In short, you need to find the reason for the difference.

2.Pre-test force has been applied normally, but the main test force is not added after pressing the load button.

Cause: The load-stop switch in the 2 stroke switches that control the loading and unloading of the main test force failed to work normally, and the reason why it cannot operate is due to the open circuit of the control relay coil corresponding to it.

Troubleshooting and corresponding analysis: First check whether the loading button is normal; use the universal meter to check the 2 line piles of the switch, and the on-off function indicates that the loading button is normal.

The application of the main test force of this Rockwell hardness tester is carried out by the ejector lever supporting the load lever under the action of the motor, so that the load lever is completed by the weight of the hanging bar and the hanging code.

As for the removal of the main test force, the reverse rotation of the motor causes the jack to support the load bar upward.

That is to say, the main test force of the hardness tester is driven by the forward and reverse rotation of the motor, and the forward and reverse rotation of the motor is controlled by the corresponding travel switch and the corresponding DZ-6 type relay.

Upon inspection, the DZ-6 type relay coil corresponding to the stroke switch to which the main test force is applied is not used for a long time, so that the main test force cannot be applied. If the same type of relay is replaced, the main test force can be applied normally.

Supplementary note: When the DZ-6 type relay has a fault such as a coil break and cannot work normally, the up and down movement of the ejector lever controlled by it will be abnormal, resulting in the failure to add or remove the main test force;

And because of the randomness and mismatch of the upper and lower positions, it also causes the pre-test force to not be applied normally.

In the process of repairing, the above situation is often encountered. In this case, as long as the DZ-6 relay and the corresponding travel switch can work normally, other problems will be solved.

3.After the main test force is applied, the main test force is automatically removed when the requirement to maintain the load for 10 seconds is not reached.

Cause: The time relay does not work properly.

Troubleshooting: After checking, the coil of JSJ-Y type transistor time relay is moldy because it is not used for a long time. Since it can not be purchased, it will be welded at the broken line, and it can be normally loaded for 10 seconds after loading. .

4.The hardness value is not accurate: that is, the difference between the actual hardness indication value and the standard hardness block value exceeds the allowable error range.

Cause: The arm ratio of the load lever or measuring lever changes.

Troubleshooting: If the actual hardness indication exceeds the allowable difference, it can be solved by adjusting the arm ratio of the measuring lever.

Adjustment method is as follows: Since the contact point of the probe of the hardness indication table and the measuring lever is the force point of the measuring lever, changing the force point, that is, the front and rear positions of the hardness indicating table, can change the size of the measuring lever arm ratio. The direction of the hardness indication table moving forward and backward depends on the positive and negative of the actual hardness indication error: if it is positive, the hardness indicator is moved forward to increase the measurement lever arm ratio, that is, increase the force value and decrease Hardness indication; if it is negative, the opposite is true. As for the operation of moving the hardness indicator table back and forth, it is easy to move the fastening bolt and then move it back and forth.

However, if the actual hardness indication exceeds the tolerance value, it is impossible to adjust the arm ratio of the measuring lever.

At this point, it is necessary to adjust the arm ratio of the load lever. There are two ways to adjust the load lever arm ratio:

One is to adjust the position of the key blade ( the blade on the lifting bar and the hanging code).

The second is to adjust the position of the blade (the spindle and the blade above the head).

The difference between the two ways is that the change of the hardness indication value caused by the position of the blade at the adjustment force point is greater than the change of the hardness indication value caused by adjusting the position of the key edge. Therefore, it is generally preferable to adjust the position of the blade at the point of the adjustment force.

The adjustment method is as follows: remove the lifting code bar and the hanging weight code, and lift the load lever slightly upwards (if the adjustment is not made, the blade is damaged when the adjustment is made), and then loosen the force of the blade to tighten the blade with the appropriate rotation force. Angle and re-tighten its nut.

The hardness is tested again and the effect of the force point edge adjustment is verified by the change in the hardness indication error. Repeat this adjustment several times until the hardness is acceptable. As for the adjustment of the key position of the load lever, the adjustment method is similar.

5.The actual hardness indication error is -25HRC, which far exceeds the tolerance value; and the indication value is unstable, and the variability also exceeds the tolerance requirement; at the same time, there is a creeping phenomenon of shaking and shaking when the pointer of the hardness indicator moves.

Cause: The measurement lever is obstructed by the rubbing of the edge of the elliptical hole that passes through it.

Troubleshooting: Practice has shown that the hardness indication error that occurs under the above conditions is too poor, no matter how to adjust the arm ratio of the load lever, it will not work.

In fact, when adjusting the value of the test force to adjust the hardness indication value and the effect is very small, it should be considered whether the test force value is not caused by the excessive friction of a certain movable part of the hardness tester. qualified.

Upon careful inspection, it was found that the measuring lever rubbed against the edge of the elliptical hole of the spindle through which it passed. Pulling the measuring lever to the middle of the elliptical hole of the spindle no longer rubs against it, and all three of the above-mentioned fault phenomena are solved.


The above describes the repair practice of several faults of the HRD-150 electric Rockwell hardness tester. From this we can get the understanding that for the various faults of the hardness tester, it is necessary to comprehensively analyze and find out the root cause of the fault. How quickly and economically to solve and troubleshoot.

Standards: GB/T 230.1,GB/T 230.2, JJG 112

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