Application Note Tribology and Mechanical Testing Unit Test Methods for Rockwell Hardness and Rockwell Superficial Hardness of Metallic Materials Using the CETR-UMT 2, CETR-UMT 3, or CETR-APEX per ASTM E18-05 Summary of Test Method: This test method describes the setup and procedure for determining the Rockwell Hardness and the Rockwell Superficial Hardness of materials using the CETR-UMT 2, CETR-UMT 3, or CETR-Apex systems. The choice of hardness scale is based on the material to be tested. The apparatus consists of either a conical tip diamond indenter or a tungsten carbide ball indenter mounted under a force sensor on a motor-driven vertical positioning carriage. The specimen is mounted on either a stationary table or a linear stage directly under unde r the indenter. A capacitance displacement sensor is used to measure the depth of penetration. Rockwell Hardness: For Rockwell Hardness measurements the carriage presses the inden ter downward against the specimen to apply a preliminary (minor) load of 10 kg for 3 seconds using the force sensor for feedback to control the load. Then the carriage increases the load for 3 seconds to either 60 kg or 100 kg, depending on the scale that is used. The hold time may be longer if the specimen shows time-dependent plasticity. The load is then decreased to 10 kg. Load and displacement are recorded vs time. The difference in displacements measured at the end of the first 10 kg load period and at the end of the last 10 kg load period is the total displacement. The Rockwell Hardness is : HRx = E E -- e where x is the scale, E scale, E is either 100 or 130 depending on scale (see Table Table 1), ande and e is the number of .002mm units in the total displacement.
A B
Priliminary Load kg 10 10
D E
10 10
F H L M R S
10 10 10 10 10 10
Scale
Table 1 1.. Rockwell Hardness Scales Total Indenter and Holder Indenter E Load kg CETR Part Numbers 60 Diam ond Cone 100 BM372011/AM30B264C-1 100 100
1/16" bal l Diam ond Cone
130 100
100 60 60 60 100 60 100
1/8" ball 1/16" bal l 1/8" ball 1/4" ball 1/4" ball 1/2" ball 1/2" ball
130 130 130 130 130 130 130
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BM110016/A M30B276C -1
BM372011/AM30B264C-2
BM110056/M30B271D-1
BM110016/A M30B276C -1
BM110056/M30B271D-1
BM110055/AM30B263A
BM110055/AM30B263A
B M110054/AM30B 1035 B M110054/AM30B 1035
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Application Note Tribology and Mechanical Testing Unit Rockwell Superficial Hardness: For Rockwell Superficial Hardness measurements the carriage presses the indenter downward against the specimen to apply a preliminary (minor) load of 3 kg for 3 seconds using the force sensor for feedback to control the load. Then the carriage increases the load for 3 seconds to 15kg, 30 kg or 45 kg, depending on which scale is used (see Table 2). The load is then decreased to 3 kg. Load and displacement are recorded vs time. The difference in displacements measured at the end of the first 3 kg load period and at the end of the last 3 kg load period is the total displacement. The Rockwell Superficial Hardness is : HRx=100 - e where x is the scale (see Table 2), and e is the number of .001mm units in the total displacement.
Scale 15N 30N 45N 15T
Table 2. Rockwell Superficial Hardness Scales Priliminary Total Indenter and Holder Indenter Load kg Load kg CETR Part Numbers 15 Diamond Cone BM372011/AM30B264C-1 3 3 30 Diamond Cone BM372011/AM30B264C-2 3 45 Diamond Cone BM372011/AM30B264C-3 3 15 1/16" ball BM110016/AM30B276C-1
30T 30W 45W 15X 30X 45X 15Y 30Y 45Y
3 3 3 3 3 3 3 3 3
30 30 45 15 30 45 15 30 45
1/16" ball 1/8" ball 1/8" ball 1/4" ball 1/4" ball 1/4" ball 1/2" ball 1/2" ball 1/2" ball
BM110016/AM30B276C-0
BM110056/M30B271D-2
BM110056/M30B271D-3
BM110055/AM30B263A
BM110055/AM30B263A
BM110055/AM30B263A
BM110054/AM30B1035 BM110054/AM30B1035 BM110054/AM30B1035
UMT Hardware Configuration: 4” Mounting Block M30C366-2
Model DFH-100 Dual Friction/Load Sensor range 1.0 to 100 kg
Rigid Adapter for type DFH sensors
Indentor and Holder (Ref. RH Tables 1 and 2)
Capacitance Sensor CAP-2
Capacitance Sensor Reference Plate M30B979-1
Stationary Specimen Table
Optional Additional Sensors Mod. HT-100 Humidity and Temperature Measurement & Recording
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Email:
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Application Note Tribology and Mechanical Testing Unit UMT Software Test Setup for Rockwell Hardness: UMT Options File: Load the options file which contains settings for the 100kg force/load sensor and capacitance sensor.
Test Sequence: The Test Sequence should consist of 3 steps. Step 1 asserts the 10-kg minor load for 3 seconds. General - Controlled Carriage/Load, Constant Force(Fz), Duration 3 sec. Carriage - Force -10 kg Spindle -Velocity is 0 revs/min. Slider – idle. Step 2 asserts the total (minor = Major) load for 3 seconds. General - Controlled Carriage/Load, Constant Force(Fz), Duration 3 sec. Carriage - Force (See Table 1 for total force for selected scale) Spindle –Velocity is 0 revs/min, Slider – idle. Step 3 asserts the 10-kg minor load for 5 seconds. - Controlled Carriage/Load, Constant Force(Fz), Duration 5 sec. General Carriage - Force -10 kg Spindle -Velocity is 0 revs/min. Slider – idle.
Data Collection: The following should be checked under DataFile: Fz – Normal Force C1 - Capacitance Sensor T – Time Z1 – Carriage Position Rh input - Relative Humidity (optional) Te input – Temperature (optional)
UMT Software Test Setup for Rockwell Superficial Hardness: UMT Options File: Load the options file which contains settings for the 50kg force/load sensor and capacitance sensor.
Test Sequence: The Test Sequence should consist of 3 steps. Step 1 asserts the 3-kg minor load for 3 seconds. General - Controlled Carriage/Load, Constant Force(Fz), Duration 3 sec. Carriage - Force -3 kg Spindle -Velocity is 0 revs/min. Slider – idle. Step 2 asserts the total (minor = Major) load for 3 seconds. General - Controlled Carriage/Load, Constant Force(Fz), Duration 3 sec. Carriage - Force (See Table 2 for total force for selected scale) Spindle –Velocity is 0 revs/min, Slider – idle. Step 3 asserts the 3-kg minor load for 5 seconds. - Controlled Carriage/Load, Constant Force(Fz), Duration 5 sec. General Carriage - Force -3 kg Spindle -Velocity is 0 revs/min. Slider – idle.
Data Collection: The following should be checked under DataFile: Fz – Normal Force C1 - Capacitance Sensor T – Time Z1 – Carriage Position Rh input - Relative Humidity (optional) Te input – Temperature (optional)
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Application Note Tribology and Mechanical Testing Unit Report: Use the Viewer program to plot test results. Open the data file with the box checked for Open all data in a single step. Check the Fz and C1 boxes under Parameters on the Viewer screen. Note the difference on the C1 scale between the Initial Displacement and the Final Displacement. Divide that difference by .002 for Rockwell Hardness or .001 for Rockwell Superficial Hardness to get e. The Rockwell Hardness is : Hrx = E - e where x is the scale, E is either 100 or 130 depending on scale (see Table 1.). The Rockwell Superficial Hardness is : Hrx = 100 - e.
Verification by Standardized Hardness Test Block: The UMT or Apex machine should be checked each day that the machine is used for hardness testing. The same test sequence that is used for hardness testing of normal test specimens is used for verification tests on standardized test blocks. Make at least three hardness readings on the test block on the scale and at the hardness level at which the machine is being used. If the mean of these values falls within the tolerances marked on the block the machine is considered satisfactory. Table 3 list three standardized hardness test blocks available from CETR.
Table 3. Test Blocks for Calibration A Scale, Steel A Scale, Brass D Scale, Steel
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Part Number BM260036 BM260037 BM260038
Email:
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