Difference between revisions of "Rockwell Hardness Tester"

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|contact=Host Cold Metals
 
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|value=$500
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== Rockwell Hardness ==
 
== Rockwell Hardness ==
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The Rockwell scale is a hardness scale based on indentation hardness of a material. The Rockwell test determines the hardness by measuring the depth of penetration of an indenter under a large load compared to the penetration made by a preload.  There are different scales, denoted by a single letter, that use different loads or indenters. The result is a dimensionless number noted as HRA, HRB, HRC, etc., where the last letter is the respective Rockwell scale. When testing metals, indentation hardness correlates linearly with tensile strength.  This important relation permits economically important nondestructive testing of bulk metal deliveries with lightweight, even portable equipment, such as hand-held Rockwell hardness testers.
+
The Rockwell scale is a hardness scale based on indentation of a material. The Rockwell test determines the hardness by measuring the depth of penetration of an indenter under a large load compared to the penetration made by a preload.  There are different scales, denoted by a single letter, that use different loads or indenters. The result is a dimensionless number noted as HRA, HRB, HRC, etc., where the last letter is the respective Rockwell scale. When testing metals, indentation hardness correlates linearly with tensile strength.  This important relation permits economically important nondestructive testing of bulk metal deliveries with lightweight, even portable equipment, such as hand-held Rockwell hardness testers.
  
−
Copied from Wikipedia. See Wikipedia for additional background
+
See wikipedia for additional background.
  
 
==Scales and values==
 
==Scales and values==
−
There are several alternative scales, the most commonly used being the "B" and "C" scales. Both express hardness as an arbitrary [[dimensionless number]].
+
There are several alternative scales, the most commonly used being the "B" and "C" scales. Both express hardness as an arbitrary dimensionless number.
−
 
 
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{| class="wikitable" border="1"
 
−
|+ Various Rockwell scales
 
−
|-
 
−
! Scale !! Abbreviation !! Load !! Indenter !! Use
 
−
!N
 
−
!s
 
−
|-
 
−
| A || HRA || 60 [[Kilogram-force|kgf]] || 120° diamond spheroconical<sup>†</sup> || [[Tungsten carbide]]
 
−
|100
 
−
|0.002mm
 
−
|-
 
−
| B || HRB || 100 kgf || {{convert|1/16|in|mm|adj=mid|-diameter|3}} steel sphere || Aluminium, brass, and soft steels
 
−
|130
 
−
|0.002mm
 
−
|-
 
−
| C || HRC || 150 kgf || 120° diamond spheroconical || Harder steels >B100
 
−
|100
 
−
|0.002mm
 
−
|-
 
−
| D || HRD || 100 kgf || 120° diamond spheroconical
 
−
|
 
−
|100
 
−
|0.002mm
 
−
|-
 
−
| E || HRE || 100 kgf || {{convert|1/8|in|mm|adj=mid|-diameter|3}} steel sphere
 
−
|
 
−
|130
 
−
|0.002mm
 
−
|-
 
−
| F || HRF || 60 kgf || {{convert|1/16|in|mm|adj=mid|-diameter|3}} steel sphere
 
−
|
 
−
|130
 
−
|0.002mm
 
−
|-
 
−
| G || HRG || 150 kgf || {{convert|1/16|in|mm|adj=mid|-diameter|3}} steel sphere
 
−
|
 
−
|130
 
−
|0.002mm
 
−
|-
 
−
| colspan=5 | <sup>†</sup>Also called a ''brale indenter''
 
−
|
 
−
|
 
−
|}
 
−
 
 
−
* Except for testing thin materials in accordance with A623, the steel indenter balls have been replaced by tungsten carbide balls of the varying diameters.  When a ball indenter is used, the letter "W" is used to indicate a tungsten carbide ball was used, and the letter "S" indicates the use of a steel ball. E.g.: 70 HRBW indicates the reading was 70 in the Rockwell B scale using a tungsten carbide indenter.<ref>E18-08b Section 5.1.2.1 & 5.2.3</ref>
 
−
 
 
−
The ''superficial'' Rockwell scales use lower loads and shallower impressions on brittle and very thin materials.  The 45N scale employs a 45-kgf load on a diamond cone-shaped Brale indenter, and can be used on dense [[ceramic]]s.  The 15T scale employs a 15-kgf load on a {{convert|1/16|in|mm|adj=mid|-diameter|3}} hardened steel ball, and can be used on [[sheet metal]].
 
−
 
 
−
The B and C scales overlap, such that readings below HRC 20 and those above HRB 100, generally considered unreliable, need not be taken or specified.
 
  
 
===Typical values===
 
===Typical values===
−
* Very hard steel (e.g. chisels, quality [[List of blade materials|knife blades]]): HRC 55–66 (Hardened High Speed Carbon and Tool Steels such as M2, W2, O1, CPM-M4, and D2, as well as many of the newer powder metallurgy Stainless Steels such as S30V, CPMS-154, ZDP-189, etc.)<ref>[https://web.archive.org/web/20080531085629/http://www.cutleryscience.com/reviews/blade_materials.html Knife blade materials]</ref>
+
* Very hard steel (e.g. chisels, quality knife blades): HRC 55–66 (Hardened High Speed Carbon and Tool Steels such as M2, W2, O1, CPM-M4, and D2, as well as many of the newer powder metallurgy Stainless Steels such as S30V, CPMS-154, ZDP-189, etc.)
−
* [[Axe]]s: about HRC 45–55
+
* Axe: about HRC 45–55
−
* Brass: HRB 55 (Low brass, UNS C24000, H01 Temper) to HRB 93 (Cartridge Brass, UNS C26000 (260 Brass), H10 Temper)<ref>[http://www.matweb.com matweb.com], accessed 2010-06-23</ref>
+
* Brass: HRB 55 (Low brass, UNS C24000, H01 Temper) to HRB 93 (Cartridge Brass, UNS C26000 (260 Brass), H10 Temper)
  
−
Several other scales, including the extensive A-scale, are used for specialized applications. There are special scales for measuring [[Case hardening|case-hardened]] specimens.
+
Several other scales, including the extensive A-scale, are used for specialized applications. There are special scales for measuring case-hardened specimens.
  
 
Copied from wikipedia
 
Copied from wikipedia
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<gallery>
 
<gallery>
 
File:Rockwell_Label.JPG|Label
 
File:Rockwell_Label.JPG|Label
 +
File:Rockwell_Indentor_Holder.jpg|Holder for indentor
 +
File:Rockwell_Indentors.JPG|Indentors
 
File:Rockwell_Anvil_adjust.JPG|Handwheel to adjust the anvil to apply the minor load
 
File:Rockwell_Anvil_adjust.JPG|Handwheel to adjust the anvil to apply the minor load
 
File:Rockwell_Major_Load_Lever.JPG|Major Load Lever
 
File:Rockwell_Major_Load_Lever.JPG|Major Load Lever
 
File:Rockwell_Dial.JPG|Dial   
 
File:Rockwell_Dial.JPG|Dial   
 +
File:Cold_Metals_Tan_Cabinet.JPG|Tan Cabinet 
 
</gallery>
 
</gallery>
  
 +
The indentors and hardness test blocks and spare anvils are in the tan cabinet, fifth drawer down.
 +
 +
=== Indentor / Penitrator Choice ===
 +
 +
  Diamond indentor, marked 'MC' for hard materials RHC scale ( see wikipedia for scale explanation)
 +
  Ball indentor for RHB scale.
 +
 +
=== Procedure ===
 +
 +
1. Select the penetrator/indentor.
 +
 +
Soft materials are usually tested in the Rockwell B Scale, using 1/16″ ball penetrator and 100 Kg Major Load. Hardened steel and hard alloys are tested in the Rockwell C Scale, using a diamond penetrator and a 150 Kg Major Load.  Do not use the ball penetrator with the steel test block or when testing hard steel. Such a procedure will damage the penetrator and result in invalid tests
 +
 +
2. Set up the tester
  
−
Select the correct indentor - diamond for HRC other material for HRC  ( what is an indentor? need identification and use of indentors in stock)
+
Secure the penetrator/indentor and the appropriate anvil in the tester.
 +
Select correct weight, 150kg for C scale 100 kg for B scale. Three weights are stacked in the tester, the bottom is 60kg, next is 40kg then 50kg. With all three weights the total is 150kg, for the C scale. Remove the top weight and you have 100 kg for the B scale.
  
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1) Install indentor  (photo ?)
+
3. Apply Minor Load
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2) Support load (how?)
+
 
−
3) Place component on anvil, use a specialized anvil if needed ( eg. round stock)
+
Slowly turn the hand wheel to bring the small dial indicator hand to the line. This applies a minor pressure load to the penetrator.
−
4) Turn handwheel to apply the 'minor load' until needle points to indicator mark on dial. ( id handwheel photo?)
+
 
−
5) Zero out dial.
+
4. Apply Major Load
−
6) Depress lever to apply 'major load' , allow time to settle.  (where is lever? what is depress? move forward?)
+
 
−
7) Release lever
+
Turn the major load lever back to apply major load.
−
8) Read dial for hardness. (photo example how?)
+
 
 +
5. Release major load
 +
 
 +
Turn the major load lever forward to release major load.
 +
 
 +
6. Take the reading
 +
 
 +
With the diamond penetrator, read Column C on the barrel dial (black numbers).
 +
With the ball penetrator, read column B (red numbers).
 +
NOTE: The first two or three tests may be low until the penetrator and anvil have become firmly seated.
  
 
== Testing ==
 
== Testing ==
−
Test samples explained.
+
Test samples in the drawer are marked with hardness.
−
 
 
  
 
== Notes ==
 
== Notes ==
−
As of October 2015, the machine shop doesn't have a diamond indenter for the Rockwell C scale -- but we do have spherical indenters for Rockwell B.
 
  
 
Keep the dust cover on. Use calibration discs if you care about your results. Accessories for the tester are in the tan colored cabinet.
 
Keep the dust cover on. Use calibration discs if you care about your results. Accessories for the tester are in the tan colored cabinet.

Latest revision as of 20:09, 23 January 2018


Rockwell Hardness Tester
Rockwellhardness.jpg
Owner/Loaner PS:One
Serial Number 4MM 344
Make/Model 4M
Arrival Date Summer, 2015
Usability yes
Contact Host Cold Metals
Where Cold Metals, on a bench
Authorization Needed no
Hackable no
Estimated Value $500
Host Area Cold Metals


Rockwell Hardness Tester Area: Cold Metals https://wiki.pumpingstationone.org/wiki/Rockwell_Hardness_Tester




Rockwell Hardness

The Rockwell scale is a hardness scale based on indentation of a material. The Rockwell test determines the hardness by measuring the depth of penetration of an indenter under a large load compared to the penetration made by a preload. There are different scales, denoted by a single letter, that use different loads or indenters. The result is a dimensionless number noted as HRA, HRB, HRC, etc., where the last letter is the respective Rockwell scale. When testing metals, indentation hardness correlates linearly with tensile strength. This important relation permits economically important nondestructive testing of bulk metal deliveries with lightweight, even portable equipment, such as hand-held Rockwell hardness testers.

See wikipedia for additional background.

Scales and values

There are several alternative scales, the most commonly used being the "B" and "C" scales. Both express hardness as an arbitrary dimensionless number.

Typical values

  • Very hard steel (e.g. chisels, quality knife blades): HRC 55–66 (Hardened High Speed Carbon and Tool Steels such as M2, W2, O1, CPM-M4, and D2, as well as many of the newer powder metallurgy Stainless Steels such as S30V, CPMS-154, ZDP-189, etc.)
  • Axe: about HRC 45–55
  • Brass: HRB 55 (Low brass, UNS C24000, H01 Temper) to HRB 93 (Cartridge Brass, UNS C26000 (260 Brass), H10 Temper)

Several other scales, including the extensive A-scale, are used for specialized applications. There are special scales for measuring case-hardened specimens.

Copied from wikipedia

Operation

Major Components

  • Label

  • Holder for indentor

  • Indentors

  • Handwheel to adjust the anvil to apply the minor load

  • Major Load Lever

  • Dial

  • Tan Cabinet

The indentors and hardness test blocks and spare anvils are in the tan cabinet, fifth drawer down.

Indentor / Penitrator Choice

 Diamond indentor, marked 'MC' for hard materials RHC scale ( see wikipedia for scale explanation)
 Ball indentor for RHB scale.

Procedure

1. Select the penetrator/indentor.

Soft materials are usually tested in the Rockwell B Scale, using 1/16″ ball penetrator and 100 Kg Major Load. Hardened steel and hard alloys are tested in the Rockwell C Scale, using a diamond penetrator and a 150 Kg Major Load. Do not use the ball penetrator with the steel test block or when testing hard steel. Such a procedure will damage the penetrator and result in invalid tests

2. Set up the tester

Secure the penetrator/indentor and the appropriate anvil in the tester. Select correct weight, 150kg for C scale 100 kg for B scale. Three weights are stacked in the tester, the bottom is 60kg, next is 40kg then 50kg. With all three weights the total is 150kg, for the C scale. Remove the top weight and you have 100 kg for the B scale.

3. Apply Minor Load

Slowly turn the hand wheel to bring the small dial indicator hand to the line. This applies a minor pressure load to the penetrator.

4. Apply Major Load

Turn the major load lever back to apply major load.

5. Release major load

Turn the major load lever forward to release major load.

6. Take the reading

With the diamond penetrator, read Column C on the barrel dial (black numbers). With the ball penetrator, read column B (red numbers). NOTE: The first two or three tests may be low until the penetrator and anvil have become firmly seated.

Testing

Test samples in the drawer are marked with hardness.

Notes

Keep the dust cover on. Use calibration discs if you care about your results. Accessories for the tester are in the tan colored cabinet.

Resources

Wikipedia : https://en.wikipedia.org/wiki/Rockwell_scale

This video shows another machine but it has a good explanation of the test: https://www.youtube.com/watch?v=G2JGNlIvNC4

Again a different machine but shows procedure : https://www.youtube.com/watch?v=3FX3wFhk0mQ

Source for diamond indentor: http://www.westportcorp.com/dpc1.html

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