Hardness Testing of Materials

Table of Contents

Introduction

Tested materials Table

Hardness Comparison ROCKWELL C

Hardness Comparison ROCKWELL B

Hardness Comparison SHORE D

Approximate Comparisons of Hardness Scales

Scale Value Comparisons

Hardness Comparison BRINELL

Hardness Comparison MOHS

Summary…

Bibliography…


1 Introduction.

            There are several methods used to check the hardness of materials. 
Hardness testing is a test to measure the resistance and stress of the material for bending, penetration, scratching, or abrasion.  the most commonly used hardiness tests are those that measure the resistance to penetration of the material. Some of the testers and scales that can be use for hardness testing are Rockwell B&C,  Shore A&D , Brinell, and Mohs.  (1988)

In this  experiment,  Rockwell B, Rockwell C, and Shore A, Shore D , Brinell, and Mohs are used to test the hardness of materials.

  Specimen Hardness Tester and Scale
1 King pin  57.3 Rockwell  C
2 Hydraulic lifter 45.5 Rockwell  C
3 HSS 58.5 Rockwell  C
4 Bearing race 60.5 Rockwell  C
5 File 39 Rockwell  C
6 3/4 Socket 43.9 Rockwell  C
7 Copper 48.9 Rockwell  B
8 Brass 63.2 Rockwell  B
9 Aluminum 6061T6 63.5 Rockwell  B
10 Cast Iron 95.9 Rockwell  B
11 Low Carbon Steel 91.3 Rockwell  B
12 Acrylic  87.2 Shore  D
13 Bakelite 90.5 Shore  D
14 Transoptic 82 Shore  D
15 P.V.C Gray Channel 76 Shore  D
 

SCALE VALUE COMPARISONS
SPECIMEN BRINELL ROCKWELL B ROCKWELL C SHORE D MOHS
KING PIN 621   57.3   6.8
HYDRAULIC LIFTER 495   45.5   6.2
HSS 645   58.5   6.8
BEARING RACE 665   60.5   7.0
FILE 435   39   5.7
3/4 SOCKET 470   43.9   6.0
COPPER 82 48.9     2.8
BRASS 108 63.2     2.9
ALUMINUM 6061 T6 104 63.5     2.8
CAST IRON 204 95.9     4.4
LOW CARBON STEEL  195 91.3     4.3
ACRYLIC 69     90.5 6.9
BAKELITE 65     95.5 2.6
TRANSOPTIC 59     82 7.2
P.V.C GRAY CHANNEL 55     76 7.2

Summary & Conclusion

        
Hardness is an important factor when choosing a material for a special purpose.  Fifteen specimens  of materials were chosen for hardness testing in this lab. The samples were designed on an approximate comparison of hardness scales chart to show the relationship between the hardness values of the samples.  A table of comparisons was developed to show the hardness values of the samples on the different scales.

In this lab,  it was found that Rockwell B is  being use for soft steels and nonferrous metals. On the other hand, Rockwell C can be applied to hardened metals. The shore scleroscope measures hardness in terms of the elasticity of the material.  Shore D  measures the penetration of a steel penetrator with a static spring load applied

The hardest material sampled was Bearing Race  with a hardness rating of 60.5 Rc. The softest material tested was Polyvinylcloride (PVC) with a hardness rating of 76 Sd.

 


 

Bibliography


Pollack, Herman W. Materials Science and Metallurgy. fourth edition. 1988


Paglierani, Gary. IT 283 Hardness Testing of Materials. 2005