hardness testers

Hardness Testing Information Guide

This brief guide is intended to be a refresher for those a ready involved in hardness as well as a reference for first time users of hardness testers. Hardness is a characteristic of a material, not a fundamental physical property. It is defined as the resistance to indentation, and it is determined by measuring the permanent depth of the indentation. More simply put, when using a fixed force (load)* and a given indenter, the smaller the indentation, the harder the material. Indentation hardness value is obtained by measuring the depth or the area of the indentation using one of over 12 different test methods.

Section 3: How to Assure a Good Hardness Test.

Fundamental to all reliable hardness tests are several factors.

1. Choose the correct test method based on the application. Plan to use the highest test force and largest indenter possible.

2. Verify that the test results are repeatable. Conduct a gage R&R study to see how much error the operator and measurement system contribute.

NOTE: Select the right hardness tester for the application. There are significant differences between levels of performance within each classification of tester. A difficult job on one tester could be very simple and fast on another. So, although most hardness testers within a test method and classification look alike, there are many features that can significantly affect productivity and accuracy. A good example of features affecting performance is demonstrated in bench Rockwell hardness testing systems. All can handle large parts, however the Versitron can usually test large parts more quickly and accurately, when compared to other bench testers which require external support stands or fixtures. The Indentron, on the other hand, is much easier to use on small, awkward parts. If you need assistance with your application, contact a Newage Testing Instruments sales representative.

TEST SPECIFICATIONS

Many questions may need to be answered in order to determine the scale and tester to be used:

Is there a hardness scale specified?
What is the materials being tested and is it suitable for a a particular test?
How large are the parts?
Is the test point difficult to reach?
What volume of testing is to be done?
How accurate do the results need to be?
What is the budget?
What are the problems that have occurred in the past?

TEST	TEST METHOD	TEST FORCE RANGE	INDENTER TYPES	ASTM TEST METHOD	MEASURE METHOD
Rockwell	Regular	60, 100, 150 kgs	Conical Diamond & Small Ball	E 18	Depth
	Superficial	15, 30, 45 kgs	Conical Diamond & Small Ball	E 18	Depth
	Light Load	3, 5, 7 kgs	Truncated Cone Diamond	N/A	Depth
	Micro	500, 100 grams	Small Truncated Cone Diamond	N/A	Depth
	Macro	500 to 3000 kgs	5, 10 mm Ball	E 103	Depth
Micro-Hardness	Vickers	5 to 2000 grams	136º Pyramid Diamond	E 384	Area
	Knoop	5 to 2000 grams	1300 x 1720º Diamond	E 384	Area
	Rockwell Type	500, 3000 grams	Truncated Cone Diamond	N/A	Depth
	Dynamic	.01 to 200 grams	Triangular Diamond	N/A	Depth
Brinell	Optical	500 to 3000 kgs	5mm, 10 mm Ball	E 10	Area
	Depth	500 to 3000 kgs	5mm, 10 mm Ball	E 103	Depth
Shore	Regular	822 (A), 4550 (D) grams	35º Cone (A) 30º Cone (D)	D 2240	Depth
	Micro	257 (A), 1135 (D) grams	35º Cone (A) 30º Cone (D)	N/A	Depth
IRHD	Regular	597 grams	2.5 mm Ball	D 1415	Depth
	Micro	15.7 grams	.395 mm Ball	D 1415	Depth