Bench Rockwell Hardness Tester

What is the Bench Rockwell Hardness Tester?

A bench Rockwell hardness tester presses a diamond cone or hardened ball into the specimen under a preliminary and main load and reads hardness from the additional penetration depth. It is the standard production acceptance test for hardened steel.

Overview

The specimen rests on a rigid anvil and is raised until it contacts the indenter, which applies a preliminary load of 10 kgf to eliminate surface effects. A main load of 60, 100 or 150 kgf is then added, held for a dwell time of a few seconds and removed, and the residual increase in penetration depth is converted to a Rockwell number. Because depth measurement is fast, the test is well suited to production control and to heat treatment verification on flat, clean surfaces with a thickness at least ten times the depth of the impression. Digital models display and store results, can apply statistical limits and print reports, and can be fitted with motorized stages for repeatable positioning on curved or large parts. Typical scales are HRC for hardened steel, HRB for softer metals and HRA for very hard materials.

How does it work?

Hardness expresses resistance to local plastic deformation. In Rockwell testing a diamond cone or hardened ball is pressed in with a preliminary and then a main load, and hardness is read from the additional depth of penetration, which makes the method fast and simple. Brinell testing presses a tungsten carbide ball at a high load and measures the impression diameter optically, giving an average value that suits coarse or inhomogeneous material. Vickers and Knoop testing use a diamond pyramid with loads from grams to kilograms and measure the diagonal lengths of the impression, which allows individual phases, thin cases and small features to be tested. Leeb rebound testing measures the velocity of an impact body before and after striking the surface, giving a portable measurement that is converted to other scales by comparison. The measured value depends on test force, indenter geometry, dwell time, surface finish and support of the specimen, so these are all defined by the standards.

What are the key features?

• Preliminary and main load sequences per ISO 6508 or ASTM E18
• Diamond cone and tungsten carbide ball indenters
• Load options of 60, 100 and 150 kgf
• Digital display with statistics and printer output
• Motorized stage option for repetitive positioning
• Rigid frame and anvil suited to heavy specimens

What are the technical specifications?

A typical bench rockwell hardness tester configuration offers preliminary test force of 98 N (10 kgf), main test forces of 588, 980, 1471 N (60, 100, 150 kgf), scales of HRA, HRB, HRC and others, resolution of 0.1 HR, dwell time of 1–15 s settable and minimum specimen thickness of About 10 times impression depth. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Bench Rockwell Hardness Tester is used in hardened steel acceptance testing, heat treatment verification, production control of machined parts and incoming inspection of bar and plate. Across the wider Hardness Testing class, laboratories also deploy it for hardened and tempered steel acceptance testing, case depth measurement after carburizing or nitriding and casting and forging hardness control.

Which standards and certifications apply?

Relevant standards and methods include ISO 6508, ISO 6506, ISO 6507, ASTM E18, ASTM E10, ASTM E384, ASTM E140 and IEC 61010-1. Certification candidates for this model are CE and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Verify each tester daily or per shift with a certified reference block whose hardness lies close to the working range, and record the reading, the block identity and the date. Have the machine verified annually for test force, indenter geometry, depth or optical measurement and timing, either in house with traceable devices or by an accredited body. Handle indenters carefully, inspect them for chipping, and replace damaged ones, since a chipped diamond or flattened ball biases every result. Prepare surfaces by grinding or polishing to the roughness stated in the method, support thin specimens rigidly and ensure the surface is perpendicular to the indenter. Report the scale, test force, dwell time and number of readings with every result, and treat scale conversions as estimates rather than equivalent values.

How do I select the right Bench Rockwell Hardness Tester?

Select the bench Rockwell tester as the primary acceptance instrument for hardened steel, and confirm the scale and load set, specimen height capacity, digital output and stage options you need. Include certified reference blocks covering the working scale.

How does it compare with other Hardness Testing variants?

Select the scale from the material, the size of the feature and the acceptance criteria in your specification. Rockwell C is standard for hardened steel, Rockwell B for softer metals, Brinell for castings and large forgings where the impression is acceptable, and Vickers or Knoop for thin cases, coatings, welds and individual microstructural constituents. Choose the load range to cover your thinnest feature, remembering that Vickers hardness depends on load at low values. Decide whether you need a manual, digital or fully automatic machine: automatic machines with traverses and motorized stages are used for case-depth series and for high volumes, and they should store test programs so that results are repeatable. Portable rebound testers suit field inspection of large parts but need a conversion relationship established against a bench machine on the same material, and they cannot test thin sections or small parts reliably.