| Indentec, Zwick’s specialist hardness testing division, has developed a stand-alone automatic Jominy hardness testing system with Corus Steel in the UK.
A Jominy test is used to assess the hardenability of a steel. A standard specimen is 25mm in diameter and 100mm long with a flanged end. The specimen is heated to an austenitic condition and then end-quenched using a standardised water jet. When cool a flat is ground along the length of the bar and hardness measurements made along the flat. The hardness results are then plotted against distance from the quenched end to give a Jominy hardenability curve for the steel.
The instrument uses Indentec's popular 4150 SK Rockwell hardness tester and incorporates a motorised leadscrew, Jominy translation stage and specimen clamp. The unique nose mounted indenter and dead weight, friction free, load application system make this instrument eminently suitable for automatic applications.
The specimen clamp is designed to eliminate movement due to losses in the translation stage, lead screw and component support interfaces during the test cycle. Any losses when the 150 kgf main load is applied will result in 'soft' answers which would impair/compromise the first two or three test results. The clamp saves test time normally spent performing dummy indentations.
A PC and controlling software are not required as the hardness testers internal computing power has been used to manage the test cycle automatically.
The operator can select either to test according to the ISO 642 or ASTM A255-02 International Jominy Standards.
Alternatively, using the touch screen front panel, it is possible to define a non-standard traverse pattern to suit individual customer requirements.
Results are automatically downloaded via the RS232 port into data capture software for storage, retrieval and analysis.
The same system can be utilised to test many other samples other than traditional Jominy specimens. Indentec offers an in-house design facility which is able to adapt existing solutions to individual customers’ requirements.
As with all Indentec products, the system is UKAS accredited in line with Rockwell standards ISO 6508, ASTM E18 and quality standard ISO 17025.
The instrument is supplied with certified test blocks and indenters which are traceable to the National Physical Laboratory in London. |
