What are the steps for testing H13 material with a portable hardness tester?

To ensure accurate and trustworthy findings for figuring out whether the heat treatment quality satisfies standards, the fundamental procedures for testing H13 material using a portable hardness tester comprise test point selection, surface treatment, instrument calibration, multi-point measurement, and data recording.

 

1. Getting ready for the test

Instrument calibration: Before using the instrument, check that the indication error is <= ±1 HRC on a standard hardness block;

Environmental confirmation: Steer clear of areas with high temperatures (>50℃), vibration, or intense electromagnetic interference;

Workpiece condition: The surface of the workpiece to be evaluated should be free of oxide scale, rust, and oil after it has cooled to room temperature.

Leeb hardness testers that offer on-site operation and automatic HRC conversion, like the HLN-200, are suggested tools.

 

2. Conventional Testing Method

Choose the surface, edge, center, and thickness transition zone as three to five crucial points for each piece.

To increase representativeness, cover areas that are susceptible to uneven cooling.

Oil stains and oxide layers can be removed by sanding with sandpaper until it has a shiny sheen.

To prevent low readings, make sure the probe makes good contact.

To test that the equipment is operating normally, check on a typical block.

Avoid systematic deviations.

Calculate the average value after measuring each point three times.

Adjacent indentations should be spaced at least 3 mm apart. Improve repeatability and decrease chance errors.

Calculate the range (highest value minus minimum value) and standard deviation by recording the values at each location in real time.

Check to see if the variation falls within the permitted range.

Acceptance criteria: batch average between 48 and 52 HRC, single item hardness range <=2 HRC.

 

3. Processing After Inspection

Cross-verification: A tabletop Rockwell hardness tester can be used in a laboratory to verify samples of crucial workpieces;

<=2 HRC fluctuation: Releaseable, qualified3 HRC fluctuation: Isolate, retest, and, if required, submit for metallographic examination.