The working principle of the imported Rockwell hardness tester from Japan is based on indentation method, which involves pressing the indenter (diamond cone, steel ball or hard alloy ball) into the surface of the sample in two steps under specified conditions. Apply initial test force and record the depth of indentation; Subsequently, apply the main test force and maintain it for a certain period of time before removing it, and measure the residual indentation depth. The magnitude of the hardness value is inversely proportional to the residual depth of the indentation, that is, the shallower the indentation, the higher the hardness.

According to the application method, it can be divided into general type, surface type, and comprehensive type. The general type is suitable for hardness testing of conventional materials; Surface type is specifically used to test the hardness of material surfaces, which can more accurately reflect the surface hardness condition; The comprehensive type combines multiple functions to meet the hardness testing needs of different types of materials and testing requirements.

According to the operation method, Japanese FT imported Rockwell hardness testers can be divided into two types: manual and electric. The manual type relies on manual operation of loading and unloading test force, with simple and direct operation, relatively low requirements for operating environment, and relatively low cost, suitable for use in some small laboratories or on-site inspections. The electric type applies and unloads test force through an electric device, which can more accurately control the application process of test force, improve the accuracy and repeatability of testing, and effectively reduce the labor intensity of operators, especially suitable for rapid detection scenarios with a large number of samples.

Verification method for imported Rockwell hardness tester from Japan FT:

1. Appearance inspection:

-Check whether the various components of the hardness tester are intact, free from damage, deformation, rust, and other conditions. The pressure head should be free of wear and breakage, and the workbench should be flat, smooth, etc.

2. Coaxiality inspection:

-For hardness testers with diamond indenters, coaxiality errors need to be checked. Place the worktable of the hardness tester in a horizontal position, install a flat worktable, place a dedicated coaxiality tester or standard hardness block on the worktable, slowly raise the worktable to make contact between the indenter and the tester or standard hardness block, observe the uniformity of the indentation edge, and determine whether the coaxiality meets the requirements.

3. Inspection of initial and main test forces:

-Use high-precision force measuring devices to measure the initial and main test forces of the hardness tester, and check whether the deviation between the actual applied force value and the nominal value is within the specified range.

4. Inspection of indicators:

-Check whether the scale of the indicator is clear and uniform, whether the pointer is flexible, and whether the return error is within the allowable range. It can be determined by repeatedly loading and unloading the test force and observing the changes in the indicator.

5. Verification of hardness indication error and repeatability:

-Select standard hardness blocks that meet the requirements of the verification regulations, whose hardness values should cover the measurement range of the hardness tester and be evenly distributed in different hardness ranges.

-Place the standard hardness block on the worktable of the hardness tester, perform multiple hardness tests on each standard hardness block according to the operating procedures of the hardness tester, and record the results of each test.

-Calculate the hardness indication error and repeatability based on the test results, and determine whether it meets the requirements of the verification regulations. Generally speaking, the hardness indication error should be within the specified allowable error range, and the repeatability should also meet the corresponding requirements.