Lcd Display Digital Hardness Tester , Double Rockwell Hardness Testing Machine

Overview

Mitech MHRX-45-150DX Digital Double Rockwell Hardness Tester, based on the mechanical principle of conical diamond or hard alloy indenter pressing into the sample surface to produce indentation, realizing the material hardness measurement by measuring the depth of the indentation. Capable of inspecting the finished or semi-finished parts of the machined sample, it is suitable for high accuracy hardness testing for batches parts with various metal or non-metallic materials. According to statistics, Rockwell hardness testing is the most widely used hardness testing method in metal processing industry, which utilization ratio is more than 70%. With novel appearance, stable performance and integration of electro mechanical integration and touch screen, it can be tested on the hardness of all rockwell and surface rockwell scale. It is widely used in metal processing and manufacturing, various metal material’s failure analysis and other fields like colleges and research institutions, and it is the sophisticated detection equipment to test the Rockwell hardness of metal and other materials.

Working Principle

The Rockwell hardness test is taking the diamond cone with 120°apex angle or the hardened steel ball with specified diameter as the indenter to press into sample surface with specific test force, then get the Rockwell hardness of the measured metallic materials according to the sample surface indentation depth.

The Rockwell hardness measurement principle is shown as below figure. 0-0 is the position that the diamond indenter is not yet in contact with the sample. 1-1 figure is the indenter position under the affect of the preliminary test force, the indentation depth is h₁. The preliminary test is to eliminate the influence to the testing result accuracy caused by the roughness of the sample surface. 2-2 in the figure is the indenter position under the influence of the testing force (the preliminary test force and the main test force). The depth is h₂. 3-3 in the figure is the indenter position after dismounting the main test force. As the metal elasticity will recovery some degree after deformation, the really indentation depth of the indenter is h₃. The plastic deformation caused by the main test force make the indenter pressing into the depth is h＝h₃－h₁. Rockwell hardness value is determined by the size of h, the greater the depth h, the lower the hardness, otherwise, the higher the hardness.

In the traditional concept, usually use a constant C minus h to represent the level of hardness, while the depth of indentation per 0.002mm as a unit of hardness. The hardness value obtained is called the Rockwell hardness value, denoted by the symbol HR.

In the formula, c is a constant (for HRC, HRA, c is 0.2; for HRB, c is 0.26). The Rockwell hardness value HR obtained is an unknown number which is usually read directly on the test machine indicator when testing.

Rockwell hardness tester working principle Figure

It should be noted that the measured hardness values would be different with different indenter and test force. Therefore, the Rockwell hardness testing specifies 15 different hardness test scales according to the different indenter specification and test force sizes. And the HRB, HRC, HRA are the most widely used.
Features

• Widely used for high-precision hardness testing for parts with a variety of metal and non-metallic materials;
• Mechanical and electrical integration of high-tech products, high test efficiency;
• Option for various specifications of the indenter, support many types of Rockwell hardness scales testing;
• Equipped with high-speed thermal printer, quickly print out the test data;
• Support the conversion among various hardness scales such as Brinell, Vickers and etc;
• Adopt touch screen display interface, display operation integration, simple and intuitive, the technical requirements of the operator is not high;
• With RS-232C interface, serial communication with the computer for the user to expand the function;
• Equipped with excellent performance of the carbide indenter or diamond indenter, high hardness, wear resistance, good toughness, with high temperature, corrosion resistance, accurate measurement, stable and reliable;
• The use of automatic closed-loop pressure sensor control system, showing the instantaneous force value, can dynamically reflect the loading process load changes;
• With the error value correction function, the hardness value of the error can be corrected by key input, the hardness value more accurately meet the test requirements;
• With threshold overrun automatic alarm function, apply to the bulk of finished products or semi-finished pieces of paper-by-piece detection;
• Original environment temperature real-time display function, to avoid the instrument in the case of high or low temperature for a long time, otherwise it will lead to increased test error, the instrument life is reduced;
• Consistent with GB / T230.1 GB / T230.2, JJG112, GB / T230.2 ISO 6508-2, ASTM E18 and other relevant domestic and foreign standards.

Applications

• Used for quality control in metal processing manufacturing
• Used for failure analysis testing of metallic materials;
• Demonstration experiment for education and teaching in Colleges and Universities;
• Hardness testing of materials in scientific research institutions.

Working Conditions

• Operation Temperature:10～30℃；
• Relative Humidity:≤65％；
• The surrounding environment should avoid of vibration, strong magnetic field, corrosive medium and heavy dust.

Configurations

Maintenance and care

• The test personnel should follow the operating procedures.Before and after the test,it should be repeated with standard block calibration equipment;
• If the specimen has visible deformation marks on the back and edges, the test result would be useless. It should choose the intender or test force to test again;
• Normally, the first point is only used to offset the gap of each support surface without needing to record the test result. Record the statistical test result from the second point;
• During testing, to ensure accuracy, please make sure the distance between the adjacent indentation center and the distance from the indentation center to edge of the specimen is greater than 3mm;
• Pay attention to palm the instrument for carrying to forbid falling across. Please fix well the measuring lever, counterweight and boom before carrying;
• It is strictly prohibited to turn the variable loading handwheel when the instrument load or unload the test force. Rotating the handwheel forcibly will cause the internal gear dislocation, test force in chaos and even damage the internal parts of the instrument;
• Turn off the power after using the instrument. When not in use for a long time, please cover the dust cover to prevent dust into the instrument interior. And the hardness block, indenter should be coated with antirust oil to prevent rusting after using;
• Long time after the re-enabled,it should be preheated the electrical components before test
• The hardness tester should be calibrated at least once a year to ensure its accuracy;
• Don’t disassemble the instrument without authorization, for maintenance related matters, please contact MITECH after-sale service department with 4000600280.