The hardness tests are used to measure the hardness character of the metal. There are a number of hardness testing methods, whose values can be converted through hardness scales. The different hardness scales are represented by, Vickers, Rockwell C, Rockwell B, Leeb, Shore, and Brinell. They are abbreviated as HV, HRC, HRB, HL, HS, and HB.
Here, we will discuss one of the dynamic methods called the Leeb method and it’s one of the conversion charts: Leeb to Brinell Hardness Conversion Chart.
I. What is HL in Hardness?
HL in Hardness stands for hardness according to Leeb. It is one of the hardness testing methods. The Leeb hardness test is used to determine the hardness of materials such as metals. The Leeb is defined according to the ISO 16859 and ASTM A956 standards. The test is dynamic in nature. The hardness of the moving impact body from the Leeb method is calculated by the ratio between rebound velocity to impact velocity. Here, the impact velocity depends on the method and is between the range of 1.4 to3.0 m/s. Tungsten carbide cobalt, a ceramic, the ball shaped indenter, and the diamond are used as the impact body in the Leeb test.
II. What is HB in Hardness?
HB in hardness stands for hardness according to Brinell. It is one of the early hardness testing methods. Brinell hardness is the mechanical property of the object. Brinell hardness test is used to determine the hardness of the metal through its ability to avoid permanent indentation deformation. This test is performed under special standardized conditions by creating penetration by an indenter in a spherical shape.
The test is performed by creating the indentation by throwing a hard steel ball on the test metal surface The test load is also set for an accurate result. Then the obtained Brinell hardness number is calculated by dividing the load (kg), by the surface area of the indention.
III. Can you Convert between Hardness Scales?
Conversion between hardness scales is possible if the used method for any test material is performed under specified and standardized conditions. Keep in mind that there is no universal or direct correlation between hardness scales. But there are some national standards that have introduced some hardness conversion tables, equations, and formulas. These hardness tables are established through many experiments, and hardness readings then these values have been placed at specified tables.
These standards are BS EN ISO 18265:2013, and ASTM E140: 2012. Conversion tables of both standards are almost similar but not exactly the same. Both have incorporated Vickers, Rockwell B, Rockwell C, shore, Brinell, and Leeb hardness testing methods. Their conversion tables are for limited material types and shape only.
IV. Leeb to Brinell Hardness Conversion Table
Leeb Hardness, | Brinell Hardness |
828 819 809 800 791 782 773 764 755 746 737 729 720 712 703 695 687 679 671 663 655 647 640 632 625 618 611 603 596 590 583 576 570 563 557 551 545 539 533 527 521 516 510 | 721 699 675 654 634 614 595 577 559 542 526 511 496 482 467 455 442 430 418 407 395 385 375 365 356 347 338 328 320 313 305 297 291 283 276 270 264 258 252 246 240 235 229 |
Conclusion
To conclude, the most important step in any hardness testing method is the accurate use of hardness conversion tables according to the standard guidelines. Conversion tables are a standard method but the performer needs to understand additional boundaries and practical circumstances of the test to ensure correct interpretation and decision-making of the test for quality control. To learn more about the hardness testing methods, its hardness conversion scales, and the process, visit our website.