Dear Dr. Siva prasad Kondapalli,

in the Vickers test the surface is subjected to a pre-defined load exerted by a four-sided pyramidal diamond indenter for a standardized length of time referred to as the dwell time. The diagonal of the resulting indentation is measured under a microscope and the Vickers Hardness value read from a conversion table. Vickers test systems have found acceptance in the most demanding quality control applications including the inspection of welds on submarine hulls and heavy duty machinery utilized in manufacturing operations.

Among the variety of test methods used for quality assurance is the test on welded joints (EN ISO 9015).To prevent cracks due to age-hardening, the welded joint is heat-treated and the heat-affected zone is then subjected to Vickers hardness tests. Vickers hardness is tested in the parent metal and in the heat-affected zones, as well as along the weld line and within the weld metal. The indentation position must be listed with the results in the test report.

The indentation positions can be ‘taught’ in the video image via a mouse click and their position automatically stored in the test system software. Different lens magnifications can be used for the teaching and the measuring, ensuring maximum image area and maximum measurement resolution. Multiple hardness traverse tests are performed automatically, with all indentations automatically made, focused and measured. The test report with the required results and data is automatically generated in the test system software so that the results are available quickly and cost-efficiently.

For more details, please see the source (Quality Magazine - Hardness Testing Assures Quality in Advanced Materials) at web site: https://www.qualitymag.com/articles/91828-hardness-testing-assures-quality-in-advanced-materials

You should have a look also at: https://www.azom.com/article.aspx?ArticleID=14200

Good work and best regards, Pierluigi Traverso.

In general welds are made according a certain standard or Rule. In these documents the testmethod is normally prescribed. In general for steel welds HV10 is used. Depending on the material also other loads can be used. HB and HR in general are not used. Missing information; welding process, material specification.

It depends on the material used and its thickness and it also involves the method of welding, does it involves any consumables and also the HAZ of the welding. But in general rockwell B and C hardness is more accurate to the true properties which i have observed.

ASTM E92 - 17 Standard Test Methods for Vickers Hardness and Knoop Hardness of Metallic Materials... Please refer the significance and scope we have to choose the load.