Apply the load for the specified dwell (10–15 s Brinell; 2–6 s Rockwell major-load dwell); take at least 3 readings spaced ≥ 3 indent diameters apart.<\/li>\n<\/ol>\nCalculation & Reporting<\/h2>\n
Brinell: HBW = 0.102 × 2F \/ (πD(D − √(D² − d²))); Rockwell reads directly. Report scale, load, mean value and location, e.g. “245 HBW 10\/3000” or “45 HRC”.<\/p>\n
Acceptance Criteria<\/h2>\n
Per material spec: e.g. S355 plate typically 146–187 HBW; quenched-and-tempered bolts class 8.8 = 250–320 HV equivalent; weld procedure specs commonly cap HAZ hardness at 350 HV to avoid hydrogen cracking. Approximate steel tensile strength (MPa) ≈ 3.45 × HBW.<\/p>\n
Frequently Asked Questions<\/h2>\nWhich scale should I choose?<\/h3>\n
Match the expected hardness and section: Brinell for coarse or inhomogeneous material (large indent averages structure), Rockwell C for hardened steel, Rockwell B or Brinell for soft steel, Vickers for thin cases, welds and sub-size sections.<\/p>\n
Why do readings near an edge or a previous indent read low?<\/h3>\n
Plastic flow needs supporting material \u2014 closer than 2.5–3 diameters to an edge or another indent, the metal yields sideways and the indent grows oversize. Respect the standard’s spacing rules.<\/p>\n
Recommended Apparatus<\/h2>\n
NL Scientific manufactures the Micro Hardness Tester (Touch Screen)<\/a> for this method. Browse the full Steel Testing Equipment<\/a> range or request a quotation<\/a> from our engineers.<\/p>\n
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