Hardness Testing Rockwell and Brinell test blocks at a variety of hardness levels.(A)Aluminum Brinell, (B) Steel Brinell, (C) Vickers, (D) Rockwell, (E) 187.5kg/2.5mm Brinell, (F) Extra-Soft Rockwell and (G) Brass Rockwell. Test Blocks and Accessories for Hardness Testers Starrett blocks can be used to test Rockwell, Brinell or Vickers scales. They are available in steel, brass and aluminum. Each block is serialized, with a certificate detailing the environmental conditions used to test the block. Actual readings are given, with the averages of these readings: min. reading, max reading and a repeatability figure. The blocks are calibrated according to ASTM E-18 standards, ANSI (NCSL) Z540-1, (ISO) 10012-1, ISO/IEC 17025 and Mil-std 45662A. Starrett hardness test blocks are manufactured from square steel or brass plates, as opposed to the more common round bar stock. The use of the plate gives a more accurate and consistent surface for inspection. Metallurgical tests have proven that during the production of round bar stock, suspended carbides in the mix migrate to the center of the rod. The scientific name for this condition is carbide segregation and results in different readings being found in the center of a rod rather than at its outer edges. Some manufacturers remedy this situation by removing the centers from their blocks. Hardness test blocks are designed to be used only on one side and the indents should be more than .010" from the centers of two indents or no closer to the block's edge than .040". Calibration kits are also available from Starrett. No facility with a hardness tester in use should be without a calibration kit. These kits come with from 3 to 20 calibrated test blocks and the serialized penetrator that was used to inspect each of the blocks in the set. When a discrepancy is detected in a tester, these kits allow you to determine the direction to proceed to resolve the issue. G A B C D E F Rockwell Test Blocks Part No. Description † PT05050 RC63 Test Block PT05051 RC60 Test Block PT05052 RC55 Test Block PT05053 RC50 Test Block PT05054 RC45 Test Block PT05055 RC40 Test Block PT05056 RC35 Test Block PT05057 RC30 Test Block PT05058 RC25 Test Block PT05059 RB90 Test Block PT05060 RB80 Test Block PT05061 RB70 Test Block PT05062 RB60 Test Block PT05063 RB50 Test Block PT05064 RB40 Test Block PT05065 RB30 Test Block PT05067 RB20 Test Block PT05068 RB10 Test Block PT05069 RA80 Test Block PT05091 RA70 Test Block PT05092 RA60 Test Block PT05100 RF100 Test Block PT05101 RF90 Test Block PT05102 RF80 Test Block PT05103 RF70 Test Block PT05104 RF60 Test Block PT05105 RF50 Test Block PT05106 RE100 Test Block PT05107 RE90 Test Block PT05108 RE80 Test Block PT05112 RE70 Test Block PT05113 RE60 Test Block † Values expressed are not exact but will range within acceptable limits Rockwell Test Blocks Part No. Description † PT05114 RE50 Test Block PT05115 HR30N80 Test Block PT05122 HG30N70 Test Block PT05123 HR30N60 Test Block PT05124 HR30N50 Test Block PT05125 HR30N40 Test Block PT05127 HR30T80 Test Block PT05128 HR30T70 Test Block PT05129 HR30T60 Test Block PT05130 HR30T50 Test Block PT05177 HR30T40 Test Block PT05178 HR30T30 Test Block PT05179 HR30T20 Test Block PT05180 HR30T10 Test Block PT05181 HR15N90 Test Block PT05182 HR15N80 Test Block PT05183 HR15N70 Test Block PT05184 HR15T90 Test Block PT05185 HR15T80 Test Block PT05186 HR15T70 Test Block PT05187 HR15T60 Test Block PT05188 HR45T70 Test Block PT05189 HR45T60 Test Block PT05191 HR45T50 Test Block PT05192 HR45T40 Test Block PT05193 HR45T20 Test Block PT05194 HR45T10 Test Block PT05195 HRH90 Test Block PT05196 HRH80 Test Block PT05197 HRR120 Test Block PT05198 HR30Y Test Block PT05199 HRM Test Block PT05200 HR15W Test Block † Values expressed are not exact but will range within acceptable limits 240 G age A mps , H ardness and S urface T esters