SAE J445

J445 defines laboratory procedures that quantify two parameters important in selecting peening media, namely service life and the effectiveness of impact. Aerospace peening practice documents cite the report for comparing media quality, describing durability as the number of machine cycles required to replace the tested sample and transmitted energy as inferred from the arc height induced on a standard Almen strip after a prescribed exposure in the test machine. The document is framed for comparing shipments and manufacturers rather than calculating operating conditions for specific blast rooms or wheel machines.^[5]

In industrial laboratories the J445 procedures are implemented with compact wheel-type bench machines derived from the Ervin Test Machine. A weighed and sieved sample of metallic shot or grit is propelled repeatedly against a hardened target and then re-sieved at fixed intervals to measure breakdown and loss. The report recognises several durability determinations, including an average life calculated from the breakdown curve, a stabilised loss-rate method, and a 100 percent replacement method that runs the machine in fixed increments, replaces the fraction lost each increment with new media, and determines the number of passes required for complete replacement of the original sample. Transmitted energy is evaluated by using a peening attachment that holds a standard Almen A strip and measuring the resulting arc height after a set number of cycles.^[6][7]

Trade and training articles that reproduce the report's cautions advise that average life figures are best used for shipment uniformity checks and for comparing abrasives when test sieves and machine settings reasonably match production conditions, and they discourage treating bench data as a direct proxy for field economics where part hardness, wheel maintenance and reclaim streams differ.^[8]

Although written for SAE users, the approach aligns with international practice. ISO 11125-9 defines laboratory wear testing and performance methods for metallic blast-cleaning abrasives, addressing service life and cleaning performance, and equipment makers describe their test machines as supporting both SAE J445 and ISO 11125-9 procedures.^[9][10]