The tool steel AISI D2 is usually processed by vacuum hardening followed by multiple tempering cycles. Deep cold treatment in between the hardening and tempering processes could reduce processing time and improve the final properties. Blocks of AISI D2 were vacuum hardened from different austenitizing temperatures. The hardened blocks were then subjected to various combinations of single and multiple tempering steps (520 and 540°C) and deep cold treatments (−90,− 120, and − 150°C). The results showed that for all austenitizing temperatures a single deep cold treatment followed by a single tempering cycle was sufficient to reduce the retained austenite to below 1%.
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Surberg et al. (2009) studied this question.