Silver Hardness Chart

Learn how to heat-harden sterling silver and what common hardness terms mean for fine silver and for sterling.

Last edited: 5/28/2020
Heat-Hardening Sterling Silver

To harden sterling silver, heat it to 600°F (316°C) for 30–50 minutes in a kiln or furnace. Air-cool the sterling silver before pickling. The hardness will be equal to the hardness achieved by cold-working it to a 50% reduction (or ¾-hard). If you want to make your sterling silver harder than ¾-hard, you must physically reduce the cross-sectional area using the chart below.

Rockwell Hardness Common Term Reduction in Cross-Sectional Area
Fine Silver Sterling Silver   Wire Sheet
43 70 Soft (annealed) 0% 0%
65 80 ¼-hard 21% 11%
72 82 ½-hard 37% 21%
74 83 ¾-hard 50% 29%
76 85 Hard 60% 37%
80 87 Spring 84% 60%

Example: If you start with a dead-soft wire and reduce the cross-sectional area by drawing it down 50%, your material will become ¾-hard.