Silver Hardness Charts

Learn how to heat-harden sterling silver, measure and compare silver hardnesses and select silver solder.

Last edited: 1/13/2020

Silver Hardness Charts

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

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.

 

Comparing Silver Hardnesses

This chart shows the Vickers hardness for fine silver, sterling and Argentium® Silver across each common annealing term.

Comparing Silver Hardnesses

  Vickers Hardness (dph)
Common Term Fine Sterling Argentium
Soft (annealed) 54 66-76 50-70
¼-hard 62-71 78-88 90-105
½-hard 77-89 90-100 106-120
¾-hard 84-94 102-114 121-135
Hard 89-103 116-130 136-148
Spring 103-108 132-148 150-160
Age-hardened 100-120 100-120
 

Measure Hardness

Quickly reference the hardness, Rockwell scale and tensile strength of differently worked silver using this chart.

Measure Hardness

  Hardness (dph) Rockwell (15T) Tensile (PSI)
 Annealed 50–90 65–71 40,000
¼-hard 91–100 72–78 40,000
½-hard 101–115  79–82 60,000
¾-hard 116–130 83–85 70,000
Full-hard 131–150 86–88 75,000
Spring hard 175–195 89–93 90,000
 

Selecting Silver Solder

Select the best silver solder for the temperature and application you'll be working on with this chart.

Selecting Silver Solder

When assembling, start with your highest melting point solder. As you assemble each piece, use a lower temperature solder. The chart below describes the uses for and flow temperatures of four standard types of solder.

Solder Flow Points Use for
Extra-hard 1490°F/810°C Laser welding, repair operations
Hard 1450°F/788°C First soldering operations
Medium 1360°F/738°C General soldering;
intermediate operations
Easy 1325°F/719°C General soldering and repairs;
intermediate or final operations
Extra-easy 1207°F/653°C Final soldering
 
 

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