What T6 means
T6 is used for heat-treatable alloys such as 6061 and 7075. The material is solution heat treated and artificially aged to develop higher strength. It is common for structural, machining and general engineering use.
What T651 adds
T651 starts from a T6 condition and adds controlled stretching to relieve internal stress. For thicker plate and machined parts, this can reduce movement after cutting or CNC machining.
What H116 means
H116 is used on 5xxx-series marine alloys such as 5083. It is strain hardened and controlled for marine corrosion resistance. This is why buyers often specify 5083-H116 for hull plate rather than simply asking for 5083.
| Temper | Typical alloy family | Common reason to specify it |
|---|---|---|
| T6 | 6061, 7075 | Higher strength after heat treatment |
| T651 | 6061 plate, 7075 plate | Improved machining stability |
| H116 | 5083, 5086 | Marine corrosion resistance |
Always quote alloy and temper together. "6061 plate" and "6061-T651 plate" are not the same buying request.
For a broader reference, open the temper designation guide.