Initially case hardening was used but didn't offer any aesthetics.

A process called case hardening may be used.

Case hardening is a weathering phenomenon of rock surface induration.

Case hardening describes lumber or timber that has been improperly kiln-dried.

Another common application of case hardening is on screws, particularly self-drilling screws.

Case hardening is specified by hardness and case depth.

Case hardening is a process diffusing alloying elements into the surface of a piece of metal.

Case hardening of steel is achieved by heating finished steel components in carbon powder.

For screws and fasteners, case hardening is achieved by a simple heat treatment consisting of heating and then quenching.

On the rock surface in the case hardening of alkaline felsic rocks, the weathering selectively affects certain minerals.

Case hardening is a thermochemical diffusion process in which an alloying element, most commonly carbon or nitrogen, diffuses into the surface of a monolithic metal.

Check out this HowStuffWorks podcast to learn how case hardening allows manufactures to get the best of multiple types of steel.

Anti-fatigue - (Martensitic) case hardening can drastically improve the service live of mechanical components with repeated loading/unloading, such as axles and cogs.

Cyanides are employed in a number of chemical processes, including fumigation, case hardening of iron and steel, electroplating, and the concentration of ores.

Color case hardening occurs when soft steels were packed in a reasonably airtight crucible in a mixture of charred leather, bone charcoal and wood charcoal.

Case hardening is a less time-consuming and less expensive way to obtain a blade with balanced toughness and hardness than pattern welding two types of iron.

Case hardening involves packing the low-carbon iron within a substance high in carbon, then heating this pack to encourage carbon migration into the surface of the iron.

In such applications, case hardening can provide a part that will not fracture (because of the soft core that can absorb stresses without cracking) but also provides adequate wear resistance on the surface.

Case hardening is usually done after the part has been formed into its final shape, but can also be done to increase the hardening element content of bars to be used in a pattern welding or similar process.

In industry, barium chloride is mainly used in the purification of brine solution in caustic chlorine plants and also in the manufacture of heat treatment salts, case hardening of steel, in the manufacture of pigments, and in the manufacture of other barium salts.