You could say that 12L14 is built for speed—machining speed. It is the fastest generally available machining carbon steel grade today. And that’s important when you consider it primary end use: the production of high-volume, short-sized pieces like screws or fasteners.

What is 12L14 steel?

If you are categorizing 12L14, it falls under screw stock. This grade in particular is ideal for high-volume part machining.
12L14 is a lead-bearing steel with average machining rates that are 30-40% faster than 1215, which is another commonly used grade in this series. 

Let’s break down 12L14 by the numbers: 

As we learned in the Grade Anatomy of Carbon Bars, many grades of carbon are classified under the ‘10xx’ designation for non-resulfurized carbon steel. 12L14 falls into a different category in which the ‘12xx’ stands for re-sulfurized and re-phosphorized steels.

The ‘L’ in carbon and alloy steels stands for the addition of .15-.35% lead for machining

The ‘14’ indicates the low level of carbon. In the case of 12L14, it’s not ‘14’ like you would think based on the number. Instead, it contains .09 max carbon. This means that the grade generally does not get hardened/case hardened. 

Variations of this grade include 12L14+Te (which has added tellurium) and 12L14+Se (which has added selenium). These grades can increase parts production by a minimum of 25% over conventional leaded steel. These grades are very rare and require high volumes to obtain. 

What is 12L14 used for?

Since 12L14 is an extraordinarily fast machining steel, it has become the favorite for automatic screw machine work. Screw machines are automated lathes which are used to machine turned parts. It, along with 1215, is nearly always used for simple parts like screws and fasteners that are not hardened. This grade also conforms to ASTM A108.

Can 12L14 be heat treated?

In general, heat treatment is not recommended for 12L14, due mainly to the low levels of carbon and machining additives contained within the grade.

What is the price and availability of 12L14?

12L is commonly stocked as drawn rounds, hexagons and squares. 

Shop 12L14 in hexagon here.
Shop 12L14 in round here.
Shop 12L14 in square here