L-6 is an oil hardening steel for use in tools, dies and machine parts requiring a good combination of hardness, toughness, and wear resistance. The relatively large percentage of nickel contained in this grade produces an alloy with greater toughness than the standard oil hardening types while retaining desirable hardness and wear resistance.

L-6 is well suited for cold work applications requiring extra toughness. It is often used for punches, dies, and cold forming tools. Where greater stability in heat treatment and greater wear resistance are required, an air hardening steel such as A-2 or a high carbon-high chromium steel like D-2 should be considered.

For large or intricately shaped sections or where deformation may be a problem, preheating is advisable. Preheat slowly 1100-1200° F before transferring to the hardening furnace. L-6 should be heated slowly to 1450-1500° F, held at this temperature until uniformly and thoroughly heated, then oil quenched. Light sections will develop moderate hardness if cooled by as dry air blast.

Salt bath hardening is also satisfactory providing the molten bath has been properly rectified with respect to dissolved oxides. For pressurized gas quenching, the quench rate to 1000° F is critical for obtaining the desired properties.

Temper L-6 immediately after quenching to room temperature. Parts should be heated slowly to the desired tempering temperature and held for a period of 1 to 6 hours, depending upon its size. Remove from the furnace and allow to cool in still air. For most cold works applications, tempering should be performed in the range of to 300 - 600° F or higher. Hardening happens between 1450-1500° F.

Double tempering is recommended for best results.

L-6 is an oversized material,