420LC Tool Steel - 1.2099 - ~X5CrS12 - Technical Data

420LC a pre-hardened, corrosion resistant plastic mold steel is magnetic in its annealed and hardened condition, showing improved machinability and corrosion resistance compared to 420FM. 420LC is used for mold assemblies, mold frames, corrosion resistant tools, basic components but also for tools with high cutting volumes. It is noted for its high dimensional stability and consistent hardness in all cross sections as well as its good compressive strength, heat conductivity and weldability. For this steel grade, further heat treatment is not intended.

Corrosion resistance

This corrosion resistant mold steel can be used for the processing of aggressive plastics, in humid climatic conditions and condensation.

Heat treatment

As 420LC corrosion resistant plastic mold steel comes pre-hardened, further heat treatment is not intended.

Soft annealing

Uniformly heat the 420LC work piece to a temperature of 1562-1616°F (850-880°C) and cool them in the furnace.

Stress relieving

Heat the work piece uniformly to 896°F (480°C) and hold at the temperature for 2 hours, then cool the 420LC in the furnace or in sand.

Hardening

If further or re-hardening of the 420LC mold steel is necessary, heat the parts to a temperature of 1922°F (1050°C) and hold it for half an hour.

Quenching media

• Oil

Tempering

Double temper the 420LC work pieces for a minimum of 2 hours directly after hardening.

For our tempering diagram, please click here.

Machinability

Welding

420LC can be welded without pre or post heating. Fillers should be similar to the chemical composition and mechanical properties of the base metal. No overhardened heat affected zones are developed around the weld material. As a result, the risk of weld-induced cracking during repairs or later in operation is eliminated. If large weld repairs are done it is recommended to reduce residual stresses by stress relieving the parts at a maximum temperature of 896°F (480°C).