Can untreated H13 material be used directly?

It is not possible to use untreated H13 material directly. It lacks the strength, wear resistance, and thermal stability needed for molds or hot runner systems because of its low hardness (23–28 HRC) and pearlite + ferrite microstructure, rendering it extremely vulnerable to deformation, wear, or failure during service.

 

1. Why is it not directly usable?

Inadequate hardness: Untreated H13 has a hardness of only 23–28 HRC, which is much lower than the necessary 48–52 HRC. As a result, it has poor wear resistance and compressive strength.

Subpar microstructure: Because the matrix is composed of annealed pearlite and ferrite rather than tempered martensite, it cannot tolerate high pressures and temperatures.

Plastic deformation susceptibility: When it comes into touch with molten metal during injection molding or die casting, it will quickly soften, collapse, or tear.

Extremely short lifespan: During actual use, untreated H13 workpieces may sustain significant damage in a matter of hours.

Safety Principle: Before being used, all H13 workpieces must undergo tempering (550–600°C) and quenching (1020–1050°C oil cooling).

 

2. Appropriate Usage Method

Stage

The operation

Goals

① Machining

In the annealed state (without heat treatment), carry out precision machining operations like milling, drilling, and grinding.

For easier cutting, use low hardness.

② Stress Reduction

After machining, do stress-relieving tempering at 500–600°C.

avoid distortion and get rid of any remaining machining stress.

③ Last Heat Treatment

Tempered martensite structure is achieved by quenching and high-temperature tempering.

Raise the hardness to 48–52 HRC.

④ Surface Treatment/Finishing

like polishing, nitriding, etc.

strengthen resistance to wear and corrosion and improve surface characteristics.

For instance, in order to provide long-term stable production, hot runner nozzles must be finely ground and nitrided after tempering.

 

3. Danger Alert

Don't Forget Heat Treatment: Untreated H13 is regarded as a "semi-finished product," and using it directly is the same as using regular carbon steel, even if the appearance is intact.

Prevent Mistakes: Strict screening through hardness testing is necessary since some reconditioned parts may employ untreated blanks to mimic useable parts.

Liability: If untreated parts are utilized, the manufacturer is solely liable for any equipment damage or safety incidents.