Choosing the right steel is the first and most important decision when making a mold. These names may look like codes, but each has its own strengths. Here's a quick guide.
P20 – Entry Level, Best Value
Inexpensive (20-40 RMB/kg), easy to machine, good enough for most jobs. Suitable for under 300,000 shots of ordinary plastic parts like appliance housings and daily goods. Weaknesses: average wear resistance and rust protection.
Best for: Standard products, small batches, tight budgets
718H – The Reliable Workhorse
An upgraded P20 (35-60 RMB/kg). Better wear resistance and can achieve a high-gloss polish. Ideal for 500,000-800,000 shots of automotive interiors, appliance panels, and transparent parts. The most commonly used mold steel.
Best for: Medium batches, cosmetic surfaces, the safest choice
S136 – Stainless Steel, Rust-Resistant and Beautiful
Excellent rust protection (80-150 RMB/kg). Can be polished to a mirror finish. The first choice for medical devices, food-contact products, and transparent parts. Expensive, but worth it.
Best for: Medical/food applications, transparent parts, humid environments
H13 – Heat-Resistant Tough Guy
Designed for high-temperature plastics (60-120 RMB/kg), such as nylon and PPS. Also used for die-casting molds. Overkill for ordinary plastics.
Best for: High-temperature materials, die-casting molds
One Quick Selection Guide:
Small batches and tight budget? Go with P20. Medium batches and good appearance? Choose 718H. Medical, food, or transparent parts? Pick S136. High-temperature plastics? H13 is your answer.
Next time a mold supplier gives you a quote, ask: "What steel are you using and why?" You'll know right away if they're professional.
Need help selecting the right steel for your mold? Feel free to reach out.
