718 Acciaio per stampi preduro: Proprietà, Usi & Produzione per una realizzazione efficiente di stampi

If you’re looking for apre-hardened mold steel that cuts production time, offre stabilità dimensionale costante, and works for high-precision molds—718 Pre Hard is the ideal choice. Ampiamente usato negli stampi per iniezione plastica e automobilistica, questa lega elimina la necessità del trattamento termico post-lavorazione, risolvere punti critici comuni come la deformazione dello stampo o le tempistiche di progetto ritardate. In questa guida, analizzeremo le sue proprietà chiave, applicazioni del mondo reale, fasi di produzione, and how it compares to other materials—so you can build high-quality molds faster and more cost-effectively.

1. Material Properties of 718 Acciaio per stampi preduro

718 Pre Hard’s popularity stems from its well-balanced composition and ready-to-usepre-hardened condition. Let’s explore its properties in detail:

1.1 Composizione chimica

The elements in 718 Pre Hard work together to enhance machinability, tenacità, and corrosion resistance—tailored for mold-making. Below is its typical composition (per industry standards):

1.2 Proprietà fisiche

These properties determine how 718 Pre Hard behaves during mold manufacturing and use—such as heat transfer and shape retention. All values are measured at room temperature unless noted:

• Densità: 7.85 g/cm³ (consistent with most mold steels, making it easy to calculate mold weight).
• Punto di fusione: 1450 – 1500 °C (high enough to withstand forging and pre-hardening heat treatment).
• Conducibilità termica: 31 Con/(m·K) (good heat transfer, ensuring plastic parts cool evenly in injection molds).
• Coefficiente di dilatazione termica: 11.8 × 10⁻⁶/°C (da 20 A 600 °C; low expansion reduces mold warping during production).
• Specific Heat Capacity: 470 J/(kg·K) (efficient at absorbing and releasing heat, reducing plastic injection cycle times).

1.3 Proprietà meccaniche

As a pre-hardened steel, 718 Pre Hard is supplied ready for machining—no extra heat treatment needed. Below are its typical mechanical properties (in pre-hardened state):

1.4 Altre proprietà

• Resistenza alla corrosione: Bene. Chromium content protects against rust in workshop environments and mild chemical exposure (per esempio., plastic additives or mold release agents).
• Resistenza all'usura: Moderate to Good. Suitable for most plastic and die casting applications; for high-wear molds, add a surface coating like nitriding.
• Lavorabilità: Eccellente. Its pre-hardened hardness (HRC 32–36) and fine grain structure make it easy to mill, trapano, and turn—reducing machining time by 25–30% vs. unhardened steels.
• Temprabilità: Eccellente. It maintains uniform hardness across thick sections (fino a 100 mm), so large molds (per esempio., automotive molds for bumpers) have consistent performance.
• Stabilità dimensionale: Outstanding. Low thermal expansion and pre-hardened state prevent mold warping—critical for optical molds or precision consumer product molds.
• Pre-hardened Condition: Ready to use. Eliminates post-machining heat treatment, cutting mold production time by 30–40%.

2. Applications of 718 Acciaio per stampi preduro

718 Pre Hard’s mix of efficiency, precisione, and durability makes it versatile for diverse mold types. Ecco i suoi usi più comuni, con esempi reali:

2.1 Plastic Injection Molds

• Esempi: Molds for making plastic parts like smartphone casings, componenti interni automobilistici (per esempio., dashboard vents), o custodie per dispositivi medici.
• Why it works: Pre-hardened state speeds up production, while dimensional stability ensures part consistency. A Chinese plastic manufacturer used 718 Pre Hard for smartphone case molds—production time dropped by 35% contro. using unhardened steel.

2.2 Automotive Molds

• Esempi: Molds for automotive exterior parts (per esempio., grille inserts) or under-hood components (per esempio., alloggiamenti dei sensori).
• Why it works: Toughness handles the stress of high-volume production, and corrosion resistance stands up to workshop chemicals. A German automotive supplier used 718 Pre Hard for sensor molds—mold life increased from 150,000 A 300,000 parti.

2.3 Consumer Product Molds

• Esempi: Molds for cosmetic containers, stoviglie (per esempio., high-gloss plastic bowls), or toys.
• Why it works: Machinability lets you create complex shapes, while polishability delivers premium surface finishes. A French cosmetic brand used 718 Pre Hard for lipstick tube molds—customer complaints about surface flaws fell to zero.

2.4 Optical and Medical Device Molds

• Esempi: Molds for optical components (per esempio., plastic lenses) o dispositivi medici (per esempio., barili di siringa).
• Why it works: Dimensional stability ensures precision, and corrosion resistance meets medical hygiene standards. Un americano. medical manufacturer used 718 Pre Hard for syringe molds—part tolerance accuracy improved by 20%.

3. Manufacturing Techniques for 718 Acciaio per stampi preduro

Girando 718 Pre Hard into high-quality molds is streamlined thanks to its pre-hardened state. Ecco un'analisi dettagliata:

1. Fusione: Materie prime (iron, nichel, cromo, ecc.) are melted in an electric arc furnace (EAF) at 1550–1650 °C. Strict control ensures uniform element distribution (critical for consistent hardness).
2. Colata: Molten steel is poured into ingot molds or continuous casters to form slabs. Raffreddamento lento (50–100 °C/hour) prevents internal defects and refines grain structure.
3. Forgiatura: Slabs are heated to 1100–1200 °C and pressed/hammered into mold blanks (per esempio., 600x600x300 mm for large injection molds). Forging improves toughness and eliminates voids.
4. Pre-hardening Heat Treatment:
   • Ricottura: Heat to 800–850 °C, hold 2–4 hours, cool slowly. Softens steel for initial processing.
   • Tempra: Heat to 880–920 °C, hold 1–2 hours, dissetare nell'olio. Hardens steel to HRC 40–45.
   • Temperamento: Reheat to 580–620 °C, hold 2–3 hours, cool. Sets final pre-hardened hardness (HRC 32–36).
5. Lavorazione: Mold blanks are milled, drilled, or turned into mold cavities using CNC machines. Carbide tools are recommended for tight tolerances (±0,001 mm).
6. Lucidatura: Molds are polished to the desired finish—from matte (per le parti funzionali) to mirror (per i prodotti di consumo). 718 Pre Hard’s fine grain structure lets it achieve Ra ≤ 0.01 μm with diamond paste.
7. Trattamento superficiale (Opzionale):
   • Nitrurazione: Creates a hard surface layer (HRC 60–65) to boost wear resistance for high-cycle molds.
   • Galvanotecnica: Adds a chrome or nickel coating to improve corrosion resistance (ideal for medical or food-contact molds).

4. Caso di studio: 718 Pre Hard in Automotive Dashboard Mold

A Korean automotive parts manufacturer faced a problem: their P20 mold steel dashboards required post-machining heat treatment, which caused warping and delayed production by 2 weeks per mold. They switched to 718 Pre Hard, and here’s what happened:

• Processo: Mold blanks (pre-hardened to HRC 34) were CNC-machined to dashboard geometry, polished to Ra 0.8 µm, and nitrided for extra wear resistance.
• Risultati:
  • Production time per mold dropped from 4 settimane a 2.5 settimane (37.5% miglioramento) — no post-heat treatment needed.
  • Warping eliminated (718 Pre Hard’s dimensional stability kept mold shape consistent).
  • Dashboard quality improved: fewer fitment issues (tolerance accuracy ±0.05 mm vs. ±0.1 mm with P20).
• Why it works: 718 Pre Hard’s pre-hardened state skipped heat treatment, while its nickel and molybdenum content prevented warping—solving both timeline and quality issues.

5. 718 Pre Hard vs. Other Mold Materials

How does 718 Pre Hard compare to common alternatives for mold-making? Let’s evaluate key properties:

Key takeaway: 718 Pre Hard offers the best balance of precision, velocità, and durability for high-volume, stampi di alta qualità. It’s more dimensionally stable than P20, more machinable than stainless steel, and far more reliable than aluminum for production molds.

Yigu Technology’s View on 718 Acciaio per stampi preduro

Alla tecnologia Yigu, 718 Pre Hard is our go-to for clients needing fast, high-precision mold production—like automotive and consumer product manufacturers. Its pre-hardened state cuts lead times by 30–40%, while its dimensional stability ensures consistent part quality. We often recommend it for complex molds, as its machinability lets us create intricate geometries without warping. For clients needing extra wear resistance, we pair it with nitriding to extend mold life. 718 Pre Hard isn’t just a material—it’s a way to streamline production and deliver molds that meet the strictest standards.

FAQ About 718 Acciaio per stampi preduro

1. Can 718 Pre Hard be used for die casting molds (per esempio., aluminum or zinc)?

SÌ, but we recommend adding a nitrided surface layer (HRC 60–65) per aumentare la resistenza all’usura. 718 Pre Hard’s toughness handles die casting pressure, but the coating prevents premature wear from molten metal flow.

2. Is 718 Pre Hard suitable for molds that need mirror finishes (per esempio., contenitori per cosmetici)?

Assolutamente. 718 Pre Hard’s fine grain structure and low sulfur content let it achieve mirror finishes (Ra ≤ 0.01 µm) with diamond paste polishing. It’s a top choice for consumer product molds requiring premium aesthetics.

3. How does 718 Pre Hard’s cost compare to P20, and is it worth the extra expense?

718 Pre Hard costs about 30% more than P20, but it’s worth it for high-precision or high-volume molds. It eliminates heat treatment costs, reduces warping (lower scrap rates), and lasts 50–100% longer—saving money in the long run.