718 Mold Steel
Eliminating thermal quench distortion in large-scale mold blocks while securing superior core hardness uniformity over standard P20 requires an advanced nickel-alloy pre-hardened steel, which 718H (DIN 1.2738) mold steel delivers. Pre-hardened to a uniform 32–38 HRC, 718H steel contains nickel additives that ensure consistent hardness across thick tool sections up to 400mm depth, taking a fine SPI B-1 polish and crisp photo-etched textures. At Jucheng Precision, a certified ISO 9001 and IATF 16949 contract manufacturer, we specialize in 5-axis CNC machining of large 718 steel mold cavities. Delivering tool shot lives up to 500,000+ cycles, our 718 molds reliably process automotive panels and appliance enclosures, verified by Zeiss CMM inspection.
High-precision 718 Mold Steel cavity manufacturing for large-scale appliance housings and automotive interior panels. Pre-hardened with nickel alloy addition to 32–38 HRC, 718H (DIN 1.2738) steel provides exceptional deep-section hardness uniformity and zero heat-treatment distortion across 500,000+ production cycles.
718H Mold Steel Metallurgical & Large Block Profile
718H is an upgraded nickel-chromium-molybdenum pre-hardened steel, engineered to maintain consistent hardness across thick mold core blocks:
| Metallurgical Parameter | 718 Steel Spec Metric | Large Tooling Advantage |
|---|---|---|
| Nickel-Alloy Pre-Hardening | 32 – 38 HRC (340 HB) | Pre-hardened at higher hardness than P20, offering superior resistance to core deformation under high injection pressures. |
| Deep Section Uniformity | DIN 1.2738 / AISI P20+Ni | Nickel additions prevent soft centers in thick steel blocks (up to 400mm depth), ensuring uniform 5-axis CNC cutter wear. |
| Texturing & Polishability | SPI B-1 & Mold-Tech Etching Compatible | Takes uniform acid-etched textures for automotive interior trims and high-gloss paper polishing without grain distortion. |
718 Steel Polymer Compatibility & Application Matrix
718H pre-hardened steel is the industry benchmark for medium-to-large non-corrosive plastic components in Plastic Injection Molding:
| Polymer Resin Class | Recommended Base Material | 718 Tooling Strategy |
|---|---|---|
| Large Household & Packaging | Polypropylene (PP), Polyethylene (PE), ABS, Polystyrne (PS) | Delivers 500,000+ shot tool life for large logistics crates, television back covers, and washing machine tubs. |
| Automotive Interior & Bumper Trims | Polycarbonate (PC), Polyamide (PA/Nylon), PC/ABS Alloys | Supports intricate acid-etched grain textures for automotive door trims, glove boxes, and dashboard bezels. |
718 Mold Steel Tooling Engineering & Pre-Hardened Blueprint
Molding with pre-hardened 718H steel balances toolmaking speed against cavity accuracy through four engineering advantages:
Zero Heat-Treatment Distortion (35 HRC)
Because 718H steel is pre-hardened at the steel mill, no post-machining quench heat treatment is needed. This eliminates thermal stress distortion across large core plates, guaranteeing true-to-CAD dimensions on large appliance molds during Custom Mold Making.
Deep-Section Uniform Hardness (Nickel Addition)
Unlike standard P20, 1% nickel addition in 718H prevents core softening in massive steel blocks. Jucheng’s 5-axis CNC machining centers cut deep cavity walls with uniform tool wear and ±0.005 mm accuracy.
Key Application Fields for 718 Steel Injection Molds
- Automotive Exterior & Interiors (IATF 16949): Large Production Injection Mold tools for bumper fascia trims, door panels, glove boxes, and dashboard bezels.
- Large Consumer Appliances: Washing machine tubs, refrigerator door liners, television back enclosures, and air conditioner housings.
- Industrial Logistics & Commodities: Heavy-duty stackable crates, recycling bins, agricultural trays, and Two-Shot Injection Molding or Insert Injection Molding hardware.
Properties
| Density (DIN 1.2738 / 718H Steel) | 7.85 g/cm³ |
| Hardness Range (Pre-Hardened) | 32 - 38 HRC |
| Brinell Hardness Equivalent | 340 HB |
| Tensile Yield Strength | 920 MPa |
| Ultimate Tensile Strength | 1,100 MPa |
| Elongation at Break | 18 % |
| Flexural Modulus | 205 GPa |
| Thermal Conductivity (20°C) | 29.5 W/(m·K) |
| Coefficient of Thermal Expansion (20-100°C) | 12.8 10⁻⁶/K |
| SPI Polishing Surface Capability | SPI B-1 (Paper Polish) - |
| Texturing Capability | Mold-Tech / VDI 3400 Compatible - |
| Guaranteed Tool Shot Life | 500,000+ Cycles |
| Maximum Mold Cavity Block Size | 2200 x 1600 mm |
| Minimum Machining Tolerance | +/- 0.005 mm |