Introduction: The Die-Casting Core Is Under Constant Thermal Shock
New-energy vehicle (NEV) structural parts are increasingly die-cast (e.g. with large integrated rear underbody designs). The die-casting core (压铸型芯) sits inside molten aluminium at 600–700 °C, then quenches every cycle. Cracking and heat-checking are not ‘if’ but ‘when’ — unless the material, heat treatment and cooling are designed together.
This article explains why NEV die-casting cores crack and how to extend their life.
1. Root Causes of Cracking
- Thermal fatigue: repeated heating/cooling creates a network of fine cracks (heat-checking) that propagate under stress.
- Residual stress: aggressive machining and quenching leave internal stress that relieves uncontrolled during service.
- Material mismatch: low-toughness grades or improper hardness crack early under impact and erosion.
- Poor cooling design: hot spots accelerate local fatigue.
2. Material and Heat-Treatment Strategy
Cores are typically SKD61 / H13 hot-work steel. The life lever is the heat-treatment route: vacuum hardening + multiple stress-relief tempering reduces retained austenite and internal stress, improving toughness. For higher demands, optimized tempering profiles and surface treatments (nitriding / PVD coatings) raise erosion and soldering resistance.
3. Machining and Verification
SHENGQI controls geometry with precision grinding to ±0.002 mm and verifies on CMMs, then validates cooling-channel consistency. A DFM review at the quoting stage flags thin sections and hot spots before steel is cut — the single biggest contributor to longer core life.
4. What Buyers Should Specify
Ask for documented heat treatment, a stress-relief route, and a machining tolerance budget — not just ‘H13’. SHENGQI PRECISION brings 21+ years of non-standard precision experience, two bases (Dongguan + Huangshi, 40,000 m²), 330+ machines and ISO 9001 / 14001 certification to NEV die-casting tooling.
Looking for a long-life NEV die-casting core? Contact SHENGQI PRECISION — Jason Wong, +86 13652919880, jasonwong@shengqi.com, www.dgshengqi.com.
