Ductile Iron Sand Cast Truck Exhaust Manifold

Product Overview

As a critical component in heavy-duty trucks, buses, and off-road vehicles, this manifold must withstand extreme thermal cycling, corrosive exhaust gases, and constant vibration—challenges that our sand-cast ductile iron solution addresses with advanced material science and precision engineering. Unlike traditional gray iron manifolds, our ductile iron design offers 50% higher thermal fatigue resistance, making it ideal for modern high-pressure common rail diesel engines that operate at higher temperatures and pressures. With IATF 16949:2016 certification, we supply Tier 1 automotive suppliers and truck manufacturers worldwide, ensuring compliance with strict emissions and performance standards.

Material

Our exhaust manifolds are crafted from SiMo ductile iron, a specialized alloy formulated for elevated temperature applications. Its chemical composition is meticulously controlled: carbon (C) 3.2-3.8%, silicon (Si) 4.0-5.0%, molybdenum (Mo) 0.5-1.5%, magnesium (Mg) 0.03-0.07%, and sulfur (S) ≤0.02%. This unique blend enhances high-temperature strength and oxidation resistance, allowing continuous operation at 750°C manifold temperature and intermittent exposure to 820°C exhaust gases—values verified through thermal shock testing per SAE J2779 standards. The material undergoes spheroidizing heat treatment to convert graphite flakes into spherical nodules, improving ductility to ≥15% elongation and impact strength to ≥10 J/cm², preventing crack propagation under thermal stress.

Features

Thermal Shock Resistance

The manifold’s microstructure minimizes thermal expansion mismatch between cylinder head and manifold flanges, reducing gasket failure rates by 40% compared to conventional designs. Its ability to withstand 1,000+ thermal cycles from -40°C to 750°C ensures long-term reliability in diverse climates.

Optimized Gas Flow

Advanced computational fluid dynamics (CFD) simulations optimize port geometry, reducing exhaust backpressure by 15% and improving engine fuel efficiency by up to 3%. Smooth internal surfaces with Ra 12.5 μm finish minimize turbulence and particulate buildup.

Corrosion Protection

The SiMo alloy forms a protective chromium oxide layer, resisting exhaust gas corrosion (including sulfur dioxide and nitrogen oxides) for 150,000+ km service life in heavy-duty applications. Salt spray testing per ASTM B117 shows no significant corrosion after 48 hours of exposure.

Dimensional Stability

Sand casting with ISO 8062 CT12 tolerance maintains critical flange sealing dimensions within ±0.63 mm for lengths up to 250 mm. Post-casting stress relief annealing ensures dimensional stability through subsequent thermal cycling.

Custom Service

We specialize in manifold customization for various engine configurations, including inline-4, V6, and V8 layouts. Our engineering team provides full 3D modeling and FEA analysis within 10 business days to validate design performance. Material options include high-nickel ductile iron (13-36% Ni) for extreme temperature applications up to 900°C, suitable for performance trucks and off-road machinery. Production capabilities range from 100-piece prototypes to 5,000-unit monthly runs, with flexible surface treatments such as ceramic coating for additional heat insulation. All custom manifolds undergo pressure testing at 50 kPa and leak rate verification (<0.1 standard cubic feet per minute) to ensure emissions compliance. We offer PPAP documentation and full traceability from raw material to finished product, supporting our clients’ quality management systems.