Case Study: Hydraulic Manifold Block -350 Bar, No Impregnation

Customer: Industrial hydraulic system integrator, Germany Program: Directional control manifold block for industrial press Annual volume: 12,000 pieces/year Material: A413 aluminum alloy Weight: 1.8 kg Requirement: 350 bar burst, 85 bar working pressure, helium leak <10^-6 mbar·L/s, no VPI impregnation

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The Challenge

Previous source: sand casting, Germany. Sand casting gave adequate pressure tightness but poor dimensional consistency -3 setups required for SAE boss port machining. Customer specification prohibits VPI impregnation (long-term sealant compatibility concerns with hydraulic fluid).

The solution had to be: genuine cast-in pressure tightness at 85 bar working / 350 bar burst, with no impregnation.

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Solution

Alloy: A413 (Near-Eutectic)

A413's 12% silicon produces the finest solidification microstructure of any standard die casting alloy. Shrinkage porosity significantly below A380. Accepted 8% strength reduction (290 vs 317 MPa tensile) in exchange for superior internal soundness.

Process: VADC

Cavity vacuum <25 mbar. Fill time: 95 ms at 38 m/s gate velocity. First-article X-ray: ASTM E505 Class 1 across all port face sections. Class 2 at one thick section -corrected with chilling insert on T1 modification.

Gate Placement via Mold Flow Simulation

Simulation confirmed gating at the port-face end minimized weld lines at SAE boss locations -the most pressure-critical sections. This gate position was non-obvious; the conventional choice would have placed the gate centrally.

Testing: 100% Pressure + 2% Helium Sample

• 100% nitrogen decay at 130 bar, 45s hold, <3 cm³/min limit
• 2% helium mass spectrometer sampling, <10^-6 mbar·L/s limit

Zero failures in first 8,000 production pieces. Burst qualification: 8 parts tested to destruction, all above 370 bar (minimum 350 bar).

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Results vs Previous Sand Casting

Metric	Sand casting	KastMfg A413 HPDC
Unit cost	Baseline	-8%
Port face flatness (as-cast)	0.4-0.8 mm	0.15-0.25 mm
Machining setups for ports	3	1
Production leak test pass rate	96.2%	100% (first 8,000 pcs)
Burst pressure (min of 8)	380 bar	371 bar
Production lead time	8 weeks	5 weeks

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Contact KastMfg: yaoqingpu1983@gmail.com | +86 138 1403 4409 | No.6, Rungu Road, Nanjing, China