Precision Machining of QT500-7 Ductile Iron Pump Housings for a European Construction Machinery Manufacturer

In early 2025, a leading European construction machinery manufacturer was struggling to ramp up production. A key part of its new hydraulic system — a QT500-7 ductile iron pump housing — ran into several problems at once during mass production: late deliveries, rising costs, and sealing that did not meet the standard. The part is complex. It has internal oil passages and big differences in wall thickness, and it needs very dense castings, reliable sealing under high pressure, and precise machining. The old supply chain was split up — casting, machining, and inspection were done by three different suppliers — so coordination was poor, the scrap rate stayed high, and quality was hard to trace.

▶  Delivery pressure: From drawing to the first qualified samples, the plan took 16 weeks — too slow to match the new machine's launch schedule.

▶  Performance targets: The part must meet the QT500-7 mechanical property requirements (tensile strength ≥ 500 MPa) while using thinner walls to cut weight by more than 8% versus the previous generation.

▶  Quality control: The high-pressure oil passages must pass a 100% pressure test (≥ 200 bar, no leakage). The key mounting surfaces must stay flat within 0.05 mm, and all mounting holes must be positioned within ±0.05 mm.

▶  Cost control: Cut the cost per part without hurting performance — especially by reducing machining scrap.

Step 1: Co-design and Process Simulation

▶ Our engineers finished the design review within two weeks and raised 3 key suggestions: optimize the gating and riser design to remove shrinkage risks at hot spots; cast some deep oil passages directly as formed instead of machining them, to reduce deep-hole machining work; and unify the machining datum and clamping plan to reduce distortion during clamping.

▶ We used casting simulation software to analyze the filling and solidification process, so we could avoid possible shrinkage and gas porosity areas in advance. We also ran CAM machining simulation to confirm the "one setup" plan would work.

Step 2: One Integrated Manufacturing Process

▶ Precision casting: We used resin sand molding. QT500-7 ductile iron was melted in an electric furnace, treated for nodularizing, and checked with spectrometer and metallographic tests before pouring. This ensures high density and good internal quality, giving a stable base for the next steps.

▶CNC precision machining: In a temperature-controlled workshop, we finished all surfaces, holes and oil passage ports in one go on a large 5-axis machining center. With a "one setup, multiple operations" strategy, we kept the flatness and hole positions exactly where they needed to be.

▶ Full inspection: We ran 100% full-size inspection with a coordinate measuring machine (CMM) and pressure-tested the high-pressure oil passages at up to 200 bar to make sure nothing leaked.

▎Project Results and Data

▶Delivery: From final drawing confirmation to the first qualified samples, it took only 9 weeks — 7 weeks shorter than the customer's original plan.

▶Performance: The final parts show stable tensile strength above 520 MPa and nodularity above 90%. Flatness stays within 0.03 mm, all key mounting holes are positioned within ±0.03 mm, and the oil passages pass the pressure test 100%.

▶Cost: With integrated manufacturing and process optimization, we cut the customer's total cost per part by about 18%.

▶Mass production: After the samples were approved, we moved into mass production smoothly. So far, we have delivered over 3,000 pump housings, with a pass rate of 99.6%.

▎Customer Feedback

> "Matech is more than just a supplier — they are an extension of our project engineering team. Their proactive casting suggestions and the seamless work from raw casting to finished part solved our biggest headaches around sealing and coordination. This is not just about one part — it is about the launch schedule of our whole machine."

> — Customer Project Department Director

▎Our Mission and Commitment

The success of this project comes from the service philosophy Matech has always held:

"We are not just a parts manufacturer — we are a co-builder of our customer's product success."

We promise that for every customized project, we will:

▶Full ownership: From design review to final delivery, a dedicated team stays with the project from start to finish, so every step is well connected, and responsibilities are clear.

▶Technology first: We actively use our manufacturing experience to do Design for Manufacturing (DFM), improving the design from the very beginning for better performance and lower cost.

▶Quality as our anchor: We build a fully traceable quality system from raw material to finished part. We let the data speak, so every single part is reliable and worry-free.

▶On-time delivery: We strictly keep every milestone and give you transparent production updates, so you stay informed and at ease.

We always believe that true value is helping customers solve their core problems — not just completing orders. Matech is committed to being your most trustworthy precision manufacturing partner, with professionalism and craftsmanship.