Transmission housing (cast gearbox housing)

01

Choose the casting process and alloy

SAIVS’s transmission-part page has a basic-information table listing grey or ductile iron, sand/resin-bonded/investment/die casting and pressing/forging, with a 0.5–500 kg weight range. A separate section on that page lists aluminium grades A356-T6, A360.0, A355, A319, A413, AlSi7Mg, AlSi12 and AlSi10Mg and an 8.00 kg casting example. These entries do not establish that every process and alloy is available over the entire weight range. [4] Its separate aluminium gear-housing page also lists an 8.00 kg example, CNC machining and surface-treatment options. [3]

US patent 7,188,416, on high-pressure die-cast (HPDC) engine blocks, states that HPDC inherently yields more porosity than low-pressure die casting, squeeze casting or semi-solid casting, which cost more, and that the process produces parts with a porosity of 0.5 percent (typ.). [2]

Editorial note: the casting route trades cost against porosity and section thickness; give the supplier the drawing, annual volume, alloy or strength requirement, and the faces and bores that must seal, so the process and inspection can be matched.

Give the supplier the drawing and 3D model, material and heat treatment, casting process preference, annual and batch volumes, machined features and tolerances (bearing bores, joint faces, dowel and bolt holes), sealing faces, leak test method and limit, porosity or X-ray acceptance level, surface treatment, cleanliness requirement, and inspection reports required.

02

Control porosity at machined faces and leak-test the housing

US patent 7,707,870 (Method and apparatus for oil leak testing) describes machining die-cast engine and transmission components to form shapes, bores and through-holes. It explains that porosity in the casting can be opened or joined by machining into leak paths, so these components are tested for oil leaks. In what the patent calls a cold test, pressurised air is injected and its decay rate measured; the part is rejected if decay is too high. The patent explains that a cold test can miss leaks that appear when the part expands at operating temperature, and describes washing the machined part at about 130 °F, heating it in a 10–40 ft tunnel buffer to about 180 °F (200–300 °F or greater contemplated, depending on application), then air-testing it hot. [1]

In its engine-block discussion, US 7,188,416 says surface pores as small as 0.010 in in diameter may cause inadequate O-ring sealing. Its described polymer-putty repair approach cannot treat pores smaller than 0.080 in without enlarging them; the patent says HPDC with that putty approach may still result in rejection rates of 5–50%. These are claims about the patent’s engine-block and repair context, not an acceptance rule or rejection forecast for an ordered gearbox housing. [2]

Editorial calculation: assuming these are absolute temperatures, (180 − 32) × 5/9 ≈ 82 °C and (130 − 32) × 5/9 ≈ 54 °C. With 1 in = 25.4 mm, 0.010 in = 0.254 mm (rounded to 0.25 mm) and 0.080 in = 2.032 mm (rounded to 2.0 mm). These are conversions of the patent examples, not manufacturer ratings or measured housing data. Agree test temperature, pressure and decay limit for the actual drawing; the examples do not establish the housing’s service-temperature range. [1] [2]

03

Drawing-specific sand and die-cast gearbox cases

The verified offers include cast gear housings and an automotive actuator-gearbox housing. The order drawing must identify which bearing bores and sealing faces are machined.

Ask for the casting process, alloy certificate, porosity acceptance criteria and any permitted repair or impregnation. Define machining inspection and a leak-test record against the same drawing revision.

04

Oil-retaining walls, bearing seats and mating faces

The cast body, bearing bores and joint faces have different inspection tasks. This is a functional feature reference rather than a manufacturer’s parts BOM. [1] [2]

05

Set bearing-bore tolerances and a separate leak-test specification

Separate service design limits from the test conditions. The patent’s hot-test example does not rate the housing’s operating range.

06

Send the drawing, process and quality data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Drawing: [2D; 3D; revision]
Material: [alloy; temper; iron grade]
Process: [die; sand; investment; gravity]
Machining: [bores; faces; holes; tolerances]
Tightness: [leak method; pressure; limit; warm or cold]
Porosity: [X-ray level; impregnation]
Volume: [annual; batch]
Reports: [dimensional; material; leak]

See manufacturer records Send an enquiry through CNFX