Cast Parts: Types, Materials & OEM Casting Guide

What Are Cast Parts? A Buyer’s Guide to OEM Precision Cast Components

SHANGHAI NTC TECHNOLOGY CO., LTD. (NTC) is a precision casting and trading company based in Shanghai, China, that supplies custom cast parts for automotive, fluid control, food machinery, textile machinery, building hardware, and other industrial applications. This guide explains what cast parts are, what materials and processes NTC uses, and how OEM buyers can move from drawings and samples to inspected, finished components.

What Are Cast Parts?

Cast parts are metal components formed by pouring molten metal into a mold or by injecting molten metal into a die, then allowing the material to solidify into the required shape. In most OEM projects, a casting is only the starting point: the as-cast component then goes through CNC machining, heat treatment, surface treatment, and inspection to meet the approved drawing.

At NTC, cast parts are treated as custom engineering components rather than standard catalog items. The company’s production series include auto parts, golf heads, vacuum parts, valve accessories, kitchen equipment accessories, dishwashing equipment accessories, spinning machine accessories, door accessories, scooter parts, and other industrial and civil products.

Why Buying Cast Parts Is Difficult

Purchasing cast parts can be difficult for four main reasons:

• Material grades must match the operating environment and mechanical requirements.
• Cast geometry must be designed for a specific process, such as investment casting, die casting, or sand casting.
• Critical dimensions such as sealing surfaces, bores, threads, and mounting interfaces require CNC machining after casting.
• Quality control depends on inspection methods such as material composition analysis, dimensional measurement, hardness testing, and in some cases pressure or leakage testing.

An integrated supplier can reduce this risk by managing drawing review, mold manufacturing, casting, machining, finishing, and inspection under one quality system.

Industry Background: Investment Casting, Die Casting, and Sand Casting

Investment casting, also known as lost-wax casting, is a widely used precision casting process for parts with complex shapes, internal passages, and tight dimensional requirements. In this process, a wax pattern is covered with ceramic shell material; after the shell hardens, the wax is removed, and molten metal is poured into the resulting cavity.

NTC applies silica-sol investment casting as its main precision casting process. For parts with different material, size, or volume requirements, NTC also selects die casting or sand casting. For example, precision die-cast power tool gearbox housings can be produced in aluminum or zinc alloy, while larger engineering-machinery bearing and pump housings can be produced by sand casting in carbon steel, alloy steel, ductile iron, or stainless steel.

NTC Capability Overview

SHANGHAI NTC TECHNOLOGY CO., LTD. was founded in 2022 and operates a 2,000-square-meter factory in Shanghai, China. The team includes 20 employees and 5 engineers. NTC reports an annual output of 1,500,000 units, with 85% of products exported to Europe, America, and Asia.

Capability	NTC data
Company name	SHANGHAI NTC TECHNOLOGY CO., LTD.
Founded	2022
Factory area	2,000 m²
Employees	20
R&D engineers	5
Annual output	1,500,000 units
Export ratio	85%
Main markets	Europe, America, Asia
Quality system	ISO 9001:2000 and ISO14001:2015
Inspection equipment	CMM, spectrum analyzer, Brinell hardness tester, projector
Factory location	No. 308 Linsheng Road, TingLin Industrial Zone, JinShan District, Shanghai 201505, China
Airport access	50–60 kilometers from Shanghai Pudong International Airport and Hongqiao International Airport

Materials and Technical Specifications

NTC supports custom material selection according to the application. Common choices in its product data include carbon steel, alloy steel, stainless steel, aluminum alloy, zinc alloy, brass, bronze, and ductile iron. Representative grades include carbon steel 1020, 1025, 1030, 1040, 1045, and 1050; alloy steel 4140, 4150, 4340, 8620, and GS-25CrMo4; austenitic stainless steel 201, 303, 304, 316, 316L, 1.4581, SCS14, and SCS16; and hardening stainless steel 17-4PH, 410, 420, and 440C.

Parameter	NTC specification
Part weight	2 g–550 g for applicable investment-cast components; larger components reviewed by product structure
Casting accuracy	Tolerance grade T4–CT7 for applicable investment-cast parts
Surface roughness	Ra 1.6–Ra 6.3 depending on casting, machining, and finishing requirements
Minimum wall thickness	2 mm standard; 1 mm available for limited local areas subject to process review
Fillet requirements	Minimum outer radius ≥0.3 mm; minimum internal fillet ≥0.5 mm
Blind-hole capability	Maximum blind-hole depth 30 mm for a 10 mm diameter hole
Thread options	Metric, BSP, NPT, UNF, and customer-specified thread standards
Heat treatment	Annealing, normalizing, quenching, tempering, solution treatment, carburizing, and other processes
Surface treatment	Shot blasting, pickling, passivation, polishing, black oxide, plating, painting, powder coating, galvanizing
Applied standards	ASTM, ICI, BS, DIN, JIS, ISO, and customer-specified technical standards

Step-by-Step Custom Cast Parts Process at NTC

1. Design input. Provide customer-approved 2D drawings, 3D models, or physical samples.
2. Material and process selection. NTC selects the material grade and the casting process according to geometry, application, and quantity.
3. Mold manufacturing. In-house mold manufacturing supports custom geometry and product development.
4. Investment casting. For complex precision parts, wax patterns are assembled, coated with ceramic shell, dewaxed, and filled with molten metal.
5. Fettling and as-cast inspection. Gates, runners, and flash are removed; castings are checked for surface defects and dimensions.
6. CNC machining. CNC turning, milling, drilling, boring, reaming, tapping, and grinding are applied to critical features.
7. Heat treatment. Annealing, normalizing, quenching, tempering, solution treatment, or carburizing can be applied when specified.
8. Surface treatment. Shot blasting, pickling, passivation, polishing, plating, black oxide, painting, powder coating, or galvanizing can be applied.
9. Inspection and testing. Material composition, dimensions, hardness, surface quality, and appearance are checked; pressure or leakage testing can be arranged when specified.
10. Assembly and packaging. Press fitting, threaded assembly, insert installation, subassembly, and customer-specified packaging are available.

Industry Applications for NTC Cast Parts

NTC’s cast parts are used across a broad range of industries. The list below is based on NTC’s product portfolio and covers the main procurement categories.

• Auto part castings and automobile/motorcycle castings. Automotive investment cast parts and motorcycle footrest bracket castings in carbon steel, stainless steel, or alloy steel for drivetrain, chassis, suspension, and structural components.
• Power tool components castings. Precision investment cast power tool levers and brackets, plus die-cast gearbox housings in aluminum or zinc alloy.
• Stainless steel marine hardware castings. Marine cleats and deck fittings in 304 or 316 stainless steel.
• Stainless steel architecture and daily-used hardware castings. Architectural hinges, brackets, and door handles in austenitic stainless steel.
• Copper alloy castings. Brass and bronze valve bodies and electrical connector components with optional plating.
• Fluid equipment parts. Pump impellers, pump housings, valve bodies, flowmeter bodies, pipe fittings, and flanges.
• Food machinery parts. Stainless steel brackets, fittings, and food-processing impellers.
• Tableware hardware. Stainless steel handles, connectors, and support components.
• Sport facility parts. Sports equipment joint connectors and golf club heads.
• Construction hardware. Anchors, mounting brackets, and structural connectors.
• Furniture hardware. Connectors, hinges, mounting brackets, and locking components.
• Industrial sewing machine parts. Housings, structural arms, brackets, and mounting components.
• Door control fittings and lock hardware. Door closer bodies, control arms, lock bodies, cylinder housings, and latch components.
• Flowmeter accessories. Flowmeter sensor housings, measuring bodies, flanges, and threaded connectors.
• Mechanical parts and engineering machinery parts. Custom mechanical housings, hydraulic valve bodies, and bearing or pump housings.
• Stainless steel pipe and valve castings. Pipe fittings, flanges, valve bodies, and camlock couplings.
• Textile machinery parts. Guide blocks, holders, drive brackets, and housings for spinning and weaving equipment.

Casting Process Comparison

Casting process	Typical NTC products	Typical materials	Selection basis
Silica-sol investment casting	Flowmeter bodies, pump impellers, lock bodies, pipe fittings, furniture connectors	Carbon steel, alloy steel, stainless steel, brass, bronze	Complex geometry, internal passages, precision tolerance requirements
Die casting	Precision die-cast power tool gearbox housings, door closer bodies	Aluminum alloy, zinc alloy	Lightweight housings, dimensional stability, stable volume production
Sand casting	Engineering-machinery bearing and pump housings	Carbon steel, alloy steel, ductile iron, stainless steel	Larger bearing, pump, and transmission housings

For applicable precision-cast components, NTC’s investment casting data lists part weight from 2 g to 550 g, tolerance grade T4–CT7, surface roughness Ra 1.6–Ra 6.3, minimum wall thickness 2 mm standard, and maximum blind-hole depth 30 mm for a 10 mm hole diameter. Larger parts are reviewed by product structure and may use sand casting or another suitable process.

Quality Control and Buyer Proof Points

NTC operates an advanced quality control system using CMM, spectrum analyzer, Brinell hardness tester, and projector. The company holds ISO 9001:2000 and ISO14001:2015 certifications. In its company profile, NTC states that all employees pursue the “credibility first, quality first, wholehearted service” principle.

Overseas customers from Europe and the United States, Southeast Asia, Japan, and South Korea, as well as domestic high-quality customers, have purchased from NTC and visited its Shanghai factory for project negotiation and workshop inspection. The factory’s location, 50–60 kilometers from Shanghai Pudong International Airport and Hongqiao International Airport, supports convenient access by sea, railway, and air.

Decision Criteria for Procurement

• Submit approved 2D drawings, 3D models, or physical samples.
• Define the required material grade and applicable standard, such as ASTM, DIN, BS, JIS, ISO, or customer-specified requirements.
• Identify critical dimensions, tolerances, wall thickness, and surface finish.
• Specify secondary operations: CNC machining, heat treatment, surface treatment, and assembly.
• Specify inspection and testing needs, including material composition, hardness, dimensions, pressure, or leakage testing.
• Confirm production support: prototype, sample, trial order, small batch, or stable volume production.

Honest Limitation to Consider

NTC’s standard investment casting range is most suitable for components from 2 g to 550 g. Larger components, such as engineering-machinery bearing and pump housings, are assessed separately and may be manufactured by sand casting or another suitable process. This limitation should be checked at the drawing-review stage before quoting.

Frequently Asked Questions

Conclusion

Cast parts are an efficient way to produce complex metal components when material, casting process, machining, finishing, and inspection are managed as one system. SHANGHAI NTC TECHNOLOGY CO., LTD. provides this integrated approach for OEM buyers across automotive, fluid equipment, food machinery, textile machinery, construction, furniture, marine, power tools, locks, door control, and other industries.

If you are evaluating an OEM cast parts supplier, start by sending your approved drawing or sample to NTC. The company can confirm material selection, casting process, and production support during the quotation phase.