Precision CNC Machining Manufacturer in China
Steel CNC Machining Services
Precision CNC machining for carbon steel, alloy steel, and tool steel parts. From prototypes to low-volume production, we deliver tight tolerances, consistent quality, and reliable lead times.
Steel CNC Machining
YD Rapid delivers precision CNC machined steel parts for automotive, industrial equipment, energy, tooling, and more.
From prototype to production, we machine a wide range of steel grades with excellent accuracy and repeatability.
- Precision machining with tight tolerances
- Expert material selection and process optimization
- Handles heat-treated and hardened steels
- Surface finishes tailored to your requirements
- Reliable lead times and production support

Steel Material Options
| Steel Grade | Type | Tensile Strength (MPa) | Hardness | Machinability | Common Applications |
|---|---|---|---|---|---|
| AISI 1018 | Carbon Steel | 440–530 | 125–160 HB | Excellent | Shafts, pins, fasteners, fixtures |
| AISI 1045 | Medium Carbon Steel | 570–670 | 149–197 HB | Good | Gears, shafts, spindles, crankshafts |
| AISI 4140 | Alloy Steel (Cr-Mo) | 655–915 | 28–32 HRC | Fair | Bolts, axles, shafts, mechanical parts |
| AISI 4340 | Alloy Steel (Ni-Cr-Mo) | 930–1080 | 32–36 HRC | Fair | High-strength gears, shafts, aerospace components |
| A2 Tool Steel | Air-Hardening Tool Steel | 1860–2070 | 57–61 HRC | Fair | Molds, dies, punches, cutting tools |
| D2 Tool Steel | High-Carbon High-Chromium Tool Steel | 2070–2410 | 58–62 HRC | Poor | Dies, wear parts, slitting knives |
Steel CNC Machining Capabilities
Our CNC milling, turning, and 5-axis machining capabilities support complex steel parts with tight tolerances, consistent surface finishes, and reliable repeatability from prototype to low-volume production.

Steel CNC Milling
High-precision milling for complex geometries, pockets, slots, and contours with excellent surface finishes.

Steel CNC Turning
Precision turning for shafts, bushings, threaded parts, and cylindrical components.

5-Axis Steel Machining
Simultaneous 5-axis machining for intricate shapes, undercuts, and tight-tolerance parts.

Prototype & Low-Volume
Rapid prototypes and bridge production with consistent quality and quick lead times.
Quality Control for Steel CNC Machining
- CMM inspection for critical dimensions
- Surface roughness measurement (Ra)
- Hardness testing and material verification
- Dimensional inspection to tight tolerances
- 100% inspection of key features
- Inspection reports available upon request

Machined Steel Parts Display

Steel Gearbox Housing

Precision Steel Shaft

Mounting Bracket

Threaded Coupling

Tool Steel Insert

Steel Valve Component
Steel CNC Machining FAQs
What types of steel can you CNC machine?
We machine carbon steel, alloy steel, and tool steel, including AISI 1018, 1045, 4140, 4340, A2, and D2. Other steel grades can be sourced based on your drawing and performance requirements.
What tolerances can you achieve on CNC machined steel parts?
Our standard machining tolerance is typically ±0.005 in (±0.125 mm). Tolerances down to ±0.0005 in (±0.0125 mm) may be achievable for critical features, depending on part geometry, material condition, and size.
Can you machine hardened steel?
Yes. We can machine pre-hardened and heat-treated steel using suitable tooling and machining parameters. Please specify the required hardness and heat-treatment condition on your drawing.
What surface finishes are available for steel parts?
Available options include as-machined, grinding, polishing, black oxide, zinc plating, nickel plating, powder coating, and heat treatment. The appropriate finish depends on corrosion resistance, wear resistance, and appearance requirements.
Can you provide heat treatment for steel components?
Yes. We can arrange annealing, normalizing, quenching and tempering, case hardening, nitriding, and other heat-treatment processes through qualified partners.
Do you support prototypes and low-volume production?
Yes. We produce one-off prototypes, engineering samples, and low-volume steel parts. Production quantities can be scaled after the design and machining process have been validated.
What information is needed for a quotation?
Please send your 2D drawings and 3D CAD files, along with the steel grade, quantity, tolerance, heat-treatment, surface-finish, and inspection requirements. We accept STEP, STP, IGES, X_T, DWG, DXF, and PDF files.
Get a Quote for Custom Machined Steel Parts
Send us your CAD files and drawings. We will review the steel grade, tolerances, heat treatment, surface finish, and quantity before providing a quote.
- Carbon, Alloy & Tool Steels
- DFM Review Included
- Quote Within 24 Hours
