CNC Machining
Mild Steel
Mild steel (low carbon steel) is the undisputed workhorse of industrial manufacturing. Offering an unbeatable balance of high machinability, excellent weldability, and cost-effectiveness, it is the premier choice for structural chassis, custom jigs, heavy-duty flanges, and large-scale machinery bases.
Core Mechanical Properties
Mild steel generally contains less than 0.25% carbon, which keeps it ductile and easy to machine. Below is the typical mechanical data for the most common low-carbon steel grades used in CNC machining.
| Alloy Grade | Yield Strength | Tensile Strength | Hardness |
|---|---|---|---|
| 1018 (Cold Drawn) | ~ 370 MPa | ~ 440 MPa | ~ 71 HRB |
| 1020 (Cold Rolled) | ~ 350 MPa | ~ 420 MPa | ~ 68 HRB |
| A36 / Q235 (Hot Rolled) | ~ 250 MPa | ~ 400 - 550 MPa | 119 - 159 HB (Brinell) |
International Grade Comparison
Use our cross-reference chart to match American standards (AISI/ASTM) with European (DIN/EN) and Chinese (GB) mild steel equivalents for global manufacturing.
| AISI / ASTM (USA) | DIN / EN (Europe) | GB (China) | Key Characteristics |
|---|---|---|---|
| 1018 | 1.1151 / C22E | 20 / 20# | The most commonly available cold-rolled steel. Excellent machinability, uniform structure, and great for case-hardening processes. |
| 1020 | 1.1151 / C22 | 20 / 20# | Very similar to 1018 but with slightly lower manganese. Exceptional weldability and high ductility for structural forming. |
| A36 | S235JR / 1.0038 | Q235B | The global standard for structural carbon steel. Typically hot-rolled. Highly cost-effective for large welded frames and heavy bases. |
Hardcore Industrial Applications
Wherever immense volume, structural rigidity, and cost-efficiency are required simultaneously, mild steel is the foundational material.
Custom Jigs & Fixtures
Due to its stability and low cost, 1018 steel is heavily CNC milled to create precision mounting blocks, assembly jigs, and welding fixtures used in automotive and aerospace production lines.
Heavy Machinery Bases
A36 / Q235 structural steel is welded and subsequently CNC faced to create massive, rigid base plates and frames for industrial automation equipment and robotics.
Industrial Flanges & Couplings
Precision CNC turned from 1020 steel, these components securely connect high-pressure piping systems and heavy motor shafts in the energy and oil & gas sectors.
Expert Machining Tips
While mild steel is highly machinable, its low carbon content makes it ductile and "gummy". Huade engineers utilize specific strategies to prevent tool damage and poor surface finishes:
- 1
Aggressive Chip Breaking
Mild steel's ductility causes it to form long, stringy chips that can wrap around tooling. We use cutting inserts with aggressive chip-breaker geometries and specific feed rates to force the chips to curl and snap cleanly.
- 2
Mitigating Built-Up Edge (BUE)
The "gummy" nature of 1018 steel can cause the material to weld to the cutting edge, destroying the surface finish. We run higher Surface Feet per Minute (SFM) and use TiN or TiCN coated tools to resist this adhesion.
- 3
Heavy Roughing Passes
Because mild steel is relatively cheap and easy on spindle load, we can take massive depth-of-cuts (DOC) during roughing. This drastically reduces overall machining time and lowers the cost for our clients.
Top 3 Surface Treatments
Mild steel contains no chromium and will rust rapidly if exposed to moisture. A reliable post-processing surface treatment is absolutely mandatory.
1. Zinc Plating (Galvanizing)
The most cost-effective rust prevention method. A thin layer of zinc (clear, blue, or yellow) is electroplated onto the steel, acting as a sacrificial anode to protect the core.
2. Black Oxide (MIL-DTL-13924)
A chemical conversion that leaves a sleek black finish with zero dimensional buildup. Ideal for precision machine parts, gears, and fasteners where plating would ruin tight tolerances.
View Black Oxide Process3. Powder Coating
For industrial enclosures, heavy bases, and external brackets, powder coating provides a highly durable, colorful, and thick protective barrier against severe impacts and weathering.
Start Your Manufacturing RFQ
Upload your 3D CAD files today. Our engineering team will review your carbon steel specifications and provide a free DFM report along with highly competitive pricing.