VT machining offers CNC Milling for Q345 Steel (GB/T 1591 (now Q355) / ~S355JR), typically supplied hot-rolled. Chinese low-alloy high-strength steel; replaced by Q355 in GB/T 1591-2018.
CNC Milling Notes for Q345 Steel
Q345 Steel mills well with conventional strategies; finishing passes are planned to meet flatness and finish callouts.
For estimating, a 100 × 100 × 10 mm block of Q345 Steel weighs about 0.79 kg.
Starting Parameters for CNC Milling Q345 Steel
| Cutting speed (carbide) | 160-275 m/min |
|---|---|
| Feed per tooth | 0.035-0.123 mm |
| Spindle speed, Ø10 mm end mill | 5090-8750 rpm |
| Insert / tool class | ISO P — CVD-coated carbide |
| Coolant | Emulsion (5-8%); dry is possible for interrupted cuts |
| Thermal growth, 100 mm part, +10 °C | 11.7 µm (CTE 11.7 µm/m·K) |
Starting values for Q345 Steel, Hot-rolled; optimised on the first article.
Q345 Steel Data Relevant to CNC Milling
| Equivalent designations | GB/T 1591 (now Q355) / ~S355JR |
|---|---|
| Key composition | C ≤0.20%, Mn ≤1.7% |
| Typical supply condition | Hot-rolled |
| Hardness (typical) | ~150 HB |
| Machinability rating | 65% (AISI B1112 = 100%) |
Typical values; we work to your drawing and mill certificate.
How Q345 Steel Differs
Chinese low-alloy high-strength steel; replaced by Q355 in GB/T 1591-2018.
Typical applications: Bridges, machine bases, pressure parts.
Q345 Steel vs Similar Grades
| Q345 Steel | Q235 Steel | SPCC Steel | S355JR Steel | |
|---|---|---|---|---|
| Key composition | C ≤0.20%, Mn ≤1.7% | C ≤0.22%, Mn ≤1.4% | C ≤0.15% | C ≤0.24%, Mn ≤1.6% |
| Hardness | ~150 HB | ~120 HB | ~50-65 HRB | ~150 HB |
| Tensile (MPa) | 470-630 | 370-500 | ≥270 | 470-630 |
| Machinability % | 65 | 70 | 55 | 65 |
| Typical use | Bridges, machine bases, pressure parts | Frames, plates, general fabrications | Sheet-metal enclosures, brackets, panels | Machine frames, heavy brackets, cranes |
More on CNC Milling Steel
Finishing options, quality documentation and general cnc milling guidance for all steel grades are on our CNC Milling Steel page.
No drawing yet? Sketch the part in our free 3D + 2D builder and send it with your RFQ.
Quoting CNC Milling Q345 Steel
Send a STEP/IGES model or PDF drawing, confirm Q345 Steel and its condition (we usually see it supplied hot-rolled), the quantity, critical tolerances and any finish or certificate requirements.
Q345 Steel in Other Processes
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Send the drawing, the Q345 Steel condition and the quantity — pricing and lead time come back the same or next business day.
Request a QuoteFrequently Asked Questions
Can VT machining make custom Q345 Steel parts to my drawing?
Yes. Q345 Steel machining is made to order from your CAD/2D drawing. Share your geometry, material grade, tolerance and quantity and we will confirm feasibility, lead time and pricing.
Why is Q345 Steel a good choice for CNC Milling?
Q345 Steel is strong, economical and widely available, which makes it well suited to CNC Milling. We tune the process to the alloy so the finished Q345 Steel machining part meets your dimensional and functional requirements.
What is the typical lead time and minimum order for CNC Milling Q345 Steel?
CNC Milling prototypes for Q345 Steel can be produced quickly and scaled to series production. Send your drawing and quantity and we will advise lead time and any minimum order.
What is CNC Milling Q345 Steel and how is it done?
CNC Milling Q345 Steel refers to multi-axis milling cutters remove material to produce prismatic features, pockets, slots and contoured 3D surfaces. Applied to Q345 Steel — strong, economical and widely available — VT machining produces each part to your CAD drawing, selecting parameters from your tolerance, finish and quantity requirements.
What material thickness or size range suits CNC Milling Q345 Steel?
We machine Q345 Steel across a broad size range; share your part envelope for confirmation.
Does CNC Milling Q345 Steel require dedicated tooling?
Most Q345 Steel machining work uses standard cutting tools and CNC programs; dedicated fixtures are made only when geometry or volume requires them.