VT machining offers CNC Milling for 42CrMo Steel (GB/T 3077 / ~4140 / 42CrMo4), typically supplied Q&T. Chinese equivalent of 4140/42CrMo4.
CNC Milling Notes for 42CrMo Steel
42CrMo 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 42CrMo Steel weighs about 0.79 kg.
Starting Parameters for CNC Milling 42CrMo Steel
| Cutting speed (carbide) | 120-210 m/min |
|---|---|
| Feed per tooth | 0.035-0.123 mm |
| Spindle speed, Ø10 mm end mill | 3820-6680 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 42CrMo Steel, Q&T; optimised on the first article.
42CrMo Steel Data Relevant to CNC Milling
| Equivalent designations | GB/T 3077 / ~4140 / 42CrMo4 |
|---|---|
| Key composition | C 0.38-0.45%, Cr 0.9-1.2%, Mo 0.15-0.25% |
| Typical supply condition | Q&T |
| Hardness (typical) | ~28-32 HRC |
| Machinability rating | 62% (AISI B1112 = 100%) |
Typical values; we work to your drawing and mill certificate.
How 42CrMo Steel Differs
Chinese equivalent of 4140/42CrMo4.
Typical applications: Gears, shafts, high-strength bolts.
42CrMo Steel vs Similar Grades
| 42CrMo Steel | 40Cr Steel | 20CrMnTi Steel | EN19 Steel | |
|---|---|---|---|---|
| Key composition | C 0.38-0.45%, Cr 0.9-1.2%, Mo 0.15-0.25% | C 0.37-0.44%, Cr 0.8-1.1% | C 0.17-0.23%, Cr 1-1.3%, Mn 0.8-1.1%, Ti | C 0.36-0.44%, Cr 0.9-1.2%, Mo 0.25-0.35% |
| Hardness | ~28-32 HRC | ~28-32 HRC | ~58-62 HRC case | ~28-32 HRC |
| Tensile (MPa) | ~1080 Q&T | ~980 Q&T | ~1080 core | ~850-1000 |
| Machinability % | 62 | 60 | 60 | 62 |
| Typical use | Gears, shafts, high-strength bolts | Shafts, gears, bolts | Automotive gears, shafts | Shafts, gears, studs |
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 42CrMo Steel
Send a STEP/IGES model or PDF drawing, confirm 42CrMo Steel and its condition (we usually see it supplied Q&T), the quantity, critical tolerances and any finish or certificate requirements.
42CrMo Steel in Other Processes
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Send the drawing, the 42CrMo Steel condition and the quantity — pricing and lead time come back the same or next business day.
Request a QuoteFrequently Asked Questions
Which industries use CNC Milling 42CrMo Steel parts?
CNC Milling 42CrMo Steel parts are used across aerospace, medical, automotive, electronics, semiconductor and general industrial sectors — anywhere precise 42CrMo Steel components are required.
Does CNC Milling 42CrMo Steel require dedicated tooling?
Most 42CrMo Steel machining work uses standard cutting tools and CNC programs; dedicated fixtures are made only when geometry or volume requires them.
What is CNC Milling 42CrMo Steel and how is it done?
CNC Milling 42CrMo Steel refers to multi-axis milling cutters remove material to produce prismatic features, pockets, slots and contoured 3D surfaces. Applied to 42CrMo 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 tolerances can you hold for CNC Milling 42CrMo Steel?
Achievable tolerances for 42CrMo Steel machining depend on the alloy, geometry and feature size. Milling holds positional and dimensional tolerances to around ±0.01 mm, tighter with precision setups. Exact figures are confirmed against your drawing callouts.
Why is 42CrMo Steel a good choice for CNC Milling?
42CrMo 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 42CrMo Steel machining part meets your dimensional and functional requirements.