Steel is the most widely used core material in the CNC machining industry. Its comprehensive advantages are highly compatible with the high precision, high efficiency, and multi-scenario machining requirements of CNC, making it the first choice for machining various parts:
Grade: AISI 1018, Q235, 20# steel
Properties: Low hardness (HB 120–160), good plasticity, easy to cut, easy to weld, good cold formability; moderate strength, prone to rusting
Machining: High-speed cutting capability, low tool wear; roughing allows for large feed rates and depths of cut; rust prevention treatment required
Applications: Brackets, fixtures, housings, non-load-bearing structural components, sheet metal parts
Grade: AISI 1045, 40# steel
Properties: Balanced strength, hardness, and toughness; overall performance can be significantly improved through quenching and tempering; good machinability
Machining: Direct machining or finishing after quenching and tempering; moderate cutting parameters; suitable for all processes including turning, milling, drilling, and grinding
Applications: Shafts, gears, bolts, connecting rods, mold bases, load-bearing structural components.
Grades: 65Mn, AISI 1095, T8, T10
Properties: High hardness, good wear resistance, good elasticity; high strength but poor toughness and brittleness; poor machinability
Machining: Mostly rough machining in the annealed state; after quenching, it can only be ground; tools wear easily, requiring low speed and small depth of cut.
Applications: Cutting tools, punches, springs, wear blocks, measuring tools
Grades: 12L14, 1215, Y15, Y40Mn
Properties: Easy chip breakage during cutting, high surface finish, long tool life, high machining efficiency; strength and toughness are slightly lower than ordinary carbon steel.
Machining: Suitable for high-speed, high-feed machining; suitable for automatic lathes and CNC batch production of small precision parts.
Applications: Precision shafts, pins, nuts, electronic components, instrument parts.
Grades: 40Cr (AISI 4140), 20CrMnTi, 35CrMo
Properties: Strength, fatigue strength, and wear resistance are far superior to carbon steel; good hardenability and minimal deformation after heat treatment; good machinability
Machining: Excellent machinability after quenching and tempering; suitable for heavy-duty, high-precision parts; requires matching cutting tools and parameters
Applications: Gears, splined shafts, high-strength bolts, mold inserts, hydraulic components
Grades: Cr12、Cr12MoV、D2、SKD11
Properties: High hardness (HRC 58–64), high wear resistance, high compressive strength; moderate toughness.
Applications: Cold stamping dies, shearing dies, drawing dies, forming dies, wear blocks.
Grades: H13、SKD61、4Cr5MoSiV1
Properties: High-temperature strength, resistance to thermal fatigue, good thermal conductivity; excellent toughness.
Applications: Die casting molds, hot forging molds, extrusion molds, injection mold cores/cavities.
Grades: S136、NAK80、P20
Properties: S136 is corrosion-resistant and can be mirror-polished; NAK80 is pre-hardened and requires no heat treatment; P20 is highly versatile.
Applications: High mirror finish molds, corrosion-resistant molds, and ordinary injection molds.
| Material | Grade | Carbon Content | Advantages | Applications |
|---|---|---|---|---|
| Low Carbon Steel | 1018, Q235, 20# steel | ≤0.25% | Easy to process, inexpensive | Supports, fixtures |
| Medium Carbon Steel | 1045, 40# steel | 0.45% | Good overall performance | Shafts, gears, mold bases |
| High Carbon Steel | 65Mn, 1095, T8, T10 | ≥0.6% | High hardness, wear resistance, good elasticity | Tools, punches, springs |
| Free-cutting Steel | 12L14, 1215, Y15, Y40Mn | 0.15% | Fast cutting, high surface finish | Precision shafts, pins, electronic components |
| Alloy Steel | 40Cr (4140), 20CrMnTi, 35CrMo | 0.40% | High strength, wear-resistant | Gears, splined shafts, hydraulic parts |
| Cold Work Die Steel | Cr12, Cr12MoV, D2, SKD11 | 1.5% | High hardness, wear-resistant | Cold stamping dies, shearing dies, forming dies |
| Hot Work Die Steel | H13, SKD61, 4Cr5MoSiV1 | 0.4% | Resistant to thermal fatigue | Die casting molds, hot forging molds, injection mold cores |
| Plastic Mold Steel | S136, NAK80, P20 | 0.3%-0.4% | High versatility, can be polished/pre-hardened | High mirror finish molds, general injection molds |
Tool Compatibility: Prioritize the use of carbide tools, matching the coating to the steel's hardness (e.g., TiAlN coating for ordinary carbon steel, CBN tools for high-hardness steel) to reduce tool wear and chipping.
Cutting Parameters: Follow the principle of "high speed, large feed for soft steel, low speed, small depth of cut for hard steel," setting the spindle speed, feed rate, and depth of cut appropriately to avoid excessive cutting forces or thermal deformation.
Cooling and Lubrication: Ensure proper cooling and lubrication throughout the machining process, using a coolant suitable for the steel (e.g., extreme pressure coolant for high-alloy steel), spraying it directly onto the cutting zone to reduce cutting heat and minimize tool sticking.
Clamping Rigidity: Ensure secure clamping, minimizing tool overhang and preventing vibration and displacement during machining. High-hardness steels require specialized fixtures to ensure dimensional accuracy.
Process Specifications: Perform roughing and finishing separately. Roughing removes excess material and releases internal stress, while finishing ensures surface accuracy and dimensional stability, prioritizing climb milling.
CNC Turning of Adapter Fitting
CNC Turning of Piston
New energy vehicle parts
New energy vehicle parts
A: For ordinary carbon steel (low carbon steel, medium carbon steel), TiAlN coated cemented carbide tools are preferred due to their best wear resistance and compatibility. For high-hardness steel (high carbon steel, mold steel), CBN or ceramic tools with a TiCN coating are necessary to effectively prevent tool chipping and wear.
A: There are three main reasons: First, the tool hardness is incompatible with the steel; an unsuitable tool was not selected. Second, the cutting parameters were unreasonable; for hard steel, the rotation speed and depth of cut were not reduced, resulting in excessive cutting forces. Third, the clamping was not secure, and machining vibration caused chipping.
A: Roughing removes most of the workpiece material, and the cutting heat and internal stress generated during the process can cause slight deformation of the workpiece. Separating the roughing and finishing processes allows the workpiece to fully release internal stress after roughing, and then the finishing process precisely controls dimensional accuracy and surface quality, avoiding deformation that could affect the machining results.
A: No special cooling enhancement is needed. Free-cutting steel contains sulfur, lead, and other elements, making chips easier to break and less prone to sticking to the tool. Ordinary emulsions are sufficient for machining. The key is to ensure smooth chip removal. Increasing the spindle speed and feed rate appropriately can improve efficiency.
A: Specialized fixtures should be used to ensure clamping rigidity and reduce tool overhang (L/D≤3) to avoid vibration and workpiece displacement during machining. Excessive clamping force should also be avoided to prevent workpiece deformation and ensure dimensional accuracy meets requirements.
A: The core principle is to match the type of steel. Ordinary carbon steel can be machined with ordinary emulsions; high-alloy steel and mold steel require extreme pressure coolants containing sulfur/chlorine additives, which can effectively reduce cutting heat, reduce tool sticking, and extend tool life.
