Learn what E335 steel is, whether E335 is suitable for CNC machining, what parts it is used for, how it compares with maraging steel, and how to control machining challenges in custom CNC steel parts.
What Is E335 Steel?
E335 is a European non-alloy quality structural steel grade commonly associated with EN 10025 hot-rolled structural products. In practical purchasing language, it is chosen when a designer needs higher strength than very low-strength mild steel, but does not need the extreme strength, heat treatment response, or alloy cost of advanced tool or aerospace steels. For CNC machining suppliers, E335 usually arrives as hot-rolled plate, bar, or structural stock, then is converted into brackets, blocks, shafts, fixtures, and welded-machined components.
Material Classification
The key point is that E335 is not a stainless steel and not a precipitation-hardening alloy. It is a carbon or non-alloy structural steel grade, so its performance depends mainly on yield strength, product thickness, delivery condition, and the quality of the original mill stock. This makes it familiar to many machine shops because cutting behavior is closer to medium-strength carbon steel than to exotic high-alloy materials.
How the Name Is Used in Drawings
In engineering drawings, E335 may appear together with a numeric designation such as 1.0060, a delivery standard, a thickness range, or a surface finish requirement. The grade name alone is not always enough for procurement because yield strength and elongation can vary with product thickness. For CNC machined E335 steel parts, drawings should define grade, standard, delivery condition, tolerance, critical surfaces, and any coating or welding requirements.
Is E335 Steel Suitable for CNC Machining?
E335 is suitable for CNC machining, especially when the part requires practical strength, relatively low material cost, and common steel shop capability. It is not normally selected because it is the fastest steel to cut; it is selected because it offers a balanced combination of strength, availability, weldability, and price. For many industrial parts, E335 can be turned, milled, drilled, tapped, bored, and surface finished using standard CNC machining strategies.
When E335 Is a Good CNC Choice
E335 is a good fit when the final part is a structural or mechanical component rather than a wear tool or ultra-high-strength component. It works well for parts where the customer wants stronger steel than common low-carbon stock but does not want the cost and process control of maraging steel. Typical long-tail search intent around this topic includes “E335 steel CNC machining service,” “custom CNC machined structural steel parts,” and “E335 steel machined brackets.”
When Another Steel May Be Better
Another steel may be better when the part needs high corrosion resistance, very high hardness, extreme fatigue performance, or predictable strength after aging heat treatment. In those situations, stainless steel, alloy steel, tool steel, or maraging steel may be more appropriate. The decision should be based on load, environment, tolerance, surface finish, and budget, not only on nominal strength.
Common CNC Machined Parts Made from E335 Steel
E335 is often used for CNC machined parts that must carry load, hold alignment, or connect larger structures. Because it is a structural steel, the most common applications are functional industrial components rather than decorative parts. Many customers choose it for medium-duty parts where machining accuracy is needed after flame cutting, sawing, welding, or hot-rolled stock preparation.
Industrial and Structural Components
For CNC machining, E335 can be used to manufacture machine frames, base plates, support blocks, guide brackets, mounting plates, spacers, bearing supports, welded-machined assemblies, and equipment connection parts. These parts often combine simple geometry with a few critical machined features, such as flat mounting faces, accurate hole positions, key slots, counterbores, or tapped holes.
Parts That Benefit from Machined Accuracy
The value of CNC machining appears when a part cannot rely on raw structural stock accuracy alone. Flatness, hole location, thread quality, and bearing seat dimensions often need CNC control. A rough steel plate may be economical, but a machined plate can control assembly alignment and reduce installation problems. This is why E335 steel CNC machining is commonly linked with custom fixtures, machine mounting parts, and medium-load industrial hardware.
| Part Type | Typical CNC Features | Reason E335 May Be Used |
| Mounting plate | Milled faces, drilled holes, counterbores | Good strength and economical stock |
| Support bracket | Milled profiles, slots, tapped holes | Carries load with moderate machining cost |
| Spacer or block | Parallel faces, bores, chamfers | Stable enough for functional assemblies |
| Welded-machined component | Post-weld facing and hole machining | Combines structural fabrication and precision features |
Why Maraging Steel Is Chosen for CNC Machined Parts
Maraging steel is discussed together with E335 because both can be machined as steel parts, but the reason for choosing them is very different. Users normally choose maraging steel when the part must combine ultra-high strength, toughness, dimensional stability after aging, and reliable performance under demanding mechanical loads. It is not a low-cost structural substitute; it is a premium material for critical components.
Strength After Aging
Maraging steel is typically supplied in a relatively machinable solution-annealed condition and then aged to reach very high strength. This is attractive for CNC parts with complex features because the shop can machine the geometry before final aging, reducing the need to cut fully hardened steel. Customers often care about whether the part will distort after heat treatment; maraging steel is valued because dimensional change during aging is comparatively small when the process is controlled.
Typical Reasons Customers Specify Maraging Steel
The buying reasons are usually performance-driven rather than cost-driven. Users ask whether maraging steel is worth the price, whether it can be machined before aging, whether it needs special heat treatment, and whether it offers better reliability than conventional high-strength steels. These questions usually come from aerospace tooling, high-load mechanisms, precision dies, shafts, and parts where failure would be expensive.
- Very high yield and tensile strength after aging.
- Good toughness for a high-strength steel.
- Machinability in the annealed condition before final aging.
- Low distortion during controlled aging treatment.
- Good polishability and repair weldability for tooling and precision components.
E335 Steel Chemical Composition and Material Properties
The composition of E335 is intentionally simple compared with maraging steel. Instead of relying on nickel, cobalt, molybdenum, and titanium precipitation hardening, E335 is defined as a non-alloy structural steel with limited residual elements. The most useful way to evaluate E335 for CNC machining is to look at strength, hardness, elongation, density, and thermal behavior together, because these properties influence cutting force, workholding, burr formation, and dimensional control.
Chemical Composition
Public material databases commonly list E335 with iron as the balance and tight limits on phosphorus, sulfur, and nitrogen according to the relevant standard. Exact chemistry should always be checked against the ordered material certificate because supplier stock, product form, and standard revision can matter. For CNC quotations, the certificate is more useful than a generic web table when the part has critical load or inspection requirements.
| Element | Typical Standard Limit or Role | CNC Machining Relevance |
| Eisen | Rest | Base matrix for carbon or non-alloy structural steel |
| Phosphorus | Low maximum level | Excess can reduce toughness and affect consistency |
| Sulfur | Low maximum level | Influences chip breaking and machinability when controlled |
| Stickstoff | Low maximum level | Can affect aging behavior and mechanical consistency |
Physical and Mechanical Properties
E335 is stronger than many basic mild steel choices, but it remains far below maraging steel after aging. A typical density is about 7.9 g/cm3, so weight is similar to other carbon steels. Elastic modulus is close to common steel values, meaning stiffness is not dramatically different from other steels of the same geometry. Designers should not expect a large stiffness change by switching from another carbon steel to E335 unless geometry or heat treatment also changes.
| Eigenschaft | Typischer Wert oder Bereich | Konstruktionsbedeutung |
| Dichte | About 7.9 g/cm3 | Steel-like weight; not a lightweight material |
| Young’s modulus | About 190 GPa | Good stiffness for structural parts |
| Streckgrenze | Often around 335 MPa minimum in thinner products | Useful for medium-load parts |
| Zugfestigkeit | Often around 540–770 MPa depending on thickness | Higher strength than many low-carbon steels |
| Dehnung | Varies by thickness, commonly lower than soft mild steel | Forming and impact needs should be checked |
| Härte | Around 180 HB as a typical reference | Machinable with standard carbide strategies |
Maraging Steel Chemical Composition and Material Properties
Maraging steel is a different material family. Its high strength comes from a very low-carbon iron-nickel martensitic base strengthened by aging reactions. Common grades such as C250, C300, and C350 include nickel, cobalt, molybdenum, titanium, and aluminum. These alloying elements make maraging steel more expensive than E335, but they also create the properties that customers are paying for in critical CNC machined parts.
Typical Composition of Common Grades
The most commonly discussed maraging steels are 18Ni grades. They have very low carbon and silicon, with nickel near 18 percent. Cobalt and titanium increase as the grade strength increases. This chemistry is one reason maraging steel can be machined in a softer condition and then aged to high strength. It also explains why material traceability and heat treatment records matter more than they do for ordinary structural steel.
| Qualität | Ni | Co | Mo | Ti | Al | Fe |
| C250 | About 18.5% | About 7.5% | About 4.8% | About 0.4% | About 0.1% | Rest |
| C300 | About 18.5% | About 9.0% | About 4.8% | About 0.6% | About 0.1% | Rest |
| C350 | About 18.5% | About 12.0% | About 4.8% | About 1.4% | About 0.1% | Rest |
Mechanical Behavior After Aging
After aging, maraging steel reaches strength levels far above E335. Depending on grade, tensile strength can move into the range used for highly stressed tooling and structural components, and hardness can exceed 50 HRC. This performance comes with machining consequences: aged maraging steel requires rigid machines, sharp tools, stable setup, and abundant coolant. Many shops therefore prefer to rough and finish most features before aging, leaving only light finishing operations afterward when necessary.
E335 vs Maraging Steel CNC Machinability
The machining comparison between E335 and maraging steel should not be reduced to “which one is better.” E335 is easier to justify for economical structural CNC parts, while maraging steel is justified when the part needs very high strength and dimensional stability after aging. A buyer should compare machinability, heat treatment sequence, surface finish expectations, tolerance risk, and total part cost.
Cutting Behavior in the Machine Shop
E335 generally cuts like a medium-strength structural steel. It may generate moderate cutting forces and burrs, but it can normally be machined with standard carbide tooling and conventional milling or turning strategies. Maraging steel in the annealed condition is also machinable, but it is not the same purchasing decision: the later aging step must be planned, and the shop must understand what features can be finished before heat treatment.
Process Risk and Cost Difference
E335 usually has lower material cost and simpler processing. Maraging steel has higher material cost, tighter process control, and heat treatment documentation needs. However, maraging steel may reduce finishing difficulty compared with machining a conventional hardened steel from start to finish. For custom CNC machining, this means E335 is often a practical production material, while maraging steel is a specialized performance material.
| Bearbeitungsfaktor | E335 Steel | Maraging Steel |
| Main selection reason | Economical structural strength | Ultra-high strength and low distortion aging |
| Typical cutting condition | Machined as supplied or normalized/hot worked stock | Often machined annealed, then aged |
| Tooling demand | Standard carbide tooling | Sharp carbide; strict tool control after aging |
| Heat treatment role | Usually not the main value driver | Central to final properties |
| Toleranzrisiko | Stock stress and clamping distortion | Aging sequence and hard-condition finishing |
| Beste Passform | Brackets, plates, blocks, supports | Critical shafts, tooling, high-load precision parts |
Key User Concerns When Comparing E335 and Maraging Steel
Users often compare these materials because both are steels that can be CNC machined, but their questions usually reveal different priorities. E335 questions focus on whether the material is strong enough, affordable, weldable, and available. Maraging steel questions focus on heat treatment, distortion, strength, and whether the premium cost is justified. Addressing these concerns directly helps a CNC machining article become more useful than a generic material page.
Cost and Availability
E335 is normally easier to source as structural stock, which helps reduce lead time for plates, blocks, and medium-duty machined components. Maraging steel is more specialized, so availability, minimum order quantity, certification, and heat treatment capacity can influence the quote. The lowest material price is not always the lowest final part cost, but for simple structural parts E335 is usually the more economical choice.
Strength, Failure Risk, and Over-Specification
A common concern is whether a stronger steel is always safer. In CNC machined parts, over-specifying maraging steel can create unnecessary cost and process complexity. E335 may be enough for a base plate or support bracket if the design stress is moderate. Maraging steel becomes reasonable when strength-to-size ratio, fatigue resistance, dimensional stability after aging, or critical service reliability are central to the application.
Surface Finish and Corrosion Protection
Neither E335 nor common non-stainless maraging steels should be treated as corrosion-proof. E335 often needs painting, black oxide, zinc plating, phosphate, oiling, or another protective finish depending on the environment. Maraging steel can offer better resistance than some tool steels, but it may still need surface protection. The finish should be specified early because coating thickness can affect threads, bores, and precision fits.
How to Machine E335 Steel Successfully
E335 is not unusually difficult compared with many steels, but successful CNC machining still requires attention to stock condition, cutting force, burrs, heat, and workholding. Many quality problems come from treating structural steel stock as if it were precision ground material. Hot-rolled surfaces, residual stress, scale, and uneven stock thickness can all affect the final part if the machining plan is too aggressive or the datum strategy is weak.
Main Machining Difficulties
The most common E335 machining difficulties include tool wear on scaled surfaces, burr formation around drilled or milled edges, vibration during heavy roughing, thread quality problems in deep tapped holes, and distortion after removing material from one side of a plate. These issues are manageable, but they should be considered before quoting tight flatness or position tolerances on large structural components.
Process Measures That Reduce Risk
A reliable process starts with stable stock, sufficient machining allowance, and a cutting plan that removes scale before precision finishing. For larger plates, rough machining on both sides can balance internal stress. For holes and threads, proper pilot drilling, coolant, chip evacuation, and thread inspection reduce scrap. If the part will be welded before final machining, final datums should be created after welding and stress relief when required.
- Use carbide tools with suitable coating for carbon steel and keep cutting edges sharp.
- Remove mill scale before finishing critical surfaces.
- Use climb milling where the setup allows stable cutting and good surface finish.
- Plan roughing and finishing passes separately to control heat and distortion.
- Apply coolant or air blast to manage chips during drilling, tapping, and pocketing.
- Deburr threaded holes, slots, and sharp edges before inspection and coating.
Tolerance and Inspection Control
For CNC machined E335 parts, tolerances should match the function of the feature. A general structural face may not need the same tolerance as a bearing bore or alignment hole. Over-tight tolerance on large hot-rolled stock can increase cost because extra setup, stress control, and inspection time are required. Practical drawings identify critical datums, functional holes, mating faces, thread class, surface roughness, and coating allowance.
Fazit
E335 is a practical non-alloy structural steel for CNC machined plates, brackets, supports, blocks, and medium-load machine parts. It offers useful strength and economical sourcing, but it needs good control of stock condition, burrs, stress, and corrosion protection. Maraging steel is chosen for a different reason: very high strength, toughness, and low-distortion aging for critical components. For most structural CNC parts, E335 is sufficient; for high-load precision parts where failure risk is severe, maraging steel may justify its cost.
FAQ
Is E335 steel the same as mild steel?
E335 is not simply a casual name for any mild steel. It is a defined European non-alloy structural steel grade with specified mechanical requirements. It may machine similarly to many carbon steels, but its yield strength level, delivery standard, and product thickness should be checked before substitution. If a drawing specifies E335 or 1.0060, confirm the equivalent grade with the customer before changing material.
Can E335 steel be CNC milled and tapped?
Yes. E335 can be CNC milled, drilled, bored, and tapped with standard steel machining methods. The shop should pay attention to chip evacuation, tool sharpness, burr control, and clamping stability. For deep threads or large plates, process planning matters more than the grade name alone. Thread class, coating allowance, and inspection method should be included on the drawing when fit is important.
Is maraging steel easier to machine than E335?
It depends on condition. Annealed maraging steel can be machined effectively, but aged maraging steel is much harder and requires more careful tooling and cutting conditions. E335 is generally simpler and cheaper for ordinary structural parts. Maraging steel becomes attractive when the part can be machined before aging and then hardened with minimal dimensional change.
Does E335 need surface treatment after CNC machining?
In many applications, yes. E335 is not stainless steel, so corrosion protection should be considered when the part will be exposed to moisture, handling, outdoor use, or industrial environments. Common choices include painting, oiling, black oxide, phosphate, or zinc plating. The finish should be specified before machining when coating thickness may affect threads, bores, press fits, or sliding surfaces.