Steel Materials for CNC Machining: The Complete Guide 2024

Updated: December 01, 2023

Introduction

CNC machining is a method and manufacturing process in which pre-programmed codes and software control cutting tool movement. Steel is among the extensively prioritized materials in CNC machining. It undergoes the machining process on an industrial scale for manufacturing various instruments and machinery products, exhibiting greater accuracy and precision. This guide is all about the use of steel material for CNC machining.

1. Benefits of using steel in CNC machining

No doubt, steel is a commonly used material for CNC machining. It is a good choice for machining because of its appreciable properties. But, instead of having excellent machining characteristics, you may need some help throughout the manufacturing process. To successfully machine steel parts, you must know all the advantages and difficulties of using steel in CNC machining. Here are the common benefits you may face while machining steel through a computerized controlled machining process.

The main benefits of selecting the steel material for the CNC machining process are discussed below.

1.1 Cost-Effective

One of the major reasons behind using steel in CNC machining for various industrial products is its economical use. It can be machined as thinly as possible according to the requirements of other materials. It is great for manufacturing products with much lower thicknesses, such as pipes. It makes it a very cost-effective material. So, if you want a budget-friendly material for CNC machining, steel is a must-to-go material.

1.2 Higher Durability

Steel is a very strong material that automatically enhances its durability. So, steel is a very durable material, a main requirement for the CNC machining process. It is shock-resistant, so it doesn’t break when an unexpectedly greater force is applied. The CNC-machined steel parts show long-term functioning. You can confidently use it as a durable material for plumbing and buildings and as a supporting road source.

1.3 Recyclable

In comparison to most materials, steel shows greater recyclability. It can be easily machined into desired structures and forms. Any damage to the steel part during machining does not end up with any loss. This loss is because it can easily recycle. As it is recyclable, it is considered an eco-friendly material. It does not cause any damage to the surrounding environment.

1.4 Easily Handled

Steel can easily be handled during machining without extra equipment and effort. Mishandling of the material during cutting can result in an undesirable product. Thus it can lead to a false end product and a waste of time. This is not the case with steel because you can safely run the machining process because of its easy handling.

1.5 Excellent Surface Finish

Steel is a great choice for CNC machining because of its excellent surface finish. You can enhance this surface finish by various physical and chemical means, e.g., polishing treatments.

2. Challenges of using steel in CNC machining

Challenges you may face while machining steel parts may vary according to the type of steel. Here are some common challenges.

2.1 Complex Geometry

Most of the steel grades have complex geometries. Therefore, the machining of such steel grades is quite difficult. They may have asymmetrical shapes or other varying geometric patterns, which are harder for the machine.

2.2 Heat Sensitivity

One of the main challenges you may face while machining steel parts is their heat sensitivities. The steel may be exposed to heat during the cutting. Many steel grades are very sensitive to high temperatures. Thus, they may undergo melting and deformation on exposure to heat, resulting in their destruction.

2.3 Tool Breakage

Machining of the steel parts can cause tool breakage if they are not handled properly. This breakage is due to the reason that various steel grades are tough. You must set an appropriate force and speed for the tools and choose them accordingly during steel cutting; otherwise, they will break.

2.4 Longer Production Time

Steel machining may require a longer time because of its poor machinability. It can directly affect its production time. Thus, it takes more time to produce the end products.

3. Types of steel materials you need to know

3.1 Stainless Steel

Stainless steel is a type of steel, and it contains 10.5% chromium, 1.2% carbon, and different alloying elements. It shows a wide range of surface finishes and excellent mechanical properties. It is highly resistant to fire and heat. Moreover, it is easy to clean and can be easily recycled. It is widely known for its automotive, medical, and kitchen applications.

Stainless steels can be identified based on their crystalline structure. This includes Austenitic, ferritic, martensitic, and duplex.

Austenitic stainless steel, such as 300- and 200-series stainless, is extremely formable and does not function to harden. They are also non-magnetic in a stiff problem.
Ferritic stainless steels are magnetic and use far better thermal conductivity than austenitic stainless. They can not be solidified by warmth therapy.
Martensitic stainless steel such as quality 416 and 420 can be hardened with multiple techniques of aging or heat therapies.
Duplex stainless steel, also called austenitic-ferritic, are grade of stainless that is highly specialized for enhanced rust resistance. Duplex steels are normal in industrial and architectural structuring.

3.2 Tool Steel

Tool steel is high-carbon chrome steel having carbon content ranging between 0.5%-1.5%. It also contains varying amounts of vanadium, cobalt, molybdenum, and other elements. This type of steel is suitable for the manufacturing of tools. Tool steel is well known for its toughness, heat, hardness, and wear resistance. Tool steel is often with heat treatment.

3.3 Alloy Steel

Alloy steel comprises carbon, iron, and other elements such as chromium, copper, manganese, etc. Its composition contains 5% of alloying elements. Alloying elements enhance its corrosion resistance and machinability. It is commonly used for the manufacturing of pipes and heating appliances.

3.4 Carbon Steel

Similar to stainless steel, carbon steel contains carbon and iron. Carbon steel differs only due to the alloy content. The alloy content in carbon steel is under 10.5%. There are three sub-categories of carbon steel.

Low-carbon steel (0.03-0.15% carbon)
Medium-carbon steel (0.25%-0.50% carbon)
High-carbon steel (0.55%-1.10% carbon)
It is a perfect option for a wide range of construction projects because of its low cost and relative adaptability.

4. Mostly used steel materials in CNC machining

	Types of steel	Description	Benefits	Drawbacks	Uses
8630	Low Alloy Steel	Known for its hardness and greater strength	Better response to thermal treatments	Need thermal treatment before or after the machining process	Used in valves, crankshafts, gears, etc.
4140	Low Alloy Steel	Have low contents of manganese, molybdenum, and chromium	Shows greater machinability at the annealing point	Post-thermal treatments are essential in some conditions	Used in spindles, bolts, nuts, etc.
8620	Low Alloy Steel	It is ductile and has greater strength. It is responsive against hardening.	It is resistant to wear and has greater strength.	It doesn’t respond well to induction or flame hardening	Used in chains, fasteners, piston pins, etc.
1144	Medium Carbon Steel	It is a desulfurized carbon steel that contains sulfur and manganese	Shows resistance against wear and deformation.	It cannot use properly welded.	Used in rods, screws, gears, etc.
1018	Mild Carbon Steel	It is perfect for carburized components.	Provides greater surface toughness and machinability.	It is less pliable and offers lower strength.	Used in studs, anchor pins, chain pins, machinery parts, etc.
1045	Medium Carbon Steel	It is the most popular steel type containing sulfur, phosphorous, and carbon.	Exhibits high strength and good machinability and Weldability.	It has limited mechanical properties due to the absence of alloying contents.	Used in casters, pinions, machinery parts, etc.
SS 303	Stainless steel	It is austenitic stainless steel.	Durable, corrosion, and heat-Resistant	May rust and pit in marine environments	Used in shafts, gears, bolts, etc.
SS 304	Stainless steel	Contains 18% chromium, 8% nickel, and 0.08% carbon.	Oxidation and corrosion-resistant, durable	It may corrode	Used in industrial and household applications.

5. Design consideration for steel in CNC machining

CNC machining is a subtractive method used to fabricate precise and accurate parts. You need to consider some common considerations while using steel and want to develop machined parts.

The main design and material considerations you must keep in mind for the proper functioning of steel are:

Stainess steel has different grades or alloys, which have different ratios of corrosion resistance. Finding the most suitable grade takes time. Make sure you are using the suitable and correct type of grade for your project.

Ferritic stainless steel includes 400 grades and is the most recommended grade due to good corrosion resistance and easy-to-machine capabilities. This grade has high thermal conductivity.

Austenitic stainless steel includes grades 302 and 316. These grades have many applications and are used for household items and mechanical parts. These grades have good corrosion resistance.

Stainless steel is considered a good choice where we need strength to weight factors such as it is required for the aerospace industry. So steel is good to use for aerospace parts manufacturing.

Due to its self-healing surface features, stainless steel is most commonly used in hygiene, and sanitary applications as any surface damage heals naturally by a chromium oxide film.

6. Is steel the right choice for your project?

Choosing a certified, expert company and steel for your project can be the perfect decision because of the excellent properties of steel alloys. Different types of steel alloys are well-suited for manufacturing various products.

Its excellent mechanical properties, machinability, higher strength, and greater workability make it suitable for industrial, construction, and infrastructure industrial plans. Moreover, its low cost makes it the right choice for small-scale projects demanding lower costs.

ECOREPRAP is a professional CNC manufacturer of all types of steel, including stainless steel, alloy steel, tool steel, and carbon steel. Rich surface finish treatments are provided, for example, heat treatment, zinc plating, passivation and more. Get an accurate quotation and have your parts made on time with high quality!