Steel is one of the most popular engineering materials used today, especially in machining steel for its versatility and wide range of beneficial features. Various steel grades have been developed over the years and are widely used in machining steel parts for aerospace, automotive, and robotics industries. Each grade has its own advantages and disadvantages and can be machined in various ways. CNC machining steel is the most preferred machining method. CNC machining of steel enables machinists and users to optimize the properties of steel and minimize limitations imposed by each of these grades. You may have questions like: What are some popular CNC machining steel grades used for building parts? How do you choose the right steel grade for your application? Read this post for answers to these questions and more.
Top 7 Grades for CNC Machining Steel
Steel, widely used in machining steel applications, is an alloy comprising about 1% carbon along with other alloying elements like molybdenum and chromium in small amounts. The properties of steel vary depending on the components in each grade. Excellent machinability, ductility, weldability, and availability are a few common factors that make steel a material of choice for various industrial applications. Today, several steel grades are used for CNC machining, but this section narrows down the list to the top 7 for ease.
- SS 304:
This is the most common grade for machining steel, especially stainless steel, used today, known as 18/8 for its 8% nickel and 18% chromium composition. It offers excellent mechanical properties, including good machinability, weldability, cost efficiency, and corrosion resistance. SS 304 is commonly used in food handling applications, utensils, food processing equipment, architectural applications, screws, heat exchangers, and more. - SS 303:
SS 303 is a readily available stainless steel grade used for machining parts like electronic hardware, bolts, nuts, screws, bushings, and aircraft fittings. It offers good corrosion resistance, excellent machinability, and moderate costs. - SS 416:
This grade provides superior machinability compared to other machining steel grades and offers good strength and corrosion resistance. It is not suited for marine or chlorine environments and is used for pump shafts, valves, gears, bolts, and nuts. - 1045:
A medium carbon steel with excellent hardness and strength, 1045 is ideal for wear-resistant applications. Its machined parts typically require post-treatment for stress relief. It is used for bolts, axles, light gears, and forged connecting rods. - 1018:
Known as mild carbon steel, 1018 is typically used for carburized parts that require good weldability and machinability. It has moderate mechanical properties, including ductility and strength. - 1144:
This free-machining steel has a resulfurized carbon composition, offering high strength, wear resistance, and minimal deformation. Its poor weldability limits its applications, and it is commonly used for pistons, gears, screws, rods, and nuts. - 4140:
A low alloy steel featuring molybdenum, manganese, and chromium, 4140 has excellent machinability when annealed and provides impressive impact and wear resistance.
Choosing the Right Steel Grade for Your Application
Steel is a versatile material for machining steel parts, with most grades sharing properties like ductility, strength, corrosion resistance, and aesthetic appeal. However, not all grades are suited for every application. Consider the following tips for selection:
- For applications in marine environments, SS 304 is ideal due to its excellent corrosion resistance.
- For CNC machining of steel parts for sanitary applications, SS 304 and 316 are popular choices, offering corrosion resistance, reliability, and affordability.
- For building military and commercial aircraft parts requiring toughness, strength, and fatigue resistance, 4130 is the optimal choice.
Although machining steel offers high machinability, partnering with an experienced manufacturer is essential to maximize its potential. Princeton Industrial Products, Inc. is a custom CNC machine shop specializing in CNC steel machining. The company has been serving OEMs, defense, and electrical contractors with CNC-machined steel parts for several years. The engineering experts at Princeton have extensive experience with the mechanical properties of various steel grades and can guide you in selecting the right material if you are uncertain. Contact Princeton’s experts to discuss your project requirements.
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