| Material Group | P - Steel |
| Sub-Group | Low Carbon Steel |
| Tensile Strength | 490-800 [N/mm^2] |
| Machinability | 65% - 80% |
A633 steel, a normalized high-strength low-alloy (HSLA) steel, offers a desirable combination of strength, toughness, and weldability. However, its specific properties present unique challenges during machining that require careful consideration.
Understanding the Machinability of A633 Steel:
Composition: A633 steel contains various alloying elements such as manganese, silicon, copper, nickel, and chromium, contributing to its strength and corrosion resistance. These elements can also increase the material's hardness and work-hardening tendencies, potentially leading to increased tool wear and difficulties in chip formation.
Applications: This steel is commonly used in structural applications like bridges, buildings, and pressure vessels, where high strength and weldability are essential.
Overcoming Machinability Challenges:
Tool Selection: Choose cutting tools specifically designed for HSLA steels or materials with similar properties. Carbide tools with appropriate coatings, such as TiCN or AlTiN, can enhance tool life and cutting performance in machining A633 steel.
Cutting Parameters: Adjust cutting speeds and feeds based on the specific grade and heat treatment of the A633 steel. Generally, moderate cutting speeds and feeds are recommended due to the material's work-hardening potential and moderate hardness.
Coolant/Lubricant: Utilize a suitable coolant or lubricant to reduce heat, friction, and chip welding during machining. Water-based coolants with additives for improved lubricity are often recommended for HSLA steels.
Chip Control: Employ chipbreakers or specialized tool geometries to promote chip breaking and prevent long, stringy chips that can interfere with the machining process and potentially damage the workpiece or tool.
Additional Tips for Machining A633 Steel:
By understanding the unique characteristics of A633 steel and implementing these strategies, machinists can effectively manage its machining challenges and achieve desired results in terms of productivity, tool life, and surface finish.
For detailed carbide grade and cutting speed recommendations, refer to resources like the material supplier's datasheet or consult with a machining expert familiar with HSLA steels.
| Standard | Name |
|---|---|
| SAE | A633Gr.C |
| WNR | 1.0562 |
| DIN | StE355 |
| BS | A588 |
| ANFOR | FeE355KGN/ E335R/FP |
| UNI | FeE355KG;KW |
| UNF | AE355KG;DD |
| JS1 | SM490A;B;C;YA;YB |
| Element | A633 Grade A | A633 Grade C | A633 Grade D | A633 Grade E |
| Carbon (C) | ≤ 0.18% | ≤ 0.20% | ≤ 0.22% | ≤ 0.22% |
| Manganese (Mn) | 1.00-1.35% | ≤ 1 1/2" thick: 0.70-1.35% | ≤ 1 1/2" thick: 1.15-1.50% | 1.15-1.50% |
| Over 1 1/2" to & incl 4" thick: 1.00-1.60% |
Over 1 1/2" to & incl 4" thick: 1.25-1.60%
|
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| Phosphorus (P) | ≤ 0.030% | ≤ 0.030% | ≤ 0.020% | ≤ 0.035% |
| Sulfur (S) | ≤ 0.030% | ≤ 0.030% | ≤ 0.010% | ≤ 0.040% |
| Silicon (Si) | 0.15-0.50% | 0.15-0.50% | 0.15-0.50% | 0.15-0.50% |
| Columbium (Cb) | 0.01-0.05% | |||
| Vanadium (V) | 0.04-0.11% |
Additional notes:
It's important to refer to the specific grade of A633 steel you are working with to determine the exact chemical composition requirements. You can find this information in the material's certification or datasheet provided by the supplier.
| Application | Vc (m/min) | Vc (SFM) |
|---|---|---|
| Turning | 285-350 | 930-1150 |
| Milling | 175-220 | 570-720 |
| Parting | 135-170 | 440-560 |
| Grooving | 160-195 | 520-640 |
| Drilling | 115-140 | 380-460 |
While machining guidelines for A633 steel provide a starting point, achieving optimal cutting speeds in real-world scenarios requires understanding the factors that influence machining performance. The estimated speeds are based on ideal conditions, which may not always be achievable in practice.
Factors Affecting Cutting Speed in A633 Steel:
Carbide Grade: Selecting the appropriate carbide grade is paramount. While general recommendations exist for HSLA steels, the specific grade should be tailored to the specific A633 grade (A, C, D, or E), cutting conditions, desired surface finish, and tool life. Consult with tooling experts or refer to the material supplier's datasheet for specific recommendations.
Tool and Workpiece Clamping: Secure and rigid clamping of both the cutting tool and the workpiece is fundamental. Vibrations and movement can negatively impact accuracy, surface finish, and tool life. Ensure proper clamping techniques and utilize high-quality tooling systems to minimize these risks, especially when dealing with the high strength of A633.
Raw Material Quality: Variations in raw material quality, including chemical composition, heat treatment, and microstructure, can affect machinability. Source high-quality A633 steel from reputable suppliers and verify its properties to ensure consistent and predictable machining performance.
Tool Overhang: A shorter tool overhang minimizes deflection and vibration, leading to improved cutting stability and surface finish. Strive for the shortest possible overhang without compromising tool reach and accessibility, especially when machining thicker A633 plates or sections.
Material Hardness: The hardness of the A633 steel workpiece directly impacts cutting forces and tool wear. Verify that the material's hardness falls within the expected range for the chosen carbide grade and cutting parameters. If needed, consider preheating or adjusting cutting parameters to accommodate variations in hardness due to work hardening.
Additional Factors:
By meticulously evaluating these factors and adjusting cutting speeds accordingly, you can fine-tune your machining process to achieve superior results when working with A633 steel. Remember, the recommended cutting speeds are a guideline, and real-world optimization requires a holistic approach that considers the entire machining ecosystem.
Disclaimer: The information provided here is intended as a general guideline. It is crucial to consult with tooling experts, refer to manufacturer recommendations, and conduct thorough testing to determine the optimal cutting parameters for your specific application and the specific properties of your A633 steel.
| Honing Siz | 0.05-0.08 mm / 0.002-0.003" |
| Rake Angl | 11° -13° |
| Land Angl | Positive |
| Land Widt | 0.20-0.30 mm / 0.008-0.012" |
