Overview of Stainless Steel Types and Standards

The document categorizes stainless steels into three main types: Austenitic, Martensitic, and Ferritic. It cross-references international standards including DIN (Germany), AFNOR (France), B.S. (UK), UNI (Italy), and AISI (USA). Key grades include 1.4300 (304), 316, and 321 for Austenitic steels, and 420, 431, 410 for Martensitic steels.

Material Properties

• Austenitic Stainless Steel: Contains 16-25% chromium and 8-20% nickel, offering superior corrosion resistance. Mechanical properties include tensile strength below 850 N/mm² and hardness under 250 HB.
• Martensitic and Ferritic Stainless Steel: Exhibit tensile strength below 1100 N/mm² and hardness below 320 HB, with slightly reduced machinability compared to standard steels.

Machinability and Cutting Recommendations

• Martensitic and Ferritic steels: Require slightly reduced cutting speeds compared to standard steels.
• Austenitic steels: Most challenging to machine due to plastic chip formation causing false cutting edges and increased surface hardness; cutting speeds should be reduced by approximately 50%.
• Tool Geometry: Recommended rake angles between 15°-17°, point angles between 130°-140°, combined with low cutting speeds and high feed depths to minimize surface hardening.
• Tooling: Use sharp tools with effective cooling; specialized IZAR tools are available for drilling, threading, and milling stainless steels.

Cutting Tools and Product References

• HSSE 5% Co drills with TiAlN coatings are recommended for high-performance cutting and intensive use.
• Detailed product references include dimensions, coatings, and pricing for drills suited to Martensitic/Ferritic and Austenitic steels.
• Recommended cutting parameters such as rotational speeds (rpm), feed rates (mm/rev), and cutting speeds (Vc in m/min) are provided based on drill diameter.

Recommended Cutting Conditions

• Martensitic/Ferritic steels: Cutting speeds between 12-17 m/min; rpm and feed rates adjusted per drill diameter (e.g., 1900-2700 rpm for 2 mm diameter, feed 57-81 mm/min).
• Austenitic steels (thin sheets <5 mm): Lower cutting speeds of 6-12 m/min with specialized drill geometry to improve chip evacuation and reduce machining effort; suitable for manual power tools.

International Standards and Material Equivalents

• Cross-references among DIN, UNE, AFNOR, B.S., UNI, and AISI standards facilitate material identification and selection.
• Examples: 1.4300 (DIN) corresponds to 304 (AISI), 1.4406 to 316L, etc.

Summary of Best Practices

• Significantly reduce cutting speeds when machining stainless steels, especially Austenitic types.
• Adopt appropriate tool geometries to control chip formation and surface hardening.
• Utilize specialized coated tools (e.g., TiAlN) to enhance tool life and machining performance.
• Maintain good tool cooling and sharpness to optimize machining quality and efficiency.

Metric Hand and Machine Taps for Stainless Steel

This section details specifications and recommendations for metric hand and machine taps designed for stainless steel threading operations.

• Tap Types: Hand taps and machine taps with stages including roughing, semi-roughing, and finishing; some taps feature guides for precision.
• Materials: Tools made from HSS, HSSE 5%Co, with coatings such as TiN, TiAlN, and PMX.
• Dimensions: Comprehensive data on diameter, pitch, length, and thread length for sizes M3 to M24.

Material Classifications

• Austenitic stainless steels (e.g., 1.4300/304) with tensile strength <850 N/mm² and hardness <250 HB.
• Martensitic stainless steels (e.g., 1.4021/420) with tensile strength <1100 N/mm² and hardness <320 HB.
• Ferritic stainless steels with similar mechanical properties to martensitic steels.

Recommended Cutting Conditions

• Cutting speeds for austenitic steels range from 6 to 14 m/min depending on tool coating and operation.
• RPM and feed per revolution values are specified per tap size and steel type.
• Dry machining is possible at 50% of recommended speeds, but use of IZAR cutting oil is advised for optimal results.

Tooling Recommendations and Features

• TiN coatings reduce friction and improve tool life.
• 35º helix angles enhance chip evacuation, especially for blind holes.
• High Performance Cutting (HPC) and High Performance Intensive (HRI) taps are optimized for intensive machining and chip control.
• Spiral point taps (A.R.I.) are recommended for through holes to push chips out efficiently.

Standards and Norms

• DIN 352 for hand taps, DIN 371 and 376 for machine taps.
• Cross-references to UNE, AFNOR, B.S., UNI, and AISI standards ensure global compatibility.

Summary Tables and Data

• Includes detailed tables of tap dimensions, article numbers, material grades, cutting speeds, RPMs, and pricing.

Critical Information and Best Practices

• Select tap type and coating based on stainless steel grade and machining operation.
• Adhere to recommended cutting speeds and feeds to maximize tool life and quality.
• Prefer IZAR cutting oil lubrication; dry machining feasible at reduced speeds.
• Use guided taps for precision threading when necessary.
• Ensure compliance with DIN and international standards for material and tooling.

End Mills for Stainless Steel Machining

Detailed technical data on straight shank end mills designed for machining martensitic, ferritic, and austenitic stainless steels.

• Tool Dimensions: Diameter, shank diameter, overall length, cutting length, and tolerances specified.
• Number of Cutting Edges: Varies from 3 to 6 depending on tool type and application.
• Material Compatibility: Tools suited for martensitic/ferritic steels (tensile strength <1100 N/mm², hardness <320 HB) and austenitic steels (tensile strength <850 N/mm², hardness <250 HB).
• Coatings: TIALN and XTIALN coatings enhance performance in high-speed and high-performance cutting.

Cutting Parameters and Formulas

• Cutting speed (Vc), feed per tooth (fz), and correction coefficient (K) provided for various diameters and materials.
• Feed rate (vf) calculated as vf = r.p.m. × Z × fz × K.
• Spindle speed (r.p.m.) calculated as r.p.m. = (Vc × 1000) / (π × diameter).

Applications and Machining Types

• Finishing: Tools with 3 cutting edges (3Z) designed for high precision and surface quality.
• Fine Pitch Roughing: Tools with 4-6 cutting edges for efficient material removal with good finish.
• Roughing: Tools optimized for high material removal rates with specific coatings and geometries.

Summary of Key Parameters

Best Practices and Recommendations

• Follow specified cutting speeds and feeds based on material and tool diameter to optimize tool life and machining quality.
• Apply correction coefficient K=0.7 in feed rate calculations for accuracy.
• Select coatings and tool subgroups according to stainless steel grade to improve wear resistance and performance.
• Adhere to DIN and international standards for material and tooling compatibility.

Additional Notes

Grooving and finishing operations require attention to tool geometry and coating to achieve high-performance cutting (HPC) and high-intensity machining (HRI). The tools and standards referenced ensure international applicability across Spain, Germany, France, UK, Italy, and USA.

End Mills for Austenitic Stainless Steel

This section focuses on carbide end mills with TIALN coatings designed for finishing and super-finishing Austenitic stainless steels.

• Tool Types: HM straight shank end mills (3Z finishing), PMX super-finishing end mills with variable helix, and HM variable helix (NZ) end mills.
• Material Standards: Covers common Austenitic grades such as 1.4300 (304), 1.4406 (316 LN), 1.4541 (316 L), with tensile strength <850 N/mm² and hardness <250 HB.
• Machining Parameters: Cutting speeds (Vc), spindle speeds (r.p.m.), feed per tooth (fz), and feed rates (vf) are provided with formulas for calculation.
• Tool Life and Wear: High-performance tools demonstrate improved durability and longer tool life compared to conventional tools.

Recommendations and Best Practices

• Increase feed rates by 25-35% when using super-finishing PMX tools to enhance surface finish and productivity.
• Variable helix tools reduce vibrations, enabling higher feeds and better surface quality.
• Use TIALN coatings and carbide substrates for superior wear resistance and performance.

Product Codes and Packaging

Includes references for various end mills and tool sets covering multiple diameters and lengths, facilitating selection for diverse machining requirements.

Conclusion

This comprehensive technical guide integrates stainless steel classification, tooling specifications, machining parameters, and international standards to support optimal selection and use of cutting tools for stainless steel machining. It emphasizes best practices to maximize tool life, machining quality, and efficiency across drilling, tapping, and milling operations.