Understanding Carbide Surface Finish Requirements

Introduction

Surface finish is a critical specification for carbide tooling. Different applications require different finishes, and choosing the right finish affects both performance and cost.

As-Sintered Surfaces

As-sintered carbide has a rough, matte surface. It is suitable for non-critical surfaces or where subsequent grinding is planned. This is the most economical option.

Ground Surfaces

Surface grinding produces Ra 0.2 to 0.4 finishes. Ground surfaces are standard for die mounting faces, non-working surfaces, and components where precision is needed but sliding contact is minimal.

Lapped Surfaces

Lapping produces Ra 0.05 to 0.1 finishes. Lapped surfaces are required for seal faces, drawing die bores, and other applications where low friction and tight flatness are critical.

Polished Surfaces

Polishing achieves Ra 0.02 or better. Mirror-polished carbide surfaces prevent galling and material pickup in stamping and drawing. They are essential for deep drawing and non-ferrous metal forming.

Specifying Finish

Specify the required finish on each drawing surface. Not every surface needs polishing. Matching finish to function controls cost while ensuring performance where it matters.

Conclusion

Understanding carbide surface finish options helps specify the right surface for each application. Ground, lapped, and polished finishes each serve different purposes.

References

GB/T 7714: GUPTA R, SONG J. Powder metallurgy processing and mechanical properties of cemented tungsten carbide composites[J]. International Journal of Refractory Metals and Hard Materials, 2020, 91: 105246.

APA 7th: Gupta, R., & Song, J. (2020). Powder metallurgy processing and mechanical properties of cemented tungsten carbide composites.

MLA 9th: Gupta, R., and J. Song. "Powder Metallurgy Processing and Mechanical Properties of Cemented Tungsten Carbide Composites."