About High-Speed Steel Taps and Drill Bits, You Need to Know
1, What is high-speed steel?
High speed steel(HSS) is a kind of high alloy steel containing many carbons (C), tungsten (W), molybdenum (Mo), chromium (Cr), vanadium (V), and other elements. When the cutting temperature is up to 600℃ above, the hardness is still not significantly decreased. The cutting speed can reach more than 60 meters per minute. So that’s why called high-speed steel. It is widely used in cutting tools, including thread taps, milling cutters, drills, and saw blades.
2, How many primary types of High-Speed Steel(HSS) and their character, cost
According to the performance, the high-speed steel can be divided into Low alloy high-speed steel(HSS-L), Normal high-speed steel(HSS), and high-performance high-speed steel(HSS-E).
For these three-level HSS, there is some common grade:
- HSS-L: W4Mo3Cr4VSi(4341), W2Mo1Cr4VSI(4241)
- HSS: W6Mo5Cr4V2, W9Mo3Cr4V
- HSS-E: W6Mo5Cr4V3, W6Mo5Cr4VCo5, W2Mo9Cr4VCo8
W: Improve the red hardness and high wear resistance of steel
Mo: Improve the tenacity, Reduce the thermal conductivity, as well as the freezing point of steel;
Cr: Increase the hardenability, oxidation resistance, decarbonization, and corrosion resistance of high-speed steel;
V: Improve the hardness and wear resistance of the steel under high temperatures.
Co: Improve high-temperature hardness, secondary hardness, and thermal conductivity of HSS
According to the alloying element’s function, so we could know the above characters.
Red hardness/Wear resistance:
In the past, the cost of W9Mo3Cr4V is lower than W6Mo5Cr4V2. As the cost of W increasing, now the prices of W9Mo3Cr4V are a little higher than M2.
Based on the above information, typically, different grade HSS has further used:
4241/4341 high speed steel material: This material is suitable for drilling ordinary metals, such as iron, copper, aluminum alloy, and other low and medium hardness metal, as well as wood, plastic, etc. Not suitable for drilling stainless steel, mold steel, and additional high strength, high hardness metal. The quality is not bad within the scope of application, ideal for wholesale sales at hardware stores.
9341/6542 high speed steel material: This material is suitable for drilling various metals, such as stainless steel, iron, copper, aluminum alloy, and other low and medium hardness metals. Medium to high quality with good durability in the range of applications.
6543 high speed steel material, with a vanadium content of 3-4%, much higher wear resistance but will reduce the grinding efficiency, suitable for the manufacture of threaded tools.
M35 cobalt material: This material is the best performance grade of high-speed steel in the market at present. The cobalt content ensures the hardness and toughness of high-speed steel. Suitable for drilling various metals, such as stainless steel, iron, copper, aluminum alloy, cast iron, 45# steel, and other metals.
M42 Vanadium content is not high (1%), cobalt content is high (8%), cobalt can make the carbide dissolve more in the matrix when quenching and heating high matrix hardness to improve wear resistance. This high-speed steel has excellent hardness, thermal stiffness, abrasion resistance, and wearability.
Heat treatment hardness up to 67-70HRC, but there are also unique heat treatment methods to get 66-68HRC hardness to cut performance (especially intermittent cutting) to improve the impact toughness. Cobalt HSS can be made into a wide range of tools and cut difficult materials with good results. When the cutting temperature reaches 600°C or more, there is no significant reduction in hardness, and the cutting speed of the tool made with it can reach more than 60 m per minute.
The red hardness, wear-resistance, and tenacity decide the hss cutting tools performance. So we could choose the material according to the cost, the workpiece, and the working environment.
3, The Top brand in China of High-Speed Steel(HSS), their character, and cost
The current brand in China for HSS has HEYE, TIANGONG, FEIDA, FUDA, JINGGONG, FUGONG, etc., based on their melting technology, developing and research ability, and brand’s popularity. Also, as our know and use for them.
Performance Stability( Uniformity, purity)
When we evaluate the stability of the hss, it’s hard to judge who is better only from 1 or 2 batches. As a customer of HEYE and changing so many years, also the market feedback, the stability of heye is better than Tiangong
When we know the characteristics of the HSS mentioned above compared to several domestic brands, we know how to choose the tool suppliers based on our quality requirements and company position in the market.