Stainless steel
popular in the application,
sophisticated in the machining
High quality steel, stainless steel, rustproof and acid-resistant steels (inox): where is the difference?
High quality steel: e.g. X2CrNi12 (1.4003)
- High degree of purity (low sulfur and phosphorus content, under 0.25%), is also not necessarily a rustproof steel
Stainless steel (inox): for example, X6Cr17
- Corrosion protection by means of chromium, for example
Rustproof and acid-resistant steel: for example, X2CrNiMo18-14-3 (316L)
- Corrosion protection by means of chromium (at least 12%) or nickel, for example
- Acid protection by means of high percentage of alloy elements (chromium, nickel, copper and titanium), for example
High quality stainless steel: for example, X2CrNiMo18-14-3 (316LM)
- Combination of high degree of purity and corrosion protection
However, these concepts are often used synonymously. Many times, there is no difference made even in our texts, that is, if we talk about "stainless steel" we often mean "rustproof and acid-resistant steels" or "rustproof stainless steels".
Inox is borrowed from French (inoxydable). It means "not oxidable" and is used in many languages for "rustproof and acid-resistant steels" as well as stainless steel or high quality steel.
The characteristics
Stainless steels are generally characterized by high resistance to corrosion and acids where the higher the nickel content, the better the resistance. They have a high degree of toughness, and low electrical and thermal conductivity. They are also used more and more in mechanical engineering and in the household, due to their good formability. The corrosion resistance makes them appealing to the food, medical and chemical industries or even for the watchmaking and jewelry industries.
We make a distinction between three types of stainless steels that have different properties:
Ferritic stainless steel
- Example of material: X6Cr17 (1.4016)
- Corrosion protection: medium "slowly corrosive"
- Not heat-treatable through thermal treatment
- Magnetic
- Medium thermal conductivity
- Good hot and cold formability
- Low coefficient of thermal expansion
- Easily machinable (similar to low-alloy steels)
- Main application areas: axles, shafts
- Cost of materials: medium
Martensitic stainless steel
- Example of material: X90CrMoV8 (1.4112)
- Corrosion protection: medium to high
- Heat-treatable
- Magnetic
- Medium thermal conductivity
- Hot and cold formability: medium
- Coefficient of thermal expansion: low
- Mechanical properties: good (high tensile strength)
- Toughness: high even at low temperatures
- Machinability: good when not heat treated, difficulty increases with increasing alloy content
- Main application areas: turbine components, pump components, energy equipment, food industry, household appliances, medical technology
- Cost of materials: medium
Austenitic stainless steel
- Example of material: X2CrNiMo 18-14-3 (1.4435)
- Corrosion protection: high
- Acid resistance: medium to high
- Not heat-treatable through thermal treatment
- Not magnetic
- Thermal conductivity: low
- Hot and cold formability: very good
- Coefficient of thermal expansion: high
- Mechanical properties: good (high tensile strength, fracture toughness)
- Toughness: high even at low temperatures
- Machinability: difficult
- Main application areas: turbine construction, aviation, energy equipment, precision instruments, medical technology
- Cost of materials: high
The Challenge
As appreciated these afore mentioned qualities are in the application, they become very demanding when it comes to machining. Efficient machining often fails because of poor thermal conductivity (austenitic steels), the tendency towards strain hardening of the surface and the tough/elastic behavior of these materials. The consequences for tools, for example, are overheating and material buildup on the cutting edges, high wear and, particularly when drilling, the jamming of long chips in the flutes. Many types of drill bits or milling tools available today are only partially suitable for the machining of these materials.
The Solution
To be able to offer an efficient solution for machining with metal work tools even in small diameters, a solution that earns the addendum "best suited for stainless steels", Mikron Tool has incorporated different factors in tool development and at the same time has clearly defined the machining process. This applies to every type of centering tool, milling tool, chamfering tool or deburring tool as well as drill bits for stainless steel.
Tungsten carbide
The tungsten carbide used by Mikron Tool for the machining of stainless steels is resistant to thermal shock and at the same time possesses a high degree of bending strength and fracture toughness.
Geometry
The geometry is designed by cutting technology specialists in such a way that no high cutting forces are needed, the tool has a high degree of stability and the cutting edges guarantee good chip break. Furthermore, the flute shape (for example, when drilling tough metal) facilitates the removal of chips away from the machining area.
Cooling system
Cooling was the special focus during development. Whenever possible it is integrated into the tool either by using cooling channels going to the drill tip or through the shaft with a coolant outlet on the cone. This is the best guarantee to prevent overheating of the cutting edges and chips are flushed away regularly from the machining area. But the user does not always have an appropriately equipped machine. For this reason for example, the small drill CrazyDrill SST-Inox, is available in a drill with through-tool cooling and in a version for external coolant supply.
Coating
The coatings are selected so that they are temperature and oxidation-resistant with a high wear resistance as well as strong adhesion to metals.
Machining process
The machining process recommended by Mikron Tool is always determined in practical tests with focus on the best possible ratio of machining time, reliability and service life. In concrete terms this means high cutting speeds and feed rates plus the guarantee of good cooling of the cutting edges and simultaneously good chip flow so that jamming in the flutes is prevented.
The Application Domains
- Watch industry: housing, bracelets
- Automotive: fuel injection systems, brakes, intake and exhaust valves, brake disks
- Food industry: filters, sieves
- Chemical industry: valves
- Medicine: implants, infusion needles, surgical instruments
- Fastening components: screws, pins
- General mechanical engineering: valves, guides
- Power generation: turbines
Sample applications
Watch industry
- With CrazyDrill SST-Inox
Watch housing (e.g. hole diameter 1 mm (.0393”) /drilling depth 1.5 mm (.0591”) in austenitic stainless steel, X5CrNi18-10, 1.4301, AISI 304)
Drilling for watch strap chain links (for example, diameter 1.0 mm (.0393”) / 20 mm (.787”) deep in austenitic stainless steel, X8CrNiS18-9, 1.4305, AISI 303)
Drilling for watch strap chain links (for example Ø 1 mm (.039“) / drilling depth 3 mm (.118“) in austenitic stainless steel, X2CrNiMo18-14-3, 1.4435, AISI 316L)
Watch bracelet (e.g. milling diameter 3 mm (.118”) in austenitic stainless steel, X2CrNiMo18-14-3, 1.4435, AISI 316L)
Medical technology
- With CrazyDrill Cool XL
DHS screw, drilling for Kirschner wires (for example, hole diameter 2.7 mm (.106”) /drilling depth 40 x d in austenitic stainless steel X2CrNiMo18-14-3, 1.4441, AISI 316L)
Surgical instrument (for example, hole diameter 0.3 mm (.0118”) / 1.8 mm (.0709”) deep in austenitic stainless steel, X5CrNi18-10, 1.4301)
- With CrazyMill Cool
Component for endoscope (e.g. milling a form groove with diameter 0.8 mm (.0315”) / 8.8 mm (.346”) long in martensitic stainless steel, X105CrMo17, 1.4125)
Locking bracket (for example, internal form drilling with radius and finish with corresponding form reamer with martensitic stainless steel, X39CrMo17-1, 1.4122)
Dental technology
Tool holder for dental drill (e.g. pilot drilling on an inclination diameter 1.3 mm (.0512”) /drilling depth 2 mm (.0787”) for subsequent drilling with CrazyDrill Flex in austenitic stainless steel, X5CrNiCuNb17-4-4, 1.4548)
Aerospace industry
Injection nozzle (e.g. diameter 0.65 mm (.0256”) / 11 mm (.433”) deep in stainless steel AISI 303, X2CrNiMo 18-9-2, 1.4305)
Automotive
- With CrazyMill Cool
Fuel injection (e.g. milling different channels diameter 2.5 mm (.0984”) /milling depths 2.5 mm (.0984”) in austenitic stainless steel, X5CrNi18-10, 1.4301, AISI 304)
Coupling part (for example drilling Ø 3.9 mm (.154“), drilling depth 18 mm (.709“) in martensitic stainless steel X14CrMoS-17, 1.4104, AISI 430F)
Injection component (e.g. step drilling diameter 2.8 – 4 mm (.110” - .157”) /drilling depth 11 mm (.433”) in martensitic stainless steel, X20Cr13, 1.4021, AISI 420)
Inlet connector (e.g. finish grinding for the highest diameter precision and surface quality with diameter 5.515 mm (.217") /drilling depth 40 mm (1.575”) in austenitic stainless steel, X5CrNi18-10, 1.4301, AISI 304)
Mechanical engineering
Locking pins (e.g. deburring a cross hole with diameter 1 mm (.0393”) in austenitic stainless steel, X5CrNi18-10, 1.4301, AISI 304)
Food industry
Valve component for coffee machine (e.g. drilling with different diameters/drilling depth 28 mm (1.102”) in austenitic stainless steel, X2CrNiMo18-14-3, 1.4435, AISI 316L)
Steam valve for coffee machine (for example drilling Ø 2.75 mm (.108“), drilling depth 15 x d, in martensitic stainless steel AISI 340)
Hydraulics
- With CrazyDrill SST-Inox/oblique pilot hole with CrazyDrill Crosspilot
Protective cover (e.g. drilling diameter 0.4 mm (.0157”) / drilling depth 0.9 mm (.0354”) in austenitic stainless steel, X5CrNiMo17-12-2, 1.4401, AISI 316)
Hydraulic component (for example drilling Ø 4 mm (.157“), drilling depth 10 x d in austenitic stainless steel X2CrNiMo18-14-3, 1.4435, AISI 316L)
The Products
Mikron Tool offers a range of standardized tools, specially developed for the machining of so-called difficult materials and are suitable for the machining stainless steels. There are also many possibilities of customer-specific tools such as smallest drill bits, step drills, milling tools, reamers, deburring tools, turning tools, form tools and combined tools.
- Centering tool in the diameter range from 0.3 to 6 mm (.0118” to .236”), center tool with through-tool cooling
- Pilot drilling in the diameter range from 0.2 to 2 mm (.008” to .079”), drilling depth 3 x d, drill with through-tool cooling, with 90° chamfer
- Pilot / short drilling in the diameter range from 1 to 6.35 mm (.039“ to .25“), drilling depth 3 x d, drill with through-tool cooling, with 090° chamfer
- Pilot drilling on inclined surfaces from 0.4 mm to 6.35 mm (.0157” to .25”)
- Drilling in the diameter range from 0.2 mm to 2 mm (.008” to .0787”), drilling depth up to 12 x d, drill with or without through-tool cooling
- Drilling in the diameter range from 1 to 6.35 mm (.039“ to .25“), drilling depth up to 40 x d, drill with trough-tool cooling
- Deep-hole drilling in the diameter range from 0.75 mm to 6 mm (.0295” to .236”), drilling depth up to 15 x d, drill with through-tool cooling
- Deep-hole drilling in the diameter range from 1 mm to 6 mm (.0393” to .236”), drilling depth up to 40 x d, drill with through-tool cooling
- Micro deep-hole drilling in the diameter range from 0.2 mm to 1.2 mm (.008” to .0472”), drilling depth up to 50 x d, drill with through-tool cooling
- Groove, pocket and wall milling in the diameter range from 0.3 mm to 8 mm (.0118” to .315”), milling depths up to 5 x d, milling tool with through-tool cooling
CrazyMill Cool Square & Corner radius
- Copy and side milling in the diameter range from 0.3 mm to 8 mm (.0118” to .315”), milling depths up to 5 x d, milling tool with through-tool cooling
- Plunge directly with up to 1 x d vertically into material, plunge mill in the diameter range from 1 to 8 mm (.039" - .315"), milling depths up to 2.5 x d, milling tool with through-tool cooling
- Chamfering and deburring front and rear in the diameter range from 0.4 mm to 6 mm (.0157” to .236”)
- Custom cutting tools in the diameter range from 0.1 mm to 32 mm (.0039” to 1.259”)
Other CrazyLine tools are also suitable for the machining of stainless steels depending on the application. Contact us here to know more about these possibilities.