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Materials

This page provides some background information on the material models available in millalyzer. Each section lists the primary or standard names of the alloys along with some equivalent material designations which may be vendor trade names or national (Swedish, British, Russian, Japanese, French, US) standards, so that a text search on this page may be used to find the material name.

Aluminium alloys

Very soft wrought aluminium alloys (AlMg1, AlMg3, 1000- and 3000-series) are not suitable for machining. These materials hardly form distinct chips but tend to gum up tools and form large burrs.

2024-T351, AlCu4Mg1, 3.1355

A medium-to-high strength alloy with good fatigue properties that is commonly used in aerospace parts subjected to high-cycle tension loads. Alloy 2124 is a variant with tighter control of impurities and similar machinability. Due to the high copper content, 2024 cannot be fusion welded and should be protected from corrosion. Typical Brinell hardness is 135 HB.

5083-H116, AlMg4.5Mn, 3.3547

This alloy has very good resistance to corrosion but only moderate strength. In contrast to most other alloys, strength cannot be increased by heat treatment, but only by work hardening, for instance by cold forming processes such as rolling. 5083 is sold both as rolled plate and as cast plate up to large thickness values. Cast plates have the advantage of high dimensional stability and very low residual stresses, but their yield strength is low. Grade H116 is characterized by a very small degree of cold-work (such as might be the result from stretching for stress-relief) which would be typical of cast plates sold for machining applications. Typical Brinell hardness is 75 HB.

6061-T6, AlMg1SiCu, 3.3214

This is a very versatile alloy because it has moderate strength, good corrosion resistance, can be welded and machined with ease. As a heat-treatable alloy, 6061 is almost always sold in the warm-aged condition T6, i.e. heat treated to peak strength.

Cutting forces and power requirements in 6061 are low and its tendency to form build-up edges is less pronounced than 5083. Typical Brinell hardness is 90 HB.

6082-T6, AlSi1MgMn, 3.2315

While 6061 is common in North America; the European alloy 6082 is almost identical. It features slightly higher strength and small differences in composition, but can also be welded and machines very well.

The yield (but not ultimate) strength of 6061 and 6082 is comparable to plain mild steels such as S235JR. Typical Brinell hardness is 95 HB.

7021-T6, AlZn5.5Mg1.5, C330R

7021 is a specialized alloy that is primarily available in cast and pre-milled plates with very low residual stresses. As with cast plates of 5083, this has the advantage that the stock will not deform when machined, so that tight tolerances can be more easily achieved even if a large percentage of the stock is removed. The yield strength of 7021 is significantly higher than 5083 or even 6082 and is almost as high as 2024. Typical Brinell hardness is 120 HB.

7075-T651, AlZn5.5MgCu, 3.4365

This is a widely available heat-treatable alloy that is available both in aerospace and commercial grades. Despite its high strength, it machines very well, but cutting forces are somewhat higher than for the other alloys. 7075 cannot be fusion welded and has relatively poor corrosion resistance, especially when loaded continuously in corrosive environments (SCC). The yield strength of 7075 is comparable to plain carbon steels such as C45 that are not hardened.

Tools with extremely sharp edges such as those intended for use in plastics can be used in softer aluminium alloys, but will likely experience chipping in 7075. Typical Brinell hardness is 150 HB.

EN AC-42100, A356-T6, AlSi7Mg0.3

Due to its strength and reasonable ductility, A356 is widely used for load-bearing aluminium castings. The included material model is for the warm-aged condition (i.e. peak strength).

In order to reduce viscosity and solidification temperature span, aluminium alloys for casting contain large fractions of silicon (more than 5%). At such high concentrations, the silicon forms hard particles in the solidified metal which are very abrasive. Therefore, cast aluminium should generally be machined at lower cutting speeds that wrought alloys. Furthermore, coatings can reduce wear and increase tool life. Typical Brinell Hardness is 85 HB.

Similar: JIS AC4C, AFNOR A-S7G0.3, BS 2L99, WNr. 3.2371, GOST AL9, SS 4244

F357-T6, AlSi7Mg0.6

F357 is a variant of A357 that does not contain Beryllium. It is a slightly stronger and tougher, but also more expensive alloy than A356. As for A356, this material model is for permanent mold castings; sand castings tend to have lower strength. Typical Brinell Hardness is 90 HB.

Similar: EN AC-42200, A357

Steel & Cast Iron

Steel Most steels can tailored to a wide range of properties by heat treatment. It is common to machine steels in the annealed (soft) state. When high strength or hardness is required, the machined product is then hardened by heating, followed by quenching and tempering. During that process, the part may deform slightly, so that a second finishing pass (either by milling or grinding) can be needed. Strength and the ability to achieve high surface hardness can be obtained by increasing the carbon content, by adding alloying elements (chrome, nickel, molybdenum, vanadium, etc.) and/or by tight control of detrimental impurities. Note that the AISI/SAE designations such as AISI 420 cover a fairly wide range of compositions that frequently split into many EN materials. The equivalence is therefore not precise.

The material models listed in this category are registered in the annealed state unless stated otherwise. For hard-machining, use the material models for the tool steels H13-46 HRC or D2-60 HRC.

Most steels are rate-hardening, that is, cutting forces increase somewhat with strain rate. Small chip thicknesses and high cutting speed both contribute to higher strain rates, meaning that it can be advantageous to avoid very small chip thicknesses or very high speeds.

Mild steel HRS/CRS

Mild steel grades that are not explicitly intended for machining can vary fairly substantially in mechanical properties, as their composition and heat treatment (if any) is usually not controlled very tightly. The material models included in millalyzer are therefore intentionally conservative, i.e. predicted forces are expected to represent the upper range of what will be encountered.

AISI 1006 HRS should be chosen when milling hot-rolled plate or larger diameter bar stock. The temperatures involved in hot rolling prevent most work-hardening.

AISI 1018 CRS can be used when working with cold-rolled steel, which is common for sheet or small-diameter bar stock. Cold work entails work hardening, which increases machining forces somewhat.

Typical Brinell hardness is around 130 HB, but can vary quite much between lots.

Similar: S235JR, Q235B, St37, AFNOR E24-4, BS 40B, GOST St3sp, …

EN 1.1730 +A, AISI 1045, C45U

C45 is a widely available, low-cost, 0.45% carbon steel that is known for its good machinability and is very well characterized. Cutting forces are moderate and relatively high cutting speeds are feasible without excessive reduction of tool life. For that reason, it is a common choice for milled components with moderate strength requirements.

Typical Brinell hardness in the annealed state is 205 HB. C45 can be through-hardened in small thicknesses or case-hardened to increase wear resistance.

Similar: EN 1.1191, St70, AFNOR Y342, JIS S45C, BS 080M46, THYRODUR-1730, UNS G10450, SS 1650

EN 1.7225 +QT, AISI 4140, 42CrMo4

Widely used, this steel is available both in the annealed (A) and quenched-and-tempered (QT) condition and can still be readily machined in the QT state, but cutting forces, tool wear and torque requirements increase compared to C45. This material model can also be used as an approximation for pre-hardened mold and tool steels in the 33 HRC range, such as P20s or 1.2312, Daido PX4 or SSAB Toolox 33. Typical hardness in the tempered state for which this model is established (Rm 960 MPa) is 310 HB or 33 HRC.

Similar: EN 1.7227, 42CrMoS4, JIS SCM440, AISI 4142, AFNOR 42CD4, GOST 38HM, BS 708M40, SS 2244, UNS G41400

EN 1.2344, AISI H13, X40CrMoV5-1

1.2344 is a hot-work tool steel (used for e.g. extrusion dies) that would usually be machined in the annealed state. This material model is for the hardened and tempered state and could be used to represent similar mold steels at this hardness. H13 can be hardened to 54 HRC or more; tempered to 46 HRC (about 430 HB) it has better toughness.

Similar: AFNOR Z40CDV5, JIS SKD61, GOST 4H5MF1S, SS 2242, UNS T20811

EN 1.2379, ASTM A681 D2, X153CrMoV12

1.2379 features better dimensional stability during hardening but does not retain hardness at high temperatures as well as hot-work steels. It can be polished very well and is hence used in injection molds. Due to its hardness, it is very difficult to machine. This material model is for peak-hardened D2 at 62 HRC.

Similar: JIS SKD11, BS BD 2, AFNOR X160CrMoV12 1, GOST Ch12Mf, SS 2310, UNS T30402

EN 1.4301, AISI 304, X5CrNi18-10

1.4301 is probably the most common stainless steel, widely available, weldable and with good corrosion resistance. As all austenitic stainless steels, it cannot be hardened by heat treatment but it is strongly strain-hardening and therefore relatively difficult to machine. AISI 304 is not ferromagnetic and conducts heat poorly (compared to other steels). Thin stock (round bar, wire, sheet) that is not sold for machining may well be in the cold-worked state and hence much harder than annealed stock. The variant 1.4305 (AISI 303) contains sulphur to make it more suitable for machining. Typical Brinell hardness is 200 HB. (annealed).

Similar: AFNOR Z7CN18.09, GOST 08H18N10, SS 2332, UNS S30400

EN 1.4021, AISI 420, X20Cr13

Just like other martensitic stainless steel that can be hardened by quenching, 1.4021 is somewhat less problematic to machine than 1.4301 - it has a much reduced work-hardening tendency. Furthermore, AISI 420 is magnetic; its corrosion resistance is adequate for less challenging environments, improves with hardening, but remains somewhat worse than the austenitic alloys. 1.4021 can be polished after hardening. Typical Brinell hardness is 250 HB (annealed).

Similar: AFNOR Z20C13, GOST 20Kh13, REMANIT-4021, SS 2303, UNS S42000, BS 420S29

EN GJL-200, SA278-200

Cast iron machine bed GJL-200 is a cast iron with lamellar graphite. It is commonly used in applications where low cost or good damping properties are important. Typical Brinell hardness is about 140 HB.

Similar: WNr. 5.1300 (DIN 1561), EN-JL-1030, GOST SCh20

EN GJS-400, ASTM A536 60-40-18

This is a cast iron with spherical graphite that exhibit very much better toughness and ductility. Machining forces are slightly higher than for GJL-200. Typical Brinell hardness is approximately 160 HB.

Similar: WNr. 5.3105 (DIN 1563), GOST VCh40

Brass

EN CW614N, CuZn39Pb3

Brass CW614N contains 3% lead (and is thus not suitable for RoHS/REACH compliant products), which makes it very suitable for high-speed machining. Many mass-produced turned brass parts are made from CW614N. Corrosion resistance is good and it is suitable for soldering, but not welding. Typical Brinell hardness is approximately 125 HB.

Similar: WNr. 2.0401, BS CZ121, GOST LS58-3, UNS C38500

EN CW724R, CuZn21Si3P

Often used in parts for electronic devices, automotive components and drinking water applications (faucets, fittings) because it does not contain lead. It has good strength and excellent machining properties. CW724R has can be easily soldered and even welded. Typical Brinell hardness is approximately 150 HB.

Similar: UNS C69300, Cuphin 430 PbF

EN CC761S, CuZn16Si4-C

CC761 is a lead-free silicon brass used in die castings. Typical Brinell hardness is approximately 130 HB.

Similar: JIS SzBC2, WNr 2.0492, GOST LTS16K4, UNS C87500, TOFUFUR

Polymers

There are material models for Polyoxymethylene (POM, Delrin), Polyamide-6 (PA6, Nylon-6, Perlon, Capron, Durethan), high-density Polyethylene (HDPE), Polypropylene (PP) and Polycarbonate (PC, Makrolon, Lexan). POM, HDPE, and PA6 are frequently available in plate and round bar stock for milling; PC is often sold as glass-clear transparent or tinted translucent sheets.

Cutting forces in polymers are among the lowest of all materials; POM and HDPE are also characterized by favorably low friction coefficients. Because all of these materials melt at low temperatures, there is a risk of raised burrs, and, sometimes, molten stock clogging up the flutes. This is most likely to occur at high spindle speeds and low feed values (that is, very small chip thickness).

Almost all endmills will perform at least satisfactorily when cutting polymers. However, it is possible to use particular tools that are ground to a very sharp edge (high rake, low edge radius) in order to achieve good surface finish.

Wood

Wood differs significantly from all of the above materials because it is anisotropic, that is, most properties depend on the direction relative to the grain. Since millalyzer currently does not account for material anisotropy, the models for wood species intentionally aim to match the upper limits (worst case); this tends to occur when the cutting edge moves perpendicular to the grain direction. Actual cutting forces and power requirements will usually be lower, sometimes significantly. An exception to this rule is medium-density fibreboard (MDF), which should be reasonably isotropic.

Apart from that, conditioned (dry) wood resists cutting substantially more than moist wood. Again, models available in millalyzer are for low moisture content (12%). This is intentional as it is considered safer to err on the side of higher force predictions.

Exotic Alloys

Ti6Al4V, 3.7164

Ti6Al4V is a common alpha-beta titanium alloy that is often used for applications where strength, corrosion resistance and toughness are required. The same alloy is sometimes designated ‘Grade 5’. This alloy can be welded in protective atmospheres (or vacuum). Titanium needs to be machined at low cutting speeds (< 80 m/min), as tool flank wear increases rapidly at higher speeds. Typical Brinell hardness is approximately 240 HB.

Similar: UNS R5­64­00, BS 2TA11

EN 2.4668, NiCr19Fe19Nb5Mo3

Inconel 718 is a Nickel-based alloy that can be used at high temperature for prolonged times, where steels would soften and creep. It also maintains high strength and good toughness at cryogenic temperatures. Properties change significantly with heat treatment; this material model is for the direct-aged condition. Typical hardness in this condition is approximately 44 HRC.

Similar: Inconel DA718, UNS N07718

Not listed?

The implemented material models cover a wide range of different properties, but cannot exactly represent all available metals. Steel in particular is sold in very many variations; should your specific alloy not be listed, you could perform an approximate analysis using one of the existing models chosen as a function of the hardness level:

Hardness Material model
< 170 HB AISI 1006 HRS
170 - 220 HB C45U, AISI 1045
220 - 270 HB EN 1.4021
270 - 325 HB EN 1.7225 +QT
38 - 48 HRC EN 1.2344, H13
> 48 HRC EN 1.2379, D2